A class of simple, (2+1)-dimensional, discrete models is reviewed, which allow us to study the evolution of surface patterns on solid substrates during ion beam sputtering (IBS). The models are based on the same assumptions about the erosion process as the existing continuum theories. Several distinct physical mechanisms of surface diffusion are added, which allow us to study the interplay of e...

Mechanisms of the formation of nanoparticles of some B2 shape memory intermetallic compounds, glass-forming Zr-based alloy, and pure Ti obtained by spark erosion method in liquid nitrogen and argon are considered. One of peculiarity is a foam-like structure, which covers the surface of micron-sized particles that appear during spark erosion. Such morphology is related to the nanosized particles...

This paper uses methods of terrain representation, creation and realism described in literature. In particular a combination of terrain synthesis using Fractional Brownian Motion, and erosion procedures is examined, as well as the procedural formation of rivers via squig curves. Other techniques are examined, such as Triangulated Irregular Networks and ridges generation are discarded in terms o...

Cleaning and erosion of objects by ultrasound in liquids are caused by the action of acoustic cavitation bubbles. Experiments have been performed with respect to the erosive effect of multibubble structures on painted glass surfaces and on aluminium foils in an ultrasonic standing wave field at 40 kHz. High-speed imaging techniques have been employed to investigate the mechanisms at work, in pa...

a r t i c l e i n f o Mars accumulated and differentiated into crust, mantle and core within a few tens of millions of years of Solar System formation. Formation of Hellas, which has been adopted as the base of the Noachian period, is estimated to have occurred around 4.1 to 3.8 Gyr ago, depending on whether or not the planet experienced a late cataclysm. Little is known of the pre-Noachian per...

sand dunes mobility is one of the serious problems in arid regions. since wind regime is one of the important factors in sand dunes formation, its frequency, direction and magnitude can be effective. amount of wind energy and its directional variability (wind regime) have significant control on the morphology and maintenance of aeolian landforms. by recognizing of morphometric and morphodynamic...

BACKGROUND Glucocorticoid induced osteoporosis is a common clinical problem. OBJECTIVE To determine the pathophysiology of glucocorticoid induced osteoarthritis at the organ level. METHODS Iliac crest biopsy specimens were obtained from nine patients receiving prednisone treatment for rheumatoid arthritis. Osteocyte viability and histomorphometric indices were assessed. RESULTS Compared w...

Computed tomography (CT) were performed in 17 adults with osteomyelitis of the spine. The dominant features were paravertebral soft-tissue swelling, abscess formation, and bone erosion. In two patients there were no findings indicative of osteomyelitis on conventional radiographs, but CT revealed paravertebral abscesses and bone lysis, helping to establish the diagnosis of osteomyelitis. CT was...

Instabilities caused during the erosion of a surface by an ion beam can lead to the formation of self-organized patterns of nanostructures. Understanding the self-organization process requires not only the in-situ characterization of ensemble averaged properties but also probing the dynamics. This can be done with the use of coherent X-rays and analyzing the temporal correlations of the scatter...

quaternary sediments have occupied most of the agricultural and natural resources of urmia region. recognition of physicochemical and mineralogical properties of these soils is essential to optimum and stable use of these lands. in this study, eight soils profiles excavated on quaternary sediments of urmia region were investigated. the results showed that little thickness and evolution of studi...