نتایج جستجو برای: annular excavation
تعداد نتایج: 15329 فیلتر نتایج به سال:
The generation of multiple vortex cones using an annular aperture array and a spatial light modulator (SLM) is studied. The direct downscale imaging of an SLM on the surface of an annular aperture enables the direct-phase modulation of the annular aperture. It is experimentally demonstrated that the direct-phase modulation of an annular aperture array can control both the topological charge and...
When a tunnel passes through weak soil with different conditions, or there is a thin layer of soil on top of the tunnel, the mass of soil or rock must be stabilized. In addition, an excavation method must be chosen and applied in order to control the amount of subsidence and convergence which are among the most significant factors in excavation a tunnel especially in urban area, since the soil ...
The effects of tuning the parameters of an annular-ring circular patch antenna with a cross-slot are analyzed and discussed. Then, based on this structure, a novel antenna with an electromagnetic bandgap cell system, which consists of a 4×4 annular-slot array in the groundplane, is designed and both numerically and experimentally evaluated. When compared to the annular-ring patch antenna on a g...
The tricuspid valve leaflets and their annular attachments were recorded by two-dimensional echocardiography from a view of the right ventricular inflow tract obtained by placing the transducer at an intermediate position between the left ventricular apex and the left lower sternal border. The transducer was rotated, and recordings were made at 30 degrees rotational intervals around the circumf...
BACKGROUND It is unknown whether longitudinal rotation (LR), often seen in cardiac resynchronization therapy candidates, may affect mitral annular early diastolic (E') velocities and tricuspid annular motion. We assessed whether (1) LR affects the amplitude and timing of septal and lateral mitral annular E' velocities and tricuspid annular systolic and E' velocities and (2) if systolic strain h...
Lunar and planetary subsurface exploration is of considerable significance. The authors have studied the strategies for subsurface excavation and propulsion for the development of a lunar subsurface explorer. The authors have proposed an autonomous robotic explorer which can burrow into the soils. Based on the strategies the authors have already considered, this paper especially focuses on the ...
In studying the dynamics of ant nest excavation, the nest volume has to be continuously monitored. In many laboratory studies, the excavated substrate, such as sand, was collected, and the volume of excavation was calculated by converting the weight of the collected sand into the volume. The excavated sand can be manually collected and weighed; however, manual collection is tedious, particularl...
Excavation and earthmoving equipment mostly operate in accident-prone areas. These areas normally have rollover, confinement, and fall or may be considered harmful work areas due to demolitions and sewage removals. It is inevitable that excavation and earthmoving systems should be developed to secure the safety of operators through unmanned and remote control systems. Therefore, this research p...
Any archaeological site shows a stratification formed by single 3D volumes, the deposits and specific 3D surfaces of human origin as pits, ditches or wall-surfaces known as the units of stratification. Excavation forms the main data retrieval process in field archaeology a destructive process to be documented in three dimensions. To fully reconstruct the part of the site destroyed by excavation...
Research on data quality through the analysis of accuracy and uncertainty has become a major development in GIS science. Fisher’s taxonomy provides solutions for the processing of uncertainty in spatial data representation. However, excavation data differs from geographical data, owing to the specific features of archeology such as incompleteness, temporal and functional aspects. Therefore, arc...
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