molecular diffusion is one of the important contaminant transport mechanisms through soil and rocks. in this study the molecular diffusion coefficient of marl stone and sand stone from the urmia city landfill site was determined using the best fit method of the observed laboratory data and the predicted theoretical data. the marl stone and sand stone samples were tested under the conditions of ...

A systematic analysis of the mineral resource base (MRB) strategically important minerals for Ukrainian economy is carried out. Four categories strategic from point view their investment attractiveness are identified: traditional (iron, manganese, titanium, uranium, kaolin, sand molding, building stones, quartz raw materials, refractory clay); highly promising (rare earths, zirconium and hafniu...

An increase in intracellular Ca2+ concentration ([Ca2+]) and morphological were simultaneously observed by epifluorescence and differential interference contrast (DIC) microscopy during fertilization of the sand dollar, Clypeaster japonicus. [Ca2+], which was detected by a Ca2+ indicator, Fluo-3, initially increased just beneath the sperm-attached site on the egg surface 8.6 sec after attachmen...

We summarize information concerning Recent and Pleistocene-Holocene Uruguayan sand dollars (Mellitidae), as well as Miocene taxa (Monophorasteridae). Recent and Pleistocene-Holocene species (Encope emarginata, Mellita quinquiesperforata, and Leodia sexisperforata) are at their southernmost limits of distribution, with only E. emarginata recorded further south than Uruguay. Lower temperatures to...

Many larvae and other plankton have complex and variable morphologies of unknown functional significance. We experimentally and theoretically investigated the functional consequences of the complex morphologies of larval sand dollars, Dendraster excentricus (Eschscholtz), for hydrodynamic interactions between swimming and turbulent water motion. Vertical shearing flows (horizontal gradients of ...

introduction: aphallia is a very rare urogenital anomaly with incidence rate of 1 in 30,000,000. it usually coexists with other anomalies such as cardiovascular anomalies which are incompatible with normal life, and therefore infants are delivered stillbirth or live for a very short period of time. methods: we present an 18 months old boy with aphallia associated with congenital urethrorectal f...

Impact tests of stones on a geotextile or two loosely connected geotextiles (composites) have been performed and analysed to investigate the mechanisms that lead perforation. The were mounted concrete cylinder 0.8 m internal diameter, filled with uniformly graded dry sand. Drop blocks different shapes weighing approximately 40 kg. drop heights varied between 0.25 5.5 m. Results show shape stone...