Cones and wedges inserted between an ultrasonic transducer and the specimen provide the transducer (circular or rectangular shape) with enhanced capability for point or line contact with the specimen. Such an arrangement is useful in that the transducer can be used for transmitting to and receiving from a point (or line) source, and that it can eliminate the undesirable aperture effect that mak...

Achieving diffraction limited imaging with future ground-based optical telescopes will require adaptive optics for correction of atmospheric turbulence and also efficient techniques for atmospheric dispersion compensation. We study the benefit of using a linear atmospheric dispersion corrector (ADC) coupled with a deformable mirror on a 42-m Extremely Large Telescope (ELT) operating in the VIRJ...

The content of carbon and nitrogen, as well the carbon-to-nitrogen ratio in genetic horizons soil cover, yedoma deposits organic residues syngenetic ice wedges (IW) upper IW complex Batagay megaslump were studied. studied soils belong to silty-loam Spodic Cryosol (Dystric,Humic) post-pyrogenic (Dystric,Humic). To study nitrogen content, first second tiers tested. highest values C/N obtained hor...

The thesis describes a method of' beam steering aimed at producing a useful amount of deflection of an antenna beam from boresight, by a simple and Inexpensive method. For large antennas, It is difficult, as well as expensive, to steer the beam by more than a few beamwidths. The method studied was developed with particular reference to the beam steering requirements of Direct Broadcast Satellit...

A natural metric in 2-manifold surfaces is to use geodesic distance. If a 2manifold surface is represented by a triangle mesh T , the geodesic metric on T can be computed exactly using computational geometry methods. Previous work for establishing the geodesic metric on T only supports using half-edge data structures; i.e., each edge e in T is split into two halves (he1, he2) and each half-edge...

A method is proposed for generating dynamic wedges spanning the entire field width, defined as the collimator opening in the wedged direction, without changes to existing hardware. The technique approximates the fluence pattern of a dynamic wedge by sequentially closing the leaves of a 120-leaf multileaf collimator (MLC). Closure times for the individual leaves were derived by extending the seg...

We are concerned with free boundary problems arising from the analysis of multidimensional transonic shock waves for Euler equations in compressible fluid dynamics. In this expository paper, we survey some recent developments and corresponding related nonlinear partial differential (PDEs) mixed type. The PDEs under our include steady potential flow, full equations, unsteady elliptic–hyperbolic ...

This work numerically evaluates the role of advancing velocity on water entry rigid wedges, highlighting its influence development underpressure at fluid–structure interface, which can eventually lead to fluid detachment or cavity formation, depending geometry. A coupled FEM–SPH numerical model is implemented within LS-DYNA, and three types asymmetric impacts are treated: (I) symmetric wedges w...

Many experiments measuring blood oxygen level dependent (BOLD) signal in functional magnetic resonance imaging (fMRI) data assume that the BOLD signal is predominantly linear in space and time. Previous investigations of temporal linearity have reported that the temporal BOLD response contains both linear and nonlinear components. Here, we used a novel method to investigate spatial linearity of...