Puebla de Zaragoza, Mexico
Puebla de Zaragoza, Mexico

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Bautista-Rodriguez C.M.,Alter Energias Grupo | Rosas-Paleta M.G.A.,BUAP | Rivera-Marquez J.A.,BUAP | Tepale-Ochoa N.,BUAP
International Journal of Electrochemical Science | Year: 2011

PEMFC performance is limited by different mass transport phenomena during operation as: mass transport (conduction and diffusion) of reactive gases, ionic species and products, electron conductivity and ionic conductivity. The reagents are distributed by conduction on the diffusion layer surface of electrodes through manufactured distribution channels in the polar plates. Subsequently, the reactive gases diffuse to the active layer, where the electro-chemical semi-reactions take place. However, geometry, size, diameter, porosity and other physical characteristics in the structural basic elements for fuel cells generate particularly effects on the Proton Exchange Membrane Fuel Cell (PEMFC) performance. This paper includes an experimental comparison between different structural PEMFC designs; These designs combining different distribution plates and Gas Distribution Medias (GDM) in the PEMFC, by application of a 23 experimental design with 3 different membrane-electrodes assemblies and 3 cathodic pressure levels. The results show significant effects on the functionality and generated electrical power by the PEMFC directly related to mass transport conditions (including electron transport), depending on the combination, material nature, electrical and structural characteristics of applied materials. © 2011 by ESG.


Rodriguez C.M.B.,Grupo Mexico | Paleta M.G.A.R.,BUAP | Marquez J.A.R.,BUAP | de la Vega J.R.G.,Grupo Mexico
International Journal of Electrochemical Science | Year: 2010

Several mass transport phenomena occur during the operation of a PEMFC each one generates a resistance implying limitations during operation. The humidity in the reactive gas flows promotes the conductivity of the electrolyte membrane but increases the transport limitations at high current densities. The reactive gases are distributed in a conventional PEMFC by distributors with serpentineshaped channel, transversely covering the surface of the electrodes. This paper applies and compares a rigid gas diffusion media as gas distributor, its porosity comprises mostly of macropores, their function is improve the gases reaction distribution with the aim of reducing resistance to mass transport, in turn collects (in the anode) or distributes (on the cathode) electrons generated in the reaction sites. The results determine a complex mass transport processes in the porous media when the reagents are moistened, however at pressures greater than 10 psig, the functionality of the PEMFC is increased significantly to moisture conditions in the reagents flow and it is very favorable for the case of conventional PEMFC design. The combined effect Pressure - Humidity reduces ohmic limitations to medium current densities, while the flow rate allows a reduction in transport resistance at high current densities. The presence of heavy metals in the structure of the commercial electrodes may generate over-potentials in the cell with capacity to affect the functionality of PEMFC. © 2010 by ESG.


Antonio Rivera Marquez J.,BUAP | Moises Bautista Rodriguez C.,Grupo Mexico | Herrera C.M.,BUAP | Rosas E.R.,Centro Universitario Of Vinculacion | And 2 more authors.
International Journal of Electrochemical Science | Year: 2011

Photocatalysis of organic compounds by mean to semiconductors depends heavily on its structural and superficial properties. For this reason, the aim of this paper is to investigate the effect of the ratio Zn/O, grain size and grain number of zinc oxide (ZnO) on photocatalysis of methylene blue dye (MB). ZnO deposits were obtained by cathodic electrodeposition technique from an experimental design 23. The three growth variables were voltage, temperature and time of deposition with two different levels for each variable. Our results showed that the crystallographic orientation and morphology of ZnO electrodeposited depend on different combinations of the deposit variables according to the experimental design. We also found that there is an optimum value in the ratio Zn/O, grain size and grain number of ZnO related to the higher degradation of MB. © 2011 by ESG.


Bautista-Rodriguez C.M.,Grupo Mexico | Rosas-Paleta M.G.A.,Grupo Mexico | Tepale-Ochoa N.,BUAP | Sanchez-Grijalva D.,Grupo Mexico
International Journal of Electrochemical Science | Year: 2012

The PEMFC technology is considered as an applicable technology to portable and transportable services; however its application in stationary service has been widely questioned as a viable proposition. This paper develops a FEL study type 1 for a domestic electrical service design. 3 PEMFC prototypes were scaled and compared to supply a stationary domestic electrical service. The integrated method was applied to determine the cost of the technology and the total investment cost +/- 50% at 20 years of useful life for each prototype. Operating costs were estimated considering the consumption of hydrogen from a material balance. It was also developed a cost estimate for electrical production in each case. Finally, a simple method for a risk analyze was developed for this conceptual project. The results show the effect of the cost of materials selected for PEMFC assembly on investment costs and operating costs. This effect is also observed on the production cost when cathodic pressure is applied below 10 psi; however at higher pressures the production cost is influenced by the combination between efficiency of PEMFC assembly and its materials cost. The electrical production costs obtained by PEMFC technology are close at sold price in some regions on the world. This result permits to considerate the PEMFC application in stationary service at medium or long time; however the result of the risk analysis prevents its development by using experimental prototypes. © 2012 by ESG.


Carbajal-Gomez V.H.,National Institute of Astrophysics, Optics and Electronics | Tlelo-Cuautle E.,National Institute of Astrophysics, Optics and Electronics | Trejo-Guerra R.,Semtech | Munoz-Pacheco J.M.,BUAP
Proceedings - IEEE International Symposium on Circuits and Systems | Year: 2013

This investigation shows the modeling and simulation of the synchronization of two multi-scroll chaotic oscillators in a master-slave topology. The synchronization is performed by Generalized Hamiltonian forms and observer approach from nonlinear control theory. The case of study consists of two 4-scroll attractors based on saturated function series. Finally, the numerical simulation of the synchronization, from the mathematical description, and the circuit implementation using HSPICE models of opamps, show the good agreement between theory and experiment results. © 2013 IEEE.


Ramales-Valderrama R.,BUAP | Vazquez-Duran A.,National Autonomous University of Mexico | Mendez-Albores A.,National Autonomous University of Mexico
Toxins | Year: 2016

Mycotoxin adsorption onto biomaterials is considered as a promising alternative for decontamination without harmful chemicals. In this research, the adsorption of B-aflatoxins (AFB1 and AFB2) using Pyracantha koidzumii biomasses (leaves, berries and the mixture of leaves/berries) from aqueous solutions was explored. The biosorbent was used at 0.5% (w/v) in samples spiked with 100 ng/mL of B-aflatoxin standards and incubated at 40 °C for up to 24 h. A standard biosorption methodology was employed and aflatoxins were quantified by an immunoaffinity column and UPLC methodologies. The biosorbent-aflatoxin interaction mechanism was investigated from a combination of zeta potential (ζ), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The highest aflatoxin uptakes were 86% and 82% at 6 h using leaves and the mixture of leaves/berries biomasses, respectively. A moderate biosorption of 46% was attained when using berries biomass. From kinetic studies, the biosorption process is described using the first order adsorption model. Evidence from FTIR spectra suggests the participation of hydroxyl, amine, carboxyl, amide, phosphate and ketone groups in the biosorption and the mechanism was proposed to be dominated by the electrostatic interaction between the negatively charged functional groups and the positively charged aflatoxin molecules. Biosorption by P. koidzumii biomasses has been demonstrated to be an alternative to conventional systems for B-aflatoxins removal. © 2016 by the authors; licensee MDPI, Basel, Switzerland.


Petranovskii V.,National Autonomous University of Mexico | Espinosa M.A.H.,BUAP | Kolobova E.,Tomsk Polytechnic University | Pestryakov A.,Tomsk Polytechnic University
Advanced Materials Research | Year: 2014

By selective acid leaching, silica nanotubes were prepared from the natural mineral chrysotile asbestos. These one-dimensional tube actually represent a convolution of two-dimensional layers, and the subsequent stacking the tubes into a hexagonal assembly generates three-dimensional body. Made materials are acid- and heat-resistant and can be used as feedstock in the manufacture of filters, or as matrices for the synthesis of nanomaterials. © (2014) Trans Tech Publications, Switzerland.


PubMed | National Autonomous University of Mexico and BUAP
Type: Journal Article | Journal: Toxins | Year: 2016

Mycotoxin adsorption onto biomaterials is considered as a promising alternative for decontamination without harmful chemicals. In this research, the adsorption of B-aflatoxins (AFB and AFB) using Pyracantha koidzumii biomasses (leaves, berries and the mixture of leaves/berries) from aqueous solutions was explored. The biosorbent was used at 0.5% (w/v) in samples spiked with 100 ng/mL of B-aflatoxin standards and incubated at 40 C for up to 24 h. A standard biosorption methodology was employed and aflatoxins were quantified by an immunoaffinity column and UPLC methodologies. The biosorbent-aflatoxin interaction mechanism was investigated from a combination of zeta potential (), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The highest aflatoxin uptakes were 86% and 82% at 6 h using leaves and the mixture of leaves/berries biomasses, respectively. A moderate biosorption of 46% was attained when using berries biomass. From kinetic studies, the biosorption process is described using the first order adsorption model. Evidence from FTIR spectra suggests the participation of hydroxyl, amine, carboxyl, amide, phosphate and ketone groups in the biosorption and the mechanism was proposed to be dominated by the electrostatic interaction between the negatively charged functional groups and the positively charged aflatoxin molecules. Biosorption by P. koidzumii biomasses has been demonstrated to be an alternative to conventional systems for B-aflatoxins removal.


Sanchez-Cantu M.,BUAP | Perez-Diaz L.M.,BUAP | Maubert A.M.,Metropolitan Autonomous University | Valente J.S.,Metropolitan Autonomous University | Valente J.S.,Mexican Institute of Petroleum
Catalysis Today | Year: 2010

Binary and ternary hydrotalcite-like (HT) materials containing copper, nickel, zinc, iron, magnesium and/or aluminum were synthesized by coprecipitation and characterized by elemental analysis, powder X-ray diffraction and N2 adsorption-desorption at -196 °C. Samples were calcined at 700 °C for 4 h, obtaining mixed oxides which were tested for sulfur oxides (SOx) removal. Their performance was compared with a commercial SOx reducing additive by thermogravimetric SOx uptake. SOx adsorption was carried out by contacting the calcined solid with a mixture of 1% SO2 in air at 650 °C. The adsorbed species were reduced with H2 at 550 °C, 650 °C and 700 °C, in order to study their stability and the solid's regenerability. It was found that the isomorphic incorporation of a transition metal in the HT layers increased the mixed oxide's reduction ability. This was reflected on higher reduction rates and sulfate reduction amounts at 550 °C. Furthermore, these materials showed greater adsorption-reduction properties than the commercial additive. © 2009 Elsevier B.V. All rights reserved.


Marquez J.A.R.,BUAP | Herrera C.M.,BUAP | Fuentes M.L.,BUAP | Rosas L.M.,BUAP
International Journal of Electrochemical Science | Year: 2012

There are several studies on the morphology of zinc oxide (ZnO) in the photocatalytic elimination of organic pollutants, but few studies focus on the simultaneous effect of different operating parameters. Most studies have been carried out by unifactorial experiments, which is inefficient. For this reason, in this study, ZnO thin films were prepared by electrodeposition and the response surface methodology (RSM) was applied to evaluate the effect of variables such as: concentration of methylene blue dye (MB), pH and air flow involved on the photocatalytic degradation of methylene blue. The results showed that the RSM is a suitable technique to determine the operating conditions favorable for the degradation of MB within a determined range of study. © 2012 by ESG.

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