نتایج جستجو برای: sand dunes

تعداد نتایج: 29226  

The instability and mobility of sand dunes is a major concern of planning and management in arid coastal plains. The aim of this study is to identify morphogenetic characteristics of sand masses and their locations, as well as to identify the processes that formed and transported them in the western part of the Makran coastal plain. Research data and tools were including spatial distributions o...

2017
Daniel R. Muhs

Studies of dunefields in central and western North America show that mineralogical maturity can provide new insights into the origin and evolution of aeolian sand bodies. Many of the world’s great sand seas in Africa, Asia and Australia are quartzdominated and thus can be considered to be mineralogically mature. The Algodones (California) and Parker (Arizona) dunes in the southwestern United St...

Journal: :The European physical journal. E, Soft matter 2005
V Schwämmle H J Herrmann

Barchan dunes are found where sand availability is low and wind direction quite constant. The two dimensional shear stress of the wind field and the sand movement by saltation and avalanches over a barchan dune are simulated. The model with one dimensional shear stress is extended including surface diffusion and lateral shear stress. The resulting final shape is compared to the results of the m...

Journal: :Geographical Review of Japan 1943

2003
Houyuan Lu Kam-biu Liu

Thirty-four grass species were collected for phytolith analysis from a variety of coastal environments in the southeastern USA (Georgia, Florida, and Louisiana), including salt marshes, freshwater/brackish marshes, pine/oak forests, maritime hardwood forests, and sand dunes. Phytoliths produced by these modern grasses include a large diversity of shapes and types. We propose a preliminary relat...

Journal: :Physical review letters 2004
B Andreotti

Singing dunes, which emit a loud sound as they avalanche, constitute a striking and poorly understood natural phenomenon. We show that, on the one hand, avalanches excite elastic waves at the surface of the dune, whose vibration produces the coherent acoustic emission in the air. The amplitude of the sound (approximately 105 dB) saturates exactly when the vibration makes the grains take off the...

ژورنال: علوم آب و خاک 2019

Creating a mulch layer on the sand dunes surface has long been applied to reduce their mobility. However, application of oil mulch in some countries, in addition to high costs, has many environmental problems. In this research, the hydrated lime slurry was used as a protective cover on the sand dunes. The slurry was prepared in three treatments with 3, 5 and 7% lime and sprayed uniformly on 2×5...

2009
Colin Ogle

In the dunes of the Pouto Peninsula, north Kaipara, Northland, re-mobilised sand is invading remnants of native forest and scrub, and filling dune lakes and swamps. Some of the affected native vegetation is botanically important as remnants of regionally and even nationally rare plant communities and as the habitats of threatened plant species. The wetlands are important waterbird habitats. At ...

Journal: Pollution 2018
H.R. Asgari masume Sabzi, S.F. Afzali

Wind erosion is considered a major global environmental problem. Dust storms from the migration of sand dunes can seriously damage civil, industrial, and agricultural areas and a method to stabilize these sand dunes is mulching. The present study investigates the feasibility of using organic wastes of Press mud and Dunder with clay for the production of environmentally-friendly mulches. Sandy s...

Journal: :آب و خاک 0
سکینه پورمند احمد غلامعلی زاده آهنگر عبدالحمید دهواری

introduction: wind erosion is one of the most important factors in desert environments. prevailing winds can shift sand dunes and affect their accumulation and morphology. also, wind regime determines the direction of sand dune mobility in different ways. therefore, the wind regime, frequency, direction and velocity are supposed to be the most important factors to form the morphology of sand du...

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