Interstitial water chemistry has been widely studied to identify biological and chemical reactions in the sediment and to assess sediment-water exchange of dissolved chemical compounds (e. g. Sayles 1979; Froelich et al. 1979; Saager et al. 1990; van Raaphorst & Malschaert, 1996). However, sediment pore water sampling is tedious and requires the use of special equipment due to the possible effe...

Thuja plicata is a coniferous tree which displays remarkable water channelling properties. In this article, an easily fabricated mesh inspired by the hierarchical macro surface structure of Thuja plicata branchlets is described which emulates this efficient water collection behaviour. The key parameters are shown to be the pore size, pore angle, mesh rotation, tilt angle (branch droop) and laye...

In this paper we investigate the hypothesis that long-term sulphate (SO(4) (2-)) deposition has made peatlands a larger source of methyl mercury (MeHg) to remote boreal lakes. This was done on experimental plots at a boreal, low sedge mire where the effect of long-term addition of SO(4) (2-) on peat pore water MeHg concentrations was observed weekly throughout the snow-free portion of 1999. The...

The interaction of water vapour with Al-MCM-41, prepared by direct synthesis at ambient temperature and pressure, using tetraethoxysilane, aluminium sulfate, hexadecyltrimethylammonium bromide and ammonia, and its effect on the pore structure were studied in order to investigate the stability towards prolonged exposure to water vapour and the influence of the aluminium content. With this purpos...

Analysis of high-speed (150 frames/sec) cinematographs of the filling and expulsion of the water expulsion vesicle of Tetrahymena pyriformis shows that the vesicle fills as water is pumped into it by contractions of at least four ampullary sacs which are continuous with the endoplasmic reticulum. When filled, the vesicle is pressed against its two excretory pores by cyclotic movements of the cy...

One of soil microbiology's most intriguing puzzles is how so many different bacterial species can coexist in small volumes of soil when competition theory predicts that less competitive species should decline and eventually disappear. We provide evidence supporting the theory that low pore connectivity caused by low water potential (and therefore low water content) increases the diversity of a ...

pore pressure is an important parameter, in exploration and production of hydrocarbon resources. lack of accurate knowledge about pore pressure, before drilling phase, leads to serious dangers in drilling process. accurate knowledge about distribution of pore pressure in a field, leads to reduce risks in drilling, improve well planning and mud weight calculations. during burial, normally pressu...

A two-step acid/base-catalyzed silica gel has been aged in alcohol and water baths followed by various aprotic solvents with a wide range of surface tensions. Low temperature (CO 2) and high temperature (ethanol) aerogels were also prepared. The physical and chemical structures of gels dried from aprotic solvents were studied by a series of techniques (29Si MAS-NMR, nitrogen adsorption, SAXS, e...

the characterizations of natural diatomite from birjand deposit (iran) were studied such as chemical compositions, specific surface area, total pore volume, pore size distribution and xrd. the diatomite that was treated only with sulfuric acid displayed a larger surface area, expanded total pore volume and increased pore size in comparison with both washed natural diatomite with deionized water...

Mercury cycling in the water column and upper sediments of a contaminated area, the Largo do Laranjo, Aveiro (Portugal), was evaluated after determination of reactive and non-reactive mercury concentrations in the water column and pore waters of sediments, collected in several places of this bay. In the water column, reactive mercury concentrations varied between 10 and 37 pmol dm(-3), the high...