National Center for Research and Technological Development

Cuernavaca, Mexico

National Center for Research and Technological Development

Cuernavaca, Mexico

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Rodriguez-Lelis J.M.,National Center for Research and Technological Development | Maza-Valle C.A.,National Polytechnic Institute of Mexico | Lopez Y Rodriguez A.R.,National Polytechnic Institute of Mexico | Ruiz-Dominguez D.,National Polytechnic Institute of Mexico | And 2 more authors.
Proceedings of the ASME Design Engineering Technical Conference | Year: 2010

In this work, a model to evaluate the abrasive wear between two semi-cylindrical entities is presented. The entities represent the average roughness radius, of the contact surfaces formed between the femoral head and acetabular cup of a hip prosthesis. The contact couples employed in this work are CrCoMo-UHMWPE and DLC-UHMWPE. Here three different interference distances were employed: 1, 2.5 and 40 percent of the mean radius roughness of the UHMWPE. The energy method proposed here determines the maximum contact stresses, from where the maximum point of distortional energy is obtained. This is then linked to the geometry of the cylindrical entity, which then gives the initial failure point. Subsequent similar calculations provide with the trajectory of the wearing path. The percentage of the abrasive wear obtained from this method was compared to Archard's method. It was noted that the percentage of Archard's wear is a ten in million part from the total volume, while that the percentage of Energy's wear is between 2.760% and 7.055%, when an interference distance S=0.5 μm, was employed. It was also found that the CrCoMo-UHMWPE couple exhibited 22.84 % of volume lost compared with the 2.95 % of the DLCUHMWPE couple. Copyright © 2010 by ASME.


Estrada Q.,Autonomous University of Ciudad Juárez | Szwedowicz D.,National Center for Research and Technological Development | Majewski T.,Universidad de Las Americas Puebla | Martinez E.,National Center for Research and Technological Development | Rodriguez-Mendez A.,University of California at Berkeley
Eksploatacja i Niezawodnosc | Year: 2016

In this paper the effect of discontinuity size on energy absorption performance of steel square profiles is reported. The analysis consists of finite element simulations and experimental results of the compression strength of steel profiles with discontinuities. The discontinuities were placed at the mid span of the profiles in two walls opposite to each other. Square, rectangular and diamond initiators were evaluated at different scales. The numerical results determined the size intervals that present a good energy absorption performance in each case. Energy absorption capabilities were increased up to 12.54% with respect to a structure without discontinuities. Additionally, the peak load value (Pmax) was decreased 25.97% with the implementation of a diamond initiator. For structures with discontinuities with major axis close to the profile width, a buckling effect was observed. Finally, it was observed that the size of the initiators contributes to reduce the peak load (Pmax) value. © 2016, Polish Academy of Sciences Branch Lublin. All rights reserved.


Estrada Q.,National Center for Research and Technological Development | Szwedowicz D.,National Center for Research and Technological Development | Majewski T.,Universidad de Las Americas Puebla | Oliver M.,National Center for Research and Technological Development | And 2 more authors.
Mechanics of Advanced Materials and Structures | Year: 2016

The effect of size discontinuities on the energy absorption performance of squared steel profiles is reported. Finite element simulations of the compression strength of profiles with discontinuities, placed at mid span of the steel profiles in two opposite walls, were carried out. Circular and elliptical forms of the discontinuities were evaluated. Energy absorption capabilities were increased up to 12.54% and the peak load value was decreased to 10.52% with respect to the same structure without discontinuities. A buckling effect is observed in structures with discontinuities, which contributes to reducing the peak value while the energy absorbing characteristics decrease. © 2016 Taylor & Francis Group, LLC


Aguilera A.,National Center for Research and Technological Development | Adam M.,National Center for Research and Technological Development | Astorga C.,National Center for Research and Technological Development | Theilliol D.,Nancy Research Center for Automatic Control | Ponsart J.C.,Nancy Research Center for Automatic Control
Conference on Control and Fault-Tolerant Systems, SysTol'10 - Final Program and Book of Abstracts | Year: 2010

In this work the application of a full-order observer to a binary distillation column, using a strategy to simplify the nonlinear model is presented. Mainly for process system, it is feasible to use differential- algebraic equations for describing the dynamical behavior of the plant. A mathematical model is an extension of the traditional chemical and physical laws (such as the laws of conservation of mass, energy, momentum, etc.) to include the time-varying parameters which can be seen as singular systems. Then, the binary distillation column model is presented as a Linear Parameter Variant (LPV) singular system. Singular systems provide special features not found in traditional systems. In that sense, the proposed model maintains the dynamics and physical properties of the plant. The applied method guarantees the regularity and the convergence of the observer system. ©2010 IEEE.


Martinez-Solis F.,National Center for Research and Technological Development | Claudio-Sanchez A.,National Center for Research and Technological Development | Rodriguez-Lelis J.M.,National Center for Research and Technological Development | Vergara-Limon S.,Autonomous University of Puebla | And 2 more authors.
BioMedical Engineering Online | Year: 2014

Background: Gait analysis and research have been developed to obtain characteristics of movement patterns of people while walking. However, traditional measuring systems present different drawbacks that reduce their use and application. Among those drawbacks one can find: high price, low sampling frequency and limiting number of steps to be analyzed. Traditional measuring gait systems carry out their measurement at frequencies oscillating between 60 to 100 Hz. It can be argued about the need of higher sampling rates for gait measurements. However small displacements of the knee or hip for example, cannot be seen with low frequencies required a more detailed sampling and higher frequency sampling. Bearing this in mind, in this paper is presented a 250 Hz system based on accelerometers for gait measurement, and the particularities of knee and hip angles during gait are highlighted.Methods: The system was designed with a PCI data acquisition card instrumented with an FPGA to achieve a rate sample of 250 Hz. The accelerometers were placed in thighs and legs to calculate the joint angles of hip and knee in the sagittal plane. The angles were estimated using the acceleration polygon method without integrating the acceleration and without filters.Results: The gait of thirty healthy people of Mexican phenotype was analyzed over a flat floor free of obstacles. The results showed the gait phases and particularities associated with the walking style and people's laterality; the movement patterns were similar in the thirty persons. Based on the results, the particularities as the maximum amplitude in the angles and the shape in the movement patterns were related to the anthropometry and people phenotype.Conclusions: The sampling frequency was essential to record 340 samples in single gait cycle and so registering the gait cycle with its particularities. In this work were recorded an average of 8 to 10 gait cycles, and the results showed variation regarding works carried out in biomechanics laboratories; this variation was related to the method and reference frame used to obtain the joint angles and the accuracy of measurement system. © 2014 Martínez-Solís et al.; licensee BioMed Central Ltd.


Vazquez-Blanco A.,National Center for Research and Technological Development | Aguilar-Castillo C.,National Center for Research and Technological Development | Canales-Abarca F.V.,ABB | Arau-Roffiel J.E.,National Center for Research and Technological Development
International Power Electronics Congress - CIEP | Year: 2010

Normally fuel cell based power supply system needs a power conditioner to convert the low DC output voltage generated by the fuel cell into usable AC voltage for any practical application. For proper power conditioning design fuel cell electrical characteristics as well as customer requirements must be taken into account. Therefore, in this paper, a practical design methodology for two-stage power conditioner architecture suited for using in stand-alone power generation systems with 120VAC output voltage (sinusoidal single-phase) and low input voltage (26VDC) is presented. Proposed power conditioner architecture, which consists of an active clamp full-bridge boost converter (ACFBC) for the DCDC stage and a full-bridge sinusoidal pulse width modulation (SPWM) inverter for DC-AC stage is designed, simulated and implemented. In order to validate proposed power conditioner architecture, experimental results for 1kW power conditioner prototype are presented. © 2010 IEEE.


Estrada Q.,National Center for Research and Technological Development | Szwedowicz D.,National Center for Research and Technological Development | Baltazar M.,National Center for Research and Technological Development | Cortes C.,National Center for Research and Technological Development | And 2 more authors.
International Journal of Advanced Manufacturing Technology | Year: 2015

A numerical study of the energy absorption characteristics of structural steel is presented, by implementing geometric imperfections. The geometric discontinuities were placed at half height of the structures in two opposite walls. In this case, different curved shapes discontinuities and quadrilaterals were evaluated. The shape and aspect ratio of the discontinuity modify the behavior of the structure even though the analyzed shapes have the same area value. The best performance in energy absorption of 12.54 % compared to a shape with no discontinuities was obtained with the implementation of a curved form initiator. Finally, and with the same comparison pattern, the value of the peak load was reduced up to 22.13 % by using the diamond-shaped discontinuities. © 2015 Springer-Verlag London


Blanco A.,National Center for Research and Technological Development | Gomez F.A.,Higher Technological Institute of Puerto Vallarta | Olivares V.H.,National Center for Research and Technological Development | Abundez A.,National Center for Research and Technological Development | Colin J.,National Center for Research and Technological Development
International Journal of Automation and Control | Year: 2015

The continuous passive motion (CPM) machines are used in the rehabilitation of members that have been injured to recover their range of motion and prevent stiffness. Nowadays, some CPM machines for knee, ankle, arm and elbow are available commercially. In this paper, a novel design of a parallel robot based on an XY table for ankle rehabilitation, that provides dorsiflexion-plantarflexion and abduction-adduction movements, is presented. Some results are presented in order to show the performance of the parallel robot for ankle rehabilitation. Proportional-derivative (PD), proportional-integral-derivative (PID) and generalised proportional integral (GPI) controllers for trajectory tracking are implemented in the virtual and physical prototype. Copyright © 2015 Inderscience Enterprises Ltd.


Loranca J.,National Autonomous University of Mexico | Aguayo J.,National Center for Research and Technological Development | Claudio A.,Technical University of Madrid | Vela L.G.,National Center for Research and Technological Development | And 3 more authors.
International Review on Modelling and Simulations | Year: 2013

When a multilevel inverter has to be operated, question raises on which modulation strategy to choose in order to have lower harmonic content in the output voltage waveform. Multilevel inverters have been a subject of great interest in the field of power electronics because they present a set of properties that make them more efficient than conventional ones. The purpose of this paper is to verify and compare through simulation the output voltage total harmonic distortion and weighted total harmonic distortion employing low and high frequency and hybrid modulation techniques in an asymmetric cascaded multilevel inverter, using binary DC bus voltage progression. All modulation strategies mentioned before were analyzed in the asymmetric multilevel inverter to verify which one is the most suitable for this type of structure using the two most powerful simulation software in power electronics field, such as PSIM and Matlab-Simulink. © 2013 Praise Worthy Prize S.r.l. - All rights reserved.


Szwedowicz D.,National Center for Research and Technological Development | Estrada Q.,National Center for Research and Technological Development | Cortes C.,National Center for Research and Technological Development | Bedolla J.,Apizaco Technological Institute | And 2 more authors.
Latin American Journal of Solids and Structures | Year: 2014

This article details the experimental and numerical results on the energy absorption performance of square tubular profile with circular discontinuities drilled at lengthwise in the structure. A straight profile pattern was utilized to compare the absorption of energy between the ones with discontinuities under quasi-static loads. The collapse mode and energy absorption conditions were modified by circular holes. The holes were drilled symmetrically in two walls and located in three different positions along of profile length. The results showed a better performance on energy absorption for the circular discontinuities located in middle height. With respect to a profile without holes, a maximum increase of 7% in energy absorption capacity was obtained experimentally. Also, the numerical simulation confirmed that the implementation of circular discontinuities can reduce the peak load (Pmax) by 10%. A present analysis has been conducted to compare numerical results obtained by means of the finite element method with the experimental data captured by using the testing machine. Finally the discrete model of the tube with and without geometrical discontinuities presents very good agreements with the experimental results.

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