scholarly journals Reduction in permeability of concrete, mortar and plasters by a chemical which retards water percolation and salt transfer

Author(s):  
B. Sengupta ◽  
A. K. Chakraborty
Keyword(s):  
2010 ◽  
Vol 59 (1) ◽  
pp. 99-108 ◽  
Author(s):  
M. Takács ◽  
Gy. Füleky

The Hot Water Percolation (HWP) technique for preparing soil extracts has several advantages: it is easily carried out, fast, and several parameters can be measured from the same solution. The object of this study was to examine the possible use of HWP extracts for the characterization of soil organic matter. The HPLC-SEC chromatograms, UV-VIS and fluorescence properties of the HWP extracts were studied and the results were compared with those of the International Humic Substances Society (IHSS) Soil Humic Acid (HA), IHSS Soil Fulvic Acid (FA) and IHSS Suwannee Natural Organic Matter (NOM) standards as well as their HA counterparts isolated by traditional extraction methods from the original soil samples. The DOM of the HWP solution is probably a mixture of organic materials, which have some characteristics similar to the Soil FA fractions and NOM. The HWP extracted organic material can be studied and characterized using simple techniques, like UV-VIS and fluorescence spectroscopy.


1984 ◽  
Vol 21 (2) ◽  
pp. 232-240 ◽  
Author(s):  
Garry K. C. Clarke ◽  
Sam G. Collins ◽  
David E. Thompson

Temperature measurements in a subpolar surge-type glacier reveal a distinctive thermal structure associated with the boundary between the ice reservoir and receiving areas. In the receiving area the glacier is cold based, but bottom temperature has increased as much as 0.5 °C between 1981 and 1982, and the basal heat flux is roughly 10 times the expected geothermal flux. Water percolation through permeable subglacial material is the probable energy source. Deformation of the substrate could destroy this drainage system and trigger a surge.


2010 ◽  
Vol 4 (3) ◽  
pp. 1343-1363 ◽  
Author(s):  
P. Ginot ◽  
U. Schotterer ◽  
W. Stichler ◽  
M. A. Godoi ◽  
B. Francou ◽  
...  

Abstract. The comparison of two shallow ice cores recovered in 1999 and 2000 from the same place on Chimborazo summit glacier revealed the influence of the coincident Tungurahua volcanic eruption on their stable isotope and chemical records. The surface snow melting and water percolation induced from the ash deposition caused a preferential elution and re-localization of certain ionic species, while the stable isotope records were not very affected. Additionally, the comparison of the ionic amount and some selected ratios preserved along the ice core column reports under which processes the chemical species are introduced in the snow pack, as snow flake condensation nuclei, by atmospheric scavenging or by dry deposition. This preliminary study is essential for the interpretation of the deep Chimborazo ice core, or for other sites where surrounding volcanic activity may disturb the glaciochemical records.


2006 ◽  
Vol 55 (1) ◽  
pp. 117-126 ◽  
Author(s):  
György Füleky

The new hot water percolation (HWP) method was introduced to determine the phosphorus supply of soils from the Soil Bank of 36 Hungarian soils. The present work aimed to explain the availability of phosphorus by determining the inorganic phosphate fractions and using ryegrass test plants. Four inorganic phosphate fractions were distinguished: Fraction I, the sorbed phosphates; Fraction II, the easily soluble Ca phosphates and the Al bound phosphates; Fraction III, the Fe phosphates; and Fraction IV, the hardly soluble Ca phosphates. Fraction II, in which the easily soluble Ca phosphates and Al phosphates accumulate, was the main phosphorus source for the test plants on both calcareous and non-calcareous soils. Fraction III (the iron phosphates) plays a greater role in non-calcareous soils, while Fraction IV (the hardly soluble Ca phosphates) in calcareous soils. Both fractions are closely connected with soil development, and with soil properties such as pH and CaCO 3 content. The hot water percolation method reflects the phosphorus supply of soil as well as that measured with ryegrass plants and with the AL method. This new HWP method is in good correlation with the main source of phosphate, with fraction II. For routine purposes the first collected HWP fraction can possibly be used to determine the phosphorus supply of soil correlating well with the phosphorus uptake of test plants.


2020 ◽  
Vol 14 (4) ◽  
pp. 1273-1288 ◽  
Author(s):  
Adrien Gilbert ◽  
Anna Sinisalo ◽  
Tika R. Gurung ◽  
Koji Fujita ◽  
Sudan B. Maharjan ◽  
...  

Abstract. In cold and arid climates, small glaciers with cold accumulation zones are often thought to be entirely cold based. However, scattering in ground-penetrating radar (GPR) measurements on the Rikha Samba Glacier in the Nepal Himalayas suggests a large amount of temperate ice that seems to be influenced by the presence of crevassed areas. We used a coupled thermo-mechanical model forced by a firn model accounting for firn heating to interpret the observed thermal regime. Using a simple energy conservation approach, we show that the addition of water percolation and refreezing in crevassed areas explains these observations. Model experiments show that both steady and transient thermal regimes are significantly affected by latent heat release in crevassed areas. This makes half of the glacier base temperate, resulting in an ice dynamic mainly controlled by basal friction instead of ice deformation. The timescale of thermal regime change, in response to atmospheric warming, is also greatly diminished, with a potential switch from cold to temperate basal ice in 50–60 years in the upper part of the glacier instead of the 100–150 years that it would take without the effect of the crevasses. This study highlights the crucial role of water percolation through the crevasses on the thermal regime of glaciers and validates a simple method to account for it in glacier thermo-mechanical models.


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