Constructed wetlands are an attractive choice for removing arsenic (As) within water resources used for drinking water production. The role of substrate and vegetation in As removal processes is still poorly understood. In this study, gravel, zeolite (microporous aluminosilicate mineral), ceramsite (lightweight expanded clay aggregate) and manganese sand were tested as prospective substrates wh...

the relationship between topography, soil factors, and distribution of ecological vegetation groups in the nodoushan arid rangelands of yazd province (iran) was investigated. the present species were recorded in each vegetation group using a randomized-systematic sampling method. plant cover and density were estimated quantitatively using the transect and quadrate methods, and the two-way indic...

in this study, the role of soil properties in making difference between plant communitieswas examined. first, four plant types were identified, including pteropyrumaucheri-salsolarigida، astragalus gossypinus - acanthophyllum herateens، amygdalus scoparia – achilla millefolium and ephedra intermedia – erigon capestra, through randomized systematic sampling and field survey in representative are...

This research describes the goals, design and implementation of a quasi natural gradient, laboratory scale, sand tank (aquifer) model experiment. The model was used to study the transport of an inorganic tracer (Chloride) in groundwater, within a tropical aquifer (porous medium) material. Three-dimensional sand tank (1.8 m × 0.3 m × 0.8 m) experiments were conducted to investigate contaminant t...

The study aims at measuring the gamma activity concentration (Ra, Th and K) of sub-slab filling gravel of Finnish houses. This study forms a part of a wider study aiming at exploring factors affecting high indoor radon concentrations in Finnish dwellings. The gamma activity and radon emanation were measured from gravel samples sent from 229 Finnish municipalities, the gamma activity was reporte...

Domestic wells in North America and elsewhere are typically constructed at relatively shallow depths and with the sand or gravel pack extending far above the intake screen of the well (shallow well seal). The source areas of these domestic wells and the effect of an extended gravel pack on the source area are typically unknown, and few resources exist for estimating these. In this article, we u...

SUMMARY This Report describes work undertaken in an attempt to establish the feasibility of using models to investigate the performance of gravel arresters for aircraft. The experiments were designed using the techniques of physical similarity and dimensional analysis, Tests were carried out with 1:9.3 scale models of Lightning and Canberra aircraft in two types of sand, and the results compare...

abstract in order to investigate the removal of copper, nickel, zinc and chromium from industrial waste water by a sand–soil–organic matter filter column, this experiment was conducted at a completely randomized design with sixteen treatments and four replications. p.v.c tubes (columns) with 66.5 cm height and 10 cm diameter were chosen and filled from down to top by coarse gravel (15 cm), sand...