Tenaris (Argentina)

ABSTRACT The seismoelectric effect is an electrokinetic phenomenon that arises when seismic waves propagate in water‐containing geological formations. Given that seismoelectric signals are sensitive to the hydraulic properties of the probed porous medium, they have the capability to provide important information during subsurface characterization efforts. In this work, we present a physics‐based model for the dynamic streaming potential coupling coefficient (SPCC) in partially saturated porous media. For this, we conceptualize the porous medium as a partially saturated bundle of capillary tubes. We take into account the variation of pore size to relate the capillary pressure to the water saturation in the porous medium of interest. We then up‐scale the streaming current and conduction current within the saturated capillaries under oscillatory flow conditions from pore to sample scale. The results show that the dynamic SPCC is not only a function of water saturation and the probing frequencies but also of the properties of water, mineral–water interfaces and other microstructural parameters of the porous medium. We analyse and explain the characteristics of the dynamic SPCC for two different pore size distributions (PSD): fractal and lognormal. Results show that the PSD characteristics have a strong effect on the dynamic SPCC responses. The proposed model has a remarkable ability to replicate experimental data available in the literature. In addition, it is observed that the lognormal distribution can provide a better agreement with experimental data for sand samples, which display a relatively narrow PSD. The findings of this study provide a valuable basis for interpreting seismoelectric signals under partially saturated conditions. Our proposed technique can be applied to any PSD, regardless of the complexity, providing a flexibility that is not present in alternative models found in the literature.

Se presenta el caso de una lesión en una rama de la arteria poplítea ocurrida durante la obtención de injertos isquiotibiales en una reconstrucción de ligamento cruzado anterior (LCA). La complicación requirió una embolización de urgencia, asistencia en unidad de terapia intensiva (UTI) con transfusiones sanguíneas y una cirugía de descompresión por síndrome compartimental.

La II Guerra Mundial, la Shoah, el Gulag, Hiroshima y Nagasaki, constituyen un largo listado de hechos ignominiosos que han marcado a fuego a la humanidad. No en vano, lúcidos intelectuales y artistas alzaron sus voces para señalar el fracaso de los antiguos paradigmas racionales que sustentaron el modernismo: si ese racionalismo había conducido al fracaso, había que buscar nuevas estructuras que ayudasen a superar el pasado. Es así que avizoraron una esperanza en el resurgimiento del mito. 
 Con la posguerra, se abrió una etapa conocida como la Guerra Fría, que se caracterizó, entre otras cosas, por el vertiginoso crecimiento comunicacional, así como por el desarrollo de todo tipo de mecanismos de control y gadgets que abarcaron desde microfilms y micrófonos, hasta cámaras. La URSS y los EEUU, con sus servicios secretos jugaron una guerra de nervios donde todo parecía válido: suero de la verdad, torturas diversas y lavado de cerebros, entre otros, fueron términos que se trasladaron desde el campo político a la literatura, el cine y el teatro. Dichos elementos abonaron la imaginación de los artistas, que en casos como el que analizamos situaron en un futuro distópico las críticas al mundo que les rodeaba. 
 El presente trabajo se propone analizar algunos aspectos de la novela 1984 de George Orwell (1948), explorando las líneas de profundidad hermenéutica que dieron vida a sus personajes y conflictos, para luego abordar la transposición cinematográfica homónima. Al comparar la relación entre los medios de comunicación y el poder –un aspecto fundamental tanto en el texto literario con su incidencia en el audiovisual– sostenemos que así como la vida de los ciudadanos en la novela es totalmente controlada por los agentes de poder, esto vuelve a quedar en evidencia en la película del mismo nombre filmada en el año 1984, situación que también se extiende hasta hoy. Muy a nuestro pesar, los totalitarismos continúan vigentes en la actualidad.

The dextral Talas-Fergana Fault separates the western from the central Tien Shan. Recent work has shed light on the Cenozoic evolution of the eastern and central Tien Shan; much less attention has been paid to the western Tien Shan. In this contribution we present new thermochronological ages for the Fergana and Alai ranges that, combined with the available data set, constrain the Cenozoic exhumation history of the western Tien Shan. Following a tectonically quiet early Cenozoic period, we suggest an onset of exhumation at ~25 Ma. This early onset was followed by a period of slower exhumation and in some areas minor reheating. A final, strong late Miocene rapid cooling event is well represented in the western Tien Shan as in other sectors of the range. The early onset of uplift of the western Tien Shan dissected the previously continuous westernmost Parathethyan Sea, progressively isolating basins (e.g., Fergana, Tarim, and Alai basins) in the central Asian hinterland. Moreover, the coeval timing of late Miocene uplift along the length of entire Tien Shan implies that neither the Pamir nor Tarim can be the sole driver for exhumation of the entire range.

This chapter contains sections titled: Introduction Sulfide Stress Cracking CO2 Corrosion Summary: What are the Challenges for the Future?

Large diameter UOE pipes are being increasingly used for the construction of offshore pipelines and in the last few year, since oil discoveries are moving towards ultra-deepwater areas, such as Pre-Salt in Brazil, collapse resistance is a key factor in the design of the pipelines the demand for pipes with high thickness near the limits for fabrication and installation capacity. It is known that the cold forming, and the final expansion in the UOE line pipe manufacturing process, reduces the elastic limit of the steel in subsequent compression. Due to this, the DNV collapse formula includes a fabrication factor that de-rates by a 15% the yield strength of UOE Pipes. However, DNV also recognizes the effect of thermal treatments and the code allows for improvement of the fabrication factor when heat treatment or external cold sizing (compression) is applied, if documented. In previous work [1] it was presented the qualification of UOE pipes with enhanced collapse capacity focusing the use of a fabrication factor (alpha-fab) equal to 1. A technology qualification process according to international standard has been performed. The main aspects of the qualification process were presented and included significant material, full scale testing and final analysis. In this paper, we compare those results with the ones of the new qualification tests analyzing the more important variables affecting the collapse resistance such as ovality, compressive material strength, thermal treatment control, etc. This new qualification obtained even better results than the previous one, which will allow the use of a fabrication factor equal to 1 directly in deepwater and ultra-deepwater offshore pipeline projects with a possible reduction in material and offshore installation costs and also potentially enhancing the feasibility of many challenging offshore projects.