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Temperature and Concentration Fields in a Generator Integrated to Single Stage Heat Transformer Using Water/Carrol Mixture

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Journal of Thermal Science 2014年第6期23卷 564-571页

作者： E.Gómez-Arias J.Ibarra-Bahena L.Velazquez-Avelar R.J.Romero A.Rodriguez-Martinez M.Montiel-González Centro de Investigación en Ingeniería y ciencias Aplicadas Universidad Autónoma del Estado de MorelosAv.Universidad 1001Col.ChamilpaCuernavacaMorelosCP 62209MéXICO Facultad de ciencias Químicas e Ingeniería Universidad Autónoma del Estado de MorelosAv.Universidad 1001Col.ChamilpaCuernavacaMorelosCP 62209MéXICO posgrado en Ingeniería y ciencias Aplicadas Universidad Autónoma del Estado de MorelosAv.Universidad 1001Col.ChamilpaCuernavacaMorelosCP 62209MéXICO

The generator is the starter device of single stage heat transformer(SSHT) and its characteristics have main effects on the overall efficiency of this kind of absorption *** article reports a study of the generation of steam and changes in the concentration of the working solution(Water/Carrol mixture) into a plate heat exchanger as a function of its horizontal and vertical position by gravity *** is considered the analysis of six experimental tests;two were evaluated in a plate heat exchanger in a horizontal position and four in a vertical position(90 degree inclination).The generation of steam and increased concentration of the working solution are more sensitive to the vertical position of exchanger than in horizontal *** results of numerical-experimental analysis indicates that a heat exchanger in horizontal position,the steam generation and the change in the concentration of the working solution occurring in the middle of the plate(or at greater distance depending to the thermodynamic conditions) and instantly in vertical position(at the input of the plate).

关键词： Single stage heat transformer Plate heat exchanger Numerical modeling Temperature and concentration field Water/Carrol mixture

3D printing of ABS *** of processing and effects of multi-wall and single-wall carbon nanotubes on thermal,mechanical and electrical properties

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Journal of Materials Science & Technology 2022年第26期121卷 52-66页

作者： Sithiprumnea Dul Brenda J.Alonso Gutierrez Alessandro Pegoretti Jaime Alvarez-Quintana Luca Fambri department of Industrial engineering and INSTM Research Unit University of TrentoTrento 38123Italy Centro de Investigación en Materiales Avanzados S.C.Unidad MonterreyApodaca 66600Mexico Facultad de Ingeniería Mecánica y Eléctrica Universidad Autónoma de Nuevo LeónAvenida Universidad s/nCiudad UniversitariaSan Nicolás de los Garza 66451México

The following paper reports on a comparative study of the effects of two types of carbon nanotubes,namely multiwall(MWCNT)and single-wall(SWCNT)carbon nanotube,on the properties of 3D-printed parts produced with acrylonitrile-butadiene-styrene(ABS)nanocomposites with various CNT loadings of5-10 wt.%.Quasi-static tensile properties and Vicat softening temperature of 3D-printed parts were enhanced with the increasing CNT *** highest enhancement in tensile properties was observed for the ABS/CNT nanocomposites at 10 wt.%filler loading.3D-printed ABS/SWCNT composites showed higher tensile modulus,better creep stability and higher Vicat ***,the strength of ABS/SWCNT 3D samples is relatively lower than that of ABS/*** addition,3D-printed parts exhibited anisotropic electrical conductive behaviour,which has a conductivity of through-layer of about2-3 orders of magnitude higher than *** highest conductivity of 3D-printed samples reached25.2 S/m,and 9.3 S/m for ABS/MWCNT and ABS/SWCNT composites at 10 wt.%,*** results obtained,*** successful fuse filament fabrication and the consequent electromechanical properties,confirm that these 3D printable nanocomposite could be properly utilized for the production,and application up to about 90°C,of thermoelectric devices and/or resistors for flexible circuits.

关键词： Fuse filament fabrication Conductive polymers Nanocomposites Mechanical properties Creep behavior Resistivity

Nano Phase Characterization by Transmission Electron Microscopy: Experimental and Simulation

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Materials Sciences and Applications 2015年第11期6卷 935-942页

作者： Francisco Miguel Ascencio Aguirre Lourdes Bazá n-Dí az Rubé n Mendoza-Cruz Alfredo Gó mez-Rodrí guez Cristina Zorrilla-Cangas Raú l Herrera-Becerra posgrado en ciencia e Ingenierí a de materiales Instituto de F&iacute sica UNAM Circuito de la Investigaci&oacute n Cientí fica Ciudad Universitaria M&eacute xico D.F. M&eacute xico departamento de Materia Condensada/Instituto de Fí sica UNAM Circuito de la Investigaci&oacute n Cientí fica Ciudad Universitaria M&eacute xico D.F. M&eacute xico

This paper introduces a methodology of characterization of nanostructured systems in which trans- mission electron microscopy is used as a central element of the study. Experimental studies of HREM are performed in parallel with studies in the Simula TEM program to stimulate high-resolution images and diffraction patterns. To confirm the accuracy of the results, studies of X-ray diffraction (XRD) were performed. In order to illustrate the methodology, bismuth oxide Bi2O3 nanoparticles are synthesized by a method of biosynthesis because this sample is rich in structural information.

关键词： Transmission Electron Microscopy Nanoparticles Bismuth Oxide Bi2O3

TiO<sub>2</sub>Films Synthesis over Polypropylene by Sol-Gel Assisted with Hydrothermal Treatment for the Photocatalytic Propane degradation

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Green and Sustainable Chemistry 2014年第3期4卷 120-132页

作者： Vanessa Guzmán-Velderrain Yudith Ortega López Jesús Salinas Gutiérrez Alejandro López Ortiz Virginia H. Collins-Martínez Centro de Investigación en materiales Avanzados S. C. Laboratorio Nacional de Nanotecnología Depto. de Materiales Nanoestructurados Chihuahua México

The present investigation shows experimental results obtained with TiO2 thin films synthesized by the sol-gel method assisted with hydrothermal treatment over polypropylene, using the dip coating technique. Obtained coatings were characterized through SEM, XRD, UV-Vis and the photo- catalytic activity was monitored by GC. According to results, the hydrothermal treatment facilitates the crystallization of the TiO2 anatase phase, which is present in all synthesized films. Crystal size formed from precursor solutions (estimated by the Scherrer’s equation) depends on the time and temperature of the hydrothermal treatment, wherein solution exposed to a higher temperature treatment of 150。C for 1.5 h (H150/1.5) exhibited a larger crystal size compared to those synthesized at 80。C for 1.5 h and 3 h (H80/1.5 and H80/3). Sample H150/1.5 over polypropylene resulted in a uniform and crack free coating. This behavior was attributed to the precursor solution being denser than those synthesized at 80。C. Additionally, the photocatalytic activity of the coatings was evaluated through the degradation of propane. Coating H150/1.5 reached 100% conversion after 3 h of UV light irradiation.

关键词： TiO2 Coating Polypropylene Propane Photodegradation Photocatalysis

Light Reflection by Cuticles of Chrysina Jewel Scarabs: Optical Measurements, Morphology Characterization, and Theoretical Modeling

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Optics and Photonics Journal 2016年第7期6卷 146-163页

作者： W. E. Vargas M. Hernández-Jiménez E. Libby D. E. Azofeifa C. Barboza Á. Solis Centro de Investigación en ciencia e Ingeniería de materiales & Escuela de Física Universidad de Costa Rica San José Costa Rica Academia Nacional de ciencias de Costa Rica San José Costa Rica Centro de Investigación en ciencia e Ingeniería de materiales and Escuela de Química Universidad de Costa Rica San José Costa Rica Centro de Investigación en Estructuras Microscópicas Universidad de Costa Rica San José Costa Rica Museo Nacional de Costa Rica San José Costa Rica

Cuticles of some Chrysina scarabs are characterized by flat, graded, and twisted structures of nanosized chitin fibrils. As inferred from SEM images, each species has its own spatial period or pitch P which is dependent on the depth z through the cuticle. From Berreman’s formalism, taking into account the corresponding P(z) dependence, we evaluate reflection spectra of C. aurigans and C. chrysargyrea scarabs. The spectra display the main spectral features observed in the measured ones when small sections of the cuticles are illuminated with non-polarized light, for wavelengths between 300 and 1100 nm. By considering these twisted structures as 1D photonic crystals, an approach is developed to show how the broad band characterizing the reflection spectra arises from a narrow intrinsic photonic band width, whose spectral position moves through visible and near infrared wavelengths. The role of the epicuticle that covers the twisted structures is analyzed in terms of a waxy layer acting as an anti-reflecting coating that also shows low levels of light scattering.

关键词： Structural Color Structural Chirality Natural Broad Band Reflector Circular Polarization Jewel Scarab Chitin Refractive Index Uric Acid Refractive Index Left-Handed Twisted Structure Bouligand-Type Structure

Structural evolution and reaction mechanism of lithium nickelate(LiNiO_(2))during the carbonation reaction

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Journal of Materiomics 2018年第1期4卷 56-61页

作者： Daniela Gonzalez-Varela Brenda Alcantar-Vazquez Heriberto Pfeiffer Laboratorio de Fisicoquímica y Reactividad de Superficies(LaFReS) Instituto de Investigaciones en MaterialesUniversidad Nacional Autonoma de MexicoCircuito exterior s/nCUDel.CoyoacanCP 04510Ciudad de MexicoMexico Instituto de Ingenieria Coordinacion de Ingeniería AmbientalUniversidad Nacional Autonoma de MexicoCircuito Escolar s/nCUDel.CoyoacanCP 04510Ciudad de MexicoMexico

Lithium nickelate(LiNiO_(2))was synthesized using the lithium excess method,and then characterized by X-ray diffraction,scanning electron microscopy and N_(2) ***,differential thermal and thermogravimetric analyses were performed in CO_(2)presence,at high *** show that LiNiO_(2)is able to react with CO_(2)through a complex structural evolution process,where lithium atoms are released to produce Li_(2)CO_(3),while some nickel atoms are rearranged on different Li_(1-x)Ni_(1+x)O_(2)crystalline ***_(2)-CO_(2)reaction kinetic parameters were determined assuming a first-order reaction,where kinetic constants tended to increase as a function of ***,kinetic constant values did not follow a linear *** atypical behavior was attributed to LiNiO_(2)sintering and crystalline evolution performed as a function of temperature.

关键词： Lithium nickelate CO_(2)chemisorption Lithium diffusion coefficient Phase transition

Effects of estrogen receptor modulators on cytoskeletal proteins in the central nervous system

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Neural Regeneration Research 2017年第8期12卷 1231-1240页

作者： Julia J.Segura-Uribe Rodolfo Pinto-Almazán Angélica Coyoy-Salgado Claudia E.Fuentes-Venado Christian Guerra-Araiza Unidad de Investigacion Modica en enfermedades Neurologicas Hospital de Especialidades Centro Medico Nacional Siglo XXI Instituto Mexicano del Seguro Social Mexico City Mexico Seccion de Estudios de posgrado e Investigacion Escuela Superior de Medicina Instituto Politecnico Nacional Mexico City Mexico Unidad de Investigacion Hospital Regional de Alta Especialidad Ixtapaluca Ixtapaluca Mexico Institute for the developing Mind Children's Hospital Los Angeles Los Angeles CA USA department of Pediatrics Keck School of Medicine University of Southern California Los Angeles CA USA Consejo Nacional de ciencia y Tecnologia Mexico City Mexico Clinica de Trastornos del Sueno Universidad Autonoma Metropolitana-Iztapalapa Mexico City Mexico Servicio de Medicina Fisica y Rehabilitacion Hospital General de Zona No. 197 Texcoco Mexico Unidad de Investigacion Modica en Farmacologla Hospital de Especialidades Centro Medico Nacional Siglo XXI Instituto Mexicano del Seguro Social Mexico City Mexico

Estrogen receptor modulators are compounds of interest because of their estrogenic agonistic/antagonistic effects and tissue specificity. These compounds have many clinical applications, particularly for breast cancer treatment and osteoporosis in postmenopausal women, as well as for the treatment of climacteric symptoms. Similar to estrogens, neuroprotective effects of estrogen receptor modulators have been described in different models. However, the mechanisms of action of these compounds in the central nervous system have not been fully described. We conducted a systematic search to investigate the effects of estrogen receptor modulators in the central nervous system, focusing on the modulation of cytoskeletal proteins. We found that raloxifene, tamoxifen, and tibolone modulate some cytoskeletal proteins such as tau, microtuble-associated protein 1（MAP1）, MAP2, neurofilament 38（NF38） by different mechanisms of action and at different levels： neuronal microfilaments, intermediate filaments, and microtubule-associated proteins. Finally, we emphasize the importance of the study of these compounds in the treatment of neurodegenerative diseases since they present the benefits of estrogens without their side effects.

关键词： estrogen receptor modulators selective estrogen receptor modulators microtubules neurofilaments tibolone tamoxifen raloxifene

Application of Nejayote as a Foliar and Edaphic Fertiliser to Native Blue Maize (Zea mays L.) Crops

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American Journal of Plant Sciences 2016年第15期7卷 2221-2238页

作者： Victoria Téllez Jesús F. López Agustín Aragón Teresa Zayas posgrado en Manejo Sostenible de Agroecosistemas BUAP Puebla México Centro de Agroecología BUAP Puebla México posgrado en ciencias Ambientales Instituto de Ciencias Benemérita Universidad Autónoma de Puebla (BUAP) Puebla México

Raw and treated “nejayote” were assessed as foliar and edaphic fertilisers for native blue maize (Zea mays L.) crops in the municipality of Amozoc de Mota, Puebla, Mexico, during the 2015 agricultural cycle. Treated nejayote refers to raw nejayote subjected to a coagulation-flocculation process. Two states of nejayote were established (raw and treated nejayote) with different physicochemical properties. Foliar bio-fertilisers were prepared from raw and treated nejayote and mixed with organic matter (OM) to promote a fermentation process. The foliar treatments used were: BNC5, BNC15, BNC30 (raw nejayote-based bio-fertiliser at 5%, 15%, and 30%), BNCQ5, and NCQ30 (nejayote treated by chemical coagulation at 5% and 30%), with BT as a control (traditional bio-fertiliser). The edaphic treatments used were: NC50, NC75, and NC100 (raw nejayote at 50%, 75%, 100%), with AP as a control (drinking water), thus giving rise to 10 treatments in terms of content of raw or treated nejayote. Foliar and edaphic field treatments applied to native blue maize crops were statistically assessed using the following response variables: plant height, stem diameter, number of leaves, and grain yield. The experiment was laid out in a randomised complete block design (RCBD) with five replications of each treatment. The results obtained showed, that foliar or edaphic application at the different stages of development did not produce statistically significant differences, at P ≤ 0.05, in terms of response variables. The most significant effects occurred at the early stage of plant development and were mainly reflected in the stem diameter with foliar treatment NCQ30 and in the number of leaves with foliar treatment BNC5. At the final stage of crop development, the highest yield (0.639 ± 0.121 t·ha-1) was obtained with treatment BNC5, which produced a statistically significant difference (b) in relation to the rest of the foliar and edaphic treatments (Tukey P ≤ 0.05).

关键词： Maize Crop Foliar-Edaphic Fertiliser Raw Nejayote Treated Nejayote

Infrared Transmission in Porous Silicon Multilayers

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Optics and Photonics Journal 2013年第2期3卷 20-25页

作者： Alessio Palavicini Chumin Wang Instituto de Investigaciones en materiales Universidad Nacional Autónoma de México Mexico City Mexico

Porous silicon is a nanostructured material and exhibits efficient photo- and electro-luminescence in the visible range at room temperature, as well as a tunable refractive index determined by its porosity. Porous silicon samples can be obtained by etching a crystalline silicon wafer in a solution of hydrofluoric acid. In this work, we report the fabrication of porous silicon multilayers alternating layers with high and low porosities, which correspondingly produce low and high refractive indices. The free-standing multilayers were formed following three different sequences: periodic, Fibonacci and ThueMorse. These structures were verified by scanning electron microscopy and their infrared transmission spectra were measured by means of Fourier-transform infrared spectroscopy. On the other hand, we calculate the light transmittance of porous silicon multilayers by using the transfer matrix method for all directions of incidence and a wide range of wavelengths. The experimental measurements are compared with theoretical results and a good agreement is observed. In addition, an analysis of infrared absorption peaks due to the molecular vibrations at pore surfaces reveals the presence of hydrogen and oxygen atoms.

关键词： Porous Silicon Multilayer Infrared Transmission Quasiperiodicity