Gravity gradiometry is the study and measurement of spatial change rate of gravitational acceleration. In this paper, we develop an eigenvector analysis method to locate the centroids and horizontal boundaries of sources of gravity gradient data. The proposed method can provide a clear map of the buried complex geological sources. It can be used as an effective tool for locating the positions of exploration wells, or in 3D gravity gradient inversion algorithms. Hide

Oscillatory behavior is studied through the Hopf bifurcation mechanism. What is the role of fluids and the oscillation frequency in the mechanism of energy dissipation? Are the variations in the oscillatory behavior (in transition zone) due to external forces? What is the limit of the parameters for this to occur? The proposed limit makes the difference in the behavior, the external force only determines the type of orbits. Oscillation frequency parameter, L and fluids are associated to results. Hide

Using a nondissipative Lorenz model, we show that the nonlinear feedback loop alone may act a restoring forcing and the heating term alone can produce a saddle point. We illustrate that the nonlinear feedback loop and heating term collectively lead to three critical points and three types of solutions, which may contain a small or big energy cycle. The existence of the homoclinic orbit and two types of oscillatory solutions suggests the appearance of diverged trajectories. Hide

We examine rainfall-induced change in soil microroughness of bare soil surfaces in agricultural landscapes with initial microroughness length scales of 2 mm or less. Past studies have focused on scales between 5–50 mm. A rainfall simulator is used. Microroughness measurements are obtained via a laser scanner. Findings show a consistent increase in roughness under rainfall action for initial length scales of 2 mm. This contradicts existing literature where a monotonic decay of roughness is recorded. Hide

We develop data assimilation techniques for numerical models using moving mesh methods. Moving meshes are valuable for explicitly tracking interfaces and boundaries in evolving systems. The application of the techniques is demonstrated on a one-dimensional model of an ice sheet. It is shown, using various types of observations, that the techniques predict the evolution of the edges of the ice sheet and its height accurately and efficiently. Hide

In this paper, I study the frictional and viscous effects on multi-stable slip of earthquake based on a one-degree-of-freedom model through numerical simulations. Results show three regimes of stable, intermettent, and unstable slip, depending on the values of model parameters. Hide

This work arose from a desire to understand the nature of particle motions in turbulence. We sought a simple conceptual model that could describe such motions, then realized that this model could be applicable to an array of other problems. The basic idea is to create a string of random numbers, called a stochastic process, that mimics the properties of particle trajectories. This model could be useful in making best use of data from freely-drifting instruments tracking the ocean currents. Hide

It is analytically shown how competing nonlinearities yield new multiscaled (multi humped) structures for internal solitary waves in shallow fluids. These solitary waves only exist for large amplitudes beyond the limit of applicability of the KdV equation or its usual extensions. Multiscaling phenomenon exists or do not exist for almost identical density profiles. Trapped core inside the wave prevents appearance of such multiple scales within the core area. Hide

If climate is viewed as a chaotic dynamical system, its trajectories yielding on an object called attractor. Being perturbed by an external forcing, this attractor could be modified. With Wasserstein distance, we estimate on a derived Lorenz model the impact of a forcing similar to climate change. Our approach appears to work with small data sizes. We have obtained a methodology quantifying the deformation of well known attractors, coherent with the size of data available. Hide

In order to assess energy loss during wave propagation in fragmented media, an impact model is proposed. The proposed model can be expressed by or used together with other linear damping models, which is important for the determination of mechanical characteristics of such media and mineral exploration. Hide

The process of wave propagation in the discrete chain of bilinear oscillators subjected to several types of external harmonic excitation has been analysed. The phenomenon of sign inversion of the displacement is observed for tension-compression excitation. The solution for wave propagation in a continuous 1D bimodular rod is developed and the numerical results are compared showing good agreement. Hide

Here with a simple coupled model that simulates typical scale interactions in the climate system, we study the optimal OTWs for the coupled media so that climate signals can be most accurately recovered by CDA. Results show that an optimal OTW determined from the de-correlation time scale provides maximal observational information that best fits characteristic variability of the coupled medium during the data blending process. Hide

The article aids in understanding propagation of vibration through a complex media (for e.g. soil). It presents various techniques to better interpret signals (recorded vibrations). The mathematical work done in the article can be utilized for various engineering applications like oil/mineral exploration, designing materials for shock protection or energy trapping applications. The conclusion section of the article also mentions some of the ongoing as well as future work related to the research. Hide

Hasselmann equation (HE) is the basis of the modern surface ocean wave prediction model. Currently, they operate in the "black box with the tuning knobs" modes, since there is no consensus on universal wind input and wave breaking dissipation source terms, and require re-tuning for different boundary and external conditions. We offer physically justified framework able to reproduce theoretical properties of HE and experimental field data without re-tuning of the model. Hide