Reliability Analysis Approach For Operations Planning Of Hydropower Systems

Many existing hydropower storage facilities were built decades ago and components of these aging infrastructure facilities have higher risk of failure. Insufficient capacity or forced outages of the spillway and other waterway passage facilities during flooding incident could potentially increase the probability of dam safety incidents leading to public safety concerns. Currently approaches used to assess the risk and uncertainty in operational decision making are mainly based on qualitative assessment and expert judgment and can be significantly improved by the development of a framework that formally incorporates both qualitative and quantitative reliability analysis methods. Event tree analysis and fault tree analysis have traditionally been used in dam safety risk analysis, with results subject to data adequacy and availability. Our research shows that other methods, such as nonparametric analysis and Monte Carlo simulation techniques can yield good results as well. This study investigated the application of reliability analysis methods to existing hydropower storage facilities, with the objective of developing a new systems engineering based approach for risk and uncertainty analysis to assess and manage the risks of hydropower system operations. Our approach integrates reliability-based methods with hydro system optimization modeling to develop an operational reliability-based modeling framework and to formally treat risk and uncertainty in operations planning. This approach incorporates different sources of uncertainty that are typically encountered in operations planning of these systems, including failure probability of hydro system components such as non-power release structures and turbine facilities. This paper presents the framework we have developed and illustrates the application of our investigation for a hydropower system facility in British Columbia, Canada

A Multi-Objective Optimization Model For Operations Planning Of Multi-Reservoir Systems

This paper presents the development and evaluation of a multi-objective linear programming (LP) optimization tool for an operations planning platform (OPP). The LP optimization model is coded using a high level programming language called AMPL (A Mathematical Programming Language) and solved using a solver called CPLEX. This model was developed by closely working with operations planning engineers at BC Hydro, in Canada, with the support of a research team from the University of British Columbia. The optimization model incorporates two objectives to optimize the operation of a multi reservoir system: maximize revenue from power generation, and to minimize penalties resulting from deviations of reservoir elevations and spill releases from a preferred operating regime. Several multi-objective optimization techniques are being investigated including traditional methods such as the Weighting Method and the Constraint Method, as well as Goal Programming (GP) techniques. These methods would be tested for optimality and computational efficiency and would be generalized and used to study a number of multi-reservoir systems in British Columbia. Stochastic inflows would be considered in the model making use of chance-constraints and probability distribution functions based on historical inflow records. The model also incorporates features which simulate maintenance outages on hydropower plants. The goal is to determine the optimal maintenance schedules that minimize the cost of these outages. We present results of a case study to illustrate the capabilities of the model to provide decision makers with timely information on trade-off between different objectives. Maintenance schedules of generating units with and without optimization are also considered

Desarrollo y caracterización de películas activas con nanopartículas de plata obtenidas mediante síntesis verde

The use of edible films is a technology to extend the shelf life of food. The addition of silver nanoparticles (AgNPs) could improve the performance of edible films and avoid the growth of microorganisms that could affect food. The objective was to elaborate and characterize AgNPs by green synthesis and to evaluate the effect of their addition on the mechanical and barrier properties of films formed from Cajanus cajan protein and Tamarindus indica seed gum. An aqueous extract of Annona muricata leaves was used for green synthesis. Three films were developed containing AgNPs, aqueous extract of Annona muricata leaves and water (control). Films were evaluated by their water vapour permeability (WVP), color, opacity and mechanical properties. The AgNPs increased twice the Young's module (0.0675 MPa) and the tensile strength (2.84 MPa) in relation to control film. Moreover, the AgNPs influenced also the color and opacity of the films. However, no differences were observed in the WVP. The addition of AgNPs to films, could be an option to increase the shelf life of foods.El uso de películas comestibles es una tecnología para alargar la vida útil de los alimentos. La adición de nanopartículas de plata (AgNPs) podría mejorar el desempeño de películas comestibles y evitar el crecimiento de microorganismos que podrían afectar a los alimentos. El objetivo fue elaborar y caracterizar AgNPs mediante síntesis verde y evaluar el efecto de su adición sobre las propiedades mecánicas y de barrera de películas formadas a partir de proteína de Cajanus cajan y goma de la semilla de Tamarindus indica. Para la síntesis de AgNPs se utilizó extracto acuoso de Annona muricata. Tres diferentes formulaciones de películas se elaboraron las cuales contenían AgNPs, extracto acuoso de guanábana y agua (control). Las películas fueron evaluadas en términos de su permeabilidad al vapor de agua (WVP), color, opacidad y propiedades mecánicas. Las AgNPs incrementaron el doble el módulo de Young de las películas (0.0675 MPa) y la fuerza de tensión (2.84 MPa) con respecto al control. Además, las AgNPs influyeron estadísticamente en el color y opacidad de la película. Sin embargo, no se observaron diferencias en la PVA. La adición de AgNPs a recubrimientos podría ser una opción para incrementar la vida útil de alimentos

Reducción de residuos orgánicos en el ámbito gastronómico colombiano

Colombia actualmente enfrenta la problemática concerniente al destino final de cada uno de los desechos orgánicos que produce las cocinas colombianas, generando grandes consecuencias en el marco de una contaminación por desechos, tanto de manera explorativa con consultas bibliográficas y aplicación de instrumentos en una muestra de 26 personas, buscando identificar los diferentes factores que están causando el incremento contaminante afectando el entorno socio ambiental, con el objeto de llegar hacia la consecución de alternativas en una posible caracterización de cada uno de los sobrantes que se generan desde el entorno familiar proyectado al gremio gastronómico y determinar estrategias, basadas en la normatividad vigente, y llegar así a disminuir los daños ambientales que se generan al no realizar una respectiva descomposición y darle un segundo vistazo a como los desechos orgánicos pueden ser una fuente de beneficios, con un adecuado proceso, el cual nos puede permitir crear una excelente transformación mediante compostaje, para la oportuna descomposición de cada uno de los productos agrícolas que se utiliza para la alimentación de nuestro país mediante la educación, para fomentar la concientización social

Anemia falciforme e gravidez: relato de caso clínico

Sickle cell anemia (SCA) is a pathology with high rates of complications, when presented in pregnancy it is a medical challenge to manage patients due to the high risk of maternal and perinatal morbidity-mortality, case report and review of literature presented at the Hospital Universitario Clínica San Rafael de Bogotá (National Clinic) in 2018, a women in the third trimester of pregnancy with diagnosis of sickle cell anemia that is complicated with preeclampsia with characteristics of severity and preterm delivery.The objective of publishing this case is to review the information regarding the incidence, the maternal and perinatal morbidity / mortality of this medical condition, its management by a multidisciplinary team and the early detection of complications in order to improve the prognosis of the motherchild binomial.La anemia de células falciformes (ACF) es una patología con altos índices de complicaciones; además, cuando se presenta durante el embarazo su manejo se convierte en un desafío médico debido al riesgo elevado de morbimortalidad materna y perinatal. A continuación, se hace una breve revisión de la literatura sobre ACF y se describe un reporte de caso presentado en el Hospital Universitario Clínica San Rafael de Bogotá, Colombia, en el año 2018. La paciente era una primigestante en tercer trimestre del embarazo con diagnóstico de ACF que se complicó con una preeclampsia con características de severidad y concluyó en parto pretérmino. El objetivo de publicar este caso es revisar la información respecto a la incidencia y la morbimortalidad materna y perinatal de la ACF, teniendo en cuenta que debe ser manejada por un equipo multidisciplinario y que se debe hacer detección temprana de complicaciones con el fin de mejorar el pronóstico del binomio madre-hijo.A anemia falciforme (ACF) é uma patologia com altas taxas de complicações; quando ocorre na gravidez, é um desafio médico para gerenciar pacientes devido ao alto risco de morbidade materna e perinatal. Apresenta-se o relato de caso e revisão de literatura apresentada no Hospital Universitário Clínico SanRafael de Bogotá (Clínica Nacional) em 2018, primigestante no terceiro trimestre de gravidez com diagnóstico de anemia falciforme complicada pela pré-eclâmpsia com características de gravidade e parto prematuro.O objetivo da publicação deste caso é revisar as informações referentes à incidência, morbimortalidade materna e perinataldessa condição médica, levando em consideração que ela deve ser gerenciada por uma equipe multidisciplinar e fazer a detecção precoce de complicações, a fim de melhorar o prognóstico binomial: mãe-filho

Preservice Elementary Science Teachers' Argumentation Competence: Impact of a Training Programme

The recent literature has shown the importance of Preservice Elementary Science Teachers (PESTs) having a deep understanding of argumentation, as this factor may affect the nature of the class activities that are taught and what students learn. A lack of understanding of this factor may represent an obstacle in the development of science education programmes in line with the development of scientific competences. This paper presents the results of the design and implementation of a training programme of 6 sessions (12 hours of class participation plus 8 hours of personal homework) on argumentation. The programme was carried out by 57 Spanish PESTs from Malaga, Spain. The training programme incorporates the innovative use of certain strategies to improve competence in argumentation, such as teaching PESTs to identify the elements of arguments in order to design assessment rubrics or by including peer assessment during evaluation with and without rubrics. The results obtained on implementing the training programme were evaluated based on the development of PESTs’ argumentation competence using Toulmin’s argumentative model. Data collection methods involved two tasks carried out at the beginning and the end of the programme, i.e., pre-test and post-test, respectively. The conclusion of the study is that students made significant progress in their argumentation competence on completing the course. In addition, PESTs who followed the training programme achieved statistically better results at the end than those in the control group (n = 41), who followed a traditional teaching programme. A 6-month transfer task showed a slight improvement for the PESTs of the experimental group in relation to the control group in their ability to transfer argumentation to practice, especially to the extent to which they mentioned argumentation in their practice portfolios.This work is part of the “I+D Excelencia” project “Development and evaluation of scientific competences through context based and modelling teaching approaches” case studies (EDU2013-41952-P), funded by the Spanish Ministry of Economy and Finance through its 2013 research call

Development and evaluation of a multi-objective optimization model for multi-reservoir systems

The BC Hydro and Power Authority is the largest electric utility in the province of British Columbia, Canada. With a generating capacity of more than 12,000 MW, it serves almost 2 million customers in the province. It operates 31 hydroelectric facilities, most of them located in multi-reservoir systems. In order to facilitate the operation of these reservoirs, BC Hydro developed an in-house application called the Operations Planning Tool (OPT), a deterministic Linear Programming (LP) model that provides the optimal operation of the multi-reservoir systems considering multiple purposes. The objective of this research was to investigate, develop, incorporate and test additional modeling features that would expand the current capabilities of the OPT. This included developing a formulation for the analysis of units’ maintenance outages and changing the optimization model to consider inflow uncertainty and avoid the use of weight coefficients and penalty functions. The formulation developed for the analysis of units’ maintenance outages is based on a two-stage algorithm. In the first stage, a pre-processor defines all the possible outage solutions given some initial configurations. In the second stage, a modified OPT model is run to find an outage solution that optimizes the objectives using a Mixed-Integer Linear Programming (MILP) algorithm. The formulation was tested using the Bridge River system in British Columbia, Canada. An alternative OPT model was also developed to consider the uncertainty in the reservoir’s inflow and modify the formulation of the objective function. It was desired to avoid the use of weight coefficients and penalty functions due to the limitations that they present. The proposed alternative was based on the development of a linear decision rule and the use of chance constraints. The linear decision rule is an operating rule that defines the spillway releases and forebay elevation as a linear function of the inflow, the turbine releases and a deterministic decision variable. The chance constraints were used to consider the probability of the spillway releases and forebay elevation not being within a preferred range of values established by the user. The developed formulation was tested using the Stave Falls system.Applied Science, Faculty ofCivil Engineering, Department ofGraduat

Secuencia didáctica como estrategia pedagógica para el fortalecimiento de la competencia de resolución de problemas con operaciones básicas de números enteros, en estudiantes del grado sexto de la Institución Educativa El Bosque del municipio de Soacha, a través de la implementación de un blog.

Este proyecto tiene como objeto fortalecer la competencia de resolución de problemas con operaciones básicas de números enteros, en estudiantes de grado sexto de la institución educativa el bosque del municipio de Soacha, mediante una estrategia pedagógica basada en una secuencia didáctica presentada en un blog. La competencia de resolución de problemas matemáticos, juega un rol fundamental en el desarrollo de habilidades que son aplicables en la vida diaria. Cuando surgen diferentes dificultades en esta competencia, se ve afectado negativamente el desempeño académico de los estudiantes y su desenvolvimiento en las diferentes situaciones de su vida diaria. Por esta razón, se llevó a cabo esta investigación .MaestríaMagíster en Recursos Digitales Aplicados a la Educació