196,070 research outputs found
Advances in the simulation of debris flow erosion: The case study of the Rio Gere (Italy) event of the 4th August 2017
No full textDebris flows are natural hazards causing fatalities and damages to infrastructures every year. One of the current challenges is to improve the predictability of such events using simulation tools. In this direction, the paper aims to model debris-flow generation starting from the water component and then simulating the motion of the bulked solid-fluid mixture mass flow. The debris component is progressively increased through entrainment of the channel bed material. The simulation has been performed exploiting the tool r.avaflow, which implements a physically-based model (Pudasaini and Mergili, 2019) for the flow propagation and an empirical multi-phase model for the entrainment processes. The investigated study case occurred in the Northeastern Alps of Italy, near the town of Cortina d'Ampezzo (Veneto Region), during the summer of 2017. The debris flow was triggered by a heavy rainstorm that caused extreme surface runoff, leading to entrainment of sediment from the channel bed. The debris flow obstructed the bridge of a regional road and consequently flooded the adjacent areas. Different types of debris flow simulations are performed, testing four specific functions to compute the entrainment rate. The simulated results are then compared against field observations. The analysis considers the differences in volume and depth of entrainment and in the output hydrograph. We conclude that entrainment is correlated with the terrain slope, particularly if it is calculated on a smoothed digital elevation model, which dilutes a less significant local steepness. We calibrate a spatially distributed slope-dependent erosion coefficient that successfully reproduced the observed entrainment volumes. The outcomes highlight the great importance of simulating debris flow entrainment processes adopting a multiphase model, which resulted particularly suitable for an accurate reproduction of the investigated event. The results, corroborated by further verifications, can improve the reliability of challenging predictive simulations on debris flow erosion
Propagación de deslizamientos superficiales en terrenos montañosos tropicales. Caso de estudio: Andes colombianos
No full textilustraciones, diagramas, mapasApproximately one-fifth of the Earth’s surface is considered vulnerable to at least one natural hazards such as cyclones, droughts, floods, earthquakes, volcanoes, and landslides. Landslides are one of the most destructive; there are several triggering factors. In the Colombian Andes, rainfall is the primary triggering factor. Historical records of landslide occurrences in the country between 1900 and 2018 found that rainfall was responsible for 87 percent of them. These landslides are typically shallow and can evolve into more rapid movements such as flows or avalanches. According to recent records, debris flows have caused some of the most severe damage and some of them happened as a result of the occurrence of Clustered Shallow Landslides (CSL). In terms of spatial analysis, most study in the country focuses on estimating the areas most susceptible to the occurrence of Shallow Landslides (SL). But what happens when an SL propagates? This research focuses on parameters for modelling the propagation of SL triggered by rainfall occurred on March 31, 2017, in Mocoa that supply mass to bigger chain processes that affect the city and surrounding villages with approximately 306 dead people. The modeling is carried out through two useful tools. The empirical tool Flow-R, it requires little input information, the propagation is performed using different algorithms and friction laws, fundamental factors are the travel distance angle, velocity, and dispersion. And r.avaflow that incorporates various physics-based models. It was established for each tool the best-fit parameters for modeling with minimal requirements. Results indicated a maximum velocity of 10 m s−1, minimum travel distance angle of 15, and x value of 2 and 4 for modeling in Flow-R. In addition, the cut-off for the probability of impact was set to 25% as the minimal threshold for zoning. The results concerning to the parameters to modeling SL in r.avaflow suggest; to consider the basal friction equal to the internal friction of the material as the starting value. And to use the minimum heights in the range of 0.51 m to 0.61 m to perform hazard zoning of the possible affected areas.Aproximadamente una quinta parte de la superficie terrestre se considera vulnerable a al menos una amenaza de origen natural, como: ciclones, sequías, inundaciones, terremotos, volcanes y movimientos en masa. Siendo este último uno de los más destructivos; existen varios factores detonantes. En los Andes colombianos, las lluvias son el principal factor detonante, según registros históricos entre 1900 y 2018 el 87% de los movimientos en masa fueron detonados por lluvias, los cuales suelen ser poco profundos y pueden evolucionar a movimientos más rápidos y destructivos como flujos y avalanchas. Según registros recientes, la ocurrencia de decenas a cientos de movimientos en masa detonados por lluvias, Resultó en la ocurrencia de avenidas torrenciales, causando afectaciones sobre la población y la infraestructura. En términos de análisis espacial, la mayoría de los estudios realizados se centran en estimar las zonas más susceptibles a la ocurrencia de movimientos en masa superficiales. Pero ¿Qué ocurre cuando un movimiento en masa se propaga? Esta investigación se centra en los parámetros para la modelación de la propagación de movimientos en masa superficiales detonados por las lluvias ocurridas el 31 de marzo de 2017, en Mocoa, que fueron suplemento para un evento concatenado de mayor poder destructivo, que afecto la infraestructura y causó la muerte de aproximadamente 306 personas. La modelación se ejecuta mediante la herramienta empírica Flow-R, la cual requiere poca información de entrada, la propagación se realiza utilizando diferentes algoritmos y reglas. Y r.avaflow incorpora varios modelos basados en la física, teniendo como insumo básico la distribución de la fricción interna del material y fricción basal material – superficie. Se estableció para cada herramienta los parámetros de mejor ajuste para el modelado con requisitos mínimos. Los resultados indicaron para Flow-R una velocidad máxima de 10 m/s, un ángulo de distancia de viaje de 15 grados, y un valor para el, exponte de dispersión x de 2 y 4. Además, el umbral mínimo de la probabilidad de impacto se fijó en 25% para la zonificación. Respecto a r.avaflow, los resultados sugieren considerar la fricción basal igual a la fricción interna del material como valor de partida. Y utilizar las alturas mínimas en el rango de 0, 51 m a 0, 61 m para realizar la zonificación de la amenaza de las posibles áreas afectadas. (Texto tomado de la fuente)Brief review of state of propagation models for flow-like landslides and current state in Colombia / This chapter was written with support of Edier Aristizábal, Martin Mergili and, Oscar EcheverríExploring best-fit parameters for propagation modeling of shallow landslides, using Flow-R / This chapter was written with support of Edier Aristizábal, Martin Mergili and, Oscar EcheverríExploration of basal friction parameter in shallow landslide propagation modeling using r.avaflow / This chapter was written with support of Edier Aristizábal, Martin Mergili and, Oscar EcheverríMaestríaMaestría en Ingeniería - GeotecniaLandslide and risk managementÁrea Curricular de Ingeniería Civi
Propagación de deslizamientos superficiales en terrenos montañosos tropicales. Caso de estudio: Andes colombianos
No full textilustraciones, diagramas, mapasApproximately one-fifth of the Earth’s surface is considered vulnerable to at least one natural hazards such as cyclones, droughts, floods, earthquakes, volcanoes, and landslides. Landslides are one of the most destructive; there are several triggering factors. In the Colombian Andes, rainfall is the primary triggering factor. Historical records of landslide occurrences in the country between 1900 and 2018 found that rainfall was responsible for 87 percent of them. These landslides are typically shallow and can evolve into more rapid movements such as flows or avalanches. According to recent records, debris flows have caused some of the most severe damage and some of them happened as a result of the occurrence of Clustered Shallow Landslides (CSL). In terms of spatial analysis, most study in the country focuses on estimating the areas most susceptible to the occurrence of Shallow Landslides (SL). But what happens when an SL propagates? This research focuses on parameters for modelling the propagation of SL triggered by rainfall occurred on March 31, 2017, in Mocoa that supply mass to bigger chain processes that affect the city and surrounding villages with approximately 306 dead people. The modeling is carried out through two useful tools. The empirical tool Flow-R, it requires little input information, the propagation is performed using different algorithms and friction laws, fundamental factors are the travel distance angle, velocity, and dispersion. And r.avaflow that incorporates various physics-based models. It was established for each tool the best-fit parameters for modeling with minimal requirements. Results indicated a maximum velocity of 10 m s−1, minimum travel distance angle of 15, and x value of 2 and 4 for modeling in Flow-R. In addition, the cut-off for the probability of impact was set to 25% as the minimal threshold for zoning. The results concerning to the parameters to modeling SL in r.avaflow suggest; to consider the basal friction equal to the internal friction of the material as the starting value. And to use the minimum heights in the range of 0.51 m to 0.61 m to perform hazard zoning of the possible affected areas.Aproximadamente una quinta parte de la superficie terrestre se considera vulnerable a al menos una amenaza de origen natural, como: ciclones, sequías, inundaciones, terremotos, volcanes y movimientos en masa. Siendo este último uno de los más destructivos; existen varios factores detonantes. En los Andes colombianos, las lluvias son el principal factor detonante, según registros históricos entre 1900 y 2018 el 87% de los movimientos en masa fueron detonados por lluvias, los cuales suelen ser poco profundos y pueden evolucionar a movimientos más rápidos y destructivos como flujos y avalanchas. Según registros recientes, la ocurrencia de decenas a cientos de movimientos en masa detonados por lluvias, Resultó en la ocurrencia de avenidas torrenciales, causando afectaciones sobre la población y la infraestructura. En términos de análisis espacial, la mayoría de los estudios realizados se centran en estimar las zonas más susceptibles a la ocurrencia de movimientos en masa superficiales. Pero ¿Qué ocurre cuando un movimiento en masa se propaga? Esta investigación se centra en los parámetros para la modelación de la propagación de movimientos en masa superficiales detonados por las lluvias ocurridas el 31 de marzo de 2017, en Mocoa, que fueron suplemento para un evento concatenado de mayor poder destructivo, que afecto la infraestructura y causó la muerte de aproximadamente 306 personas. La modelación se ejecuta mediante la herramienta empírica Flow-R, la cual requiere poca información de entrada, la propagación se realiza utilizando diferentes algoritmos y reglas. Y r.avaflow incorpora varios modelos basados en la física, teniendo como insumo básico la distribución de la fricción interna del material y fricción basal material – superficie. Se estableció para cada herramienta los parámetros de mejor ajuste para el modelado con requisitos mínimos. Los resultados indicaron para Flow-R una velocidad máxima de 10 m/s, un ángulo de distancia de viaje de 15 grados, y un valor para el, exponte de dispersión x de 2 y 4. Además, el umbral mínimo de la probabilidad de impacto se fijó en 25% para la zonificación. Respecto a r.avaflow, los resultados sugieren considerar la fricción basal igual a la fricción interna del material como valor de partida. Y utilizar las alturas mínimas en el rango de 0, 51 m a 0, 61 m para realizar la zonificación de la amenaza de las posibles áreas afectadas. (Texto tomado de la fuente)Brief review of state of propagation models for flow-like landslides and current state in Colombia / This chapter was written with support of Edier Aristizábal, Martin Mergili and, Oscar EcheverríExploring best-fit parameters for propagation modeling of shallow landslides, using Flow-R / This chapter was written with support of Edier Aristizábal, Martin Mergili and, Oscar EcheverríExploration of basal friction parameter in shallow landslide propagation modeling using r.avaflow / This chapter was written with support of Edier Aristizábal, Martin Mergili and, Oscar EcheverríMaestríaMaestría en Ingeniería - GeotecniaLandslide and risk managementÁrea Curricular de Ingeniería Civi
Dr. Duane M. Jackson, Morehouse College, July 2011
No full textThis video is a conversation with Dr. Duane M. Jackson. Dr. Jackson talks about his paper, "Recall and the Serial Position Effect: The Role of Primacy and Recency on Accounting Students' Performance." Jackie Daniel, AUC Woodruff Library, is the interviewer
"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States" By M. Carey.
No full text"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States: containing bried sketches of the moral and political character of those states.
By M. Carey, member of the American philosophical, and of the American Antiquarian Society, and author of The Olive Branch, Cindiciae Hibernicae, essays on banking, on political economy, and on internal improvement.
To which are now added the English editor's comments on the subject; together with Important Advice to Emigrants, and Cautions Against Impositions Practiced in the Outports
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Dr. Glendon Swarthout
No full textHosted by Roger M. Busfield, MSU Assistant Professor of Speech and Theater, Meet the Author is designed to introduce a general audience to a contemporary author and their work through in-depth interviews. This episode features a conversation between Dr. Glendon Swarthout, prolific author and English professor at MSU, and assistant professors Sam S. Baskett and Theodore B. Strandness
Simulation of thermal plant optimization and hydraulic aspects of thermal distribution loops for large campuses
No full textFollowing an introduction, the author describes Texas A&M University and its utilities system. After that, the author presents how to construct simulation models for chilled water and heating hot water distribution systems. The simulation model was used in a $2.3 million Ross Street chilled water pipe replacement project at Texas A&M University. A second project conducted at the University of Texas at San Antonio was used as an example to demonstrate how to identify and design an optimal distribution system by using a simulation model. The author found that the minor losses of these closed loop thermal distribution systems are significantly higher than potable water distribution systems. In the second part of the report, the author presents the latest development of software called the Plant Optimization Program, which can simulate cogeneration plant operation, estimate its operation cost and provide optimized operation suggestions. The author also developed detailed simulation models for a gas turbine and heat recovery steam generator and identified significant potential savings. Finally, the author also used a steam turbine as an example to present a multi-regression method on constructing simulation models by using basic statistics and optimization algorithms. This report presents a survey of the author??s working experience at the Energy Systems Laboratory (ESL) at Texas A&M University during the period of January 2002 through March 2004. The purpose of the above work was to allow the author to become familiar with the practice of engineering. The result is that the author knows how to complete a project from start to finish and understands how both technical and nontechnical aspects of a project need to be considered in order to ensure a quality deliverable and bring a project to successful completion. This report concludes that the objectives of the internship were successfully accomplished and that the requirements for the degree of Degree of Engineering have been satisfied
Simulation of debris flows in the Central Andes based on Open Source GIS: possibilities, limitations, and parameter sensitivity
No full textA GIS-based model framework, designed as a raster module for the OpenSource software GRASS, was developed for simulating the mobilization and motion ofdebris flows triggered by rainfall. Designed for study areas up to few square kilometres, thetool combines deterministic and empirical model components for infiltration and surfacerunoff, detachment and sediment transport, slope stability, debris flow mobilization, andtravel distance and deposition. The model framework was applied to selected study areasalong the international road from Mendoza (Argentina) to Central Chile. The inputparameters were investigated at the local scale. The model was run for a number of rainfallscenarios and evaluated using field observations and historical archives in combinationwith meteorological data. The sensitivity of the model to a set of key parameters wastested. The major scope of the paper is to highlight the capabilities of the model—and ofthis type of models in general—as well as its limitations and possible solutions.Fil: Mergili, Martin. Vienna University of Technology; AustriaFil: Fellin, Wolfgang. Universidad de Innsbruck; AustriaFil: Moreiras, Stella Maris. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Stötter, Johann. Universidad de Innsbruck; Austri
Intern experience at CH���M Hill, Inc.: an internship report
No full textIncludes author's vita"Submitted to the College of Engineering of Texas A&M University in partial
fulfillment of the requirement for the degree of Doctor of Engineering."Includes bibliographical referencesA review of the author's internship experience with CH���M HILL, Inc.
during the period September 1975 through May 1976 is presented. During this nine month
internship the author worked as an Engineer II in the Industrial Processes discipline of this
large consulting engineering firm... The author's prime responsibility was as one of three
lead design engineers on the design of a large wastewater treatment facility for a pulp mill
in Hoquiam, Washington owned by ITT Rayonier Inc. The work generally consisted of the design
of individual treatment units and associated piping and pumping. The purpose of the project
was to provide wastewater treatment capabilities that would satisfy the effluent limitations
(standards) imposed upon the mill by the State of Washington Department of Ecology and the
U.S. Environmental Protection Agency. The author's assignment also entailed necessary
interaction with the project manager and other CH���M HILL design engineers and support staff
members, the client's representatives, and representatives of two other consulting engineering
firms working on the project. Thus, the internship position at CH���M HILL provided considerable
experience coordinating the author's work with the work of other engineers, guiding the design
and administrative efforts of a support staff, and interacting regularly with the client and
other consulting firms. This broad exposure to a variety of engineering and organizational
problems provided a valuable educational experience
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