Technological Institute of Saltillo

Saltillo, Mexico

Technological Institute of Saltillo

Saltillo, Mexico
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Vasquez-Elizondo L.J.,National Polytechnic Institute of Mexico | Rendon-Angeles J.C.,National Polytechnic Institute of Mexico | Matamoros-Veloza Z.,Technological Institute of Saltillo | Lopez-Cuevas J.,National Polytechnic Institute of Mexico | Yanagisawa K.,Kochi University
Advanced Powder Technology | Year: 2016

The synthesis of LiFePO4 (hereafter referred as LFP) using urea as a reducing agent under hydrothermal conditions was investigated. The synthesis was carried out by varying the temperature (150-200°C), at different times from 6 to 24h, and using different precursors of Li ions (LiCl, LiNO3, LiOH, and Li2SO4), to determine the effect of these parameters on the crystallization process of the reaction products. These were characterized by XRD, FT-IR, and FE-SEM. The results showed that the differences in the lattice parameters calculated by Rietveld refinement are affected by the synthesis temperature. In addition, the crystallization of single-phase LiFePO4 powders was achieved by the urea decomposition that occurred at reaction times longer than 12h and at moderate temperatures (170-180°C). The crystallization of LFP particles was promoted by a dissolution-precipitation mechanism, but it was not conducted in a single step, because intermediate secondary phases were produced at reaction intervals below 6h. A crystal growth stage involving the dissolution-crystallization of intermediate secondary phases led to the formation of large particle agglomerates of LiFePO4 exhibiting a flower-like morphology when the synthesis was carried out using Li2SO4. When LiCl, LiOH, and LiNO3 were used, large bulky agglomerates were obtained. © 2017 The Society of Powder Technology Japan.


Montoya-Cisneros K.L.,National Polytechnic Institute of Mexico | Rendon-Angeles J.C.,National Polytechnic Institute of Mexico | Matamoros-Veloza Z.,Technological Institute of Saltillo | Matamoros-Veloza A.,University of Leeds | Yanagisawa K.,Kochi University
Ceramics International | Year: 2016

Densification of calcium hydroxyapatite fine powders doped with different concentrations of Mg (2, 4 and 6mol% Mg, MgHA) was successfully achieved for the first time in a nearly fully dense state using the hydrothermal hot pressing (HHP) technique at low temperatures. Consolidation of MgHA powders was studied under different temperatures (150-240°C), reaction times (1-6h), and powder particle size (20nm-1.5μm). X-Ray diffraction analyses indicated that the particle densification under HHP conditions proceeded without any variation in the crystalline structure and regardless of the Mg content. The results from this work showed that an increase in temperature accelerates the reaction between MgHA particles and water (solvent) mixed during the hydrothermal treatment. Particle packing associated with bulk densification was achieved through a massive dissolution-recrystallisation mechanism, which induced the formation of small particles that rapidly crystallised on the surface of the partially dissolved original MgHA particles. The optimum conditions to obtain pellets with a high apparent density of 3.0758 ± 0.001g/cm3 and tensile strength value of 12.6 ± 0.6MPa were 10wt% of water at a temperature of 240°C with a 6h reaction time and 6mol% of Mg (MgHA3). The use of the HHP technique coupled with the fine particle size and reactivity of the MgHA precursor powders with water allowed us to produce disks that were compacted to a nearly full dense state with a low content of open porosity of 2.0%. © 2017 Elsevier Ltd and Techna Group S.r.l.


Montoya-Cisneros K.L.,National Polytechnic Institute of Mexico | Rendon-Angeles J.C.,National Polytechnic Institute of Mexico | Matamoros-Veloza Z.,Technological Institute of Saltillo | Yanagisawa K.,Kochi University
Materials Letters | Year: 2017

Hydroxyapatite powders doped with Zn contents of 2, 4 and 6 mol% were synthesized by microwave-assisted hydrothermal treatment. The ZnHA nanoparticles were characterized by X-ray diffraction, FTIR spectroscopy and transmission electron microscopy. Structural analyses conducted by Rietveld refinement indicated that Zn incorporation occurred at the Ca(II) sites of the hexagonal HA structure. However, the nominal Zn content selected did not react completely and therefore all the particles were deficient regarding the final amount of Zn in the HA structure. TEM observations confirmed that the ZnHA particles had a high crystallinity with a particle size varying between 29 and 67 nm. © 2017 Elsevier B.V.


Resendiz-Flores E.O.,Technological Institute of Saltillo | Garcia-Calvillo I.D.,Autonomous University of Coahuila
International Journal of Heat and Mass Transfer | Year: 2014

This paper proposes the use of the finite pointset method for the numerical solution of two-dimensional transient heat conduction problems. The strong formulation of the parabolic partial differential equation is directly used instead of the corresponding weak form. Moreover, a numerical comparison between the finite pointset method and the corresponding analytical solutions is reported. © 2014 Elsevier Ltd. All rights reserved.


Resendiz-Flores E.O.,Technological Institute of Saltillo | Garcia-Calvillo I.D.,Autonomous University of Coahuila
International Journal of Heat and Mass Transfer | Year: 2015

This paper presents the application of the Finite Pointset Method for the numerical solution of three dimensional and non-stationary heat conduction problems. The strong formulation of the parabolic partial differential equation is directly used instead of the corresponding weak form. Moreover, a numerical comparison between the Finite Pointset Method and the corresponding analytical solutions is reported. © 2015 Elsevier Ltd. All rights reserved.


Moncayo-Martinez L.A.,Technological Institute of Saltillo | Zhang D.Z.,University of Exeter | Zhang D.Z.,Chongqing University
International Journal of Production Economics | Year: 2013

The problem of placing safety inventory over a network, which assembles a product, is a challenging issue in supply chain design (SCD) because manufacturers always want to reduce inventory all over the supply chain (SC). Moreover, the process of designing a SC and then placing inventory, to offer high service level at the lowest possible cost, across a complex SC, is not an easy task for decision makers. In this paper we use the SC representation proposed by Graves and Willems (2000), Manufacturing & Service Operations Management 2 (1), 68-83, where a SC is divided into many supplying, manufacturing, and delivering stages. Our problem is to select one resource option to perform each stage, and based on the selected options to place an amount of inventory (in-progress and on-hand) at each stage, in order to offer a satisfactory customer service level with as low as possible total supply chain cost. A resource option here represents a supplier, a manufacturing plant (production line), or a transport mode in a supplying, manufacturing, or delivering stage, respectively. We developed an approach based on ant colony optimisation (ACO) to minimise simultaneously the total supply chain cost and the products' lead time to ensure product deliveries without delays. What are new in our approach are the bi-objective function and the computational efficiency of our ACO-based approach. In addition, ACO has not been applied to solve the inventory placement problem. As a validation of the model, we: (a) describe a successful application at CIFUNSA, one of the largest iron foundry in the world, and (b) compare different CPU time instances and metrics about multi-objective optimisation. © 2013 Elsevier B.V.


Moncayo-Martinez L.A.,Technological Institute of Saltillo | Zertuche F.,Technological Institute of Saltillo
61st Annual IIE Conference and Expo Proceedings | Year: 2011

In this paper, we developed an ant colony algorithm for minimizing the production cost and lead time of one or more products in an assembly supply chain. The problem solved by this approach is formulated in [1] just to solve the Cost of Goods Sold. We propose to extend the problem so as to minimize, simultaneously, the cost of production and the lead time. In this paper, we introduce a framework to solve the problem by means of a relatively new meta-heuristic called Ant Colony Optimization, specially the Rank-Based Ant System, which has been proved to be an efficient algorithm to solve combinatorial problems. The algorithm was tested using a standard problem reported in literature.


Resendiz-Flores E.O.,Technological Institute of Saltillo | Saucedo-Zendejo F.R.,Technological Institute of Saltillo
International Journal of Heat and Mass Transfer | Year: 2015

This paper proposes the use of the Finite Pointset Method (FPM) for the numerical simulation of heat transfer involving a moving source which are present in welding materials processing. The main ideas behind FPM as well as details of the computational implementation are presented. Numerical results of the simulation of the heat transfer process are reported and compared with those obtained by the finite element method which show that the method is promising for these applications. © 2015 Elsevier Ltd. All rights reserved.


Resendiz E.,Technological Institute of Saltillo | Moncayo-Martinez L.A.,Technological Institute of Saltillo | Solis G.,Technological Institute of Saltillo
Expert Systems with Applications | Year: 2013

This work presents the application of the Mahalanobis-Taguchi System (MTS) to a dimensional problem in the automotive industry. The combinatorial optimization problem of variable selection is solved by the application of a recent version of binary ant colony optimization algorithm. Moreover, a comparison with respect to binary particle swarm optimization algorithm is also presented and a discussion regarding the numerical results is given. © 2012 Elsevier Ltd. All rights reserved.


Resendiz E.,Technological Institute of Saltillo | Rull-Flores C.A.,Technological Institute of Saltillo
Expert Systems with Applications | Year: 2013

This work presents the application of the Mahalanobis-Taguchi system (MTS) to variable detection in the manufacturing process of automotive pedals components. The combinatorial optimization problem of variable selection is solved by the application of Gompertz binary particle swarm optimization algorithm. Moreover, a numerical comparison with respect to other common version of binary particle swarm and binary ant colony optimization algorithms is presented followed by a discussion regarding the corresponding numerical results. © 2012 Elsevier B.V. All rights reserved.

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