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Manizales, Colombia

Cardona-Morales O.,Catholic University of Manizales | Castellanos-Dominguez G.,National University of Colombia
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2016

Condition monitoring of mechanical systems is an important topic for the industry because it helps to improve the machine maintenance and reduce the total operational cost associated. In that sense, the vibration analysis is an useful tool for failure prevention in rotating machines, and its main challenge is estimating on-line the dynamic behavior due to non-stationary operating conditions. Nevertheless, approaches for estimating time-varying parameters require the shaft speed reference signal, which is not always provided, or are oriented to off-line processing, being not useful on industrial applications. In this paper, a novel Order Tracking (OT) is employed to estimating both the instantaneous frequency (IF) and the spectral component amplitudes, which does not require the shaft speed reference signal and may be computed on-line. In particular, a nonlinear filter (Square-Root Cubature Kalman Filter) is used to estimate the spectral components from the vibration signal that provide the necessary information to detect damage on a machine under time-varying regimes. An optimization problem is proposed, which is based on the frequency constraints to improve the algorithm convergency. To validate the proposed constrained OT scheme, both synthetic and real-world application are considered. The results show that the proposed approach is robust and it successfully estimates the order components and the instantaneous frequency under different operating conditions, capturing the dynamic behavior of the machine. © Springer International Publishing Switzerland 2016. Source

Mulcue-Nieto L.F.,Catholic University of Manizales | Mulcue-Nieto L.F.,International University of Andalusia | Mulcue-Nieto L.F.,University of Malaga | Mora-Lopez L.,International University of Andalusia | Mora-Lopez L.,University of Malaga
Applied Energy | Year: 2015

Photovoltaic applications are implemented on a large scale in buildings, with a view to reducing global warming sustainably, as well as to meet energy demand. Thousands of electricity generators have been installed in this process around the world. However, very few countries have technical regulations that enable the energy efficiency and yield to be optimised in building-integrated photovoltaics (BIPV). On the other hand, all these normative should be a result of a serious study of the solar resource available in each region.This paper proposes a methodology to establish technical standards in order to limit the losses due to shading and orientation of the constructed surface areas, where any country could be taken as benchmark. Colombia is also taken as a case study, by performing a comparative analysis for different cities. © 2014 Elsevier Ltd. Source

John Makario Londono B.,Catholic University of Manizales
Earth Sciences Research Journal | Year: 2010

An analysis of the seismic activity for volcano-tectonic earthquake (VT) swarms zones at Nevado del Ruiz Volcano (NRV) was carried out for the interval 1985- 2002, which is the most seismic active period at NRV until now (2010). The swarm-like seismicity of NRV was frequently concentrated in very well defined clusters around the volcano. The seismic swarm zone located at the active crater was the most active during the entire time. The seismic swarm zone located to the west of the volcano suggested some relationship with the volcanic crises. It was active before and after the two eruptions occurred in November 1985 and September 1989. It is believed that this seismic activity may be used as a monitoring tool of volcanic activity. For each seismic swarm zone the Vp/Vs ratio was also calculated by grouping of earthquakes and stations. It was found that each seismic swarm zone had a distinct Vp/Vs ratio with respect to the others, except for the crater and west swarm zones, which had the same value. The average Vp/Vs ratios for the seismic swarm zones located at the active crater and to the west of the volcano are about 6-7% lower than that for the north swarm zone, and about 3% lower than that for the south swarm zone. We suggest that the reduction of the Vp/Vs ratio is due to degassing phenomena inside the central and western earthquake swarm zones, or due to the presence of microcracks inside the volcano. This supposition is in agreement with other studies of geophysics, geochemistry and drilling surveys carried out at NRV. Source

Mulcue-Nieto L.F.,Catholic University of Manizales | Mulcue-Nieto L.F.,International University of Andalusia | Mora-Lopez L.,International University of Andalusia | Mora-Lopez L.,University of Malaga
Solar Energy | Year: 2014

The use of photovoltaic solar energy is a growing reality worldwide and its main objective is to meet electricity demand in a sustainable manner. The so-called Grid-Connected Photovoltaic Power Systems (GCPS) prevail in urban zones, together with Building-integrated Photovoltaics (BIPV); whose performance and energy efficiency depends on different factors. The main aspects include those related to the solar radiation available in the geographical location of the facility, the climate, the orientation and tilt of the used surfaces, the appropriate design of the system and the quality of the components. Therefore, several methods have been proposed to try to predict the influence of the aforementioned variables on the amount of electricity produced. However, the majority are very tedious to implement or do not take the specific characteristics of the system into account.This paper proposes a simple and reliable expression, which can be used in low latitude countries. The case study is likewise performed for Colombia, with a comparative analysis for different cities of the angular losses and due to dirt, the losses due to temperature, the DC-AC conversion losses and the Performance Ratio of the system (PR). © 2014 Elsevier Ltd. Source

Rincon A.,Catholic University of Manizales | Piarpuzan D.,National University of Colombia | Angulo F.,National University of Colombia
Mathematics and Computers in Simulation | Year: 2015

In this work, an adaptive controller for bioreactors, using the measurement of output gas flow rate to handle the uncertainty on biomass concentration and kinetic rate is developed. A mass-balance model based on a unique reaction pathway to represent the input-output behavior is considered. Time-varying and unknown but bounded behavior of plant parameters, including the substrate concentration at the inflow and the yield coefficients is taken into account in the controller. The Lyapunov-like function method to develop the controller is used. A new method to handle the unknown time-varying behavior of the control gain is developed; with this method it is assured that the output tracks the desired reference with a user-defined tolerance and parameter drifting is avoided. The main contributions of the scheme with respect to closely related works are: (i) the exact values of the plant parameters are not required to be known; (ii) upper or lower bound related to the plant parameters is not required to be known; (iii) the time-varying behavior of plant parameters in the control design and in the convergence analysis is considered. © 2015 International Association for Mathematics and Computers in Simulation (IMACS). Published by Elsevier B.V. All rights reserved. Source

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