Using molecular dynamics we study the behavior of a large particle immersed in a bed of smaller ones. The system is bidimensional, consisting of many rough inelastic hard disks of equal size plus a larger one: the intruder. All possible parameters of the system are kept fixed except for two dimensionless parameters determining the frequency and amplitude of the vibrating base. A systematic expl...

We study the stick-slip behavior of a granular bed of photoelastic disks sheared by a rough slider pulled along the surface. Time series of a proxy for granular friction are examined using complex systems methods to characterize the observed stick-slip dynamics of this laboratory fault. Nonlinear surrogate time series methods show that the stick-slip behavior appears more complex than a periodi...

The flow field and erosion pattern of continuous and pulsating impinging jets has been studied experimentally. The mean velocity field as well as turbulent and pulsation components, wall pressure and wall shear stress distr ibutions were investigated in an axisymmetric air jet impinging upon a rough wall. The results show how harmonic velocity pulsations at the nozzle affect both the mean and t...

A method of solution for the problem of slow flow of a Newtonian viscous glacier slipping over a rough bed is constructed, for the case where cavities form when the lubricating water film pressure reaches that of the local subglacial drainage system. The treatment of Nye (Proc. R. Soc. Lond. A 311, 445-477 (1969)) is reformulated as a Hilbert problem, and the solution presented for the particul...

Calculations of total reactor size have been made for the over bed combustion region of an incinerator, for a given area firing rate, assuming a variation in the completeness of reaction (conversion) "in the stirred section. As conversion increases, the overall reactor size drops to a minimum at 85 percen t con­ version and then rises again. At this minimum, the overbed heigh t required was cal...

Rough terrain control optimization for space rovers has become a popular and challenging research field. Improvements can be achieved concerning power consumption, reducing the risk of wheels digging in and increasing ability of overcoming obstacles. In this paper, we propose a terrain profiling and wheel speed adjustment approach based on terrain shape estimation. This terrain estimation is pe...

This paper deals with the analysis of the reliability of information concerning damages caused to buildings by earthquakes. This research was started after analyzing a huge amount of written sources drawn up after 1930 Irpinia (southern Italy) earthquake. The analysis led to delineate damage ‘scenarios’, useful in trying to mitigate seismic risk for most affected towns. Once analyzed the effect...

This paper investigates slip-based traction control of a planetary rover that travels over natural rough terrain. Special attention is made on tire-soil traction mechanics and articulated body dynamics. Experiments are carried out with a rover test bed to understand the physical behavior of tire-soil interaction and, thereby, a traction model is investigated using the tire slip ratio as a state...

Nowadays, new lunar or planetary exploration missions including landers and rovers have been earnestly studied in Japan. Those missions will follow up a lunar global remote sensing mission Kaguya or a small body sample return mission Hayabusa. Space robotics technologies make a lot of important roles in order to achieve those missions. They will cover a pin-point landing technology, a reliable ...

Data are presented of experiments with turbulent open channel flow over rough surfaces and large relative submergence, which are conducted in two series with different geometric boundary conditions. During the experiments an oscillating fluid motion in the uppermost filter layer is visualised by the injection of a tracer dye. It is shown that this oscillating fluid motion is driven by highly un...