Revista Visión Electrónica: algo más que un estado sólido

5-13

Authors: Juan Carlos Martínez Quintero, José de Jesús Rugeles Uribe, Edith Paola Estupiñan Cuesta

This paper evidence a channels use analysis and the spectral occupancy measurement for the downlink in Bogota, Colombia, over GSM-850 band. Two test scenarios are defined. First, we select a path of 2.96 Km over North Zone Bogotá to realize the channels search and spectrum detection. The results show parameters like: BSIC, NCC, LAI, MNC, LAC, CI, BCCH channel, uplink frequency, power level received for a mobile telephony operator. Rohde & Schwarz Qualipoc was used to perform the measurements. The Qualipoc equipment found a coverage of 17 cells on the path with a reconnection state in two cells previously identified. After the analysis, we concluded that the GMSK modulation is the most used, reporting stable power level for mobile stations as specified in 3GPP GSM05.05 statement. Finally, the spectrogram measurement indicated the coexistence of different mobile technologies, and the GSM use in several frequency channels and temporal spaces, with 95.2% spectrum occupancy.

22-31

Authors: Sebastián Gael Moctezuma Gutiérrez, Arturo Cruz Pazarán, Rubén Galicia Mejía, Luz Noé Oliva Moreno

Collaborative robots have such a big interest in control, manipulation and programmed tasks areas; part of the functionality can be found in the communication platform between them. In this research article presents the development of a platform of collaborative robots using programmable logic devices such as a Complex Programmable Logic Device (CPLD), ultrasonic sensors, and infrared sensors with the objective of executing various tasks. Depending on how the robots are programmed, those platforms can give support to many companies facing difficulties, such as the high prices of the conventional platforms. Also, they can facilitate daily work like moving objects from one place to another.

43-50

Authors: Andrés Felipe Calvo Salcedo, Arley Bejarano Martínez, Andrés Castillo González

The wireless sensor network is an innovative technology that has had great impacts in the field of engineering and in recent years has allowed technological developments focused on precision agriculture. This paper presents the results research lead to design a network of low cost wireless multisensors for the recording and monitoring of the state variables of a crop using Beaglebone Black development cards integrating with sensors of temperature, relative humidity, soil moisture and cameras Digital images. The acquired information is transmitted with wireless local area network (WLAN) communication protocol to a central server allowing to obtain a registry and control in a database, created in MYSQL with Linux base operating system. The results of this work show the reliability and energy consumption of the equipment.

58-64

Authors: Jonathan Roberto Torres Castillo, Juan Salvador Pérez Lomelí, Esperanza Camargo Casallas, Miguel Ángel Padilla Castañeda

This article describes the research that leads to the development of a wireless haptic device capable of generating vibrotractile mechanical stimuli at different points in the human skin and at desired frequencies by means of 16 actuators contained in portable bracelet isolated, designed for any extremity of the human. This prototype allows control over each actuator used as a test point, independently driven by commands transmitted wirelessly to a self-contained rechargeable control system placed on the bracelet. The completion and use of this system allowed to perform usability tests with respect to tactile perception from three experiments in healthy people, who verified the efficiency of the vibrotactile flux in the discrimination of nearby stimuli and the correct functioning of the device. With the development of this device want to perform it a wide variety of validation tests with a large sample of patients with and without neuropathies, in order to create a database to be used as set values against these patients and it is expected that the system is also used in patients with movement deficit, using tactile perception as a psychomotor stimulant in the execution of motor activities.

73-82

Authors: Wilson Enríquez, Paola Nazate, Omar Marcillo

The guideline of the present project is to create a seismic digitizer. In order to be used as a seismic field station, the digitizer should be compact, reliable and flexible to adapt at field seismic station. The objective was achieved using the Spartan-6 LX45 FPGA as the basis for the embedded continuous data acquisition system with a configurable speed up to 50 Ksps. The prototype comes equipped with Ethernet communication, 12 channels with 24-bit ADC resolution expandable up to 24 channels, data storage writable to both USB and SD, a user-friendly interface, LCD information indicator and time synchronization to UTC by external GPS. As a result of the present project, an embedded electronic device was obtained that can be utilized diverse seismic applications such as monitoring, refraction or reflection and for use in sensor arrays appropriate for volcanic applications. The prototype is compatible with visualization and seismic data management software.

89-96

Authors: Cristian Camilo Córdoba Poveda, David Alejandro Barbosa Cortes, Dora Lilia Castañeda Tibaquirá

Is presented the development of a telemetry system for the measurement of depressions and elevations in a vacant lot, implemented in an unmanned aerial vehicle (UAV) in order to obtain information that allows to know the height of the Soil Elevation or depression) with their respective geographical position. The information captured by said system is stored in SD Card memory and once it has been transmitted wirelessly, so that it can be used by the user and thus it is possible to identify the characteristics of the height of the ground relevant for what they are not Disadvantages in the future.

102-109

Authors: Luis David Cardona Calderón, Mario Javier Moreno Rincón, Luis Enrique González Olarte, Jonathan Gallego Londoño

This paper describes a prototype of a circuit with a radio-frequency identifier (RFID) intended to help blind people, to allow this social group to obtain general and specific information about a near object using audio feedback. On this implemented prototype there were used components like a board, speakers, power setup for the speaker, a memory module, radio-frequency identifiers, transponders and an Atmel AtMega328 microcontroller (Arduino). The device successfully works allowing the user to identify several objects. The wearable will device within a glove which will allow coupling the designed device with the clothe. The actual state of this prototype is the base for a final model which is going to have a power supply (lithium battery), a microUSB input for data actualization and battery charge, and a 3.5 mm minijack input for headphones, making it completely portable, personalized and internet-free

115-123

Authors: Carolina Montaño, Nicolás Rodríguez, Luz Helena Camargo

The behavior and characteristics of blood in the circulatory system have generated various models that can be applied to the flow analysis blood, including Newtonian and non- Newtonian models. This review presents eleven models proposed from experimental parameters, which include studies of viscosity with different speeds of shear and density associated with fluid dynamics. Were characterized in accordance with methods, specific parameters, used experimental values. Comparing efficiency, certainty and precision of the models used.

132-135

Authors: Rosendo López González

The development of scientific thought do not stop. In this essay we take as a starting point the classical Greece with the contributions of Aristotle and his difficulties to give the empirical evidence a theoretical construction; thus, Plato’s disciple in the renowned book Metaphysics records the basis of a science of the general. This new model of knowledge is taken in the twelfth century by the Christian West, where it is dogmatized and Thomas Aquinas in the 13th century managed to consummate a symbiosis between Aristotelian thought and Christian faith. In response to this association, renaissance humanism builds another model of scientific knowledge; In this paper, Galileo’s contribution is known as the paduana methodology. It was developed at the University of Pauda where Galileo was a physics teacher between 1592 and 1610.

1

Authors: Harold Vacca González

Nacido en Tokio (Japon) en 1927; graduado de Cientco con especialidad en Fsica Teorica, de la Universidad Imperial de Tokio. Docente de la Universidad Estatal de Ibaraki desde 1951 hasta 1962

2

Authors: Harold Vacca González

Con los libros ocurre lo mismo que con las personas: hay que tomarlos en serio.

4

Authors: Lely A. Luengas, Miguel A. Gutierrez, Esperanza Camargo

This study was designed to evaluate the average force under each foot and variation in location of center of plantar pressure during static standing, in amputees by landmines and non-amputees subjects. Fifteen subjects were evaluated (ten non-amputees, five men and five women, and five amputees, all men, age range 20-40 years), they are functional. Five measurements were performed for each subject, following the protocol established for the measurement. The template system Pedar R was used. The statistical analysis used was ANOVA, to confirm that the data obtained in the measurements are valid. It was confirmed that the location of the COP on each foot is affected by the use of dentures, it is required to confirm whether the alignment of the prosthesis influences COP, is left for further study.

5

Authors: Jhon Edwin Vera, Jhon Fredy Bayona, Ricardo Sanchez Cayanza

When it comes to alternative energy, solar panels are one of the most studied due to its excellent performance under uniform solar radiation. This paper shows the advantages, simulation and implementation algorithm developed in an incremental conductance lowend DSP -digital signal processing- Texas Instrument TMS320F28069 R, in order to find and extract maximum power, performing tests on a resistive load.

5

Authors: Jaime Andr´es Restrepo Giraldo

This paper presents the results of investigation of the likelihood that the Kyoto Protocol provides for the development of projects of the Clean Development Mechanism, CDM forestry, river basin Ot´un, Risaralda department, Colombia. It also analyzes the feasibility of implementation in this area consists of several national parks and protected areas for wildlife, likewise, the investigation establishes what are the potential risk factors (political, economic or technical) in the implementation of CDM projects and proposes guidelines for administration. The study concludes and recommends that these projects may well go ahead and be successful if clear policies by the State, if it has the support of environmental NGOs and if, fundamentally, is achieved by the active participation of local communities in the definition and ongoing assessment.

6

Authors: Javier Eduardo Martınez Baquero

There are various forms of environmental pollution, one of which is caused by oily mixtures which are particularly discharged into water sources from economic activities such as washing vehicles, service stations, and others. This article research shows a way to mitigate these polluting effects through the design and construction of an automated equipment that performs the separation of a mixture of water-oil. The separation of the oil mixture is carried out in a corrugated plate interceptor (CPI), and accompanied by a Programmable Logic Controller (PLC) S7 1200, through which the user is allowed to perform the process efficiently, thanks to high percentage of separation has been achieved with respect to the initial mixture. Then, was divided into three methodological steps , first the CPI separator built, setting turn the variables of interest, second was designed and implemented the Automation and third results were validated by testing. Three variables were defined; level, the most important in the system, also temperature and flow, for each of them has been implemented appropriate instrumentation for data collection subsequently entering the PLC. The main result is that the process is efficient as it manages to recover more than 90% of the water present in the initial oily fluid, this evidenced by the implemented instrumentation , allowing reuse and subsequent saving precious liquid.

6

Authors: Nychol Bazurto Gomez, Carlos Alberto Martınez Morales, Helbert Eduardo Espitia Cuchango

In this paper, we propose an ANFIS model based that verify their effectiveness compared to real data to determine the coffee berry borer proliferation risk in a colombian context, verifying its effectiveness compared to real data collected by the ICA in a study of the Integrated Management of Broca. As an initial step, four input variables are determined and a fuzzy model (made in another job), including factors were used: temperature, altitude, age and quality of the crop harvesting. A set of 144 rules and 20 times of training, the results were satisfactory and close to the actual infestation level, fulfilling the target of generating information regarding this problem by using engineering techniques.

7

Authors: Vıctor Manuel Gomez Ramırez, Juan Carlos Serna Bedoya, Luisa Velez Lopez

The mechanical vibration analysis has great importance in the condition based maintenance; in this sense, the bearings are elements that affect more stops rotating machinery. Therefore, this paper describes the hardware and software architecture of a vibration analyzer developed in LabVIEW R oriented to study bearings extracting its parameters or descriptors through the power spectral density (PSD) and the RMS and DC signal values in time. Shows the advantages of working with such solutions: cost and the possibility of increasing benefits as needed.

9

Authors: Marco Antonio Abarca Rodrıguez, Mariko Nakano Miyatake, Hector Manuel Perez Meana

This article present a system for creating and credential authentication personal identification (ID) safe, using one-dimensional and two-dimensional barcodes, data encryption and symmetric key technique watermark. To do this, a watermark is inserted on the photo of the user, generated from a unique identification code which will be available in printed credential so that at the time of validation of the credential is carried by calculating the cross-correlation between the watermark contained in the photograph of the user and the watermark calculated at the time of validation using the same unique identification code. We show that proper selection of parameters for inserting the watermark: length, gain, position of the watermark and decision threshold, are essential to ensure the proper functioning of the proposed scheme, ensuring maintain sufficient quality in visual image to the user recognition and in turn be robust enough to withstand the attack of converting digital-analog (D / A) and analog-digital (A/D).

10

Authors: Frank Ernesto Alvarez, Julian Bravo Castillero, Raul Guinovart Dıaz, Leslie D. Perez Fern´andez y Reinaldo Rodrıguez Ramos

The asymptotic homogenization method is applied to homogenize a one-dimensional family of elliptic boundary value problems with periodic and rapidly oscillating coefficients which depend on two fast variables. The homogenized problem, the local problems and the corresponding effective coefficient are obtained. A necessary and sufficient condition for constructing an asymptotic solution with periodic terms is demonstrated. Based on a Maximum Principle the proximity between the solutions of the homogenized and original problems is proved. Some numerical computations are used to illustrate the mathematical justification.

10

Authors: Felipe A. Corredor Ch, Juan D. Villamarın V.

Everyday in network management, it is complex the process to correlate events in different dimensions: legal violation, intrusions, monitoring failures, violation to security policies or breach of standards; to which face professionals, teaching and students in this area in Colombia. This article presents the technological aspects for the design and development of a distributed system for the computational anomalies detection that was termed “Asturiux”, which arises as a product from a research project in the teleinformatics area. To addressing this problematic it use the network security administration, and anomalies detection. The system was fully developed with free software, in which were integrated different technologies for the communication, authentication, persistence, computational intelligence and remote alerts. The verification instruments and the realized tests, reflect a high level of system efficiency, and acceptation from the actors involved

12

Authors: Hugo Segura Benavides, Carlos Andres Porras Niño, Henry Montaña Quintero

The purpose of this article is to monitor the vibrational behavior of the gas compressor Worthington, with a global view point system process production plant Turgas S.A. ESP, about a PC in the control room, for reasons of comfort and safety. Thus this technology with safe and timely decisions, real time, taking into account the relative dangers of natural gas. By monitoring the vibration level compressor wanted quality improvement process, production weather facilitates work and reduces costs. Additionally, the research project aims to develop a technique that allows the noun, plural follow vibrational analysis applied to predictive maintenance, for machine stoppages and thus evaluate when are necessary preventive maintenance scheduled so avoiding unwanted accidents operational personnel, disruption the environment, apart from expensive damage in electrical or mechanical components represented in volume production, time and money invested for Company.

1

Authors: Harold Vacca González

http://revistas.udistrital.edu.co/ojs/index.php/visele/article/view/7977/9607

4

Authors: Harold Vacca

http://revistas.udistrital.edu.co/ojs/index.php/visele/article/view/7854/9585

7

Authors: Fabio Hernando Castellanos Moreno, Jaime Francisco Pantoja Benavides

This article presents a method that provides a simple way to find the constant coefficients required in the solution of a differential equation with Cauchy-Euler structure. Although this method is not fundamental in the solution of a differential equation of this type, it does propose an innovative and practical vision of differential equations of higher order with Cauchy structure in order to find the constant coefficients. Firstly, the article offers an introduction to differential equations and their usefulness (e.g. solid mechanics, buckling of columns); then, the structure of a Cauchy-Euler equation is presented followed by the proposed method, including mathematical proof, which guarantees the reliability of the method. Finally, conclusions are drawn regarding the usefulness of the method. http://revistas.udistrital.edu.co/ojs/index.php/visele/article/view/7863/9592

8

Authors: Marcelo Herrera Martínez, Edwar Jacinto Gómez, Edilberto Carlos Vivas G.

The present paper deals with the subjective evaluation of audio coding technologies using the “Similarity Rating” psychometric method. Compressed audio excerpts are presented to a group of experienced listeners by pairs of stimuli. Each pair represents a different type of distortion, with compression included. These types of distortion correspond to three psychoacoustic attributes, sharpness, roughness, and fluctuation strength. Listener’s task is to evaluate the degree of similarity between the pairs. The final output is the localization of each measured codec in this psychoacoustic space. Multidimensional scaling is the statistic technique, belonging to Multivariate Statistical methods, which allows processing the results obtained from this method. http://revistas.udistrital.edu.co/ojs/index.php/visele/article/view/7867/9595

9

Authors: Jeimy Lorena Pérez Ibarra, Hernán Darío Toro Zapata

The immune system is responsible for the body defense against strange organisms. This type of control is performed by molecules and cells in an organized way. The proposed model consists in a system of ordinary deferential equations intended to resemble the interaction between HIV and the immune response when considering cytotoxic cells. Standard local stability analysis at the virus free equilibrium is carried out to determine the theoretical conditions that avoid infection. Simulations were run to obtain results for particular immunological conditions and also to describe the dynamics of the system when facing infection states http://revistas.udistrital.edu.co/ojs/index.php/visele/article/view/7862/9591

9

Authors: Carlos Enrique Montenegro Marín, Juan Manuel Cueva Lovelle, Jordan Pascual Espada

This article is aimed at determining the feasibility of using a common mechanism to define the configuration in games for mobile devices. Such a configuration is intended to increase the level of abstraction up to a point where the definition of a platform game in XML format is made independent. This should then be read and deployed in an automatic way over any mobile platform. http://revistas.udistrital.edu.co/ojs/index.php/visele/article/view/7887/9598

9

Authors: Hector Arturo Flórez Fernández

Nowadays, human disabilities are very common in all places around the world. However, when one person has a disability affecting one of the senses (e.g., sight, hearing), that person usually increases his/her capabilities with other senses. For instance, people with sight-associated disability normally increase their acuteness in senses like hearing and smell. Taking advantage of this human characteristic, in this paper we propose a prototype to offer patients with sight disability the opportunity to identify a set of colors using small amounts of particular essence. http://revistas.udistrital.edu.co/ojs/index.php/visele/article/view/7890/9600

10

Authors: Carlos H. Caicedo E, Ali Smida, Ricardo Romero U.

La rationalité signifie principalement un calcul et une faculté calculable; est l’usage adéquat de la théorie, du pratique et de l´évaluation de la raison, c’est-à-dire: qu´elle doit être utilisée pour adopter des croyances, prendre des décisions et évaluer correctement. D’un autre côté, l’irrationalité apparaît quand on reconnaît et évalue positivement la spécificité de l’affectif, c’est-à-dire: les passions, les émotions, les sentiments et les désirs. Cet article réfléchit sur la rationalité (irrationalité) de l’utilisation des technologies de la santé - médicaments, les dispositifs médicaux et chirurgicaux et des systèmes de soutien organisationnel et où ces soins est donné - et leur cycle de vie correspondant, dans un pays en développement comme la Colombie, quand existe une pression de la part de l’Industrie pour incorporer de manière continuelle et massive les nouveaux dispositifs et les équipements sans évaluer et identifier les critères de prix a caractère effectif des innovations versus les technologies existantes. http://revistas.udistrital.edu.co/ojs/index.php/visele/article/view/8033/9639

11

Authors: Alma G. Rodríguez, Luis R. Vidal P, Juan Miguel Díaz M, Cesar Leonardo González Pinzón

This paper discusses the development process involved in making a user interface translate G-Code (ISO6983) using Microsoft Visual Basic 2010 together with communication protocol OPC. This interface was developed in three modules, the first one verifies syntax and lexicon, the second is a command converter for a Programmable Logic Controller Allen Bradley L63 using a SERCOS interface card and servo drive ULTRA 3000, and the last one executes motion control instructions. The interface is used for a profile milling process, on an XY plane and using G00, G01, G02 and G03 codes generated in a Fanuc postprocessor 3XMILL. The interface shows errors detected in the verification module according to the parameters established and identifies the corresponding line; it also monitors the XY position in real time, The interface allows line-by-line execution or automatic mode. The interface does not require information for cutting speed, tool advance speed, and spindle speed or tool compensation from the NC program. The interface was also developed using incremental and reuse oriented methodologies. http://revistas.udistrital.edu.co/ojs/index.php/visele/article/view/7888/9599

12

Authors: carlos Arturo Castillo Medina, Octavio José Salcedo Parra, Felipe Forero Rodríguez

This article gathers relevant information that sheds light into the basic principles that motivated the study of the so called Next Generation Networks (NGN). The concepts presented herein include the most recent studies and standards that have been proposed for a suitable operation of NGN. The issues associated to the use of new types of networks and services are illustrated and analyzed; in particular the article illustrates important aspects issues like network architecture, network management and mobility. Additionally, trends for future studies are suggested according to the main challenges of NGN. The current trend suggests that certain key aspects are yet to be solved before establish the actual owner of an NGN network. http://revistas.udistrital.edu.co/ojs/index.php/visele/article/view/7893/9603

14

Authors: José A. Martínez V, Fredy H. Martínez S.

Tree-related power outages represent significant costs and failure rates in power supply. The existence of trees implies that the solution to this problem should focus on optimizing pruning cycles. This optimization is of great importance because of the costs associated to such maintenance. This paper is intended to propose a methodology for the maintenance of trees based on data analysis. Starting from the information captured in the field, we use techniques and models based on fuzzy logic and genetic algorithms, which keeps maintenance tasks on the optimal time and place. The strategy is aimed at two key aspects: first, the history of failures caused by trees on medium-voltage power supplies, this information is used to calculate quality indicators (energy not supplied [ENS] and number of users affected [NU]*) only regarding to tree-associated failure. We use a fuzzy logic based system to ponder and find the critical circuits on which forest maintenance should be performed. Second, we construct an objective function based on treenetwork distance and growth patterns of trees per species in order to simulate forest maintenance. To this end, a genetic algorithm is used to determine the optimum pruning cycle of a given power supply. We use real historical data of medium voltage circuits for the system setting as well as for the evaluation of performance. http://revistas.udistrital.edu.co/ojs/index.php/visele/article/view/7868/9596

14

Authors: Alfonso Toledo Ballén

This article presents an exercise in political science simulation applied via artificial neural networks software called Easy NN-plus 15.0, with reference to possible political scenarios that can emerge once conclude the dialogue between the guerrillas of the armed revolutionary forces of Colombia (FARC-EP) and Juan Manuel Santos’s administration, whose aims to solve through negotiated via the internal armed conflict that is afflicting Colombia more than half a century ago. The political scenarios referred to as input layer for the Perceptron were: democratic stability, civil war, coup d’État, revolution, political reform and authoritarian modernization; the output layers were: democratic openness and the continuation of the conflict; while the interlayer was formed with the complex interrelationship of the six entry scenarios. The computer program was used to relate complex non-linear factors of the political challenge posed by the dialogue, to improve the analytical understanding of the situation. http://revistas.udistrital.edu.co/ojs/index.php/visele/article/view/7898/9605

21

Authors: Yuly Jazmin Oviedo, Karen Lorena Espítia, Luis Fernando Pedraza

This paper presents the design and implementation of a web platform for student tracking and notification using SMS and email (at a school called Instituto San Francisco (Bogotá,Colombia). Firstly, the document addresses the needs of the school, which represent the main concern for this academic web platform. Subsequently, this paper shows the analysis of technologies and describes the design of the platform based on the requirements of the institution. Additionally, the web platform performance analysis and testing results are included. Finally, results of implementing the academic web platform at Instituto San Francisco are provided together with the conclusions and recommendations drawn at the end of the project. http://revistas.udistrital.edu.co/ojs/index.php/visele/article/view/7866/9594

1

Authors: Harold Vacca

Nacido en febrero de 1893 en Székesfehérvár, Hungría, fallecido en junio de 1974 en Budapest, Hungría.

8

Authors: Alejandro Rodríguez, Darío Segura

Este artículo describe la investigación y el desarrollo de un sistema para la formación de imágenes por difracción de tiempo de vuelo (TOFD). El proceso para generarlas se logra con base en la adquisición de señales A-Scan, producto de la exploración de una probeta metálica utilizando ultrasonido, y la posterior agrupación de estas para generar un tipo de imagen bidimensional, denominada D-Scan. Dado que la metodología para obtener las señales implica un desplazamiento de los transductores de ultrasonido en dirección perpendicular a la sección transversal de la cual se desea obtener la imagen, se produce una deformación en esta que impide su utilización confiable a la hora de dictaminar una evaluación de una inspección. Para solucionar el problema se desarrolló un algoritmo que consta de dos partes: el filtrado de las muestras y su alineamiento. El algoritmo se implementó en una aplicación de C# dentro del sistema experimental de generación de imágenes TOFD. Se presentan los resultados obtenidos al explorar la unión soldada en una probeta de acero.

8

Authors: Heylen Polo C, Ambrosio Valencia R, Javier Roldan M, James Díaz G.

Para un mayor aprovechamiento de los sistemas de solares, es indispensable un adecuado dimensionamiento de cada uno de los componentes que los conforman. El presente trabajo describe una metodología para la seguridad de una estructura soporte para panel fotovoltaico con seguimiento solar y su integración a una interfaz gráfica de usuario-GUI desarrollada en Matlab®, la cual, de manera didáctica y a través de un entorno visual amigable e interactivo, reúne los parámetros mecánicos básicos que influyen en el factor de seguridad de la estructura, con la opción de adaptarse a las condiciones de operación del sistema. Usando SolidWorks®, se comparan los resultados de factor de seguridad obtenidos versus análisis de elementos finitos (FEA).

9

Authors: Ramiro Rueda B, Anny Rubio L.

Uno de los principales problemas para las empresas de distribución de energía eléctrica es la localización de fallas en redes de media tensión, lo cual ocasiona largos periodos de interrupción, disminución de la calidad del servicio y un aumento de pérdidas por la energía dejada de suministrar. La forma convencional de solución implica que las cuadrillas en terreno, de forma manual, deben encontrar el lugar del circuito con problemas, a partir de las señales luminosas emitidas por los indicadores de falla dentro de la red. Sin embargo, un modelo automático basado en sistemas de localización geográfica con los datos exactos de las ubicaciones de los indicadores de falla, así como de las cuadrillas en terreno, sería mucho más eficiente ya que se reducirían los tiempos de recuperación del servicio. Este artículo describe la investigación que condujo al diseño e implementación de un sistema inteligente geoespacial de localización de fallas eléctricas en redes de distribución de media tensión, realizado por la empresa Pixis Consultoría SAS.

9

Authors: Diana P. Meneses S, Omar D. López M, Santiago Laín B.

El estudio de turbinas de eje vertical ha cobrado gran interés en los últimos años debido a su gran potencial. Herramientas de análisis alternativas a la experimentación, como la dinámica de fluidos computacional (CFD), están siendo utilizadas para el entendimiento del problema. Este artículo muestra y discute los resultados del estudio computacional paramétrico del perfil alar de los alabes en una turbina Darrieus tipo H. Se evaluó la influencia de dos parámetros del perfil: espesor y curvatura en el desempeño hidrodinámico, estimado por medio de CFD. Se diseñó un experimento factorial 32 en el cual cada factor tiene tres niveles: espesor (6, 12 y 15) y simetría/asimetría (00XX, 24XX y 44XX). Las nueve simulaciones finales fueron realizadas en el software comercial Fluent, mientras que la malla fue parametrizada en el software comercial Gridgen. El desempeño hidrodinámico de la turbina se evaluó mediante el análisis de tres coeficientes adimensionales: coeficiente de momento (Cm), coeficiente de fuerza tangencial (Ct) y coeficiente de fuerza radial (Cn). Los resultados numéricos muestran una gran influencia del espesor del perfil en Cm y Ct, mientras que la asimetría del perfil tiene influencia en Cn, la cual puede ser relevante desde el punto de vista de diseño a fatiga de la turbina.

10

Authors: Arnaldo Verdeza V, Jorge Mendoza F, Rafael Gómez V, Adrián Ávila G.

La utilización de aire caliente en diversos procesos hace necesario el desarrollo de investigaciones que hagan más eficientes y económicos los métodos de producirlo, donde la primera opción por evaluar son los colectores solares. Este trabajo desarrolla una modelación de un colector solar de placa plana y lecho poroso, empleando la solución de ecuaciones analíticas en diagramas de bloques, para estructurar un software que permite simular el comportamiento del colector en estado transitorio, bajo diversos parámetros. En la aplicación se evalúa teóricamente el comportamiento del lecho poroso, la eficiencia, la caída de presión, la distribución de temperaturas y los materiales empleados para su construcción. Esto permite un análisis del comportamiento térmico, con un error promedio comparado con resultados experimentales de 6 %. El modelo se valida experimentalmente, con datos de un colector real, donde se mantiene un flujo de aire de 0,119 kg/s y se varía la radiación entre 400 y 500 W/m2; se observa la distribución de temperaturas, la eficiencia térmica y las caídas de presión. En los resultados obtenidos se alcanzan temperaturas de 360 y 375 K en el aire de salida y caídas de presión de 10,27 y 14,27 Pa, con valores de eficiencia de 36,5 y 51,7%, respectivamente, para nivel de radiación. Esto demuestra la idoneidad de este tipo de colectores como una opción para captar energía solar.

10

Authors: Juan Carlos Carrasco, Isaith Berdugo, Rafael Ospina, Jimy Unfried S

El objetivo de esta investigación es describir los pasos necesarios para el diseño y la construcción de la herramienta con pin cónico roscado no consumible para la soldadura por fricción-agitación (SFA) en una fresadora convencional universal del laboratorio de mecanizado de la Universidad Autónoma del Caribe. La SFA tiene bajos niveles de defectos, excelentes propiedades mecánicas y no requiere material de aporte. Además, tiene alto potencial de aplicación en la industria de construcción de barcos, aviones, etc. El presente artículo describe el diseño de tres diferentes tipos de configuración para las herramientas, así: pin cónico roscado y hombro liso, pin cónico roscado con espiral en el hombro y pin cónico roscado con círculos concéntricos en el hombro. Se describe la selección del material, su proceso de fabricación, los parámetros de corte y las herramientas de corte utilizadas. Se optimizó el diseño con base en la geometría y las limitaciones del cabezal de la fresadora donde se acopla la herramienta. Para la herramienta de pin cónico roscado con hombro liso se adjunta la ecuación básica que gobierna su diseño. Se realizó la soldadura por fricción y agitación de placas de aluminio AA1100 con la herramienta de pin cónico roscado con hombro liso y se obtuvieron resultados satisfactorios.

10

Authors: Javier A. Rosero G, Sandra M. Téllez G, Omar F. Prias C.

Este artículo presenta una prospectiva de integración del sistema de gestión integral de energía en los procesos industriales de las empresas colombianas y, además, la respectiva de los sistemas y procesos de la empresa sobre una red inteligente que permita la integración de sistemas de medida, comunicación y sistemas de información y gestión de datos y toma de decisiones. Se analizan los diferentes actores que se deben considerar en la gestión integral de la empresa y la energía, por medio del uso de estrategias de gestión, sistemas de supervisión y control, smart grids y nuevas tecnologías.

12

Authors: L. J. Esquivel-Rodríguez, Rafael Alvarado C, C. I. Mota-Hernández, Jaime R. Santos R.

El empleo de equipo electrónico portátil que emite radiación no ionizante en el espectro electromagnético se incrementa de manera constante y marca una tendencia proclive a la integración de funcionalidades y la miniaturización. Particularmente, la telefonía celular es usada amplia e intensivamente alrededor del mundo por un extenso número de usuarios, a pesar de que poco se sabe de los efectos que podrían tener en la salud humana o la certeza sobre los resultados obtenidos al investigarlos: algunos han alcanzado resultados alarmantes –ruptura del ADN, genotoxicidad–, mientras que otros no han encontrado amenazas potenciales o significativas, es decir, los resultados no son concluyentes. El presente documento de investigación realiza un análisis con enfoque integral de la documentación especializada previa, realizada por organismos reconocidos, para favorecer y enriquecer la discusión de este tema, considerado polémico.

13

Authors: Helbert E. Espitia C, Jorge I. Sofrony E.

En la naturaleza se pueden observar diferentes comportamientos en enjambres, los cuales pueden ser fuentes de inspiración en la propuesta de algoritmos de optimización. En particular, el comportamiento que es de atención en este trabajo consiste en el movimiento circular de partículas, con la formación de un vórtice, ya que se considera que esta estrategia de locomoción que emplean algunos seres vivos para buscar alimento y evadir obstáculos puede ser útil en procesos de optimización. Para el desarrollo del algoritmo de optimización se toma como referencia un modelo que permite describir el comportamiento de vorticidad. Considerando este modelo se propone la estrategia de optimización. Para mostrar el concepto se emplea una función de prueba en dos dimensiones y se varían los parámetros del modelo, con el fin de observar las características del proceso de búsqueda propuesto.

13

Authors: María F. Díaz V, Eduardo Caicedo B, Humberto Loaiza C.

Los sistemas sonoros a dos vías requieren procedimientos de alineación de tiempo entre las diferentes cajas acústicas, usando procesadores de audio. Enmarcado en este objeto de estudio, el presente artículo describe la implementación de una herramienta software para el análisis de sistemas sonoros. Esta herramienta fue desarrollada en el entorno de programación visual de Matlab®, Simulink®, y es de gran utilidad para evaluar el desempeño de un equipo de sonido en un recinto mediante el análisis de su respuesta en frecuencia, la cual es afectada por la acústica del local. Las pruebas demuestran que el software es confiable y que presenta errores relativos inferiores al 4% en los diferentes modos de operación.