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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.

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.

PubMed | Catholic University of Manizales, Ohio State University and University of Toledo
Type: Journal Article | Journal: The Plant cell | Year: 2016

Core promoters are crucial for gene regulation, providing blueprints for the assembly of transcriptional machinery at transcription start sites (TSSs). Empirically, TSSs define the coordinates of core promoters and other regulatory sequences. Thus, experimental TSS identification provides an essential step in the characterization of promoters and their features. Here, we describe the application of CAGE (cap analysis of gene expression) to identify genome-wide TSSs used in root and shoot tissues of two maize (Zea mays) inbred lines (B73 and Mo17). Our studies indicate that most TSS clusters are sharp in maize, similar to mice, but distinct from Arabidopsis thaliana, Drosophila melanogaster, or zebra fish, in which a majority of genes have broad-shaped TSS clusters. We established that 38% of maize promoters are characterized by a broader TATA-motif consensus, and this motif is significantly enriched in genes with sharp TSSs. A noteworthy plasticity in TSS usage between tissues and inbreds was uncovered, with 1500 genes showing significantly different dominant TSSs, sometimes affecting protein sequence by providing alternate translation initiation codons. We experimentally characterized instances in which this differential TSS utilization results in protein isoforms with additional domains or targeted to distinct subcellular compartments. These results provide important insights into TSS selection and gene expression in an agronomically important crop.

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.

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.

Corpas-Iguaran E.J.,Catholic University of Manizales
Revista Ciencias de la Salud | Year: 2010

The research nurseries serve as a initiative designed for the purpose of contribute to the breakdown of seizure paradigms of knowledge, supported by a theoretical model of discernment that exceed the traditional method of learning in the classroom, to transcend critical insights into transforming the environment under an autonomous space to provide tools essentially scientific, but with ethical criterion and social commitment. Such a conception, however, could be perceived as talkative, and even metaphorical, at the contrast of reality purely versatile in which the neophyte not only tries to get enough of the fruit of knowledge, but also requires that appropriate strategies are put forward to achieve seizure. Then arises, from the formative entelechy the use of technological tools based on virtual learning environments, in order to enhance motivation as an alternative against the blurring of perspectives and the emerging business in some types of nurseries, stranded attitude, that sometimes not far from the master model.

The purpose of this paper is to assess the socio-environmental benefits generated by the implementation of cleaner production strategies in the agriculture and livestock sectors, in the middle part of the Chinchi-na river basin, Colombia. The methodology involves recording of field data on the basis of interviews and semi-structured dialogue; processing and analysis of data on the basis of matrix adaptation and network diagramming; and assessment of socio-environmental benefits, with determination of socio-environmental significance, based on adaptation of the Leopold methodology, using the parameters of magnitude and importance. The main results are: i) the cleaner production strategies implemented in the farms located in the study zone were identified and categorized into conservation, reduction or elimination strategies; ii ) the corresponding socio- environmental benefits were evaluated by determining primary, secondary and tertiary benefits related to both the benefits provided by ecosystems and the social benefits generated.

Within the activities for quality control in the laboratory, the final results of a particular analyte are now recognized as intermediates, due to the relevance given to quality assurance, as the ultimate goal of programs for quality management. This concept makes it necessary to establishment of integral tools, to detect events such as cross-contamination, and measures to avoid affecting the analysis method. Objective: to established a system for monitoring and control of crosscontamination in the laboratory of microbiological analysis of food. Materials and methods: Flowcharts were developed to control the proceedings on the populations of aerobe mesophilics and molds originated from pollution in the environment, surfaces, sterile material and culture media, which included a decision tree designed to perform control actions based on tolerance intervals, which were established as objective tool to decision-making leading to normalize counts of microbial populations in question. Results: Warning limits stricter were obtained for aerobic mesophilic and mold populations in the different controls, except for environment of media preparation and the corresponding for sterile material. Conclusion: The process developed allowed to complement the system of internal quality control in the laboratory, to provide of an objective tool for closing nonconformities because of cross-contamination.

Rincon A.,Catholic University of Manizales | Erazo C.,National University of Colombia | Angulo F.,National University of Colombia
Journal of Process Control | Year: 2012

In this work an adaptive controller for an anaerobic digester is developed taking into account the input constraints. The following assumptions are considered: (i) the biomass and chemical oxygen demand concentrations are unknown, (ii) the model parameters are unknown and vary but they are bounded, and (iii) the upper or lower bounds of model parameters are unknown. The Lyapunov-like function method is used to derive the controller. A state observer is employed to handle the saturation of the control input, and updated parameters are used to handle the unknown bounds of the plant parameters. Some features of the control design are: (i) discontinuous signals are avoided, (ii) the boundedness of the updated parameters is ensured despite input saturation, in order to avoid parameter drifting, and (iii) the convergence of the observer error to a residual set of user-defined size is ensured despite input saturation. © 2012 Elsevier Ltd. All rights reserved.

Rincon A.,Catholic University of Manizales | Angulo F.,National University of Colombia
Journal of Process Control | Year: 2012

In this work a two-valued state feedback control is developed for a plant of second order with known constant coefficients and no disturbance, and for a plant with unknown varying coefficients and additive disturbance with known upper and lower bounds. A reference model is used in order to avoid large commutation rate of the control input. In the first part of the present work, the controller is developed by means of the Lyapunov-like function method achieving the convergence of the tracking error to a residual set whose size is user-defined. In the second part, the Lyapunov function at zero time is inside a predefined set and the developed controller forces the Lyapunov function to dwell inside such set. The size of this set is chosen such that the tracking error asymptotically converges to a residual set of user-defined size. © 2012 Elsevier Ltd. All rights reserved.

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