Debris flow modeling in the Huaycoloro stream located in the Lurigancho-Chosica district in Lima-Perú

El presente trabajo consiste en el modelamiento hidrológico e hidráulico de la quebrada Huaycoloro ubicado en el distrito de Lurigancho – Chosica con fin de proponer soluciones de mitigación estructural y no estructural que integren los modelos. Comenzando por un análisis de eventos de flujo de escombros en el Perú con marco teórico que aborda conceptos básicos relacionados al estudio de hidrología e hidráulica. Para el modelo hidrológico, se realizó la caracterización de la cuenca de la quebrada obteniendo sus parámetros principales, así también se realizó el análisis de precipitaciones y así realizar un modelamiento hidrológico mediante HEC-HMS en colaboración con ArcGIS y determinar caudales máximos con periodo de retorno de 100, 200 y 500 años. El modelo hidráulico fue trabajado con el software FLO-2D PRO y el software libre japonés KANAKO -2D, cuyos parámetros de entrada son hidrogramas calculados por el modelo hidrológico, la topografía digital del terreno, los parámetros físicos y reológicos del flujo, entre otros. Para luego obtener velocidades y profundidades máximas para cada uno de los periodos de retorno mencionados anteriormente cuyos resultados serán comparados entre sí en determinados puntos de control y así precisar cuál de ambos softwares es el mejor, para posteriormente modelar los escenarios incluidas las estructuras y poder determinar su óptimo pre-dimensionamieto y analizar su nivel de mitigación frente al impacto de los flujos de escombros. Finalmente, se realizó la comparación de las modelaciones con estructuras y se propuso de manera conceptual y básica medidas no estructurales, realizando su respectivo análisis, viabilidad y eficiencia para mitigar este tipo de eventos.The present work consists of the hydrological and hydraulic modeling of the Huaycoloro stream located in the district of Lurigancho - Chosica in order to propose structural and non-structural mitigation solutions that integrate the models. Starting with an analysis of debris flow events in Peru with a theoretical framework that addresses basic concepts related to the study of hydrology and hydraulics. For the hydrological model, the characterization of the basin of the creek was carried out, obtaining its main parameters, as well as the analysis of precipitation and thus perform a hydrological modeling using HEC-HMS in collaboration with ArcGIS and determine maximum flows with return period of 100, 200 and 500 years. The hydraulic model was worked with the FLO-2D PRO software and the Japanese free software KANAKO -2D, whose input parameters are hydrographs calculated by the hydrological model, the digital topography of the terrain, the physical and rheological parameters of the flow, among others. To then obtain maximum velocities and depths for each of the aforementioned return periods, the results of which will be compared with each other at certain control points and thus determine which of the two softwares is the best to subsequently model the scenarios including the structures and be able to determine their optimum pre-dimensioning and analyze their level of mitigation against the impact of debris flows. Finally, a comparison of the modeling with structures was carried out and non-structural measures were proposed in a conceptual and basic manner, performing their respective analysis, feasibility and efficiency to mitigate this type of events.Tesi

Response of behavior of two mathematical models in debris flow events

Este trabajo fue realizado en la quebrada Huaycoloro el cual forma parte de la cuenca que lleva el mismo nombre ubicada en el distrito de Lurigancho-Chosica en la provincia de Lima, donde se busca explicar los criterios de modelación de flujo de detritos aplicando dos modelos matemáticos de análisis para este tipo de flujos. El primero de libre acceso KANAKO-2D y el segundo de acceso de paga FLO-2D, ambos modelos requieren datos de entrada en común como la topografía digital del terreno, valores de rugosidad del canal, hidrogramas para diferentes periodos de retorno, propiedades reológicas del fluido a dos fases (agua-sedimento) entre otros. Para esta investigación se realizó un Modelo de Elevación Digital (DEM por sus siglas en inglés) con resolución espacial de 5mx5m, donde al hidrograma liquido se le añade el porcentaje de concentración de sedimentos para la representación del flujo de escombros en los modelos correspondientes, los parámetros reológicos (viscosidad, porcentaje de concentración, esfuerzo de cedencia) son tomados de manera referencial comparando resultados de estudios hechos en la quebrada con muestras validadas recopiladas de la literatura. Para finalmente con el procesamiento de estos datos en ambos programas, obtener resultados como profundidad de flujo, velocidad, concentración de sedimentos, fuerza de impacto, etc. De los cuales, este artículo se centró en la comparación de la profundidad del flujo de escombros de los respectivos modelamientos con un evento real, donde para el modelo Kanako-2D, Flo-2D y la medida en campo se presenta una profundidad promedio de 2.20, 2.50 y 2.60 metros respectivamente, por lo que se concluye que el programa Flo-2D es más preciso en su modelamiento para esta situación en especial.This work was carried out in the Huaycoloro stream which is part of the basin that bears the same name located in the district of Lurigancho-Chosica in the province of Lima, where it seeks to explain the criteria of debris flow modeling applying two mathematical models analysis for this type of flows. The first one with free access KANAKO-2D and the second one with paid access FLO-2D, both models require common input data such as digital terrain topography, channel roughness values, hydrographs for different return periods, rheological properties of the two-phase fluid (water-sediment) among others. For this research, a Digital Elevation Model (DEM) was carried out with spatial resolution of 5mx5m, where the percentage of sediment concentration is added to the liquid hydrograph to represent the debris flow in the corresponding models, the Rheological parameters (viscosity, concentration percentage, yield stress) are taken as a reference, comparing results of studies carried out in the stream with validated samples collected from the literature. Finally, with the processing of these data in both programs, obtain results such as flow depth, velocity, sediment concentration, impact force, etc. Of which, this article focused on the comparison of the depth of the debris flow of the respective modeling with a real event, where for the Kanako-2D, Flo-2D and the field measurement an average depth of 2.20 is presented , 2.50 and 2.60 meters respectively, so it is concluded that the Flo-2D program is more accurate in its modeling for this particular situation.Trabajo de investigació

Phenolic compounds and related enzymes as determinants of quality in fruits and vegetables

24 pages, 4 tables.Phenolic secondary metabolites play an important role in plant-derived food quality, as they affect quality characteristics such as appearance, flavour and health-promoting properties. Their content in foods is affected by many factors that influence phenolic stability, biosynthesis and degradation. In terms of their biosynthesis the key enzyme phenylalanine ammonia-lyase (PAL) is especially relevant, as it can be induced by different stress (environmental) conditions. In addition, polyphenol oxidases (PPO) and peroxidases (POD) are the main enzymes responsible for quality loss due to phenolic degradation. The different factors affecting phenolic-related food quality are reviewed. These include internal (genetic) and environmental (agronomic) factors, technological treatments applied during postharvest storage of fruits and vegetables, as well as processing and storage of the processed products. The different strategies that are required to either maintain or enhance the phenolic-related quality of foods are critically reviewed. Genetic modification designed to decrease polyphenol oxidases or peroxidases is not always a feasible method, owing to side problems related to the growth and defence of the plant. Agronomic treatments can be used to enhance the phenolic content and pigmentation of fruits and vegetables, although the information available on this topic is very scarce and even contradictory. Some postharvest treatments (cold storage, controlled or modified atmospheres, etc) can also improve phenolic-related quality, as well as new processing methods such as irradiation (gamma, UV), high-field electric pulses, high hydrostatic pressures and microwaves.The authors are grateful to the Spanish CICYT (projects ALI97-0681, ALI98-0843 and AGL2000-2014) for financial support of this work. Dr. Juan Carlos Espín is holder of a postdoctoral contract from the Spanish Ministerio de educación Cultura y Deporte (project IFD97-1337-C02-01)Peer reviewe