Equilibrium scour depth (S) of seabed is critical to the safety offshore pipelines which one most important topics in ocean engineering. Compared sands, few experiments have been done for silty seabed. In present work, under wave-only action were performed both sandy and seabeds. Together with data from literature, abundant dataset at stage established. Based on this, two practical formulas S o...

Anchors may exhibit various complicated behaviors in the seabed, especially for deepwater anchors including gravity installed (GIAs) and drag embedment plate (drag anchors), stimulating development of an efficient analytical tool that applies to a variety anchors. The present paper introduces unified model analyzing different anchor both clay sand, consisting concepts, mechanical models, proced...

Ocean ambient noise is generated in many ways such as from winds, rain and shipping. A technique has recently been developed (Harrison and Simons, J. Acoust. Soc. Am, Vol. 112 no. 4, 2002) that uses the vertical directionality of ambient noise to determine seabed properties. It was shown that taking a ratio of upward looking beams to downward produces an estimate of the reflection loss. This te...

Pipelines have been used as one of the main transportation methods for offshore industry, with increasing activities in marine resources recently. Prediction seabed instability is key factors that must be taken into consideration an pipeline project. As first step scour process, sediment incipient motion has intensively studied past. Most previous investigations didn’t consider wave-induced see...

This paper presents a comparison study on the application of two electromagnetic inverse scattering algorithms, SEABED [1] and the synthetic aperture method, to experimental multi-static UWB (Ultra Wide-Band) radar data. A linear UWB antenna array with a wideband frequency (1.5-8 GHz) was used for the multi-static radar measurement in a realistic environment. The results clearly show the advant...

Sensor network systems with UWB signal have a great potential for a fast communication and a high-resolution imaging, which are required for house-hold robots or rescue robots. For this application, we have already proposed a fast imaging algorithm, SEABED based on a reversible transform between the received signals and the target shape[1]. However, the image with SEABED is instable in a noisy ...

the effects of dominant shrub species on soil organic matter (som), including total soil carbon (sc), total nitrogen (n) and particulate organic matter (pom) were studied in three stands differing in the type of shrub species, i.e. astragalus microcephalus (shrub), pteropyrum aucheri (shrub) and prangus uloptera (non-shrub).the stands were located in arid grasslands of north-western iran. for t...

background: the municipal waste landfill sites have high a potential of contaminating the ‎ environment and having effects of the human health due to waste degradation, production of leachate, carbon dioxide and ‎ methane gases. the present study aims to evaluate the location of the solid waste landfill using gis and based on the oleckno index. assessment parameters included average annual rain...

strict new safety rules announced after the Deepwater Horizon disaster, but in most cases won't be subjected to new environmental reviews. The announcement means that some drilling could resume within weeks, although the exact timing remains unclear. But the policy doesn't affect the more than a dozen permit requests that were pending when the moratorium took effect or have been filed since. Th...