In order to improve the durability of fly ash concrete, a series of experimental studies are carried out, where durability improving admixture is used to reduce drying shrinkage and improve freezing-thawing resistance. The effects of durability improving admixture, air content, water-binder ratio, and fly ash replacement ratio on the performance of fly ash concrete are discussed in this paper. ...

[1] In the McMurdo Dry Valleys, Victoria Land, Antarctica, melting of glacial ice is the primary source of water to streams, lakes, and associated ecosystems. To understand geochemical fluxes and ecological responses to past and future climates requires a physically based energy balance model. We applied a one-dimensional model to one site on Taylor Glacier using 11 years of daily meteorologica...

A 1.4 m3 ice Cherenkov tank was installed at the South Pole during the 2000-2001 austral summer. The penetrating muon rate was measured for three different incident angles with a scintillator muon telescope incorporating the tank as absorber. The freezing process was monitored and the detector was calibrated with the penetrating muons. The calibration is compared to a GEANT simulation of the de...

The time-dependent freezing rate (TDFR) model here described represents the formation of ice particles by immersion freezing within an air parcel. The air parcel trajectory follows an adiabatic ascent and includes a period in time when the parcel remains stationary at the top of its ascent. The description of the ice nucleating particles (INPs) in the air parcel is taken from laboratory experim...

We examined the stability of retinol in blood and serum samples, kept in the dark, under different handling procedures. Samples not protected from contact with air oxygen were highly unstable, even when kept at ice temperature. Samples collected under anaerobic conditions, with Vacutainer Tubes, or treated with nitrogen after collection to displace the air from the tubes were stable during the ...

OBJECTIVES Compare the efficacy of two walking assistance devices (wheeled walker and standard walker) to unassisted walking for patients with PD and gait freezing. BACKGROUND Although numerous walking devices are used clinically, their relative effects on freezing and walking speed have never been systematically tested. METHODS Nineteen PD patients (14 non-demented) walked under three cond...

Although water and land pollution are very dangerous, air pollution has its own peculiarities due to its transboundary dispersion of pollutants over the entire world. In any well planned urban set up, industrial pollution takes a back seat and vehicular emissions take precedence as the major cause of urban air pollution. In the present study, Air pollution tolerance index was calculated for var...

Effective improvement of the frost resistance concrete in cold regions is critical for durability airport pavement plateau. This paper intends to contribute a better knowledge effects combined air-entraining superplasticizer and surface treatments on against freezing-thawing salt freezing. First, an optimum mixing by considering w/c, cement content, sand ratio, was obtained comparing compressiv...

. introduction weathering is crushing, decomposition and decaying the rocks of outer earth's crust by natural processes such as; running waters, wind blowing and ice creeping and biological actions and so on. the study of weathering is important because this process lead to formation of all known of soil types in outer part of earth crust finally. climate is the most important parameter in crea...