Subjects -> ENGINEERING (Total: 2791 journals)
    - CHEMICAL ENGINEERING (248 journals)
    - CIVIL ENGINEERING (242 journals)
    - ELECTRICAL ENGINEERING (176 journals)
    - ENGINEERING (1402 journals)
    - ENGINEERING MECHANICS AND MATERIALS (452 journals)
    - HYDRAULIC ENGINEERING (56 journals)
    - INDUSTRIAL ENGINEERING (100 journals)
    - MECHANICAL ENGINEERING (115 journals)

ENGINEERING (1402 journals)                  1 2 3 4 5 6 7 8 | Last

Showing 1 - 200 of 1205 Journals sorted alphabetically
3 Biotech     Open Access   (Followers: 2)
3D Research     Hybrid Journal   (Followers: 17)
AAPG Bulletin     Hybrid Journal   (Followers: 9)
Abstract and Applied Analysis     Open Access   (Followers: 1)
Aceh International Journal of Science and Technology     Open Access   (Followers: 3)
ACS Nano     Hybrid Journal   (Followers: 189)
Acta Geotechnica     Hybrid Journal   (Followers: 6)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 8)
Acta Nova     Open Access  
Acta Polytechnica : Journal of Advanced Engineering     Open Access  
Acta Universitatis Cibiniensis. Technical Series     Open Access   (Followers: 1)
Active and Passive Electronic Components     Open Access   (Followers: 5)
Additive Manufacturing Letters     Open Access   (Followers: 7)
Adsorption     Hybrid Journal   (Followers: 4)
Advanced Energy and Sustainability Research     Open Access   (Followers: 4)
Advanced Engineering Forum     Full-text available via subscription   (Followers: 10)
Advanced Engineering Research     Open Access  
Advanced Journal of Graduate Research     Open Access   (Followers: 1)
Advanced Quantum Technologies     Hybrid Journal   (Followers: 1)
Advanced Science     Open Access   (Followers: 12)
Advanced Science Focus     Free   (Followers: 5)
Advanced Science Letters     Full-text available via subscription   (Followers: 9)
Advanced Science, Engineering and Medicine     Partially Free   (Followers: 3)
Advanced Synthesis & Catalysis     Hybrid Journal   (Followers: 19)
Advanced Theory and Simulations     Hybrid Journal   (Followers: 2)
Advances in Applied Energy     Open Access   (Followers: 6)
Advances in Catalysis     Full-text available via subscription   (Followers: 7)
Advances in Complex Systems     Hybrid Journal   (Followers: 10)
Advances in Engineering Software     Hybrid Journal   (Followers: 25)
Advances in Fuzzy Systems     Open Access   (Followers: 5)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 19)
Advances in Heat Transfer     Full-text available via subscription   (Followers: 27)
Advances in Natural Sciences : Nanoscience and Nanotechnology     Open Access   (Followers: 28)
Advances in Operations Research     Open Access   (Followers: 13)
Advances in OptoElectronics     Open Access   (Followers: 6)
Advances in Physics Theories and Applications     Open Access   (Followers: 12)
Advances in Polymer Science     Hybrid Journal   (Followers: 50)
Advances in Remote Sensing     Open Access   (Followers: 58)
Advances in Science and Research (ASR)     Open Access   (Followers: 8)
Aerobiologia     Hybrid Journal   (Followers: 2)
Aerospace Systems     Hybrid Journal   (Followers: 7)
African Journal of Science, Technology, Innovation and Development     Hybrid Journal   (Followers: 7)
AIChE Journal     Hybrid Journal   (Followers: 31)
Ain Shams Engineering Journal     Open Access   (Followers: 1)
Al-Nahrain Journal for Engineering Sciences     Open Access  
Al-Qadisiya Journal for Engineering Sciences     Open Access  
AL-Rafdain Engineering Journal     Open Access  
Alexandria Engineering Journal     Open Access   (Followers: 1)
AMB Express     Open Access   (Followers: 1)
American Journal of Applied Sciences     Open Access   (Followers: 21)
American Journal of Engineering and Applied Sciences     Open Access   (Followers: 7)
American Journal of Engineering Education     Open Access   (Followers: 13)
American Journal of Environmental Engineering     Open Access   (Followers: 6)
American Journal of Industrial and Business Management     Open Access   (Followers: 23)
Annals of Civil and Environmental Engineering     Open Access   (Followers: 2)
Annals of Combinatorics     Hybrid Journal   (Followers: 3)
Annals of Pure and Applied Logic     Open Access   (Followers: 4)
Annals of Regional Science     Hybrid Journal   (Followers: 7)
Annals of Science     Hybrid Journal   (Followers: 9)
Annual Journal of Technical University of Varna     Open Access  
Antarctic Science     Hybrid Journal   (Followers: 1)
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 3)
Applicable Analysis: An International Journal     Hybrid Journal   (Followers: 1)
Applications in Energy and Combustion Science     Open Access   (Followers: 2)
Applications in Engineering Science     Open Access  
Applied Catalysis A: General     Hybrid Journal   (Followers: 7)
Applied Catalysis B: Environmental     Hybrid Journal   (Followers: 9)
Applied Clay Science     Hybrid Journal   (Followers: 6)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 16)
Applied Energy     Partially Free   (Followers: 25)
Applied Engineering Letters     Open Access  
Applied Magnetic Resonance     Hybrid Journal   (Followers: 3)
Applied Nanoscience     Open Access   (Followers: 7)
Applied Network Science     Open Access   (Followers: 2)
Applied Numerical Mathematics     Hybrid Journal   (Followers: 4)
Applied Physics Research     Open Access   (Followers: 5)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 5)
Arab Journal of Basic and Applied Sciences     Open Access  
Arabian Journal for Science and Engineering     Hybrid Journal   (Followers: 1)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 5)
Archives of Foundry Engineering     Open Access  
Archives of Thermodynamics     Open Access   (Followers: 10)
Arctic     Open Access  
Arid Zone Journal of Engineering, Technology and Environment     Open Access  
ArtefaCToS : Revista de estudios sobre la ciencia y la tecnología     Open Access  
Asian Journal of Applied Science and Engineering     Open Access  
Asian Journal of Applied Sciences     Open Access   (Followers: 2)
Asian Journal of Biotechnology     Open Access   (Followers: 8)
Asian Journal of Control     Hybrid Journal  
Asian Journal of Technology Innovation     Hybrid Journal   (Followers: 5)
Assembly Automation     Hybrid Journal   (Followers: 2)
ATZagenda     Hybrid Journal  
ATZextra worldwide     Hybrid Journal  
AURUM : Mühendislik Sistemleri ve Mimarlık Dergisi = Aurum Journal of Engineering Systems and Architecture     Open Access   (Followers: 1)
Australasian Journal of Engineering Education     Hybrid Journal   (Followers: 3)
Australasian Physical & Engineering Sciences in Medicine     Hybrid Journal   (Followers: 1)
Australian Journal of Multi-Disciplinary Engineering     Hybrid Journal  
Autocracy : Jurnal Otomasi, Kendali, dan Aplikasi Industri     Open Access  
Automotive and Engine Technology     Hybrid Journal  
Automotive Experiences     Open Access  
Automotive Innovation     Hybrid Journal  
Avances en Ciencias e Ingenierías     Open Access  
Avances: Investigación en Ingeniería     Open Access  
Balkan Region Conference on Engineering and Business Education     Open Access   (Followers: 2)
Bangladesh Journal of Scientific and Industrial Research     Open Access  
Basin Research     Hybrid Journal   (Followers: 6)
Batteries     Open Access   (Followers: 8)
Batteries & Supercaps     Hybrid Journal   (Followers: 5)
Bautechnik     Hybrid Journal   (Followers: 1)
Bell Labs Technical Journal     Hybrid Journal   (Followers: 27)
Beni-Suef University Journal of Basic and Applied Sciences     Open Access  
Beyond : Undergraduate Research Journal     Open Access  
Bhakti Persada : Jurnal Aplikasi IPTEKS     Open Access  
Bharatiya Vaigyanik evam Audyogik Anusandhan Patrika (BVAAP)     Open Access  
Bilge International Journal of Science and Technology Research     Open Access   (Followers: 1)
Biointerphases     Open Access   (Followers: 1)
Biomaterials Science     Hybrid Journal   (Followers: 11)
Biomedical Engineering     Hybrid Journal   (Followers: 11)
Biomedical Engineering Letters     Hybrid Journal   (Followers: 3)
Biomedical Engineering: Applications, Basis and Communications     Hybrid Journal   (Followers: 4)
Biomedical Microdevices     Hybrid Journal   (Followers: 8)
Biomedical Science and Engineering     Open Access   (Followers: 4)
Biomicrofluidics     Open Access   (Followers: 7)
Biotechnology Progress     Hybrid Journal   (Followers: 42)
Black Sea Journal of Engineering and Science     Open Access  
Botswana Journal of Technology     Full-text available via subscription   (Followers: 1)
Boundary Value Problems     Open Access  
Bulletin of Canadian Petroleum Geology     Full-text available via subscription   (Followers: 12)
Bulletin of Engineering Geology and the Environment     Hybrid Journal   (Followers: 15)
Cahiers Droit, Sciences & Technologies     Open Access   (Followers: 1)
Calphad     Hybrid Journal  
Canadian Geotechnical Journal     Hybrid Journal   (Followers: 28)
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 51)
Carbon Resources Conversion     Open Access   (Followers: 2)
Carpathian Journal of Electronic and Computer Engineering     Open Access  
Case Studies in Thermal Engineering     Open Access   (Followers: 9)
Catalysis Communications     Hybrid Journal   (Followers: 7)
Catalysis Letters     Hybrid Journal   (Followers: 3)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 9)
Catalysis Science and Technology     Hybrid Journal   (Followers: 9)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 4)
Catalysis Today     Hybrid Journal   (Followers: 4)
CEAS Space Journal     Hybrid Journal   (Followers: 6)
Cell Reports Physical Science     Open Access  
Cellular and Molecular Neurobiology     Hybrid Journal   (Followers: 2)
CFD Letters     Open Access   (Followers: 7)
Chaos : An Interdisciplinary Journal of Nonlinear Science     Hybrid Journal   (Followers: 3)
Chaos, Solitons & Fractals     Hybrid Journal   (Followers: 1)
Chaos, Solitons & Fractals : X     Open Access   (Followers: 1)
Chinese Journal of Catalysis     Full-text available via subscription   (Followers: 2)
Chinese Journal of Engineering     Open Access   (Followers: 1)
Chinese Journal of Population, Resources and Environment     Open Access  
Chinese Science Bulletin     Open Access  
Ciencia e Ingenieria Neogranadina     Open Access  
Ciencia en su PC     Open Access   (Followers: 1)
Ciencia y Tecnología     Open Access  
Ciencias Holguin     Open Access   (Followers: 1)
CienciaUAT     Open Access  
Cientifica     Open Access  
CIRP Annals - Manufacturing Technology     Hybrid Journal   (Followers: 10)
CIRP Journal of Manufacturing Science and Technology     Hybrid Journal   (Followers: 12)
City, Culture and Society     Hybrid Journal   (Followers: 23)
Clay Minerals     Hybrid Journal   (Followers: 7)
Cleaner Engineering and Technology     Open Access   (Followers: 5)
Cleaner Environmental Systems     Open Access   (Followers: 5)
Coastal Engineering     Hybrid Journal   (Followers: 16)
Coastal Engineering Journal     Hybrid Journal   (Followers: 7)
Coastal Engineering Proceedings : Proceedings of the International Conference on Coastal Engineering     Open Access   (Followers: 1)
Coastal Management     Hybrid Journal   (Followers: 29)
Coatings     Open Access   (Followers: 2)
Cogent Engineering     Open Access   (Followers: 1)
Cognitive Computation     Hybrid Journal   (Followers: 2)
Color Research & Application     Hybrid Journal   (Followers: 1)
COMBINATORICA     Hybrid Journal  
Combustion Theory and Modelling     Hybrid Journal   (Followers: 18)
Combustion, Explosion, and Shock Waves     Hybrid Journal   (Followers: 21)
Communications Faculty of Sciences University of Ankara Series A2-A3 Physical Sciences and Engineering     Open Access  
Communications in Numerical Methods in Engineering     Hybrid Journal   (Followers: 2)
Components, Packaging and Manufacturing Technology, IEEE Transactions on     Hybrid Journal   (Followers: 27)
Composite Interfaces     Hybrid Journal   (Followers: 6)
Composite Structures     Hybrid Journal   (Followers: 246)
Composites Part A : Applied Science and Manufacturing     Hybrid Journal   (Followers: 179)
Composites Part B : Engineering     Hybrid Journal   (Followers: 224)
Composites Part C : Open Access     Open Access   (Followers: 1)
Composites Science and Technology     Hybrid Journal   (Followers: 151)
Comptes Rendus : Mécanique     Open Access   (Followers: 2)
Computation     Open Access   (Followers: 1)
Computational Geosciences     Hybrid Journal   (Followers: 17)
Computational Optimization and Applications     Hybrid Journal   (Followers: 9)
Computer Applications in Engineering Education     Hybrid Journal   (Followers: 6)
Computer Science and Engineering     Open Access   (Followers: 15)
Computers & Geosciences     Hybrid Journal   (Followers: 30)
Computers & Mathematics with Applications     Full-text available via subscription   (Followers: 8)
Computers and Electronics in Agriculture     Hybrid Journal   (Followers: 7)
Computers and Geotechnics     Hybrid Journal   (Followers: 11)
Computing and Visualization in Science     Hybrid Journal   (Followers: 6)
Computing in Science & Engineering     Full-text available via subscription   (Followers: 31)
Conciencia Tecnologica     Open Access  
Continuum Mechanics and Thermodynamics     Hybrid Journal   (Followers: 8)
Control Engineering Practice     Hybrid Journal   (Followers: 46)

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Ciencia e Ingenieria Neogranadina
Number of Followers: 0  

  This is an Open Access Journal Open Access journal
ISSN (Print) 0124-8170 - ISSN (Online) 1909-7735
Published by SciELO Homepage  [656 journals]
  • Edición especial en geociencias

    •  
  • Paleoenvironmental Interpretation of Last Millennium Sediments in the
           Marriaga Swamp, Atrato Delta, Colombia

    • Abstract: : This paper presents the first paleoenvironmental reconstruction of the last 1,130 a of the Marriaga Swamp in the Atrato River delta in northwestern Colombia. The geochemical analyses of a 220 cm sediment core retrieved from the swamp reveal interesting climatic episodes and sedimentary changes in the last millennium. We split the core into three segments, according to sediment features, organic carbon content (OC), and geological ages. Records show different alternations of humid and dry periods, biological productivity, carbonate precipitation, weathering grade, and high heavy metal concentrations. The segments also concur with the geochemical differences determined by (Zr+Rb)/Sr, Ca/Ti Mn/Fe, OC/Ti, Mg/Ca Ba/Al, Sr/Al, and Ca/Al ratios. The older sequence (between 1,130 ± 90 a and 870 ± 70 a) shows a dry period with intermittent flooding events and high OC production in subareal conditions, followed by a more humid environment between 870 ± 70 a and 530 ± 40 a, with depletion of trace element ratios and OC. The more recent period (530 ± 40 a to present) evinces an environment dominated by the fluvial regime, based on a lower Ca/Al ratio and a rise of OC. The statistical correlations display three main clusters that distinguish among organic-biological productivity, bedrock source components, and heavy metal inputs.Resumen: En este estudio se presenta la primera reconstrucción paleoambiental de los últimos 1130 años de la Ciénaga de Marriaga en el delta del río Atrato, en el noroeste de Colombia. Los análisis geoquímicos de un núcleo de sedimento de 220 cm recuperado en la ciénaga revelan episodios climáticos interesantes y cambios sedimentarios en el último milenio. Se dividió el núcleo en tres segmentos, según las características de los sedimentos, el contenido de carbono orgánico (CO) y las edades geológicas. Los registros muestran diferentes alternancias de períodos húmedos y secos, la productividad biológica, precipitación de carbonato, grado de meteorización y altas concentraciones de metales pesados. Los segmentos también coinciden con las diferencias geoquímicas determinadas por las relaciones (ZR+RB)/Sr, Ca/Ti Mn/Fe, CO/Ti, Mg/Ca Ba/Al, Sr/Al Ca/Al. La secuencia inferior (entre 1130 ± 90 a y 870 ± 70 a) muestra un período seco con inundaciones intermitentes y una alta producción de CO en condiciones subaéreas, seguida de un entorno más húmedo entre 870 ± 70 años y 530 ± 40 años, con agotamiento de las proporciones de oligoelementos y CO. El período más reciente (530 ± 40 a al presente) evidencia un ambiente dominado por el régimen fluvial, basado en una relación Ca/Al más baja y un aumento de CO. Las correlaciones estadísticas muestran tres grupos principales que distinguen entre la productividad biológica orgánica, los componentes de la roca madre y los aportes de metales pesados.
       
  • Determination of Critical Mud Window Pressures by Applying Analytical
           Models and Geo-Mechanical Characterization

    • Abstract: Resumen: En Colombia, las cuencas sedimentarias son estructuralmente complejas y presentan un alto tectonismo, por lo que la tendencia es que las operaciones de perforación en yacimientos de hidrocarburos sean complejas y, en consecuencia, causen pérdidas de tiempo y dinero a la industria de hidrocarburos. La aplicación de áreas del conocimiento como la geomecánica es una solución viable al desafío de estabilizar pozos. Este estudio propone algoritmos para evaluar los modelos preexistentes, con modelos nuevos que describen la concentración de los esfuerzos alrededor del pozo y el criterio de falla, estableciendo la relación de falla entre la resistencia de la roca y los esfuerzos que concentra. Ello permite describir el estado de esfuerzos de la pared del pozo, al combinar los criterios de fallas tensionales y compresionales, para obtener las presiones críticas de fractura y colapso, respectivamente. Junto con la presión de poro, aquellas presiones son los componentes de la ventana de lodo, con la que puede mejorarse la estabilidad del pozo, a partir del peso del lodo y la dirección del pozo. Se encontró que, en modelos tensionales, con respecto a la presión crítica tensional, las regiones se encuentran para Azpozo entre 150-330° y 180-360° e Incpozo entre 60° y 90°; también, que valores menores del overbalanced concuerdan con la dirección más estable, que se encuentra para Incpozo en 0-20°, aproximadamente, lo que hace que los pozos de poca inclinación tengan distribución más uniforme de esfuerzos, en comparación con los pozos altamente desviados. : In Colombia, sedimentary basins are structurally complex and have a high tectonism, meaning that drilling operations in hydrocarbon deposits are also complex and, consequently, causing time and money losses to the hydrocarbons industry. Applying areas of knowledge such as geo-mechanics is a viable solution to the challenge of stabilizing wells. This study proposes algorithms to evaluate pre-existing models, with new models describing the concentration of the stresses around the well and the failure criterion, establishing the failure relationship between rock resistance and the stresses it concentrates. This allows to describe the stress state of the well wall by combining tension and compressional failure criteria to obtain critical fracture and collapse pressures, respectively. Along with pore pressure, those pressures are the components of the mud window, with which the well stability can be improved, from the weight of the mud and the direction of the well. It was found that, in tension models, with respect to tension critical pressure, the regions are found for Azwell between 150-330° and 180-360° and Incwell between 60° and 90°. Also, that lower overbalanced values agree with the most stable direction, which is found for Incwell at approximately 0-20°, which makes low-slope wells to show more evenly distributed stress, compared to highly diverted wells.
       
  • Temperature and precipitation trend analysis for the department of Caldas
           (Colombia), using wavelets

    • Abstract: Resumen: El cambio climático, entendido como una alteración del clima, debida o no a la actividad humana, sumada a la variabilidad climática, es un área de estudio primordial en estos momentos. Este estudio se hizo con el objetivo de generar información de tendencias de las variables temperatura y precipitación para el departamento de Caldas, Colombia, mediante la técnica de análisis wavelets. Para tal fin, se seleccionaron las estaciones del Ideam, ubicadas en el territorio, para los periodos 1971-2010, en el caso de precipitación; y para el periodo 1981-2010, en temperatura. Las estaciones registran datos diariamente, los cuales fueron transformados en datos mensuales, cuya tendencia se calculó mediante el análisis multirresolución (MRA), seleccionando la wavelet Daubechies (dB5) con seis niveles de descomposición. Los análisis evidencian tendencias lentas y crecientes en precipitación para las quince estaciones analizadas. Resultado similar se obtuvo para temperatura mínima. Mientras que, para temperatura máxima, se registraron tendencias lentas decrecientes, en una estación. Para los planes integrales de gestión de cambio climático, se recomienda el seguimiento a estas tendencias, en lo posible con series históricas de mayor longitud, para identificar señales de cambio y posibles efectos en el clima regional. : Climate change, understood as an alteration of the climate, due or not to human activity, added to climate variability, is a primary area of study at this time. This study was carried out with the objective of generating information on trends of the temperature and precipitation variables for the department of Caldas, Colombia, using the wavelets analysis technique. For this purpose, the Ideam stations, located in the territory, were selected for the periods 1971-2010, in the case of precipitation; and for the period 1981-2010, for temperature. The stations record data daily, which was transformed into monthly data, their trend was calculated by multi resolution analysis (MRA), selecting the Daubechies wavelet (dB5) with six levels of degradation. The analysis shows slow and increasing trends in precipitation for the fifteen stations analyzed. A similar result was obtained for minimum temperature. While, for maximum temperature, slow decreasing trends were recorded in one station. For comprehensive climate change management plans, it is recommended to monitor these trends, if possible with longer historical series, to identify signs of change and possible effects on the regional climate.
       
  • Local Hydro-Climatology and Impacts on Sochagota Lake, Paipa, Boyacá

    • Abstract: Resumen: El lago Sochagota es un sistema construido que actúa como una laguna de oxidación. Su nivel está regulado, posee afloramiento de agua termomineral y recibe escorrentía de suelos sulfatados ácidos y una porción de agua dulce del río Chicamocha; y descarga en el distrito de riego de Usochicamocha. Al incrementar la concentración de sales termominerales, el sistema entra en tensión, pues la alta salinidad amenaza la biodiversidad y se convierte en fuente de conflictos por el uso del agua en la cuenca. Este trabajo recopiló datos de conductividad, precipitación de treinta años y batimetría, procesados, analizados y modelados, para presentar la variabilidad temporal (periodos contrastantes secos y húmedos) y espacial. De igual forma se realizaron ensayos de ecotoxicidad para evidenciar los posibles efectos de la salinización sobre el ecosistema, la biota y los riesgos asociados con cambios en la hidroclimatología de la zona. Los resultados señalan que el lago es altamente sensible a las disminuciones de precipitaciones que favorecen la acumulación de las sales hidrotermales provenientes de su cuenca y afloramientos, lo que acentúa la eutrofización cultural, lo que puede conducir a fenómenos que afecten el ecosistema y el potencial agropecuario de la zona de influencia. : Lake Sochagota is a built system that acts as an oxidation pond. Its level Is regulated. It has an outcrop of thermo-mineral water, and receives runoffs from acid sulphated soils and a portion of fresh water from the Chicamocha river. It discharges in the irrigation district of Usochicamocha. By increasing the concentration of thermo-mineral salts, the system comes into tension, as high salinity threatens biodiversity and becomes a source of conflict over water use in the basin. This paper shows conductivity, thirty-year precipitation and bathymetry data, processed, analyzed and modeled, to present temporal (dry and wet contrasting periods) and spatial variability. Similarly, ecotoxicity tests were conducted to demonstrate the possible effects of salinization on the ecosystem, biota and risks associated with changes in hydro-climatology in the area. The results indicate that the lake is highly sensitive to decreases in precipitation that favor the accumulation of hydrothermal salts from its basin and outcrops, which accentuates cultural eutrophication, this can lead to phenomena that affect the ecosystem and the agricultural potential of the zone of influence.
       
  • Estimation of Water Loss Due to Evaporation in the El Cazadero Dam,
           Mexico, during a Drought

    • Abstract: : In Mexico, large dams have been a critical component of the water supply. However, the places where they can be built are scarcer every day, a situation that adds to the high costs and social conflicts that they cause. Much of the water stored in dams is lost due to evaporation, so technological alternatives are currently being investigated to reduce it. Regarding the determination of evaporated volumes, data obtained with evaporimeters do not represent actual evaporation, being necessary to apply theoretical models in combination with field measurements to reach better approximations. The main objective of this research is to calculate the water evaporation in the El Cazadero dam located in the State of Zacatecas, Mexico, through Penman's semi-empirical equation using data from the El Cazadero or 32006 weather station. The study area was selected due to its aridity and recurring drought problems that affect water availability. Evaporation results obtained from applying the theoretical model are compared with those reported by the weather station, showing a good correlation. In addition, results of the average daily evaporation are used to determine the approximate volume of water evaporated in the hydrological year between November 2010 and October 2011, when a severe drought occurred, whose magnitude and economic value indicates the necessity to carry out more research on this subject and propose public policies to develop and implement technological alternatives that mitigate this phenomenon.Resumen: En México, las grandes represas han sido un componente crítico del suministro de agua. Sin embargo, los lugares donde se pueden construir son cada día más escasos, una situación que se suma a los altos costos y conflictos sociales que causan. Gran parte del agua almacenada en las presas se pierde debido a la evaporación, por lo que actualmente se están investigando alternativas tecnológicas para reducirla. En cuanto a la determinación de volúmenes evaporados, los datos obtenidos con evaporómetros no representan la evaporación real, siendo necesario aplicar modelos teóricos junto con mediciones en campo para lograr mejores aproximaciones. El objetivo principal de esta investigación es calcular la evaporación del agua en la presa El Cazadero, ubicada en el Estado de Zacatecas, México, a través de la ecuación semiempírica de Penman, utilizando datos de la estación meteorológica El Cazadero o 32006. El área de estudio fue seleccionada debido a su aridez y problemas recurrentes de sequía que afectan la disponibilidad de agua. Los resultados de evaporación obtenidos de la aplicación del modelo teórico se comparan con los reportados por la estación meteorológica, mostrando una buena correlación. Además, los resultados de la evaporación media diaria se utilizan para determinar el volumen aproximado de agua evaporada en el año hidrológico entre noviembre de 2010 y octubre de 2011, cuando se produjo una grave sequía, cuya magnitud y valor económico indica la necesidad de realizar más investigaciones sobre este tema y proponer políticas públicas para desarrollar e implementar alternativas tecnológicas que mitiguen este fenómeno.
       
  • Optimization of Water Transparency Monitoring through MOD09GA: A Case
           Study in Lake Guamues, San Juan de Pasto, Colombia

    • Abstract: Resumen: El lago Guamués (LG) es considerado humedal Ramsar desde el 2000. Debido a su importancia, los ecosistemas lénticos como el LG requieren de programas de monitoreo que sobrepasen su cobertura espacial y temporal. En este estudio se demuestra que usar productos de reflectancia de superficie, generados por el sensor MODIS, puede ser útil para verificar la dinámica espaciotemporal de la profundidad medida con el disco de Secchi (PDS), en el periodo 2001-2020. Para calibrar el modelo, se utilizó una imagen coincidente con los trabajos de campo realizados; se correlacionaron los datos de transparencia de la columna de agua medida con el disco de Secchi con los píxeles de la imagen captados en la banda centrada en los 858,5 nm. Para validar el modelo, se utilizó el método Leave out One Cross Validation (LOOCV). Así, se determinó que el modelo cuadrático presenta mejores resultados con un ajuste en su R2 = 0,74 y un error asociado a las observaciones inferior a los 0,013 m. El análisis espacial reveló que el LG presenta zonas localizadas en sus márgenes donde la PDS puede ser inferior a los 0,5 m. De la misma forma el promedio en su PDS para la imagen del 24 de abril es de 3,87 m. El análisis temporal del lago indica que en 2006-2008 y 2017-2020, se ha presentado mayor variabilidad para los puntos observados, con valores de 3,3 y 2,8 m, respectivamente. : Lake Guamues (LG) has been considered a Ramsar Wetland since 2000. Due to its importance, lenttic ecosystems such as LG require monitoring programs that exceed their spatial and temporal scope. This study shows that using surface reflectance products, generated by the MODIS sensor, can be useful in verifying the spatial dynamics of the Secchi disk depth (ZSD), in the 2001-2020 period. To calibrate the model, an image matching the field work performed was used. The transparency data of the Secchi disk-measured water column was correlated with the image pixels captured in the band centered at 858.5 nm. To validate the model, the Leave Out One Cross Validation (loocv) method was used. Thus, it was determined that the quadratic model showed better results with an adjustment in its R2 = 0.74 and an error associated with observations less than 0.013 m. Spatial analysis revealed that LG has areas located at its banks, where the ZSD may be less than 0.5 m. Likewise, its ZSD average in the image taken on April 24 is 3.87 m. The temporal analysis of the lake indicates that between the 2006-2008 and 2017-2020 periods, greater variability has been reported for the observed points, with values of 3.3 and 2.8 m, respectively.
       
  • Determination of the Hydraulic Behavior of Aquifers in Northern Orinoquia,
           Colombia

    • Abstract: Resumen: La "sequía del Casanare" (2014-2015) prendió las alarmas sobre el desequilibrio que ocurre en algunas zonas de la Orinoquia, debido al inadecuado uso del suelo, la tala indiscriminada y la ausencia de las entidades reguladoras. Como consecuencia, se presenta creciente estrés hídrico, cuyo resultado es la muerte masiva de animales y la pérdida de cultivos, etc. Por tanto, se hacen necesarios estudios adicionales para entender la dinámica hídrica en el norte del Casanare, en las veredas de Caño Chiquito y Centro Gaitán, donde se presentaron los mayores estragos ambientales. Se investigaron los aspectos geológicos y geofísicos de la zona y se realizó la caracterización hidráulica, a partir de pruebas de bombeo, con las que se determinaron parámetros como la transmisividad, la capacidad específica, la conductividad hidráulica y el coeficiente de almacenamiento; con la finalidad de dar a conocer aproximaciones de las condiciones hidrogeológicas de la zona. La geología está determinada por el ambiente de depositación de abanico aluvial influenciado por corrientes fluviales en la sección media y depósitos eólicos en la zona más alejada del piedemonte, información corroborada por las secciones de tomografías. De acuerdo con las pruebas de bombeo, se estableció que se encuentran acuíferos de productividad que va de muy pobre a buena, de acuerdo con los valores de transmisividad, con permeabilidades que oscilan de muy bajas a bajas, en relación con los valores de conductividad hidráulica; además, según su capacidad específica, los acuíferos varían en su extensión y continuidad, cuando se trata de acuíferos locales (depósitos cuaternarios) a regionales (Formación Guayabo). : The "Casanare Drought" (2014-2015) triggered alarms on the imbalance taking place in some areas of the Orinoquia region, due to inadequate soil use, indiscriminate felling, and the absence of regulatory agencies. As a consequence, there is increasing water stress, resulting in the mass death of animals and loss of crops, among other phenomena. Further studies are needed to understand the water dynamics in northern Casanare, especially in the small villages of Caño Chiquito and Centro Gaitán, where the greatest environmental damage occurred. The geological and geophysical aspects of the area were studied along with a hydraulic characterization, based on pumping tests, which determined parameters such as transmissivity, specific capacity, hydraulic conductivity and storage coefficient. All of this was conducted to know the hydrogeological conditions of the zone. The geology of the area is determined by the environment of deposition of alluvial fan influenced by river currents in the middle section, and wind deposits in the farthest area of the foothills. This information is corroborated by the tomographic sections. As a result of the pumping tests, it was possible to determine that there are aquifers with a wide productivity range goes from very poor to good, according to the transmissivity values, with permeabilities that range from very low to low, in relation to the values of hydraulic conductivity. In addition, according to their specific capacity, aquifers vary in extension and continuity, when they are local aquifers (quaternary deposits) to regional aquifers (Guayabo formation).
       
  • Geostatistical Evaluation of Hydro-Physical Soil Properties at the
           Tunguavita Farm, Paipa, Colombia

    • Abstract: Resumen: Dada la Influencia en la explotación agrícola de los atributos físicos de los suelos, es necesario su estudio geoestadístico, con el fin de conocer la distribución y variabilidad que poseen, y su efecto sobre las restantes características del suelo. Por lo anterior, se realizó la medición de 80 puntos en un transecto de la granja de la Universidad Pedagógica y Tecnológica de Colombia. Se analizó la densidad real (Dr), la densidad aparente (Da), la porosidad total (PT), el contenido de carbono orgánico (CO), el tamaño de las partículas y la infiltración básica (Ib), mediante un análisis descriptivo, geoestadístico y multivariado. Las propiedades físicas que presentaron los menores coeficientes de variación (cv) fueron la Dr (7,50%) y la Da (4,33%). Todas las variables evaluadas mostraron bajo cv, a excepción de la Ib. Los valores de CO de la granja son muy bajos (1,97 %). La Dr, el CO y la PT se ajustaron a semivariogramas lineales y tuvieron los mayores rangos (75 m). La arcilla se correlacionó negativamente con la arena y el limo; mientras que la PT tuvo correlación directa con la Dr, e inversa con la Da. La porosidad y el tamaño de partículas tienen gran influencia en la varianza de las propiedades físicas de los suelos de la granja, de acuerdo con el análisis de componentes principales. Probablemente, la ganadería intensiva practicada allí afecta la porosidad y la Dr, lo que disminuye la Ib y aumenta la compactación del suelo. : Given the influence on the agricultural exploitation of the physical properties of soils, it is necessary to study its geo-statistics to know their distribution, variability, and their effect on the remaining soil properties. 80 points were measured in a transect of a farm belonging to the Universidad Pedagógica de Colombia. True density (Td), apparent density (Ad), total porosity (Tp), organic carbon content (OC), particle size and basic infiltration (Bi) were analyzed using a descriptive, geostatistical, and multivariate analysis. The physical properties with the lowest coefficients of variation (cv) were Td (7.50 %) and Ad (4.33 %). All variables showed a low cv, saved the Bi. OC farm values are very low (1.97 %). Td, OC and TP were adjusted to linear semi-variograms and showed the highest ranges (75 m). Clay correlated negatively with sand and lime; while the TP correlated directly with Td, and inversely with Ad. Porosity and particle size have a large influence on the variance of the physical properties of the farm soils, as per the analysis of the main components. It is possible that intensive cattle farming affect the porosity and Td, which decreases the Bi and increases soil compaction.
       
 
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