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Alejo R.,Tecnologico de Estudios Superiores de Jocotitlan | Valdovinos R.M.,Valle de México University | Garcia V.,Jaume I University | Pacheco-Sanchez J.H.,Toluca Institute of Technology
Pattern Recognition Letters | Year: 2013

Class imbalance and class overlap are two of the major problems in data mining and machine learning. Several studies have shown that these data complexities may affect the performance or behavior of artificial neural networks. Strategies proposed to face with both challenges have been separately applied. In this paper, we introduce a hybrid method for handling both class imbalance and class overlap simultaneously in multi-class learning problems. Experimental results on five remote sensing data show that the combined approach is a promising method. © 2012 Elsevier B.V. All rights reserved.

Salgado-Gomez N.,Toluca Institute of Technology | Salgado-Gomez N.,Instituto Nacional de Investigaciones Nucleares | Macedo-Miranda M.G.,Toluca Institute of Technology | Olguin M.T.,Instituto Nacional de Investigaciones Nucleares
Applied Clay Science | Year: 2014

In the present investigation, zeolite-rich tuff from the state of Chihuahua, which was conditioned with a sodium chloride solution and subsequently modified with a hexadecyltrimethylammonium bromide solution, was used to evaluate the removal of Cr(VI) from aqueous systems prepared with Na2CrO4, K2Cr2O7 or a mixture of both Na2CrO4 and K2Cr2O7 salts. The zeolitic materials were characterized by scanning electron microscopy and X-ray diffraction, and their surface area was also determined. These experiments were performed in a batch system in which the influences of the pH, contact time between phases, and concentration of Cr(VI) in solution on the adsorption of Cr(VI) by surfactant-modified zeolite-rich tuff were investigated. The removal efficiency of chromium ions from aqueous solution is influenced by pH and the specific chromium species involved plays an important role in the adsorption process. The Cr(VI)-Na2CrO4 and Cr(VI)-K2Cr2O7 adsorption kinetics data were fit to a pseudo-second-order model, and the Langmuir isotherm adequately described the experimental results of these mono-component systems. In the Cr(VI)-Na2CrO4:Cr(VI)-K2Cr2O7 mixture, the surfactant-modified zeolite-rich tuff adsorbed more Cr(VI) depending on the initial ratio of Na2CrO4:K2Cr2O7 salts in the bi-component aqueous system. © 2014 Elsevier B.V.

Chavez R.-H.,Instituto Nacional de Investigaciones Nucleares | Guadarrama J.J.,Toluca Institute of Technology
Clean Technologies and Environmental Policy | Year: 2015

This paper presents the characterization of ashes generated from different incineration processes, such as (a) coupled kilns, (b) conventional kiln, (c) wood, and (d) fly and bottom of Petacalco power plant, in order to set which is the best one for the purification of biogas from landfill. The techniques employed for the characterization were scanning electron microscopy, X-ray diffraction, and transmission electron microscopy. The ashes from these sources were analysed through their microstructural properties and features such as the efficiency of carbon dioxide reduction due to chemical reaction with the calcium oxide present in the ashes. Calcium carbonate mineral was obtained as a highly stable and insoluble salt. The results indicate that the ash from wood is the most appropriate to reduce the carbon dioxide due to its high calcium content. Dry fly ash from Petacalco power plant has the ability to carry out a process of carbonation according to the samples analyzed. It was noted that elements such as aluminium, sodium, potassium, and magnesium led to the formation of some other mineral species in the ash resulting from incineration processes. © Springer-Verlag Berlin Heidelberg 2015.

Diaz-Nava M.C.,Toluca Institute of Technology | Olguin M.T.,Instituto Nacional de Investigaciones Nucleares | Solache-Rios M.,Instituto Nacional de Investigaciones Nucleares
Journal of Inclusion Phenomena and Macrocyclic Chemistry | Year: 2012

Bentonite was modified with hexadecyltrimethylammonium bromide or bencylhexadecyldimethylammonium chloride. Phenol adsorption kinetic and isotherms experiments were performed; in both cases, phenol was determined in the aqueous solutions by UV-Vis spectroscopy. The results showed that the adsorption of phenol depends on the kind of surfactant, and pH of the solutions. The adsorption was higher for the clay modified with bencylcetyldimethylammonium chloride than hexadecyltrimethylammonium bromide. © 2011 Springer Science+Business Media B.V.

Baeza-Alvarado M.D.,Instituto Nacional de Investigaciones Nucleares | Baeza-Alvarado M.D.,Toluca Institute of Technology | Baeza-Alvarado M.D.,S.A. de C.V. | Olguin M.T.,Instituto Nacional de Investigaciones Nucleares
Microporous and Mesoporous Materials | Year: 2011

The kinetics of the removal of Ba2+ and fulvic acid by a surfactant-modified Mexican clinoptilolite-rich tuff was investigated. The effect of fulvic acid in a bi-component aqueous medium (Ba2+-fulvic acid) on the sorption of Ba2+ was also considered, and an unmodified zeolitic material was included for comparison. The Ba2+, fulvic acid and fulvic acid-Ba2+ solutions were placed in contact with a Mexican clinoptilolite-rich tuff in a batch system. Atomic absorption and UV-Vis spectroscopy were used to measure the remaining aqueous barium and fulvic acid, respectively. The Ba2+ and fulvic acid sorption kinetic experimental data were best fitted by a pseudo-second-order model. The amount of surfactant covering the surface of the zeolitic material and the fulvic acid influenced the sorption kinetics of Ba2+ from aqueous media by sodium and surfactant-modified Mexican clinoptilolite-rich tuffs. The presence of Ba 2+ in the aqueous medium increased the sorption of fulvic acid by the sodium-modified zeolite from Oaxaca (NaZO), but the time to reach equilibrium was greater. The Ba2+ was removed from aqueous media by ion exchange or complexation with fulvic acid, and fulvic acid was adsorbed by the surfactant-modified zeolites through a partitioning mechanism. © 2010 Elsevier Inc. All rights reserved.

Garcia-Mendieta A.,Instituto Nacional de Investigaciones Nucleares | Garcia-Mendieta A.,Toluca Institute of Technology | Olguin M.T.,Instituto Nacional de Investigaciones Nucleares | Solache-Rios M.,Instituto Nacional de Investigaciones Nucleares
Desalination | Year: 2012

The biosorption properties of the green tomato husk to remove iron and manganese from single and binary aqueous systems were investigated. This no-living biomass was characterized and modified with formaldehyde. The iron, manganese or iron-manganese adsorption kinetic results were best adjusted to the pseudo second order kinetic and the Freundlich or Langmuir-Freundlich isotherm models depending on the iron, manganese or iron-manganese aqueous systems. Modified Langmuir and Freundlich multicomponent isotherm models were also used to describe the simultaneous sorption of iron and manganese from binary aqueous solutions. Iron and manganese were removed efficiently by the formaldehyde modified green tomato husk in single systems; iron and manganese did not compete for the sorption active sites of the no-living biomass and the removal of both metals from binary systems did not decrease. The sorption mechanisms proposed for Mn 2+ were ion exchange and complexation, while the sorption mechanisms proposed for Fe 3+ were precipitation and ion exchange. © 2011 Elsevier B.V..

Chavez R.-H.,Instituto Nacional de Investigaciones Nucleares | De J. Guadarrama J.,Toluca Institute of Technology
Chemical Engineering Transactions | Year: 2011

The purpose of this work is to simulate CO2 capture process, using Monoethanolamine (MEA) at 30 % weight, at power plant and using Aspen Plus™ simulator. CO2 is removed by chemical absorption processes from the flue gases of the power plant. The main challenge of the chemical absorption CO2 capture processes is reducing the energy requirement in the stripper which has contributors from reboiler energy consumption and maximum CO2 absorption. This work presents an enhancement the structured packing study in separation columns: ININ 18, Sulzer BX and Mellapak 250Y, and the advance of CCS technologies (CO2 capture and sequestration). This ININ 18 material was developed by the Mexican National Institute of Nuclear Research (ININ by its acronym in Spanish). The parameters studied were: Separation absorption efficiency, flow ratio (L/G) values in order to find the load or turbulence regimen in absorption process, reboiler duty at desorption column, and column diameters at different treated flue gas flows. The results showed that Sulzer BX had the highest volumetric mass transfer coefficient values and the lowest height of mass transfer equivalent unit, with 3.76 s-1 and 0.317 m, respectively, with 600 t/h flue gas flow, and the paper discusses the selection of most important parameters necessary to obtain 90 % capture rate and the lowest energy consumption for CO2 capture plants in comparison with respect to the other two packings. Sulzer BX packing shows decreased reboiler energy consumption with 8.5 MJ/kg CO2. Copyright © 2011, AIDIC Servizi S.r.l.

Chavez R.-H.,Mexican National Institute of Nuclear Research ININ | de J. Guadarrama J.,Toluca Institute of Technology
Chemical Engineering and Technology | Year: 2012

The degree of CO 2 absorption by monoethanolamine (MEA) using metal structured packing material, ININ18, was studied. The aqueous solution contained 30wt-% MEA in countercurrent with CO 2 flue gas. The capture process was carried out in an absorption column with dimensions 4.0m in height and 0.3m in diameter. The mass transfer coefficient and height of mass transfer were evaluated. Results show a volumetric mass transfer coefficient of 3.76s -1, a height of mass transfer equivalent unit of 0.317m, and an absorption efficiency of 90% from flue gas. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Lopez-Lagunas A.,Toluca Institute of Technology
Journal of Signal Processing Systems | Year: 2011

High performance portable systems for real-time video/image analysis continue to demand high processing power and memory bandwidth. In embedded systems such as digital still cameras, camcorders, and camera phones, the expected performance must be delivered while meeting size, weight, and power constraints. A well-designed system should include analyses of its memory subsystem as well as the computation platform. This paper focuses on a streaming memory subsystem that leverages deterministic memory access patterns. We formalize the notion of stream descriptors as a means to define these stream access patterns and to improve memory access efficiencies by discovering locality between different data streams. Data movement for a real-time image analysis applications are performed, showing favorable bandwidth savings using stream descriptors. © 2009 Springer Science+Business Media, LLC.

Morales-Duarte A.N.,Toluca Institute of Technology | Pacheco-Sanchez J.H.,Toluca Institute of Technology
Revista Mexicana de Fisica | Year: 2013

A study of the attack to a water molecule by either aluminum or cadmium atoms is accomplished for determining their interaction geometry. The existence of certain number of geometrical zones for repulsion and attraction of Al and Cd atoms when these interact with the water molecule is obtained using Density Functional Theory. Our results clearly show the existence of defined geometries where the interaction is the strongest for chemical bonds formation.

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