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Context: Given the increasing population concentration, both the proximity of the town of Madrid to the city of Bogotá and the growing metropolitan area around the latter have a significant influence on the increased urbanization and the change in land use in the town of Madrid, Cundinamarca. Objective: The objective of this study was to carry out a multitemporal analysis of the change in coverage and land use caused by urban expansion in the municipality of Madrid between 1977 and 2020. Methodology: Satellite images were observed through supervised classification, following the Corine Land Cover methodology, which was adapted for the Colombian context, and utilizing geographic information systems. Area variation analyses were performed for each classification in each of the evaluated years. Results: The data obtained show that the forest cover area and seminatural zones have been reduced by 86% in a period of 43 years, and that artificial territories have progressively become predominant in each of the years, even reaching a coverage greater than 50% of the municipality area. The agricultural territories have maintained 66,95% of the surface of the municipality, and they correspond the land use with the largest occupied area for the evaluated period, which shows the importance of the soil for the economic development of the population. Conclusions: This situation shows that population growth and urban expansion cause variations in coverage and land uses. Their valuation is an aspect that must be considered when elaborating development plans for municipal entities.

Resumen Contexto: El análisis del flujo de agua en canales abiertos es un tema de estudio relevante en diferentes proyectos de ingeniería civil. Sin embargo, los experimentos tradicionales en hidráulica de canales abiertos y modelos a escala son limitados, y la simple revisión conceptual basada únicamente en libros de texto no permite la suficiente estimulación y motivación para los estudiantes. Por otro lado, el rápido desarrollo de dispositivos móviles y programación en la nube a través de lenguajes como Android ofrecen alternativas para el desarrollo de herramientas complementarias que apoyen los procesos educativos. Método: Este trabajo presenta el desarrollo de una aplicación que permite el análisis y diseño de canales prismáticos abiertos mediante la implementación del método numérico Newton-Raphson, incorporando un enfoque de aprendizaje basado en problemas. Resultados: Se incluyeron en la aplicación elementos interactivos para la definición de variables del problema, imágenes didácticas y salidas de datos amigables para promover el interés en el uso de la aplicación y la comprensión de la solución de los problemas. Conclusiones: La aplicación móvil es un ejemplo de las posibilidades que existen para fortalecer tanto la enseñanza de conceptos como el enfoque tecnológico para la solución rápida de problemas, las cuales promueven la apropiación de conceptos en la educación de ingeniería civil. La aplicación se llama "HydroEolm" y está disponible de forma gratuita en la Play Store de Google; ha sido descargada varios miles de veces en América Latina y el Caribe, en su mayoría por estudiantes de ingeniería, así que se infiere el impacto positivo de la aplicación para el entrenamiento académico.

Context: In this article we present an algorithm under JavaScript source code for critical flow equation solution. Method: An object-oriented programming language was implemented for Android 4.0 or higher systems based on iterative and incremental processes (Agile development). The numerical method of Newton-Raphson was used to determine the critical depth of seven hydraulic sections (rectangular, trapezoidal, asymmetric trapezoidal, triangular, asymmetric triangular, parabolic and circular). A potential function was obtained to establish the seed value in iterative process, in order to accelerate and guarantee the convergence level for each section. This value is directly associated with hydraulic problem pre-established conditions. Results: The application calculates: critical depth, critical speed, hydraulic area, specific energy, wet perimeter and mirror. The results calculated by the application were validated against Excel analysis tool (Goal Seek) results and Hcanales® software developed by Máximo Villón Béjar Engineer. Finally, the application is available for free in Google Play Store, with the name "Critical Flow in Channels. Newton Raphson Solution". Conclusions: It is possible to develop easily accessible applications that meet the technical conditions required for the resolution of engineering-related situations.

Context: The article presents the friction coefficient calculation for pressure pipes, from Newton-Raphson numerical method, under JavaScript source code for Android 4.0 or higher. Methodology: The code development is based on Colebrook-White model for turbulent flows. The app also establishes the friction coefficient for laminar flows from the Poiseuille equation and determines the range for the enter flow in a transition zone (unstable flow). An algorithm of successive approximations was implemented for non-linear equation solution based on the relative roughness and Reynolds number. Results: In the Newton-Raphson method, if the initial value moves away from zero or presents different inflection points, the probability of divergence of the method increases significantly. To overcome this anomaly, a friction coefficient equal to 0.015 was proposed as initial (seed) value; thereby we guarantee the convergence for turbulent flows with an approximation of 0.0000001. The values ​​calculated by the app were calibrated with the Excel analysis tool (Goal Seek). Conclusion: The app is available for free in Google Play Store, and is a tool to support educational processes and the professional field.

Contexto: Describir matemáticamente el comportamiento hidráulico en estructuras de control conlleva a ecuaciones diferenciales acopladas no lineales, las cuales no cuentan con solución analítica en la mayoría de los problemas de ingeniería. No obstante, es posible obtener soluciones aproximadas a partir del método de volúmenes finitos (FVM). Este método convierte un medio continuo con variables infinitas en un medio discreto con geometrías establecidas y condiciones de contorno determinadas. Método: Se desarrolló un modelo numérico en 2D sin considerar el efecto de las pilas y los estribos en el azud, a escala 1:70, bajo condiciones de flujo permanente de la estructura de control y del sistema de compuertas radiales de la represa El Quimbo, a partir de la implementación el software Ansys Fluent 17.0. El análisis hidrodinámico de la estructura se realizó bajo condiciones de superficie libre y con diferentes cargas hidráulicas, para aperturas de 704 msnm, 706,9 msnm, 709,4 msnm, 712 msnm y 724,6 msnm Posteriormente, se validó el modelo numérico a partir de la comparación de los resultados numéricos con los datos teóricos realizados por Ingetec y los datos de las pruebas realizadas en el modelo físico desarrollado por la Universidad Nacional de Colombia (sede Manizales). Resultados: Para un periodo de retorno de 100 años, el modelo numérico estimó una lámina de 0,0306 m que corresponden a 2,143 m en la estructura El Quimbo. Con esta disposición, ingresó al volumen de control un total de 80,7996 L/s y salieron 80,7324 L/s, originando una variación de caudal de 0,08316 %. La mayor variación de lámina de agua del modelo numérico con respecto a la lámina observada es de 3,1 % (0,258 m), la cual corresponde a la creciente máxima probable para una apertura de compuertas con cota (724,6 msnm) y con una descarga de 290 L/s. De igual forma, las mayores velocidades desarrolladas por el flujo en el vertedero se originan en la salida del deflector, correspondiente a la abscisa K0+ 5,19 m. Según el modelo numérico, se determinó que el impacto del chorro en el canal se hace con una velocidad máxima de 6,15 m/s. Conclusiones: La relación entre la carga hidráulica con respecto a la carga de diseño no debe superar 1,33, lo cual a su vez concuerda con lo recomendado por la USBR. Asimismo, la condición de cavitación encontrada en la rápida puede ser considerada cavitación incipiente. En el diseño de vertederos, la relación H/HD incide de manera directa en la aparición de fenómenos de cavitación sobre la estructura, en el desarrollo de altas velocidades en la rápida, en el deflector y en la capacidad de descarga del vertedero.

Context: In the last sixty years urbanization processes have increased considerably. In many of them, the number of inhabitants of the so-called "slums" amounts to more than 50% of the population. In addition, they are located in areas at risk. Objective: To determine and evaluate the monthly progression of the Damage Index (ID, in Spanish) of a group of houses located in a hillside area in the “Altos de la Estancia” sector in Bogotá, Colombia, during a period of four months. Method: The houses were classified according to their structural system in six groups: confined masonry (group A); structural masonry (group B); unreinforced masonry (group C); provisional materials (group D); reinforced concrete porches (group E); and prefabricated houses (group F). And we applied the methodology proposed by the Fund for the Prevention and Attention of Emergencies (FOPAE). Results: There was a constant increase in the ID of all groups. However, group C presented the highest values in the last sampling (2.6% of the households had high ID and 0.87% very high). In the other groups the observed ID was lower and no houses were found with records classified as very high. Conclusions: According to the results, dwellings built in unreinforced masonry show a greater degree of deterioration in short periods of time compared to those constructed with other structural systems.

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.

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.

Las aguas de lavado de tinta se catalogan como contaminantes debido a que son sustancias en su mayoría poliaromáticas, carcinogénicas, mutagénicas y teratogénicas para gran variedad de seres vivos. Dentro de los métodos de descontaminación, la electrocoagulación/electroflotación es reconocido como un tratamiento altamente eficiente para la remoción de contaminantes disueltos en agua, y su efecto sobre colorantes ha sido estudiado y descrito. No tiene, sin embargo, aplicación industrial en Colombia en la actualidad y su lugar en los objetivos de investigación académica en el país es aún muy marginal. Por esa razón, este trabajo es un estudio exploratorio del tratamiento de un residuo industrial de tinta de imprenta por medio del método de electrocoagulación/electroflotación. Se aplicó un diseño experimental 22 con un punto central. Se obtuvo un rango de porcentajes de remoción de DQO entre 10,43% hasta 50,93%. No obstante, los resultados evidencian la posibilidad de que la descontaminación por electrocoagulación puede ser reversible, y no se observa la incidencia esperada de los factores escogidos.

In water environmental planning in watersheds should contain aspects for the decontamination of receiving water body, therefore the selection of the treatment plants municipal wastewater in developing countries, you should consider aspects of the typical composition raw wastewater pollutant removal efficiency by technology, performance indicators for technology, environmental aspects of localization and spatial localization strategy. This methodology is built on the basis of technical, economic and environmental attributes, such as a tool for decision making future investments in treatment plants municipal wastewater with multidisciplinary elements.

El presente artículo muestra los resultados de una investigación cualitativa que buscó comprender las representaciones sociales de docentes y estudiantes sobre la ética en una institución de educación superior en Cúcuta, Colombia. Se utilizó el método hermenéutico, lo cual posibilitó comprender un tipo de conocimiento que se construye en el diálogo, la interacción, la intersubjetividad y la cotidianidad. La muestra fue intencional y la conformaron 25 estudiantes y 2 profesores. Los resultados del estudio evidencian que para los actores educativos la ética está relacionada con los valores de los sujetos, los cuales son aprendidos del entorno. Relacionan la ética con la sociedad y la definen como una ciencia que les da a las personas ciertos parámetros que deben seguir para cumplir con las buenas acciones dentro de la sociedad.

To meet Colombia commitments with Stockholm Convention on persistent organic pollutants (POPs), the country carried out identification and quantification of organochlorine pesticide stocks, in order to update and consolidate information on storage sites and contaminated soils. Methodology proposed by the United Nations program for development (UNDP) was used and covered the following stages: (a) consultation of secondary information available in previous inventories, (b) review activities related to these products life cycle, (c) location of warehouses and sites of destruction or burial and (d) visit a sample of identified sites. Colombia has 159 812 kg of DDT in stock and it was estimated 88 629 m3 of contaminated soil by POPs pesticides. It were unable to identify a vast underreporting quantities of pesticides used and contaminated sites, not only in the country, but in inventories in other countries of the region; reflecting that the reported results are partial and contamination from unidentified sources may occur. It is important to intensify activities of research and innovation not only for wastes and contaminated soils treatment, but for agricultural production and crop protection.

Mining extraction of building materials increased from the 19th century until the early 20th century in Bogotá D.C. (Secretaría Distrital de Ambiente, 2007) and in this period, population rapid growth, poor mining practices and legislation without concepts on sustainable development, generated numerous environmental liabilities due to: abandoned mining installations, mass removals-exposed areas, which currently generate severe negative impacts that affect the population and ecosystems. This article use Gómez Orea Environmental Impact Assessment Methodology to diagnose and analyze environmental liabilities in Villa Gloria quarry located in Ciudad Bolivar (Bogotá D.C.), and to determine the possible mitigation works allowing to give a new use to this area such as: green areas and/or areas of recreation (Secretaría Distrital de Ambiente, 2007).

This paper presents the design and implementation of a data acquisition system to identify the different vector groups of the triphase transformer DL1080. This design is based on computational tools in hardware and software such as Microchips and Labview respectively. Consequently, the prototype has a high-level algorithm. It is able to perform vector analysis of voltage in the transformer which established national and international regulations. This project also allows an interactive environment with the user through graphical tools such as a liquid crystal display with their respective buttons and software developed in Labview called "indices Horarios". This is useful to illustrate: vector diagrams, winding configurations, real time voltage, among others. This academic application is a tool in learning and strengthening areas such as: electromagnetic conversion, electrical machines and power systems. Therefore, teachers and students can reinforce their knowledge.

La biomasa es uno de los materiales más adecuados como combustible alternativo, pero por sus características de humedad, exceso de contenido de oxígeno y bajo poder calorífico, requiere ser sometida a procesos de pretratamiento. La peletización permite acondicionar la biomasa para su utilización directamente en procesos térmicos. El sector ladrillero tiene una gran demanda energética para sus procesos de secado y cocción y el uso de combustibles a partir de biomasa permite obtener reducciones importantes en emisiones atmosféricas. El estudio piloto comparó el desempeño energético y ambiental del uso de combustibles a partir de dos tipos de biomasas peletizadas —residuos de podas de césped, arbustos y árboles de la ciudad y residuos de producción de muebles y aglomerados, aserrín—. La biomasa con mejor desempeño fue el aserrín, debido a su menor consumo energético en el proceso de pretratamiento, aspecto que arroja una mayor productividad en su uso. Adicionalmente, se observó una reducción en los costos de suministro de combustible entre un 7 % y 10 %, sustituyendo un 20 % del carbón utilizado en el proceso.

This work discusses the mechanical properties of bricks that were made with clay and sludge mixtures. We analyzed 100:0, 99:1, 95:5, 90:10, 80:20 and 60:40 proportions of clay and sludge. Bricks were cooked between 35 ºC to 1100 ºC. The sludge used in this study came from sewage treatment plant of G.M. Colmotors Company. These tests were carried out: Water Absorption and mechanical resistance of bricks compression. The results of this study showed that the best percentage of sludge to mix with clay was 5 % to 10 %. Since, this percentage range meets the quality standards of the product demanded in Colombia.

This article presents results of a pilot study, where metals leaching from ceramic pieces were made with different mixes of slugde and clay from the sewage treatment plant G.M. COLMOTORES in Bogota (Colombia). The slugde have been stabilized and solidified in clays and cook in a Hoffman Furnace oven for the fabrication of bricks. The proportions of mixture of clay and sludge for the fabrication of bricks used were: 99:1, 95:5, 90:10, 80:20 and 60:40. Then, the bricks were burned at temperatures between 50 to 1,100 ° C. Moreover, clays, sludge and bricks were tested by: X ray diffraction (XRD), X-ray Fluorescence X (XRF), Thermogravimetry (TG), Differential Thermal Analysis (DTA), Atomic Absorption Spectroscopy (AA) and Scanning Electron Microscopy (SEM). Finally, other leaching tests were performed in the bricks (Toxicity Characteristic Reaching Procedure - TCLP) for the determination of heavy metals. Results from this study showed that the clay had a high affinity with the sludge and the bricks showed low levels of leaching. Also, it was considered that 95:5 of clay and sludge was the best mixing ratio for all the metals. The metal with lowest removal percentage was selenium and the highest removal percentages were arsenic, nickel, chrome, zinc and cadmium.

The objective of this research was to analyze two social housing construction models that are currently applied in low income families of Bogotá (Habitat social production ‘HSP and market models). We built a framework based on housing and habitat concepts according to recent development approaches. We characterized these construction models and designed a methodology, which was applied to analyze processes and results for each case. We concluded that, although HSP model is a variant of market model, the process for giving housing solutions were similar in both cases.

English Editorial Tecnura 49

Editorial Tecnura 49

Editorial Tecnura 43

Editorial Tecnura 43

Copyright of Tecnura is the property of Tecnura and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Tecnura is the property of Tecnura and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Tecnura is the property of Tecnura and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

An introduction is presented in which the author discusses the mission statement, journalistic ethics, and best practices espoused by the editorial committee of the journal "Tecnura."

Copyright of Tecnura is the property of Tecnura and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Tecnura is the property of Tecnura and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The author focuses on ecosystem transformation in Colombia. He comments on the relationship between ecosystems and society since the 1500s in Colombia include resource abundance and labor shortages during the colonial phase, population increase at the end of the colonial era, resource scarcity and excessive labor during the late 19th century, and finally leading to the 21st century. He reflects on how environmental deterioration and high population will result in scarcity of resources.