The deformation of the ground surface that is produced by frost heave has motivated almost a century of concerted laboratory, field and theoretical studies. Well before the development of equipment capable of resolving the microscopic films that support liquid transport towards growing ice lenses, early investigators predicted their occurrence and noted their importance. Idealized experiments c...

Abstract Parametric excitation in the pitch/roll degrees of freedom (DoFs) can induce dynamic instability floating cylinder-type structures such as spar buoys, offshore wind or wave energy converters. At certain frequency and amplitude ranges input waves, parametric coupling between heave DoFs results undesirable large rotational motion. One possible remedy to mitigate existence resonance is us...

Nonsorted circles are relatively barren patterned-ground features common in most arctic tundra regions. We studied how vegetation changes on nonsorted circles might affect cryogenic processes, which is of relevance as arctic vegetation responds to climate change. Twenty-eight circles at a moist nonacidic tundra site in northern Alaska received one of four treatments: (a) vegetation removal; (b)...

A computationally efficient quasi-two-degree-of-freedom (Q2DOF) stochastic model and a stability analysis of barges in random seas are presented in this paper. Based on the deterministic 2DOF coupled Roll-Heave model with highdegree polynomial approximation of restoring forces and moments developed in Part I, an attempt is made to further reduce the DOF of the model for efficient stochastic sta...

This paper presents a practical scheme to control heave motion for hover and automatic landing of a Rotary-wing Unmanned Aerial Vehicle (RUAV) in the presence of strong horizontal gusts. A heave motion model is constructed for the purpose of capturing dynamic variations of thrust due to horizontal gusts. Through construction of an effective gust estimator, a feedback-feedforward controller is d...

Expansive soils are considered to be the one of the highly problematic soil. These soils undergo large volume change based on the amount of moisture content.. Because of this behaviour, lightly loaded civil engineering structures founded on the expansive soils gets severely damaged. There are several mitigating techniques available to counteract the problems posed by the expansive soils. In rec...

Characteristics of heave compensation systems used on a marine drilling platform or drill-ship are analyzed. An active heave compensation system with two lift cylinders is proposed by COMRA (China Ocean Mineral Resources & Association), which will be used in 1000-m depth ocean poly-metallic nodule pilot mining system. A corresponding virtual prototype of this system is developed. The parametric...