General Electric (Argentina)

Abstract This article aims to present structural and geotechnical design challenges of the flood relief project ”Segundo Emisario del Arroyo Vega“, part of Buenos Aires city hydraulic master plan. Works comprised the execution of an 8.4 km‐long tunnel for relief of the existing sewer network. Tunnel alignment develops in a highly populated area, with important interferences such as two metro lines, three railway lines and a main potable water tunnel. All tunnel sections extend mostly within firm, silty soils. Overburden varies between 15 and 25 m. The downstream section was executed with a 6.1 m‐diameter Earth pressure Balance Tunnel Boring Machine (EPB TBM) launched from a 35 m‐diameter shaft with water table pressures up to 200 kPa. Break‐in was performed across a watertight, plastic diaphragm wall cell, which allowed safe shaft wall manual demolition, resulting in a very safe TBM launch. The tunnel upstream section, 2.85 m in diameter, was executed using pipe jacking technology, with the peculiarity of using bidirectional launch shafts along its alignment. To allow water entrance from existing system – through flow diversion chambers – into the new relief tunnel, openings were made in the TBM tunnel, with connection areas of 4 to 7 m2. Its design was particularly challenging, given that unbolted segmental lining was used.

The perforated Pediastrum Meyen s.l. species are recorded for the first time in the basal levels of the Tithonian Vaca Muerta Formation, extending its first stratigraphical record to ages as old as Late Jurassic times. Based on the ecological requirements of Pediastrum simplex var. clathratum and P. simplex var. biwaense, the previously warm paleoclimatic conditions suggested by the Late Jurassic of Neuquén Basin, are reinforced. The co-occurrence of the different mechanisms that interacted during the transport, accumulation, and early diagenesis of these sediments and their organic content would have allowed for the excellent preservation of the Pediastrum Meyen s.l. species.

Chile's main electricity supply has been carried out until recently by two independent power systems: SING (northern) and SIC (central + southern). Now, both grids operate as one National Electric System (SEN), feeding a peak load of nearly 11GW. Conventional generation is performed through hydraulic units placed in the southern region and thermal power plants mainly located in the central and northern region. The highest concentrations of loads are located in the central zone, while in the northern region there is an important mining demand. The transmission network is composed of 500kV, 220kV and 154kV lines; mainly double circuit.

Precios y crisis en una economa rioplatense.

Detailed microbial surveys were acquired over the Agua Del Cajon and El Salitral fields in the Neuquín Basin of Argentina to detect bypassed oil reservoirs. Depleted reservoirs quickly lose their associated microbial anomalies. Thus, these surveys can often detect nondepleted reservoirs. Although microbial surveys are an effective measure of hydrocarbon microseepage, they have several limitations. First, hydrocarbon microseepage is predominantly vertical, but it can be influenced by faulting and offset from the source of the anomaly. Second, we cannot determine the depth of the suspected reservoir. To provide a link from reservoir to surface, we need to delineate the hydrocarbon migration pathways. On seismic data, vertical hydrocarbon migration paths are characterized by vertically aligned zones of chaotic reflectivity, called gas chimneys. These chimneys are detected by training a neural network using multiple seismic attributes and examples of gas chimneys picked by the interpreter. The resulting chimney volume is visualized in 3D seismic volume to determine where the hydrocarbons originated and where they migrated. Results of the study show a good correlation between strong surface microbial anomalies and shallow chimneys. Many of the chimneys have a deep origin in the gas-prone Jurassic Molles interval. There is also a good correlation between deeper Jurassic gas pay and these chimneys. The Late Jurassic Vaca Muerta, a thermally mature oil-prone source shale, provides an effective top seal for these deep pays. Chimneys, associated with the major east–west-trending thrust fault and northwest-trending shear faults, penetrate the Vaca Muerta interval. Cretaceous Quintuco carbonates and Centenario clastic oil reservoirs are closely associated with these chimneys. The deep chimneys are the means to expel oil from the Vaca Muerta shales into the shallow reservoirs. The combination of microbial surveys and chimney detection is being used to successfully discover bypassed pay in this area.

Abstract The ray-tracing problem is considered the solution to a minimum travel time problem for media where each layer is a transversely isotropic homogeneous solid. The wave surface-wavefront at t=1 s, corresponding to a wave generated at the point source, associated with each layer's anisotropy is approximated by surfaces which are not more difficult to handle, from a computational point of view, than ellipsoidal surfaces. These approximating surfaces are those used in ray-tracing computation; a ray being a true ray approximation is thus obtained.--Modified journal abstract.

Subsequent to the production of American Casting Institute Type HF stainless steel castings, two types of casting defects have been found: hot tearing and shrinkage. Analyses of castings with these types of defects have been conducted. The hot tears were detected by fluorescent dye penetrant inspection and were found to be confined to certain similar locations in separate castings. The shrinkage was detected by gamma radiography and was confined to the interior of one casting. The investigation of the hot tearing condition has led to a metallographic definition of carbide distributions and a tentative microchemical description of the area containing the hot tear. A metallographic and microchemical characterization of the interdendritic region near those areas displaying shrinkage and microshrinkage in a different HF stainless steel casting has also been made. In both cases, a description of the means by which the casting defects were eliminated is included. Scanning electron microscope, energy-dispersive X-ray analysis, and surface replication techniques were used, as well as routine metallographic procedures.

Covers advancements in spacecraft and tactical and strategic missile systems, including subsystem design and application, mission design and analysis, materials and structures, developments in space sciences, space processing and manufacturing, space operations, and applications of space technologies to other fields.