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Compartment Boundaries (compartment + boundary)

Distribution by Scientific Domains

Life Sciences	50%

Selected Abstracts

Modelling microseismicity of a producing reservoir from coupled fluid-flow and geomechanical simulation

GEOPHYSICAL PROSPECTING, Issue 5 2010
D.A. Angus
ABSTRACT In this paper, we investigate production induced microseismicity based on modelling material failure from coupled fluid-flow and geomechanical simulation. The model is a graben style reservoir characterized by two normal faults subdividing a sandstone reservoir into three compartments. The results are analysed in terms of spatial and temporal variations in distribution of material failure. We observe that material failure and hence potentially microseismicity is sensitive to not only fault movement but also fluid movement across faults. For sealing faults, failure is confined to the volume in and around the well compartment, with shear failure localized along the boundaries of the compartment and shear-enhanced compaction failure widespread throughout the reservoir compartment. For non-sealing faults, failure is observed within and surrounding all three reservoir compartments as well as a significant distribution located near the surface of the overburden. All shear-enhanced compaction failures are localized within the reservoir compartments. Fault movement leads to an increase in shear-enhanced compaction events within the reservoir as well as shear events located within the side-burden adjacent to the fault. We also evaluate the associated moment tensor mechanisms to estimate the pseudo scalar seismic moment of failure based on the assumption that failure is not aseismic. The shear-enhanced compaction events display a relatively normal and tight pseudo scalar seismic moment distribution centred about 106 Pa, whereas the shear events have pseudo scalar seismic moments that vary over three orders of magnitude. Overall, the results from the study indicate that it may be possible to identify compartment boundaries based on the results of microseismic monitoring. [source]

Notch and affinity boundaries in Drosophila

BIOESSAYS, Issue 2 2006
Héctor Herranz
Cells in multicellular organisms often do not intermingle freely with each other. Differential cell affinities can contribute to organizing cells into different tissues. Drosophila limbs and the vertebrate central nervous system are subdivided into compartments. Cells in adjacent compartments do not mix. Cell interactions mediated by Notch-family receptors have been implicated in the specification of these compartment boundaries. Two recent reports analyze the role of the Notch signaling pathway in the generation of an affinity boundary in the Drosophila wing.1,2 The first report1 analyzes the connection between Notch and the actin cytoskeleton. The second report2 analyzes the differential requirements of Notch and the transcription factor Supressor of Hairless in generating the affinity boundary. BioEssays 28: 113,116, 2006. © 2006 Wiley periodicals, Inc. [source]

Villin: A marker for development of the epithelial pyloric border

DEVELOPMENTAL DYNAMICS, Issue 1 2002
Evan M. Braunstein
Abstract In the adult gastrointestinal tract, the morphologic borders between esophagus and stomach and between stomach and small intestine are literally one cell thick. The patterning mechanisms that underlie the development of these sharp regional divisions from a once continuous endodermal tube are still obscure. In the embryonic endoderm of the developing gut, region-specific expression of certain genes (e.g., intestine-specific expression of the actin bundling protein villin) can be detected as early as 9.0 days post coitum, although the morphologic differentiation of the gut epithelium proper does not begin until 4 to 5 days later. By using a mouse model in which a ,-galactosidase marker has been inserted into the endogenous villin locus, we examined the development of the stomach/intestinal (pyloric) border during gut organogenesis. The data indicate that the border is not sharp from the outset. Rather, the initial border region is characterized by a decreasing gradient of villin/,-galactosidase expression that extends into the distal stomach. A sharp epithelial border of villin/,-galactosidase expression appears abruptly at day 16 and is further refined over the next 3 weeks to form the distinct one-cell-thick border characteristic of the adult. These results indicate that an important previously unrecognized patterning event occurs in the gut epithelium at 16 days; this event may define an epithelial compartment boundary between the stomach and the intestine. The villin/,-galactosidase mouse model characterized here provides an excellent substrate with which to further dissect the mechanisms involved in this patterning process. © 2002 Wiley-Liss, Inc. [source]

Computational prediction of fatigue crack paths in ship structural details

FATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 1-2 2005
Y. SUMI
ABSTRACT The characteristics of fatigue crack propagation and the remaining life assessment of ship structures are investigated focusing attention on a curved crack path due to the effects of welds, complicated stress distributions at three-dimensional structural joints and structural redundancy. An advanced numerical simulation method is demonstrated for the remaining life assessment for curved crack propagation. The simulation method is based on a step-by-step finite-element analysis. The crack path is predicted by the perturbation method with the local symmetry criterion, which gives a higher order approximation of the crack path, while the finite-element re-zoning is carried out by an improved paving method. Fatigue crack paths in the welded structural details of the transverse girder of a ship structure are investigated by experiments and simulation. The present method may offer an efficient simulation-based tool for the design of critical details, which prevents the failure of the plates forming a compartment boundary. [source]