Agaete revisited: new data on the Gran Canaria tsunamiites.

The tsunami deposits of the valley of Agaete (Pérez-Torrado et al., 2006), north-western Gran Canaria, attributed to the Guimar flank collapse in Tenerife, have been revisited and new data are presented here. Besides the occurrences reported by Pérez-Torrado et al. (2006) a new outcrop was found and named “La Ruina” (at 28º 05’ 47,41” N; 15º 41’ 52,04” W; 71 m asl). The above-mentioned authors suggested the possibility that more than one marine conglomerate deposit could be present in the outcrops of “Llanos de Turmán” and “Berrazales”. At “La Gasolinera” and “La Aldea 1” the conglomerates are formed by a single layer representing one depositional event; at “La Aldea 2”, the conglomerates are composed of two layers directly contacting with each other, but evidence of a time hiatus between them was not found. Although the hypothesis of stacking of two depositional units within the same episode versus deposition of two distinct layers in different time-moments is debatable at the present state of knowledge, the first possibility is favoured. The field evidence at “Llanos de Turman” and “Berrazales” unquestionably shows that terrestrial sediments (colluvia; paleosols) are present and separate two marine conglomerate deposits, indicating that at least two distinct tsunami inundations are needed to explain the stratigraphy. However, at the new “La Ruina” outcrop, besides the two deposits mentioned above, a third and older marine conglomerate was found, clearly separated in time from the ones cited above. The existence of marine conglomerates emplaced in different moments is evidenced by the occurrence of intercalated paleosols, colluvia and other subaerial materials, implying significant time intervals between the emplacement of marine conglomeratic layers. A number of gastropod operculae from the tsunamiites were sent for U-Th dating to try to further constrain the age span of these deposits. The field evidence presented above shows that the emplacement of the deposits is related to, at least, three tsunami events. The lateral correlation between different outcrops is difficult due to variable number of deposits in each outcrop, lateral discontinuity and variability, and to compositional and textural similarity between distinct tsunami sediments. The occurrence of three Pleistocene tsunami deposits in the same area points to a relatively high frequency of tsunamis (generated by landslides, surface rupturing earthquakes, fast entry of voluminous volcanic deposits into the sea or large submarine eruptions). It is possible that this recurrence of tsunami inundations may reflect multiple-phased landslides responsible for the mega-landslide scars prominent in the geomorphology of the neighbouring island of Tenerife. This is a contribution from project “Estabilidad de los edificios volcánicos en Canarias: análisis de los factores geológicos, geomecánicos y paleoclimáticos. Aplicación a los flancos N y S de la isla de Tenerife” financed by MCT, Spain.

Estudio experimental del desgaste del flanco y de la rugosidad superficial en el torneado en seco de alta velocidad del acero AISI 316L

La mejora continua de los procesos de fabricación es fundamental para alcanzar niveles óptimos de productividad, calidad y coste en la producción de componentes y productos. Para ello es necesario disponer de modelos que relacionen de forma precisa las variables que intervienen en el proceso de corte. Esta investigación tiene como objetivo determinar la influencia de la velocidad de corte y el avance en el desgaste del flanco de los insertos de carburos recubiertos GC1115 y GC2015 y en la rugosidad superficial de la pieza mecanizada de la pieza en el torneado de alta velocidad en seco del acero AISI 316L. Se utilizaron entre otros los métodos de observación científica, experimental, medición, inteligencia artificial y estadísticos. El inserto GC1115 consigue el mejor resultado de acuerdo al gráfico de medias y de las ecuaciones de regresión múltiple de desgaste del flanco para v= 350 m/min, mientras que para las restantes velocidades el inserto GC2015 consigue el mejor desempeño. El mejor comportamiento en cuanto a la rugosidad superficial de la pieza mecanizada se obtuvo con el inserto GC1115 en las velocidades de 350 m/min y 400 m/min, en la velocidad de 450 m/min el mejor resultado correspondió al inserto GC2015. Se analizaron dos criterios nuevos, el coeficiente de vida útil de la herramienta de corte en relación al volumen de metal cortado y el coeficiente de rugosidad superficial de la pieza mecanizada en relación al volumen de metal cortado. Fueron determinados los modelos de regresión múltiple que permitieron calcular el tiempo de mecanizado de los insertos sin que alcanzaran el límite del criterio de desgaste del flanco. Los modelos desarrollados fueron evaluados por sus capacidades de predicción con los valores medidos experimentalmente. ABSTRACT The continuous improvement of manufacturing processes is critical to achieving optimal levels of productivity, quality and cost in the production of components and products. This is necessary to have models that accurately relate the variables involved in the cutting process. This research aims to determine the influence of the cutting speed and feed on the flank wear of carbide inserts coated by GC1115 and GC2015 and the surface roughness of the workpiece for turning dry high speed steel AISI 316L. Among various scientific methods this study were used of observation, experiment, measurement, statistical and artificial intelligence. The GC1115 insert gets the best result according to the graph of means and multiple regression equations of flank wear for v = 350 m / min, while for the other speeds the GC2015 insert gets the best performance. Two approaches are discussed, the life ratio of the cutting tool relative to the cut volume and surface roughness coefficient in relation to the cut volume. Multiple regression models were determined to calculate the machining time of the inserts without reaching the limit of the criterion flank wear. The developed models were evaluated for their predictive capabilities with the experimentally measured values.

Tower of Martín González or castle of La Raya (Soria): territory, history, defense and construction / La torre de Martín González o castillo de La Raya (Soria): territorio, historia, defensa y construcción

Abstract The Tower of Martín González, also known as castle of La Raya, is placed in the actual border between the Spanish provinces of Soria and Zaragoza and in the historical limit between the Crowns of Castile and Aragon: this is the reason for its name. The castle dominates the hedge of the plain-moors that surround the Valley of Nágima River. It is a castle with courtyard and a high tower in the western flank. The paper analyzes the castle in four main levels. All references about the castle are studied to draw a historical narration and to relate with the territory and other fortifications, both Castilian and Aragonese. Despite its advanced state of ruin, it preserves many rests that allow making an analysis of its defensive elements and constructive aspects. Resumen La torre de Martín González, también conocida como el castillo de La Raya, se sitúa en el límite actual entre las provincias de Soria y Zaragoza y en el límite histórico entre las coronas de Castilla y Aragón. Domina el extremo de los páramos que circundan el río Nágima. Es un castillo de tipo torrejón con patio de armas y una torre del homenaje adosada a su flanco occidental. El análisis contempla cuatro niveles fundamentales para el entendimiento de la arquitectura fortificada. La comunicación revisa la documentación existente sobre los elementos históricos que se ponen en relación, mediante el análisis territorial, con el sistema fortificado de frontera. A pesar de su avanzado estado de ruina, conserva restos que permiten realizar una lectura interpretativa de sus elementos defensivos y de sus aspectos constructivos.