293 research outputs found
RelaciĂłn entre las variables de proceso en la fase final de aceleraciĂłn y las variables de producto en el lanzamiento de peso
La técnica de la fase final del lanzamiento de peso, definida desde el comienzo de la última fase de apoyo doble hasta la suelta del peso, es muy similar entre los atletas a pesar de que previamente hayan utilizado un modelo técnico de lanzamiento en giro o en deslizamiento, el objetivo de este estudio ha sido analizar la interacción entre las variables biomecánicas que determinan el rendimiento en esta prueba atlética en su fase final. Se han analizado a los ocho finalistas del lanzamiento de peso hombres y a las ocho finalistas del lanzamiento de peso de mujeres durante su participación en el Campeonato del Mundo de Atletismo de Pista Cubierta, Valencia 08. Se han utilizado técnicas fotogramétricas tridimensionales (3D) a partir de la filmación del gesto con dos cámaras de video a 100 Hz y sincronizadas temporalmente mediante un sistema electrónico. El sistema de referencias ha sido un cubo con doce puntos distribuidos proporcionalmente en el espacio de lanzamiento. Finalmente, se utilizaron las técnicas de transformación lineal directa (DLT) para obtener las coordenadas espaciales. Los resultados obtenidos muestran las diferencias en las variables de proceso entre lanzadores y técnicas utilizadas, existiendo compromisos entre las variables temporales, distancias y velocidades analizadas, destacando que el ángulo utilizado en el lanzamiento es inferior al óptimo y que la velocidad del peso se muestra como factor de producto determinante en el rendimiento de esta especialidad atlética.The technique of the final phase of the shot put, defined from the beginning of the last phase of double support up to the release of the ball, is very similar among athletes in spite of the fact, that before they have used a technical model of throwing, the rotational technique or the glide technique, the aim of this study has been to analyze the interaction among the biomechanical variables that determine the performance in this athletic event in its final phase. Men and women finalist (n=16) have been analyzed during their participation in the Championship of the World of Athletics, Valencia 08. There have been used photogrammetrical three-dimensional technologies (3D) from the filming of the gesture with two video cameras to 100 Hz and synchronized temporarily by means of an electronic system. The system of references has been a bucket with twelve points distributed proportionally in the space of throwing. Finally, the linear direct transformation techniques (DLT) were in use for obtaining the spatial coordinates. The obtained results show the differences in the process variables among putters and the techniques used, existing commitments among the temporary variables, distances and analyzed speeds, emphasizing that the angle used in the shot is lower than the ideal one and that the speed of the weight appears as factor of determinant product in the performance of this athletic speciality.Peer Reviewe
DespuĂ©s del levonorgestrel, Âżserá la mifepristona (RU486) la siguiente «pĂldora del dĂa despuĂ©s»?
Analysis of Climate Change s Effect on Flood Risk. Case Study of Reinosa in the Ebro River Basin
[EN] Floods are one of the natural hazards that could be most affected by climate change, causing great economic damage and casualties in the world. On December 2019 in Reinosa (Cantabria, Spain), took place one of the worst floods in memory. Implementation of DIRECTIVE 2007/60/EC for the assessment and management of flood risks in Spain enabled the detection of this river basin with a potential significant flood risk via a preliminary flood risk assessment, and flood hazard and flood risk maps were developed. The main objective of this paper is to present a methodology to estimate climate changeÂżs effects on flood hazard and flood risk, with Reinosa as the case study. This river basin is affected by the snow phenomenon, even more sensitive to climate change. Using different climate models, regarding a scenario of comparatively high greenhouse gas emissions (RCP8.5), with daily temperature and precipitation data from years 2007Âż2070, and comparing results in relative terms, flow rate and flood risk variation due to climate change are estimated. In the specific case of Reinosa, the MRI-CGCM3 model shows that climate change will cause a significant increase of potential affected inhabitants and economic damage due to flood risk. This evaluation enables us to define mitigation actions in terms of costÂżbenefit analysis and prioritize the ones that should be included in flood risk management plans.Lastrada MarcĂ©n, JE.; Cobos Campos, G.; Torrijo, F. (2020). Analysis of Climate Change s Effect on Flood Risk. Case Study of Reinosa in the Ebro River Basin. Water. 12(4):1-14. https://doi.org/10.3390/w12041114S114124Flood Risk Management: A Strategic Approach https://unesdoc.unesco.org/ark:/48223/pf0000220870Doroszkiewicz, J., Romanowicz, R., & Kiczko, A. (2018). The Influence of Flow Projection Errors on Flood Hazard Estimates in Future Climate Conditions. Water, 11(1), 49. doi:10.3390/w11010049Zhu, T., Lund, J. R., Jenkins, M. W., Marques, G. F., & Ritzema, R. S. (2007). Climate change, urbanization, and optimal long-term floodplain protection. Water Resources Research, 43(6). doi:10.1029/2004wr003516Nyaupane, N., Thakur, B., Kalra, A., & Ahmad, S. (2018). Evaluating Future Flood Scenarios Using CMIP5 Climate Projections. Water, 10(12), 1866. doi:10.3390/w10121866Intergovernmental Panel on Climate Change https://archive.ipcc.ch/European Flood Awareness System (EFAS) https://www.efas.eu/en/news/summary-efas-notifications-2019Garijo, C., & Mediero, L. (2018). Influence of climate change on flood magnitude and seasonality in the Arga River catchment in Spain. Acta Geophysica, 66(4), 769-790. doi:10.1007/s11600-018-0143-0Garijo, C., Mediero, L., & Garrote, L. (2018). Utilidad de las proyecciones climáticas generadas por AEMET para estudios de impacto del cambio climático sobre avenidas a escala nacional. IngenierĂa del agua, 22(3), 153. doi:10.4995/ia.2018.9312ASTER. Modelo HidrolĂłgico De SimulaciĂłn Y PrevisiĂłn Aplicado A Cuencas Donde El FenĂłmeno Nival Es Relevante http://www.spesa.es/paginas/basededatos/ASTER_Manual_Usuario.pdfPolicy-Relevant Assessment of Socio-Economic Effects of Droughts and Floods, To Establish a Damage-Water Depth Relationship http://www.feem-project.net/preempt/Cobos, G., FrancĂ©s, M., & Arenillas, M. (2010). Le programme ERHIN. ModĂ©lisation nivo-hydrologique pour la gestion de l’eau du bassin de l’Ebre. La Houille Blanche, (3), 58-64. doi:10.1051/lhb/2010035Anderson, E. A. (1968). Development and testing of snow pack energy balance equations. Water Resources Research, 4(1), 19-37. doi:10.1029/wr004i001p0001
A Decrease in the Regulatory Effect of Snow-Related Phenomena in Spanish Mountain Areas Due to Climate Change
[EN] Climate change undoubtedly will affect snow events as temperature and precipitation are expected to change in the future. Spanish mountains are especially affected by that situation, since snow storage is there focussed on very specific periods of the hydrological year and plays a very important role in the management of water resources. In this study, an analysis of the behaviour of the complex snow-related phenomena in the four main mountain regions of Spain in the next 50 years is conducted. The ASTER hydrological model is applied using temperature and precipitation data as basic input, estimated under a climate change scenario. Results show different changes in the maximum and average expected flows, depending on the very different magnitude and sign of changes in precipitation. An increase of flooding episodes may occur as a result of a complex relation between changes in precipitation and an increase in maximum snowmelt intensities that range from 2.1% in the Pyrenees to 7.4% in the Cantabrian Mountains. However, common patterns are shown in a shorter duration of the snow bulk reserves, expected to occur 45 days earlier for the Cantabrian Mountains, and about 30 days for the rest of the studied mountain regions. Changes observed also lead to a concerning decrease in the regulatory effect of the snow-related phenomena in the Spanish rivers, with a decrease in the average snow accumulation that ranges from about 28% for the Pyrenees and Sierra Nevada to 42% for the Central System and the Cantabrian Mountains. A decrease in average flow is expected, fluctuating from 2.4% in the Pyrenees to 7.3% in Cantabrian Mountains, only increasing in the Central System by 4.0%, making all necessary to develop new adaptation measures to climate change.The authors acknowledge F. J. Sanchez, M. Aparicio and F. Pastor (Spanish Ministry for Ecological Transition and the Demographic Challenge), Tragsatec and ASTER model developer J. A. Collado (SPESA Ingenieria). The authors fully acknowledge the financial support provided by the Department of Geological and Geotechnical Engineering of the UPV.Lastrada, E.; GarzĂłn-Roca, J.; Cobos Campos, G.; Torrijo, F. (2021). A Decrease in the Regulatory Effect of Snow-Related Phenomena in Spanish Mountain Areas Due to Climate Change. Water. 13(11):1-20. https://doi.org/10.3390/w13111550S120131
Seasonal variability of snow density in the Spanish Pyrenees
[EN] Spanish latitudes and meteorological conditions cause the snow phenomena to mainly take place in mountainous areas, playing a key role in water resource management, with the Pyrenees as one of the most important and best monitored areas. Based on the most significant dataset of snow density (SDEN) in the Spanish Pyrenees for on-site manual samples and automatic measurements, in this study, single and multiple linear regression models are evaluated that relate SDEN with intra-annual time dependence and other drivers such as the seasonal accumulated precipitation, 7-day average temperatures, snow depth (SD) and elevation. The seasonal accumulated precipitation presented a more dominant influence than daily precipitation, usually being the second most dominant SDEN driver, followed by temperature. Average temperatures showed the best fitting to SDEN. The results showed similar densification rates ranging widely from 0.7 x 10(3) kg/L/day to 2 x 10(3) kg/L/day without showing a spatial pattern. The densification rate for the set of manual samples was set to 1.2 kg/L/day, very similar to the set of automatic measurements (1.3 kg/L/day). The results increase knowledge on SDEN in the Pyrenees. The SDEN regression models that are given in this work may allow us, in the future, to estimate SDEN, and consequently Snow Water Equivalent (SWE), using an economical and extensive SD and meteorological network, although the high spatial variability that has been found must be regarded. Estimating a relationship between SDEN and several climate drivers enables us to take into account the impact of climate variability on SDEN.The authors acknowledge F. Pastor and F. J. Sanchez (Spanish Ministry for Ecological Transition and the Demographic Challenge); M. L. Moreno (EbroWater Authority); the Ebro Water Authority and field engineers A. Pedrero-Munoz and M. Motes (SPESA Ingenieria). The authors fully acknowledge the financial support provided by the Department of Geological and Geotechnical Engineering of the UPV.Lastrada, E.; Cobos Campos, G.; GarzĂłn-Roca, J.; Torrijo, F. (2021). Seasonal variability of snow density in the Spanish Pyrenees. Water. 13(11):1-17. https://doi.org/10.3390/w13111598117131
Variabilidad de la secuencia temporal de la cadena cinética en el lanzamiento de balonmano
Análisis biomecánico de la técnica individual de los finalistas masculinos del lanzamiento de peso en el Campeonato del Mundo de Atletismo Valencia 08
El objetivo de este estudio ha sido realizar un análisis descriptivo de la tĂ©cnica individual de los ocho finalistas masculinos de lanzamiento de peso en el Campeonato del Mundo de Atletismo de Pista Cubierta, celebrado en Valencia, 2008. Para este estudio, se han utilizado tĂ©cnicas fotogramĂ©tricas tridimensionales (3D) a partir de la filmaciĂłn del gesto con dos cámaras de video sincronizadas temporalmente a 100 Hz, analizándose el mejor lanzamiento de cada atleta. Se parte de un análisis temporal, donde se ha dividido el gesto en seis fases. A partir de esas fases, se describen las gráficas de velocidad tangencial del CG y el peso con respecto al tiempo. A continuaciĂłn, se registraron los factores que determinan la trayectoria del peso durante el vuelo (factores de producto), asĂ como el compromiso de otros factores causales que determinan la eficacia del lanzamiento de peso. Además de confirmar la relaciĂłn entre los factores de producto, los resultados ponen de manifiesto que cada lanzador utiliza una secuencia temporal y ritmo de ejecuciĂłn propio e individual, confirmándose que la ejecuciĂłn tĂ©cnica del lanzamiento de peso es individual y está condicionada por caracterĂsticas antropomĂ©tricas, capacidad muscular y el grado de automatizaciĂłn de la secuencia temporal individual.The aim of this study is to make a descriptive analysis of the individual technique of the eight men finalists in the shot put in the 2008 Valencia Indoor World Championships. To do this three-dimensional photogrammetric techniques (3D) were used, filming the action with two video cameras temporally synchronized at 100 Hz. Six puts were recorded during the men’s final, subsequently analysing the longest throw of each putter. A temporal analysis was first made, dividing the throwing action into six phases. Starting from these phases, graphs of the tangential velocity of the thrower’s CG and the time taken in the shot are described. Then the factors that determine the trajectory of the shot during flight (product factors) and the contribution of the other causal factors for the efficiency of the put are recorded. As well as confirming the relation between the product factors, the results show that each thrower uses his/her own temporal sequence and rhythm of execution, confirming that the technical execution of the shot put is individual and conditioned by anthropometrical characteristics, muscular capacity and the degree of automation of the individual temporal sequence.Peer Reviewe
Estimation of cerchar abrasivity index of andesitic rocks in Ecuador from chemical compounds and petrographical properties using regression analyses
[EN] An important issue in any rock engineering project is the adequate prediction of tool consumption. Excavation tools are subjected
to wear, and repair/replacement of those tools is usually an important expense on any excavation budget. The key factor that
affects wear of excavation tools is rock abrasivity. In mining and civil engineering, rock abrasivity is typically measured by the
Cerchar abrasivity index (CAI), which is obtained in laboratory from a Cerchar abrasivity test. This paper studied the relation
between CAI and the chemical compounds and petrographical properties of andesitic rocks from the central area of Ecuador. A
series of regression analyses are performed to study the influence of the different chemical compounds and petrographical
properties on the CAI value. Results show that it is possible to make a good estimation of CAI from the plagioclase grain size
and/or the content of SiO2, FeO, MgO, CaO, Na2O and K2O compounds.Torrijo, F.; GarzĂłn-Roca, J.; Company RodrĂguez, J.; Cobos Campos, G. (2018). Estimation of cerchar abrasivity index of andesitic rocks in Ecuador from chemical compounds and petrographical properties using regression analyses. Bulletin of Engineering Geology and the Environment. 1-14. doi:10.1007/s10064-018-1306-6S114Al-Ameen SL, Waller MD (1994) The influence of rock strength and abrasive mineral content on the CERCHAR abrasive index. Eng Geol 36:293–301Alber M (2007) Stress dependency of the Cerchar Abrasivity index (CAI) and its effects on wear of selected rock cutting tools. Tunn Undergr Space Technol 9:351–539Alber M (2008) Stress dependency of the Cerchar abrasivity index (CAI) and its effects on wear of selected rock cutting tools. Tunn Undergr Space Technol 23:351–359Alber M, Yaralı O, Dahl F, Bruland A, Käsling H, Michalakopoulos TN, Cardu M, Hagan P, Aydın H, Ă–zarslan A (2014) ISRM suggested method for determining the abrasivity of rock by the CERCHAR abrasivity test. Rock Mech Rock Eng 47:261–266ASTM D3967 (2001) Standard test method for splitting tensile strength of intact rock core specimens. American Society for Testing and Materials, West ConshohockenASTM D7012 (2010) Standard test method for compressive strength and elastic module of intact rock core specimens under varying states of stress and temperatures. American Society for Testing and Materials, West ConshohockenASTM D7625 (2010) Standard test method for laboratory determination of abrasiveness of rock using the CERCHAR method. American Society for Testing and Materials, West ConshohockenAtkinson T, Cassapi VB, Singh RN (1986a) Assessment of abrasive wear resistance potential in rock excavation machinery. Int J Min Geol Eng 3:151–163Atkinson T, Denby B, Cassapi VB (1986b) Problems associated with rock material properties in surface mining equipment selection. Trans Inst Min Metall Section A Miner Ind 95:A80–A86Boland MP, Pilatasig LF, Ibandango CE, McCourt WJ, Aspden JA, Hughes RA, Beate B (2000) Geology of the western cordillera between 0°-1°N, mining development and environmental control project, map and geological information program, report no. 10, (Proyecto de Desarrollo Minero y control Ambiental, Programa de Informacion cartografica y GeolĂłgica, Informe no. 10), CODIGEM-BGS, Quito, Ecuador, p 72 (In Spanish)CERCHAR (1986) The CERCHAR abrasiveness index. Centre d’Etudes et des Recherches des Charbonages de France, Verneuil, FranceDeliormanlı A (2011) Cerchar abrasivitiy index (CAI) and its relation to strength and abrasion test methods for marble stones. Constr Build Mat 30:16–21Deliormanlı AH (2012) Cerchar abrasivity index (CAI) and its relation to strength and abrasion test methods for marble stones. Constr Build Mater 30:16–21Er S, Tugrul A (2016a) Correlation of physico-mechanical properties of granitic rocks with Cerchar Abrasivity index in Turkey. Measurement 91:114–123Er S, Tugrul A (2016b) Estimation of Cerchar abrasivity index of granitic rocks in Turkey by geological properties using regression analysis. B Eng Geol Environ 75(3):1325–1339Fowell RJ, Abu Bakar MZ (2007) A review of the Cerchar and LCPC rock abrasivity measurement methods. Proceeding of the 11th congress of the International Society for Rock Mechanics 155–160Hamzaban MT, Memarian H, Rostami J (2014a) Continuous monitoring of pin tip wear and penetration into rock surface using a new Cerchar abrasivity testing device. 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Geomechanical characterization and analysis of the Upper Cretaceous flysch materials found in the Basque Arc Alpine region
[EN] Flysch materials are one of the most challenging geological materials and often give rise to slope instability problems. Due to its natural heterogeneity, geomechanical characterization of flysch materials is somewhat difficult. The Spanish Basque Arc Alpine region is a very well-known location for flysch materials. In this paper, an area of approximately 100 km(2) in the region is intensively studied and their flysch materials geomechanically characterized. A total of 33 locations are investigated by a broad geological-geotechnical investigation, involving petrographic analyses, geomechanical stations, boreholes, and mechanical laboratory tests. In addition, a slope inventory was carried out to assess the situation in the existing slopes in the area. Characterization of materials is carried out in terms of RQD, RMR, and GSI as well as using the Hoek-Brown failure criterion. Different correlations are assessed, establishing their appropriateness for estimating the mechanical parameters of a flysch material rock mass.Financial support was provided by the Department of Geological and Geotechnical Engineering of the UPV.GarzĂłn-Roca, J.; Torrijo, F.; Company RodrĂguez, J.; Cobos Campos, G. (2021). Geomechanical characterization and analysis of the Upper Cretaceous flysch materials found in the Basque Arc Alpine region. Bulletin of Engineering Geology and the Environment. 80(10):7831-7846. https://doi.org/10.1007/s10064-021-02383-378317846801
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