A new type of electrostatic microgenerator is presented that converts mechanical microvibrational energy into electric energy. The energy conversion mechanism is as follows. External microvibrations are transmitted to the device frame. The thin electret layer sputtered to the silicon substrate surface was fixed on the frame and the moving electrode was fixed by a weak suspension and comes into ...

In the present work, utilizing the two-dimensional equations of an incompressible inviscid fluid and the reductive perturbation method, we studied the propagation of weakly nonlinear waves in water of variable depth. For the case of slowly varying depth, the evolution equation is obtained as a variable-coefficient Korteweg–de Vries (KdV) equation. A progressive wave type of solution, which sati...

SUMMARY The Ice, Cloud and land Elevation Satellite 2 (ICESat-2) laser altimetry mission, launched in September 2018, uses six parallel lidar tracks with very fine along-track resolution (15 m) to measure the topography of ice, ocean surfaces. Here we assess ability ICESat-2 data recover oceanographic signals ranging from surface gravity waves marine geoid. We focus on a region tropical Pacific...

With coasts that form three >1700 km arms which spiral outward from a point near Kodiak Island, Alaska provides a large-scale site for the study of the relationship between geodesy and sea level. The surface of a static, uniform ocean will follow an equipotential, orthometric surface. Long lived geostrophic currents or prevailing winds result in localized and large scale variations between its ...

Knowledge of the ocean dynamic topography, defined as the height of the sea surface above its rest-state (the geoid), would allow oceanographers to study the absolute circulation of the ocean and determine the associated geostrophic surface currents that help to regulate the Earth's climate. Here a novel approach to computing a mean dynamic topography (MDT), together with an error field, is pre...

The method of using Global Positioning System-leveling data to obtain orthometric heights has been well studied. A simple formulation for the weighted least squares problem has been presented in an earlier work. This formulation allows one directly employing the errors-in-variables models which completely descript the covariance matrices of the observables. However, an important question that w...

The purpose of this paper is to test the applicability of a fast boundary element method in the context of geoid computations of the gravity. The fast multipole method is the method of choice due to the its advantageous property of a fast evaluation in the post-processing. Several sets of trianglar meshes for the approximation of the unit sphere and several modifications of the prediscribed dat...

In regions with a rough topography, e.g. the European Alps, the accuracy of geoid or quasigeoid models is often reduced. For the validation and accuracy assessment of gravimetric models, astronomical levelling is a well-suited independent method. In a test area, located in the German Alps, a new astrogeodetic data set was acquired using the Hannover Digital Zenith Camera System. Vertical deflec...

The topography on Mars is dominated by the crustal dichotomy between the northern and southern hemispheres and the Tharsis rise on the equator[1]. No explanation has been offered so far as to why the dichotomy should be in its current orientation rather than another. The geoid is currently dominated by Tharsis [2] and rotational stability suggests that a Tharsis-sized load would induce polar wa...

Phase and group velocities of G2 , G3 , R 2 and R 3 (100-330 s) are measured by the single-station method and are inverted to give a spherical harmonic representation of the velocity lateral variation. Approximately 200 paths have been studied. The results are presented for degrees and orders up to 6. The even harmonics of the phase velocity representation are consistent with those obtained fro...