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Ciudad Juárez, Mexico

Becerra M.B.,CIATEC | Zitzumbo R.,CIATEC | Dominguez J.,CIMAT | Garcia J.L.,UACJ | And 2 more authors.
South African Journal of Industrial Engineering | Year: 2014

This paper presents the development of an eco-efficient product/process, which has improved mechanical properties from the introduction of natural fibres in the EPDM (Ethylene-Propylene-Diene-Terpolymer) rubber formulation. The optimisation analysis is made by a fractional factorial design 211-7. Different formulations were evaluated using a multi-response desirability function, with the aim of finding efficient levels for the manufacturing time-cycle, improving the mechanical properties of the product, and reducing the raw material costs. The development of an eco-efficient product/process generates a sustainable alternative to conventional manufacturing. © 2014 South African Institute of Industrial Engineering. All rights reserved.

Limon A.,UACJ | Moreno M.,National Institute of Astrophysics, Optics and Electronics
2015 12th International Conference on Electrical Engineering, Computing Science and Automatic Control, CCE 2015 | Year: 2015

Hybrid energy harvesting system combining multiple sources is an alternative solution to harvest energy continuously and to increase the output power to bias the electronic systems. In this work is presented a prototype for harvesting energy, which combined three different sources. It contains a piezoelectric cantilever based on Lead-Zirconate Titanate piezoelectric transducer (PZT) in order to harvest the ambient vibrations, a solar cell for sunlight and an antenna capable to harvest ambient Radio Frequency (RF) energy. The design, implementation and characterization of the circuits for signal conversion from AC to DC for the case of piezoelectric generator, and the RF to DC for the antenna are presented. The RF harvesting circuit operates at 2.4 GHz obtaining a voltage of 71mV. The prototype is capable to generate a maximum DC power around 241.3 mW when the piezoelectric, solar cell and RF devices are connected together. Thus, the output power of this hybrid harvesting circuit is very attractive for low power electronic applications. © 2015 IEEE.

Perez-Rodriguez R.,CIATEC | Jons S.,University of Guanajuato | Hernandez-Aguirre A.,CIMAT | Alberto-Ochoa C.,UACJ
International Journal of Advanced Manufacturing Technology | Year: 2014

The flexible jobshop scheduling problem permits the operation of each job to be processed by more than one machine. The idea is to assign the processing sequence of operations on the machines and the assignment of operations on machines such that the systemobjectives can be optimized. The assignment mentioned is a difficult task to implement on real manufacturing environments because there are many assumptions to satisfy, especially when the amount of work is not constant or sufficient to keep the manufacturing process busy for a long time, causing intermittent idle times. An estimation of distribution algorithm-based approach coupled with a simulationmodel is developed to solve the problemand implement the solution. Using the proposed approach, the shop performance can be noticeably improved when different machines are assigned to different schedules. © Springer-Verlag London 2014.

Heredia A.,UPAEP | Ambrosio R.,UACJ | Moreno M.,National Institute of Astrophysics, Optics and Electronics | Zuniga C.,National Institute of Astrophysics, Optics and Electronics | And 3 more authors.
Journal of Non-Crystalline Solids | Year: 2012

In this work is presented the fabrication of a thin film membrane as a bio-transducer for aural assistance detection, therefore it will operate at low pressure. The resonant membrane was deposited by PECVD technique at low temperature of deposition T = 270 °C, using SiH 4, GeH 4, and Boron gases. The membrane was suspended on a micromachined crystalline silicon frame obtained by wet chemical etching. The a-SiGe:B film presented a resistivity of 2.46 × 10 3 (Ω-cm), resistance of 20.8 kΩ. Using these experimental data we succeeded in designing a simple structure for sensing low pressure variations. The output voltage of the sensor was measured for a range of pressure from 0 to 3000 Pa and at bias voltage of 10 V. © 2012 Elsevier B.V. All rights reserved.

Maynez L.O.,UACJ | De Jesus Ochoa Dominguez H.,UACJ | Vergara Villegas O.O.,UACJ
IEEE Nuclear Science Symposium Conference Record | Year: 2013

The measurements obtained from the acquiring PET system tend to be very noisy, since randoms and scatter contamination events as well as detector efficiency are strong sources of noise. In particular, for the small animal reconstructed images, this problem becomes severe corrupting areas of interest between organs, making the identification process even more difficult. For that reason, a regularization step is of crucial importance. In this paper, performance evaluations for two different strategies to include wavelet-based regularization within the list-mode Maximum Likelihood Expectation-Maximization (MLEM) reconstruction process are established. Results are compared against the standard noise reduction PSF methods (Gaussian smoothing) used for resolution recovery. For each reconstruction model proposed, investigations on the effects of image quality were addressed. Results show that reconstruction process given by the Model 2, significantly improves the quantity accuracy of the images, especially incrementing the image contrast values in comparison with the standard noise reduction method, which tends to blur the image data. Reconstruction models were tested using list-mode measured data from the high-resolution quad-HIDAC small animal PET scanner. © 2013 IEEE.

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