We present a continuous model capable of demonstrating some salient features of aeolian sand ripples: the realistic asymmetric ripple shape, coarsening of the ripple field at the nonlinear stage of ripple growth, saturation of ripple growth for homogeneous sand, typical size segregation of sand, and formation of armoring layers of coarse particles on ripple crests and windward slopes if the san...

Introduction: Sand dunes in Earth’s large deserts are similar in size and relationship to substrate and topography to the tens of thousands of dunes seen on the surface of Titan by Cassini. Field studies of large dunes can thus inform our understanding of the evolution of similar dunes on Titan. A recent field study to the Namib Sand Sea yielded valuable results concerning the morphology, inter...

We provide the first formal foundation of SAND attack trees which are a popular extension of the well-known attack trees. The SAND attack tree formalism increases the expressivity of attack trees by introducing the sequential conjunctive operator SAND. This operator enables the modeling of ordered events. We give a semantics to SAND attack trees by interpreting them as sets of series-parallel g...

Remote sensing and field evidence are used to describe sand deposits found in associated pathways of emplacement in the eastern Mojave Desert. Two separate pathways are identified here: one extending eastward from the Bristol Playa through the Cadiz and Danby Playas and Rice Valley to the Colorado River, and a second parallel path extending eastward from Dale Playa through the Palen and Ford Pl...

The capacity degradation of bucket foundation in liquefied sand layer under cyclic loads such as equivalent dynamic ice-induced loads is studied. A simplified numerical model of liquefied sand layer has been presented based on the dynamic centrifuge experiment results. The ice-induced dynamic loads are modeled as equivalent sine cyclic loads, the liquefaction degree in different position of san...

ABSTRACT: It may be said that the shape of sand deposition is normally cone and sand grains are oriented a certain angle of deposition repose is made. This angle is such that no stability occurs. Thus the angle of repose is somewhat correlated to the sand internal friction angle. This paper presents the results of a series of laboratory experiments performed three types of sand. For this purpos...

Wind-blown sand movement often occurs in a very complicated desert environment where sand dunes and ripples are the basic forms. However, most current studies on the theoretic and numerical models of wind-blown sand movement only consider ideal conditions such as steady wind velocity, flat sand surface, etc. In fact, the windward slope gradient plays a great role in the lift-off and sand partic...

brassinosteroids are phytohormones possessing a wide spectrum of antistress activity. to seewhether this hormone is able to ameliorate the effects of water stress, the effects of 24-epibrassinolise onplant growth, accumulation of osmolytes (proline, sugars and ions), lipid peroxidation and electrolyte leakagewere investigated in colza (brassica napus l. cv. fusia) plants which were under water ...

During Ocean Drilling Program (ODP) Leg 159, four sites (Sites 959−962) were drilled along a depth transect on the Côte d’Ivoire/Ghana Transform Margin. In this study, the Pliocene–Pleistocene history of carbonate and organic carbon accumulation at Hole 959C is reconstructed for the eastern equatorial Atlantic off the Ivory Coast/Ghana based on bulk carbonate, sand fraction, organic carbon, and...

Calligonum mongolicum is a successful pioneer shrub to combat desertification, which is widely used for vegetation restoration in the desert regions of northwest China. In order to reveal the limitations to natural regeneration of C. mongolicum by asexual and sexual reproduction, following the process of sand dune stabilization, we assessed clonal shoots, seedling emergence, soil seed bank dens...