Showing papers in "Tecno Lógicas in 2015"

Adsorción de metales pesados en aguas residuales usando materiales de origen biológico

Abstract: Biosorption is a process that allows active or passive uptake of metal ions due to the property that different living or dead biomass have to bind and accumulate these pollutants by different mechanisms. The application of low-cost materials obtained from different biomass from microbial flora, agro-industrial waste and algae has been investigated to replace the use of conventional methods for the removal of contaminants such as heavy metals. Some of the metals of greatest impact to the environment due to its high toxicity and difficult to remove are chromium, nickel, cadmium, lead, and mercury. In this paper, an overview of adsorption as an alternative process for the removal of contaminants in solution and biomass commonly used in these processes, as well as some of the modifications made to improve the efficiency of adsorption of these materials is presented. It was concluded that the use of adsorption in the removal of pollutants in aqueous solution using waste biomass is applicable to these decontamination processes avoiding subsequent problems such as the generation of chemical sludge, and generating an alternative to use materials considered as waste. It is further identified that such factors as the pH of the solution, particle size, temperature, and concentration of metal effect on the process.

Control GPI-repetitivo para sistemas lineales con incertidumbre/variación en los parámetros

Abstract: Robust repetitive control problems for uncertain linear systems have been considered by different approaches. This article proposes the use of Repetitive Control and Generalized Proportional Integral (GPI) Control in a complementary fashion. The conditioning and coupling of these techniques has been done in a time discrete context. Repetitive control is a control technique, based on the internal model principle, which yields perfect asymptotic tracking and rejection of periodic signals. On the other hand, GPI control is established as a robust linear control system design technique that is able to reject structured time polynomial additive perturbation, in particular, parameter uncertainty that can be locally approximated by time polynomial signal. GPI control provides a suitable stability and robustness conditions for the proper Repetitive Control operation. A stability analysis is presented under the frequency response framework using plant samples for different parameter uncertainty conditions. We carry out some comparative stability analysis with other complementary control approaches that has been effective for this kind of task, enhancing a better robustness and an improved performance for the GPI case. Illustrative simulation examples are presented which validate the proposed approach.

Comparison of multiobjective harmony search, cuckoo search and bat-inspired algorithms for renewable distributed generation placement

Abstract: Electric power losses have a significant impact on the total costs of distribution networks. The use of renewable energy sources is a major alternative to improve power losses and costs, although other important issues are also enhanced such as voltage magnitudes and network congestion. However, determining the best location and size of renewable energy generators can be sometimes a challenging task due to a large number of possible combinations in the search space. Furthermore, the multiobjective functions increase the complexity of the problem and metaheuristics are preferred to find solutions in a relatively short time. This paper evaluates the performance of the cuckoo search (CS), harmony search (HS), and bat-inspired (BA) algorithms for the location and size of renewable distributed generation (RDG) in radial distribution networks using a multiobjective function defined as minimizing the energy losses and the RDG costs. The metaheuristic algorithms were programmed in Matlab and tested using the 33-node radial distribution network. The three algorithms obtained similar results for the two objectives evaluated, finding points close to the best solutions in the Pareto front. Comparisons showed that the CS obtained the minimum results for most points evaluated, but the BA and the HS were close to the best solution.

Análisis de las correlaciones existentes del ángulo de fricción efectivo para suelos del piedemonte oriental de Bogotá usando ensayos in situ

Abstract: To estimate the effective friction angle of soil from in situ test is a complicated job, due to high rates of strain existing in this kind of tests, which tend to be too invasive and disturb the vicinities of test depth, even the sample that eventually is taken at the site. Likewise, the most of the correlations found in the current bibliography to obtain the effective friction angle using field tests, have been developed for soils from different regions. For that reason when are implemented on tropical soils present high scatter, to compare the field parameter values with real results obtained at the lab. This research aims to use in situ tests define through of analysis of different correlations, which fits adequately to the specific conditions of the piedmont soils of Bogota. For the present study will be utilized data from SPT (widely used in Colombia) and SPT-T (never before conducted in the country), carried out considering the appropriated norms to each test, taking in account to SPT-T, doesn’t exist local standard governing such tests. The correlations for field procedures of the tests implemented were for effective confining and energy transference of the SPT hammer, since the state-of-the-art mentions it as the most affect the reliability of the final results. The final results show the tendency of the methodologies used to obtain the correlation, in relation with the real value of effective friction angle from of lab tests.

Correlation analysis between ceramic insulator pollution and acoustic emissions

Abstract: Most of the studies related to insulator pollution are normally performed based on individual analysis among leakage current, relative humidity and equivalent salt deposit density (ESDD). This paper presents a correlation analysis between the leakage current and the acoustic emissions measured in a 230 kV electrical substations in the city of Barranquilla, Colombia. Furthermore, atmospheric variables were considered to develop a characterization model of the insulator contamination process. This model was used to demonstrate that noise emission levels are a reliable indicator to detect and characterize pollution on high voltage insulators. The correlation found amount the atmospheric, electrical and sound variables allowed to determine the relations for the maintenance of ceramic insulators in high-polluted areas. In this article, the results on the behavior of the leakage current in ceramic insulators and the sound produced with different atmospheric conditions are shown, which allow evaluating the best time to clean the insulator at the substation. Furthermore, by experimentation on site and using statistical models, the correlation between environmental variables and the leakage current substation was obtained. Some of the problems that bring the external noise were overcome using multiple microphones and specialized software that enabled properly filter the sound and better measure the variables.

Desempeño mecánico y tribológico de baldosas cerámicas de arcilla roja recubiertas por proyección térmica a partir de alúmina

Abstract: Mechanical and tribological performance of red clay ceramic tiles uncoated and coated by oxy-fuel thermal spraying process from α-Al2O3 powder was evaluated. The ceramic tile substrates were manufactured by uniaxial pressing at 30 bar pressure, and sintered at 1100°C, while alumina Sulzer-Metco 105SPFTM was used as feedstock powder to elaborate coatings with three different thicknesses. Both, the bending and the deep abrasion resistances were evaluated according to ISO 10545-4 e ISO 10545-6 standards respectively. The results obtained indicate that the deep abrasion in the ceramic tiles decreases when the thickness of alumina coating increases. On the other hand, the bending resistance of ceramic tiles coated increased between 5 and 49% regarding to those uncoated. These results contribute to the development of ceramic products with high value added, which can be used in various technological applications.

Implementación de filtro digital en tiempo real para detección de la onda R

Abstract: Quantification of the instantaneous heart rate is based on the detection of the R wave of the electrocardiographic signal. This process requires the implementation of strategies for real-time filtering for the time of occurrence of each R wave. Various mathematical techniques have been implemented for the detection of the R wave and these require digital systems with high performance computing. At present, there are opportunities to implement filtering strategies in low-cost devices in real time. The principal goal of this paper is to present the results obtained by implementing a real-time digital filter for the detection of the R wave of the ECG signal. The implemented strategy is based on the averaging and derived filters theory, which have been implemented on an ARM programmable device and open hardware. The filtering system provides a binary signal indicating the occurrence of the R wave and is input to a system for quantifying the instantaneous heart rate. The results in this paper are the basis for the implementation of a system for the quantification of heart rate in real time, which is presented the step of detecting R-wave.

Elaboración de recubrimientos base cobre sobre un sustrato de porcelana mediante proyección térmica con llama oxiacetilénica

Abstract: A coated system consisting of a ceramic substrate and a coating of a copper alloy was developed in order to provide electrically conductive properties to specific surface of the substrate. The coatings were elaborated by oxy-fuel thermal spraying processes. The best way to prepare the surface of the substrate was previously determined to achieve a sufficient adherence of copper alloy particles on the ceramic substrate. In order to manufacture the coatings an Eutectic Castolin 21071TM powder was used, the oxy-fuel flames were produced from two different volumetric acetylene-oxygen ratios (1:1.15 and 1:2.5) obtaining a reducing and oxidizing flame respectively. The effect of surface preparation of the substrate, the coating thickness and the energy of the flame on the structure and coating adhesion wer

Efecto del campo magnético estático homogéneo en la germinación y absorción de agua en semillas de soja

Abstract: We present the results of the study of the effect on germination and seed water absorption on soybean exposed to homogeneous magnetic field of 125 and 300 mT during 10, 20, and 60 minutes, using as magnetic sources an electromagnet with cylindrical cores (homogeneity of 98%) and a set of toroidal magnets (homogeneity of 88%). The results showed better response in using the electromagnet that provides greater homogeneity. In the germination was determined that the mean germination time (MGT) and times necessary to germinate 10%, 25%, 50%, and 75% significantly decreased relative to control, for treatments 125 mT-10 min and 300 mT-10 min. For the water absorption was observed that in treatments expressed better response in germination show a tendency to increase the capacity of water absorption during the first 6 hours after seeding, however no significant differences in the absorption with respect to the control were recorded.

Elastic networks of the future: benefits for the Colombian internal telecommunication network

Abstract: The continuous growth in data demand is leading research to bring to light an efficient network using fiber optics and radioelectric spectrum. The next generation of networks will be the result of a convergence between the optical and wireless domain with the purpose to gather all of their virtues in a vast telecommunications network more resilient and more simplified. Colombia will not be marginalized of these advances because actually has deployed optical fiber in most of the country and therefore they must be informed of current progress in terms of new generation of telecommunications networks and guide in a better way the legal guidelines of the Ministry of ICT (Information and Communications Technology) to bring great benefits to the regulation of internal telecommunications network, concerning what was decreed about the immovable of horizontal property. In this paper, research advances are reflected concerning optical fiber transmission, including the new paradigm of hybrid fiber optic networks with wireless networks that will simplify the global telecommunications network. The elastic networks of the future suggest that internal telecommunications networks will be smaller, simple, and versatile, which will facilitate competition between communication service providers, avoiding the monopoly of spaces within horizontal property buildings.

Equivalent circuits for simulating irregular PV arrays under partial shading conditions

Abstract: Modeling and simulation of photovoltaic (PV) systems are open research areas since I-V and P-V curves are commonly required to analyze the performance of PV installations. To obtain such curves commercial software packages can be used, however the connection type and size of the PV array may cause large simulation times. To overcome such an issue several techniques based on analyzing the inflection points have been proposed to model the PV array with the aim of reconstruct accurately the required electrical curves. However, such analysis has been applied only for series-parallel (SP) configuration, which is just one alternative to connect PV arrays among several other regular or irregular options. Therefore, a more general approach is needed. This paper presents an approach to obtain the characteristics curves for any PV array, regular or irregular, by extending the inflection points analysis. Then, the calculation of the PV array electrical curves is simplified by using equivalent circuits within the intervals defined by the inflection points. Such a procedure is based on defining which modules become active due to the behavior of the bypass diodes. Finally, the proposed approach enables to analyze any PV array without requiring long electrical simulations. The solution was validated by means of simulation results obtained in Matlab®.

Evaluación de un modelo estadístico para estimar la radiación solar en Magdalena, Colombia

Abstract: The global solar radiation is an important meteorological parameter for understanding the biochemical processes in the environment. Their measurement is complex and requires a high cost of installation, operation and maintenance, but this can be estimated by empirical equations based primarily on their geolocation. However, the accuracy of the results obtained is not suitable for understanding the processes evaluated. The aim of this study was to establish a statistical correlation model for estimating global solar radiation from alternative meteorological parameter. The meteorological information was provided by the Institute of Hydrology, Meteorology and Environmental Studies of Colombia, which provided the measurement of solar radiation, temperature, relative humidity and sunshine of the day for a year. Simple regressions between variables and solar radiation were raised; and multiple regressions between the possible combinations of each variables and solar radiation. The results show a good statistical correlation between variables solar radiation, temperature and relative humidity and little relation to the hours of sunshine, where relative humidity has the higher correlation and therefore is the parameter that more influence has on the model. The multivariate models (R2 average 11.91%) have better fit than simple models (R2 average 5.66%). The best model is multivariate regression in which all variables were included (R2 of 13.75%) although not the simplest model estimation.

Estudio de la hidrofobicidad de la caolinita de La Unión, Antioquia

Abstract: In this research three methodologies to convert the hydrophilic surface of kaolinite into a hydrophobic surface are proposed, this condition is required to recover this mineral by means of froth flotation. Taking into account the anisotropy, zeta potential and complex surface electrical properties of the kaolinite, three surface chemical treatments based on the interacting and absorption of anionic collectors onto the mineral surface, causing an increase in the contact angle and thus increased hydrophobicity of kaolinite were applied. The methodologies proposed were interactions of kaolinite particles with: sodium dodecyl sulfate solutions with concentration 1x10-3M, 1x10-4M, 1x10-5M; sodium dodecyl sulfate solutions 1x10-3M, 1x10-4M, 1x10-5M with further interaction with kerosene solutions 127000 ppm; and oleic acid solutions 1x10-3M, 1x10-4M, 1x10-5M, each one with a five minutes of interaction. The experimental results obtained by zeta potential and contact angle of the kaolinite before and after applying chemical treatments indicate that larger the chain length of the collector and its concentration, bigger the contact angle and so, more hydrophobic the surface (edge or face). In order to optimize, control and understand this solid-liquid interaction phenomenon is suggested to find out about the hydrophobization mechanism of kaolinite with oleic acid and its percentage of hydrophobization.

A comparison of robust Kalman filtering methods for artifact correction in heart rate variability analysis

Abstract: Heart rate variability (HRV) has received considerable attention for many years, since it provides a quantitative marker for examining the sinus rhythm modulated by the autonomic nervous system (ANS). The ANS plays an important role in clinical and physiological fields. HRV analysis can be performed by computing several time and frequency domain measurements. However, the computation of such measurements can be affected by the presence of artifacts or ectopic beats in the electrocardiogram (ECG) recording. This is particularly true for ECG recordings from Holter monitors. The aim of this work was to study the performance of several robust Kalman filters for artifact correction in Inter-beat (RR) interval time series. For our experiments, two data sets were used: the first data set included 10 RR interval time series from a realistic RR interval time series generator. The second database contains 10 sets of RR interval series from five healthy patients and five patients suffering from congestive heart failure. The standard deviation of the RR interval was computed over the filtered signals. Results were compared with a state of the art processing software, showing similar values and behavior. In addition, the proposed methods offer satisfactory results in contrast to standard Kalman filtering.

Planeación de trayectorias para cuadricópteros en ambientes dinámicos tridimensionales

Abstract: A topic of interest on unmanned aerial vehicles is determining appropriate paths that allow them to move from an initial position to a target position, ensuring that the path is safe, in other words, that there is no risk of collision. In this article, two techniques of path planning and an obstacle avoidance strategy for quadricopters are presented. Both techniques are functional on three-dimensional environments with static or dynamic obstacles restricted to constant speeds. The techniques work on an environment modeling with planes which generate an artificial potential field. The first technique is based on moving points that connect the initial position to the goal, and then every point moves towards free zones of influence of obstacles along the potential field, which makes unobstructed paths. The second technique uses the concept of safe areas, which is used as a criterion for updating the position of the points. Additionally, a methodology of dynamic obstacles avoidance is proposed, which is to transform the problem of trajectory planning with dynamic obstacles to the case of path planning with static obstacles through a process of analyzing the possibility of a collision. The results show that these techniques overcome the drawbacks of the gradient descent-based algorithms as local minima and unstable oscillations problems.

Nanobioingeniería: Historia y futuro

Abstract: La primera mencion sobre la nanotecnologia surge en 1959, en forma conceptual, durante una conferencia del Dr. Richard Feynman, donde hablo acerca de la posibilidad de manipular directamente atomos y moleculas, pero recien en los anos 1970 fue el Dr. Norio Taniguchi el primero en utilizar el termino nanotecnologia para describir sus investigaciones [1]. El prefijo “nano” significa enano en griego, y si hablamos de dimensiones, un nanometro es una milesima de millonesima de metro. Para tener una idea de dicha magnitud, por ejemplo el diametro de la doble helice del ADN es de aproximadamente 2 nm, y el espacio que ocupa una molecula de agua es una esfera de aproximadamente 0,2 nm. Desde entonces se penso sobre el potencial para la resolucion de problemas y multiples aplicaciones, y por lo tanto el potencial economico de la nanotecnologia, tanto para el desarrollo como la implementacion de bienes y servicios, todo en escala nanometrica, por lo tanto se convierte en un desafio para la tecnologia, pero tambien una empresa muy prometedora.

Cambios del patrón de radiación en arreglos lineales de dipolos de microcinta a 2,4 GHz en presencia de elementos parásitos

Abstract: This paper presents one of the results of research conducted to study the changes in the impedance input and radiation pattern parameters of the antenna systems, specifically linear arrays of microstrip dipoles are used; it is chosen as a parameter study the radiation pattern, the input impedance parameter will be presented in another publication. For their study, the system is modeled using numerical techniques with the help of the method of moments, in the conformation of the mesh array is used basis function given by Rao-Wilton and Glisson. The model is simulated with the Matlab® tool, the radiation pattern is determined for a dipole type patch and an array of these; the parasitic elements (dipoles) are located at different distances from the original array dipole and calculates the radiation pattern again, which are compared to those originally found. Finally, the results are presented and the advantage of these studies for handling radiation pattern in radiant systems is evident. Additionally, the presence of an element of symmetry is evident, this situation allows a considerable decrease the number of simulations, since the effect of the parasitic elements located on one side of the array of dipoles is similar to the effect that occurs when the parasitic elements are located on the opposite side.

Redes elásticas del futuro: beneficios para la red interna de telecomunicaciones de Colombia

Abstract: The continuous growth in data demand is leading research to bring to light an efficient network using fiber optics and radioelectric spectrum. The next generation of networks will be the result of a convergence between the optical and wireless domain with the purpose to gather all of their virtues in a vast telecommunications network more resilient and more simplified. Colombia will not be marginalized of these advances because actually has deployed optical fiber in most of the country and therefore they must be informed of current progress in terms of new generation of telecommunications networks and guide in a better way the legal guidelines of the Ministry of ICT (Information and Communications Technology) to bring great benefits to the regulation of internal telecommunications network, concerning what was decreed about the immovable of horizontal property. In this paper, research advances are reflected concerning optical fiber transmission, including the new paradigm of hybrid fiber optic networks with wireless networks that will simplify the global telecommunications network. The elastic networks of the future suggest that internal telecommunications networks will be smaller, simple, and versatile, which will facilitate competition between communication service providers, avoiding the monopoly of spaces within horizontal property buildings.

Desempeño de redes inalámbricas y redes industriales inalámbricas en procesos de control en tiempo real bajo ambientes industriales

Abstract: The growing use of Ethernet networks on the industrial automation pyramid has led many companies to develop new devices to operate in requirements of this level, nowadays it is called Industrial Ethernet network, on the market there are various sensors and actuators to industrial scale equipped with this technology, many of these devices are very expensive. In this paper, the performance of two wireless networks is evaluated, the first network has conventional Ethernet devices, and the second network has Industrial Ethernet devices. For the process we vary four parameters such as distance, number of bytes, the signal to noise ratio, and the packet error rate, and then we measure delays and compare with metric statistics results, Box Plot graphs were used for the analysis. Finally, we conclude that under the parameters and conditions tested, wireless networks can serve as a communication system in control applications with allowable delays of up to 50 ms, in addition, the results show a better performance of Industrial Ethernet networks over conventional networks, with differences in the RTT of milliseconds. Therefore, it is recommended to establish what risk is for the process to control these delays to determine if the equipment conventional applies, since under certain features like humidity and temperature can operate properly for a considerable time and at lower cost than devices to Industrial Ethernet.

Diseño, construcción y caracterización de sistema neumático para la medición de rugosidad

Abstract: This article aims to present the results obtained from the design, construction and characterization of a pneumatic flapper-nozzle amplifier, employed in the measurement of average surface roughness. In the construction of the sensor, low cost materials were used and most pieces were obtained by machining. The data acquisition was performed through PC, using an Arduino interface board. The nonlinear mathematical model of the sensor is based on equations of perfect gas flow through an orifice and the continuity law for a control volume. The characterization of physical parameters obtained through laboratory techniques based on the transient response of the gas pressure in the pressurization and depressurization processes of constant volume chambers, using computational tools for adjusting experimental curves. The validation of the model was based on the specifications of transient response that presents a dynamic system for a step input. For the measurement of the roughness, the mathematical model of average roughness, Ra, was used, and the measured data by the sensor were obtained in sandpapers from P1000 to P2000 size, with reference for validation values of average roughness indicated by the FEPA standard.

Mechanical and tribological performance of coated ceramic tiles with alumina by thermal spraying process

Abstract: Mechanical and tribological performance of red clay ceramic tiles uncoated and coated by oxy-fuel thermal spraying process from α-Al2O3 powder was evaluated. The ceramic tile substrates were manufactured by uniaxial pressing at 30 bar pressure, and sintered at 1100°C, while alumina Sulzer-Metco 105SPFTM was used as feedstock powder to elaborate coatings with three different thicknesses. Both, the bending and the deep abrasion resistances were evaluated according to ISO 10545-4 e ISO 10545-6 standards respectively. The results obtained indicate that the deep abrasion in the ceramic tiles decreases when the thickness of alumina coating increases. On the other hand, the bending resistance of ceramic tiles coated increased between 5 and 49% regarding to those uncoated. These results contribute to the development of ceramic products with high value added, which can be used in various technological applications.

Evaluación del lactato de sodio como sustituto de los nitritos convencionales en las salchichas del pez sable

Abstract: The sodium salt of lactic acid is a natural acid produced by bacteria in the fermented foods which are rich in this component. It is produced by fermentation of sugars from some products such as corn or beets. Both lactic acid and lactates are used as preservatives, mainly against yeasts and fungi. It is also used to increase the stability of antioxidants, and to prevent loss of water from various products. The objective of this research was to determine the effectiveness of sodium lactate on the inhibition of Clostridium sporogenes in fish sausages, extending their life and reducing microbial growth. Two different formulations were made; F(A) preserved with nitrites, F(B), preserved with sodium lactate and a control sample without preservative. A positive control SPS agar inoculated with Clostridium sporogenes at different dilutions were also carried out, finally they took incubation in candle jar at 37°C for 48 h. It was found that the use of sodium lactate 2% controlled growth of spores of Clostridium reducing sulfite in 48 hours in the solutions prepared as is the use of nitrites, these being a promising alternative to replace the use of nitrite in products type sausage meat.

Algoritmos bioinspirados para optimizar el contenido de armónicos de un inversor de potencia PWM

Abstract: This paper deals with the evaluation of different bio-inspired algorithms techniques for reduction of harmonic distortion (THD) in pulse width modulation (PWM) of power inverters. A comprehensive study is performed, that identifies and develops biologically inspired optimization algorithms based mainly on tabu search, genetic algorithms (GA), particle swarm optimization (PSO), and ant colony optimization (ACO). These bio-inspired optimization methods were used to find the best operational parameters of a PWM applied to a power inverter. The best results were achieved when the pulse position is near to the middle position (Pp=0.5) or symmetry of the pulse. For the four methods analyzed he best result was obtained using ACO method based on the lowest THD content and less 5th and 7th harmonics magnitude with fewer pulses (Np=38), almost 5 times lower than the result of PSO (Np=179). It was achieved to reduce losses considerably with a reduction in the switching frequency of the power devices (4560 Hz). The algorithms developed can be easily adapted to any minimization problem, only making changes in the number of variables and selection (or elimination) criteria to obtain better results in complex problems.