Tecnura

29-42

Authors: María Angélica Acosta Pérez, Sir Alexci Suárez Castrillón , Albert Miyer Suárez Castrillón

Objectives: The present study focused on the development of a optic fiber sensor for carbon dioxide (CO2), the measuring of variations of the refractive index of a CO2 medium undergoing controlled changes of temperature and pressure, and comparing this experimental refractive index with a calculated theoretical refractive index. Materials and methods: For the making of the optical sensor, we used samples of 48 to 56 micrometers inner diameter micro-structured optic fiber with a solid silica covered hollow center; and we selected dimethilformamide as the light conductor fluid. The fiber was filled with pressure; the connectrorization of the fiber was made with the fussion, the high-temperature afhesive, and the mechanical processes. We use a refractometer for measuring the refractive index during the temperature and pressure change processes in the CO2 chamber. Results: Profiles of the refractive index vs. temperature in cooling and heating cycles were obtained, as well as the punctual measures of the refractive index in five fixed thermodynamic points tested; the calculation for the theoretical refractive index for these points was obtained, and was compared with the experimental ones. The percentage of error of the experimental refractive index was estimated between 0.016% and 0.03%. Conclusions: We achieved the measuring of transmission of white light through a fluid in different phases, and we registered significant changes in the refractive index in each phase change using the fabricated optic sensor.

55-68

Authors: Juan Gabriel Rueda Bayona, Cindy Judith Elles Pérez, Edgar Humberto Sánchez Cotte, Ángel León González Ariza, Germán Daniel Rivillas Ospina

Context: Is achieved a research through Principal Component Analysis (PCA) for determining the variability and climate patterns of two important cities in the Colombia Caribbean. Method: This research used satellite data with three hourly resolution contained in a 35 year data set (1980 to 2014), and a spatial scaling was performed using information related to Cartagena and Barranquilla cities, located in the north of Colombia. Results: The correlation results, above 80 %, show an appropriate adjustment for the information analysis of wind speed and temperature. Time lag matrixes were built for the time series with the aim of applying the Principal Component Analysis (PCA), known as Singular Spectrum Analysis. The main components were identified, which represent more than 70% of the temperature and the wind data in both cities. A Fourier analysis for the wind speed and the temperature allowed identifying similar oscillation modes (main components) detected by the PCA. Conclusions: Sea and land breezes explain the identified diurnal temperature and wind speed variability in Cartagena. Additionally were observe a quarterly variability associated with fluctuations Maden Julian, semiannual, annual, and 6-year variability associated with ENSO. Finally, the cluster analysis allowed the identification of two-climate pattern in the study area.

85-95

Authors: Carlos Adrián Correa Flórez, Geovanny Alberto Marulanda García, Andrés Felipe Panesso Hernández

Context: This article presents an evaluation method for penetration of solar photovoltaic energy in distribution systems. This evaluation considers cost minimization of energy losses during the lifetime of the solar photovoltaic panels and includes calculation of total costs of energy, and investment, operation and maintenance of the panels. Method: The parameters used in this study are based on recent studies in Colombia with the purpose of proposing more realistic alternatives. The optimization problem is solved using a specialized genetic algorithm and the method is tested on the IEEE 37- bus test-system modified, to include behavior of residential and industrial loads. Results: Power losses in feeders are graphically presented as a relationship with the number of buses with photovoltaic panels. The farther buses from the power supply are more attractive for the location of photovoltaic panels in terms of investment and total cost of energy. Conclusions: Results of the evaluation presents a reduction of power losses in lines. In addition, it shows the advantages of local reactive power support. According to the scenario, it shows that it is possible to generate with photovoltaic panels obtaining an investment return from the perspective of the network operator and investor.

106-118

Authors: Yee Wan Yung Vargas, Jorge Eliécer Cordoba Maquilón, Hugo Alexánder Rondón Quintana

Context: Porous asphalt mixtures are defined as an asphalt concrete with air voids content of around 20% and 25%, and the typical binder is a modified asphalt with some elastomeric polymer. Unlike other studies reported on the subject: i) The effect of mixing temperature between asphalt modified with GCR and stone materials (160 °C and 170 °C) was evaluated, ii) as the variation of compaction temperatures for each of (110 ºC, 130 ºC, 150 ºC) and (150 ºC, 160 ºC, 170 ºC), respectively. Method: This study measured in laboratory, the resistance to abrasion (Cantabria trial) and the stiffness under monotonic (Marshall test) and cyclical (resilient modulus) loading of a porous asphalt mixture MD. Asphalt cement CA 60-70 (PG 64-22) was used as binder. This binder was modified with recycling tyre rubber (GCR) by wet way (The GCR and binder are completely mixed to form asphalt rubber). Results: a significant increase in resistance to abrasion, resistance under monotonic loading and stiffness under cyclic loading of the MD is reported when this mixture is modified with GCR. Conclusion: The results showed that there is a highlighted influence of mix temperature (between asphalt and GCR) and compaction temperature (modified asphalt and aggregate) on the behavior of the MD modified with GCR

141-153

Authors: Adolfo León Agatón, Juan Carlos Córdoba Ruiz, Uriel Fernando Carreño Sayago

Context: Water is currently considered the most critical natural resource on the planet. Numerous worldwide studies have shown that rainwater harvesting systems have been needed to meet different basic needs. One of the most important steps in planning a rainwater harvesting system is to use a method to determine The optimal capacity of collection and storage tanks Method: In this paper we present different concepts of authors of articles at a global level that refer to the use of rainwater, its capture and use avoiding that this resource is wasted and that it reaches the sewers and raking with the garbage found What happens is that they contaminate and cover these teachers causing flooding. Results: Research has shown that rainwater harvesting systems promote water saving in a variety of settings, such as stadiums, universities, schools, airports and residential areas. Conclusions: it is determined that rainwater has not been taken into account as a saving factor, nor the use of this resource with respect to an environmental impact. As for the concept of catchment and use of rainwater, it is taken into account as any kind of technical effort, simple or complex, arising from the initiative of some people to store it and be used later for farmers, toilet flushing, urinals and irrigation of gardens, washing of floors, among other. If you go into a cost benefit study to collect it and take advantage of it to be replaced by drinking water, it would show very good results

29-44

Authors: Freddy Forero Longas, Adriana Patricia Pulido Díaz, Sergio Andrés Cabrera Navarro

Context: Within the processing technologies with membranes, osmotic evaporation is a promising alternative for the transformation of exotic fruits, generating concentrated products that can be used in the daily diet, being easier to consume, reducing transportation costs and increasing shelf life. Method: In this research, it was studied and developed a comprehensive strategy for multiphysics modeling and simulation of mass and momentum transfer phenomena in the process of osmotic evaporation through Comsol® and Matlab® software. It was used an axial geometry approach in two dimensions as simplifications of real module and the finite element method for the numerical solution. The simulations were validated experimentally in an osmotic evaporation system of laboratory scale. Results: The models used and the generated simulations were statistically significant (p <0,05) in predicting the flux behavior, taking into account the effect of flow and temperature feed together with the brine flow, being obtained correlations above 96% between experimental and calculated data. Conclusions: It was found that for the conditions studied the Knudsen diffusion model is most suitable to describe the transfer of water vapor through the hydrophobic membrane. Simulations developed adequately describe the process of osmotic evaporation, becoming a tool for faster economic development of this technology

59-74

Authors: Luis Gabriel Carmona Aparicio, Mauricio Alexander Rincón Pérez, Andrés Mauricio Castillo Robles, Boris René Galvis Remolina, Hugo Enrique Sáenz Pulido, Rodrigo Alberto Manrique Forero, Jorge Eduardo Pachón Quinche

ABSTRACT Aim: This study presents the reconciliation of inventories of mobile emission in Bogota in 2013, applying top-down and bottom-up methodologies. Method: A comparison of emissions from different vehicle categories was conducted, as well as the geographical and temporal distribution of them, by creating a processing code in JAVA. The process employed the largest amount of information available from the authorities of the Capital District, and previous studies. The innovation of this research is the estimation of the traffic flows in secondary roads, based on an algorithm that considers road geometry, interaction between arterial and secondary roads, and legal restrictions on traffic. Results: The results show the estimated emissions for pollutants CO, CO2 , VOCs, NOx , SO2 and PM, and its comparison with other studies for the city. The values obtained can be classified as minimum and maximum references of the emissions generated in 2013, due to data uncertainty. Conclusions: The project provides an upmost useful tool as input for the authorities in order to identify areas with significant emissions and to develop strategies for emissions reduction, towards improving the air quality of citizens. This method can be replicated in the generation of protocols for estimating emissions from mobile sources, but results need to be carefully reviewed given the quality of information sources.

86-99

Authors: Ariolfo Camacho Velasco, César Augusto Vargas García, Henry Arguello Fuentes

Background: (HSI) Hyperspectral Images contain high spectral resolution information, in hundreds of contiguous bands over a specific range of the electromagnetic spectrum. In science and industry, hyperspectral information is exploited by means of classification, anomaly and target detections algorithms. Specifically, in the last two decades a wide variety of hyperspectral target detection algorithms have been proposed. However, an optimal target detection algorithm with a remarkable performance over different kinds of targets and scenarios is still an active matter of research, due to the high spectral variability and diversity of real-world scenarios. Aim: This work presents a comparative study of target detection algorithms in hyperspectral imagery applied to agricultural crops in Colombia for evaluate performance in different scenarios. Method: The evaluations were performed on 20 real HSI acquired by the satellite Hyperion sensor, and 6 synthetic HSI with different noise levels. 5 synthetic targets were implemented; more than 115 spectral real signatures were extracted, 11 of those signatures were used as target in the testing process, allowing to characterize 5 agricultural crops of Colombian northeastern in 5 different areas. Results: The results show that the Adaptive Coherence Estimator (ACE) algorithm has a better performance in terms of detection probabilities PD > 90% for different scenarios and targets of agricultural type, in both synthetic and real images. Conclusions: In applications for target detection in HSI, it is critical to find an algorithm to have optimal performance for different scenarios and targets, due to the spectral variability generated by the geographical conditions countrywide. On the other hand, this work shows that is possible the development of new research fields and applications at the national level, taking advantage of hyperspectral imaging techniques for spectral detection, specifically for Colombian agriculture.

120-132

Authors: Elmer Alejandro Parada Prieto, Mario Joaquín Illera Bustos, Sergio Basilio Sepúlveda Mora, Dinael Guevara Ibarra, Byron Medina Delgado

Context/Objective: In Colombia, consumption of residential electricity accounts for about 40% of the national demand; therefore, alternatives to reduce this consumption are needed. The goal of this study was to develop a home automation prototype to control the illumination of a household and to foster the efficient use of energy. Method: The system consists of independent control modules and an information manager module; the control module regulates the luminaires using a microcontroller and a presence sensor, and exchanges data by means of a radio frequency transceiver; the manager module allows the access to the control modules from a Web interface. The prototype was implemented in a household located in the city of San José de Cúcuta, Colombia, during a 60 days period. Results: The operation of the system diminished the total electricity consumption by 3,75 %, with a z-score of -1,93 that was obtained from the statistical analysis. Conclusions: We concluded that the prototype is inexpensive in comparison to similar technologies available in the national and international markets, and it reduces the waste of electrical energy due to the consumption habits of the residents in the case study.

152-166

Authors: Gustavo Andrés Romero Duque, Jairo Acero Calderón, Marcela Jaimes Becerra

The noise in the workplace, in all kinds of productive activities, represents a menace and it true has not been truly assessed in its real dimension. Little has been seen from the people concerned in this matter to give the urgency to manage noise control programs. Therefore, disposals resulting from medical treatments and absenteeism, represented in health care and social services, result in labor-related hidden costs that directly affect the gross domestic product in any country. Method: This article compiles different studies worldwide. The studies were divided for revision into general studies about the effects of labor noise and then, particularized according to the effects of industrial noise on workers’ health. At a control level, the evaluation and measurement of noise is defined by using tools such as noise maps and their respective derivations in addition to spatial databases. Conclusions: The data provided by the case studies points to the need in Colombia, a country that is no stranger to this phenomenon, and additionally has the great disadvantage of not having significant studies in the field of noise analysis. It strengthens studies based on spatial data and measurement and control mechanism.

29-40

Authors: Juan Miguel Astorga Gómez, Rodrigo Alfonso Aróstica Córdova, Yuri Antonio Iriarte Salinas

Background: Due to massive incorporation of electronic equipment to distribution systems, distribution transformers are subject to operation conditions other than the design ones, because of the circulation of harmonic currents. It is necessary to quantify the effect produced by these harmonic currents to determine the capacity of the transformer to withstand these new operating conditions. The K-factor is an indicator that estimates the ability of a transformer to withstand the thermal effects caused by harmonic currents. This article presents a linear regression model to estimate the value of the K-factor, from total current harmonic content obtained with low-cost equipment. Method: Two distribution transformers that feed different loads are studied variables, current total harmonic distortion factor K are recorded, and the regression model that best fits the data field is determined. To select the regression model the coefficient of determination R2 and the Akaike Information Criterion (AIC) are used. With the selected model, the K-factor is estimated to actual operating conditions. Results: Once determined the model it was found that for both agricultural cargo and industrial mining, present harmonic content (THDi) exceeds the values that these transformers can drive (average of 12.54% and minimum 8,90% in the case of agriculture and average value of 18.53% and a minimum of 6.80%, for industrial mining case). Conclusions: When estimating the K factor using polynomial models it was determined that studied transformers can not withstand the current total harmonic distortion of their current loads. The appropriate K factor for studied transformer should be 4; this allows transformers support the current total harmonic distortion of their respective loads

53-67

Authors: Edward Julián Ramos Ballesteros, Gloria Margarita Varón Durán, Luis Carlos Méndez Córdoba

Context/Objectives: The objective is to design and implement a network of emulators in order to develop make a practical workshop in the future with students in the area of health, testing their knowledge and learn from the experienced before exercising their professional life. Method: The network is composed of a Central Control Module (CM), which allows teachers to create clinical scenarios, and three Emulators for students. Once created the scenarios, they are transmitted to a emulator that was chosen through a graphical interface, allowing the student to observe the values and signals of vital signs in both the physical part (ME: Dummy Emulator) and the graphic part (IE: Interface Emulator), and take action depending on the knowledge acquired in their studies. Then a response process is generated showing the results of actions to the teachers. Finally, the teacher makes a comparison of the clinical scenarios with the response, to evaluate the students and thus he also stimulates learning in them. Results: Implementation features after performing a series of tests are as follows: the maximum distances of the components with respect to MC, without losing optimum performance of network, is 8 meters for IE and 12 meters for the ME. In addition with techniques implemented, it is reduced by 13.28% runtime when programming the clinical scenario, and it is reduced by 21.78% runtime of response process, settling in 8.42 and 4.99 seconds respectively. Conclusions: Given the maximum distance and runtimes, the network of emulators is built with features necessary to implement a practical workshop in the future taking into account the technical specifications, traffic conditions, size of the classrooms, users in parallel and the frequency of used

89-99

Authors: Lina María Romero Millán, María Alejandra Cruz Domínguez, Fabio Emiro Sierra Vargas

Context: Taking into account that near 220 000 tons of oil palm shells are produced every year in Colombia, as a waste of the Elaeis Guineensis palm oil transformation process, the aim of this work is to determine the energy potential of oil palm shells, when transformed through slow pyrolysis process. Methods: Using a fixed bed lab scale reactor, different oil palm shells pyrolysis tests were performed between 300°C and 500°C. The effect of the temperature in the process product yield and in the energy content of produced solids and gases were analyzed. Results: With a maximum mass yield of 50%, the char is considered the main product of oil palm shells pyrolysis, containing up to 73% of the raw biomass energy. The heating value of char raised with the temperature, from 29,6 MJ/kg at 300°C to 31,34 MJ/kg at 500°C. Moreover, the gas produced in the established temperature range had up to 13% of the energy content of the raw biomass, with a heating value near 12,5 MJ/m3 . Conclusions: According to the results, slow pyrolysis can be considered an interesting process for the valorization of residual biomass as oil palm shells, through the production of solids and gases that can be used as fuels, or as precursor of other value-added products

115-121

Authors: Sergio Giovanny Valbuena Porras, Milton Mena Serna

Context: In a masonry wall the mortar it is between 10 and 20% of the total volume of the system, despite its effect on the behavior of it is significantly higher than this percentage indicates. Objective: The purpose of this research was to evaluate the resistance to compression of two types of mortar paste (A and B), prepared with natural sand from the town of Usme in Bogotá, in accordance with the proportions set by the Standard Colombian earthquake Resistant regulation (NSR-10). Method: Two types of mortar paste were prepared, according to the proportions of cement and sand established in NSR-10 section D.3.4-1 of (Table 1); these proportions were calculated using a 0.0028 m3 container for measuring unit weight. For type A mortar rock sand was used and river sand for type B mortar. Results: The resistance to compression for mortars type A at the end of the study was on average 84% of the expected resistance, whereas for type B mortars it averaged 64% above the expected resistance. Conclusion: Mortar mixes made with crushed or rock (type A) arena do not reach the compressive strength required demanded by regulatory standards, despite complying with the dosage established in NSR 10 and with NTC quality criteria; while the natural sand origin or natural river sand meet these standards

123-136

Authors: Germán Hernández Millán, Luís Hernando Ríos Gonzales, Maximiliano Bueno López

Context: Mobile robotics remains being an area of constant updating, which seeks to have applications to improve the life quality of human beings. Therefore, the paper presented a novel design of a position and move controller to a differential mobile robot using artificial neural networks, which aims is to bring a real applications in different fields. Method: The proposal is based on a PID controller, which has been tuned using a neural network and requires knowledge of the kinematic model of the robot Results: The simulations show the efficiency of the control position for following paths, in this case for tracking straight and curved paths. The graphical interface allows adjusting the gains easily and verifies the trajectory tracking online. Conclusions: From the results we can conclude that the proposed strategy is easy to implement since the required information is generally deliver by mobile robot sensors. Finally, tuning PID controller with the neural network allows obtaining a correct performance for trajectory tracking.

171-183

Authors: Luz Adriana Trejos Grisales, Carlos Andrés Ramos-Paja, Andrés Julián Saavedra-Montes

Context: The energy produced by photovoltaic (PV) systems operating under partial shading conditions depends on the connections between the modules and the shading pattern. Several mathematical models have been proposed to address this topic exhibiting different compromises between accuracy, calculation speed and PV model complexity. However, it is not evident how to choose a model for a given application to ensure reliable results. Method: Several mathematical models of PV systems under shading conditions were analyzed to synthetize the characteristics, advantages and drawbacks of each one of them. Three main categories have been identified: analytical, simulation and experimental methods. Analytical and simulation methods require a basic PV model and mathematical analysis supported by computational tools; while experimental methods are based in data or measurements. Results: From the analysis of the published solutions, three representative modeling techniques with different characteristics were selected to perform a practical comparison. Those techniques were implemented and contrasted in realistic scenarios to identify the effects of the compromise between accuracy, calculation speed and PV model complexity. Conclusions: To select a mathematical model it must be taken into account the connection scheme, model of the PV unit, model of the bypass and blocking diodes, size of the system, programming complexity and simulation time. This paper provides some guidelines to choose the right model for a particular application depending on those characteristics.

29-38

Authors: Edwar Jacinto Gómez, Mauricio Giral, Fredy Hernán Martínez Sarmiento

We present a model for the study, analysis, design and evaluation of collective multi-agent navigation for autonomous robots based on behaviors observed in bacteria. The system consists of a set of simple agents (artificial bacteria), which through readings and local interaction are self-organized to navigate along the environment. Given the parallel structure, also happens to be a very robust solution. We show the basic structure proposal for the design abstracting the characteristics of the biological model, together with an analysis of stability and convergence

49-56

Authors: Juan David Ramírez Ramírez, Alejandro Garcés Ruiz, Jose Santiago Arrieta Giraldo

This paper proposes a novel algorithm based on particle swarm optimization (PSO) for optimal placement of the turbines in a wind farm. Wake effect is considered for different directions and magnitudes of wind speeds according to a given compass rose. Likewise, energy optimization for a proposed case is shown which takes into account constraints related to distances between the turbines, the wind farm area and the wake effect. Simulation results demonstrate the efficiency of the proposed algorithm

71-84

Authors: Rodrigo García Alvarado, Rodrigo Herrera Ojeda, Cristián Muñoz Viveros, Gerth Wandersleben

The housing studies and design regards homes like one indoor environment, without recognizing differences between rooms, although in the daily living it perceives variations. This article presents a comparison between data from computer simulations of thermal performance and physical monitoring that records existing values of rooms, with perceptions of its inhabitants around their residential environment, from six houses located in Concepción, Chile. In order to characterize environmental differences that arise in homes, as well as those originated in different rooms, which represents comfort building. Simulations express some significant differences by venues (anual energy demands from 12 kWh/m2 to 330 kWh/m2), while physical measurements reveal more limited values (differences between environmental temperatures less than 5°C). Interviews and observation of residents suggest nearby considerations, but also provide other aspects (like higher value of upper story and rooms with high luminance). The outcomes and conclusions of the study provide data that can be of comparative interest for housing planning and design, but also an analysis that integrates the diverse studied dimensions, which is incident to environmental policies and actions improving housing, targeted to increase the residential quality

97-106

Authors: José David Alvarado Moreno

This paper presents the use of spatial analysis techniques texture images for defects identification in textiles, where the application of pre-processing techniques is presented, and the analysis of texture local binary patterns and co-occurrence matrix to extract features to highlight differences and identify defects in textiles using classifier based on the Mahalanobis distance.

119-135

Authors: Óscar Javier Espitia Mendoza, Yuri Hercilia Mejía Melgarejo, Henry Arguello

Computed tomography is a noninvasive scan technique widely applied in areas such as medicine, industry, and geology. This technique allows the three-dimensional reconstruction of the internal structure of an object which is lighted with an X-rays source. The reconstruction is formed with two-dimensional cross-sectional images of the object. Each cross-sectional is obtained from measurements of physical phenomena, such as attenuation, dispersion, and diffraction of X-rays, as result of their interaction with the object. In general, measurements acquisition is performed with methods based on any of these phenomena and according to various architectures classified in generations. Furthermore, in response to the need to simulate acquisition systems for CT, software dedicated to this task has been developed. The objective of this research is to determine the current state of CT techniques, for this, a review of methods, different architectures used for the acquisition and some of its applications is presented. Additionally, results of simulations are presented. The main contributions of this work are the detailed description of acquisition methods and the presentation of the possible trends of the technique.