scholarly journals Understanding the binder chemistry, microstructure and physical properties of volcanic ash phosphate geopolymer binder

2022 ◽  
Author(s):  
Jean Noël Yankwa Djobo ◽  
Dietmar Stephan
Keyword(s):  
Physical Properties ◽  
Volcanic Ash ◽  
Geopolymer Binder

Physical Properties of Volcanic Ash Based Geopolymer Concrete

2016 ◽  
Vol 841 ◽  
pp. 1-6 ◽  
Author(s):  
Puput Risdanareni ◽  
Adjib Karjanto ◽  
Febriano Khakim
Keyword(s):  
Tensile Strength ◽  
Fly Ash ◽  
Physical Properties ◽  
Volcanic Ash ◽  
Setting Time ◽  
Physical And Mechanical Properties ◽  
Ash Content ◽  
Geopolymer Concrete ◽  
Split Tensile Strength ◽  
Time Test

This paper describes the result of investigating volcanic ash of Mount Kelud as fly ash substitute material to produce geopolymer concrete. The test was held on geopolymer concrete blended with 0%, 25%, 50% and 100% fly ash replacement with volcanic ash. Natrium Hidroxide (NaOH) with concentration of 12 molar and Natrium Silicate (Na2SiO3) were used as alkaline activator. While alkali-activator ratio of 2 was used in this research. The physical properties was tested by porosity and setting time test, while split tensile strength presented to measure brittle caracteristic of geopolymer concrete. The result shown that increasing volcanic ash content in the mixture will increase setting time of geopolymer paste. On the other hand increasing volcanic ash content will reduce split tensile strength and porosity of geopolymer concrete. After all replacing fly ash with volcanic ash was suitable from 25% to 50% due to its optimum physical and mechanical properties.

Spatial variation in soil physical properties and effects on soil NO3– production on forest hillslopes

2020 ◽  
Author(s):  
Tomoki Oda ◽  
Megumi Kuroiwa ◽  
Naoya Fujime ◽  
Kazuo Isobe ◽  
Naoya Masaoka ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Soil Moisture ◽  
Physical Properties ◽  
Spatial Variation ◽  
Volcanic Ash ◽  
Surface Soil ◽  
Soil Physical Properties ◽  
Slope Position ◽  
Surface Soil Moisture ◽  
Slope Bottom

<p>Ammonium (NH<sub>4</sub><sup>+</sup>) and nitrate (NO<sub>3</sub><sup>–</sup>) concentrations and production rates in forest soil vary by hillslope position due to variation in ammonia-oxidizing microorganism concentrations, soil chemistry, and surface soil moisture. These spatial distributions have a significant effect on nutrient cycles and streamwater chemistry. Soil moisture conditions significantly restrict microbial activity, influencing the spatial distribution of NO<sub>3</sub><sup>–</sup> concentrations on forest hillslopes. However, studies linking forest hydrological processes to nitrogen cycling are limited. Therefore, we investigated the determinants of spatial variation in soil moisture and evaluated the effects of soil moisture fluctuations on spatial variation in NO<sub>3</sub><sup>–</sup> concentration and production rate.</p><p>The study sites were the Fukuroyamasawa Experimental Watershed (FEW) and Oyasan Experimental Watershed (OEW) in Japan. The two have similar topographies, climates, and tree species. In each watershed, a 100 m transect was set up from the ridge to the base of the slope, and soil moisture sensors were installed at soil depths of 10 cm and 30 cm at both the top and bottom of the slope. We collected surface soil samples at a depth of 10 cm at the top, middle, and bottom of the slopes using 100 cm<sup>3</sup> cores, and measured soil physical properties, particle size distribution, volcanic ash content, chemical properties (pH, NO<sub>3</sub><sup>–</sup>, NH<sub>4</sub><sup>+</sup>, nitrification rate, and mineralization rate), and microbial content (archaeal content). Spatial and temporal changes in soil moisture on the hillslope were calculated using HYDRUS-2D to examine contributing factors of soil moisture.</p><p>At FEW, high NO<sub>3</sub><sup>–</sup> concentrations and nitrification rates were observed only at the slope bottom and middle, and no NO<sub>3</sub><sup>–</sup> concentrations were detected at up slope. By contrast, at OEW, high NO<sub>3</sub><sup>–</sup> concentrations and nitrification rates were observed at all points. NH<sub>4</sub><sup>+</sup> concentrations were similar at all points in both watersheds. At FEW, 10 cm surface soil moisture fluctuated within 25–40% at the slope top but was within 40–50% at the slope bottom. At OEW, surface soil moisture was 30–40% at both the slope top and bottom, with no significant differences according to slope position. It was confirmed that soil moisture was significantly involved in NO<sub>3</sub><sup>– </sup>concentration and nitrification rates. Model simulations showed that the difference in soil moisture fluctuations between FEW and OEW was mainly explained by the spatial variation in soil physical properties. In particular, volcanic ash influenced soil moisture along the entire slope at OEW, resulting in high water retention, but only influenced soil moisture at the slope bottom at FEW. These findings indicate that spatial variability in soil physical properties has a significant effect on soil moisture fluctuation and leads to a spatial distribution of NO<sub>3</sub><sup>–</sup> production.</p>

Effect of pasture improvement managements on physical properties and water content dynamics of a volcanic ash soil in southern Chile

2018 ◽  
Vol 178 ◽  
pp. 55-64 ◽  
Author(s):  
Iván Ordóñez ◽  
Ignacio F. López ◽  
Peter D. Kemp ◽  
Constanza A. Descalzi ◽  
Rainer Horn ◽  
...  
Keyword(s):  
Physical Properties ◽  
Water Content ◽  
Volcanic Ash ◽  
Southern Chile ◽  
Volcanic Ash Soil

scholarly journals Retrieval of volcanic ash and ice cloud physical properties together with gas concentration from IASI measurements using the AVL model

2013 ◽  
Author(s):  
S. Kochenova ◽  
M. De Mazière ◽  
N. Kumps ◽  
S. Vandenbussche ◽  
T. Kerzenmacher
Keyword(s):  
Physical Properties ◽  
Volcanic Ash ◽  
Gas Concentration ◽  
Ice Cloud

Using wavelet analyses to identify temporal coherence in soil physical properties in a volcanic ash-derived soil

2020 ◽  
Vol 285-286 ◽  
pp. 107909 ◽  
Author(s):  
Sebastián Bravo ◽  
Mauricio González-Chang ◽  
Dorota Dec ◽  
Susana Valle ◽  
Ole Wendroth ◽  
...  
Keyword(s):  
Physical Properties ◽  
Volcanic Ash ◽  
Temporal Coherence ◽  
Soil Physical Properties ◽  
Wavelet Analyses

The Photometric Properties of the Ap Stars

1976 ◽  
Vol 32 ◽  
pp. 365-377 ◽  
Author(s):  
B. Hauck
Keyword(s):  
Physical Properties ◽  
Ap Stars

The Ap stars are numerous - the photometric systems tool It would be very tedious to review in detail all that which is in the literature concerning the photometry of the Ap stars. In my opinion it is necessary to examine the problem of the photometric properties of the Ap stars by considering first of all the possibility of deriving some physical properties for the Ap stars, or of detecting new ones. My talk today is prepared in this spirit. The classification by means of photoelectric photometric systems is at the present time very well established for many systems, such as UBV, uvbyβ, Vilnius, Geneva and DDO systems. Details and methods of classification can be found in Golay (1974) or in the proceedings of the Albany Colloquium edited by Philip and Hayes (1975).

The Infection of Cells by Bullet-Shaped Viruses

1969 ◽  
Vol 27 ◽  
pp. 372-373
Author(s):  
Frederick A. Murphy ◽  
Alyne K. Harrison ◽  
Sylvia G. Whitfield
Keyword(s):  
Electron Microscopy ◽  
Physical Properties ◽  
Host Cell ◽  
Thin Section ◽  
Cultured Cells ◽  
Cell Infection ◽  
Thin Section Electron Microscopy ◽  
Section Electron ◽  
Section Electron Microscopy

The bullet-shaped viruses are currently classified together on the basis of similarities in virion morphology and physical properties. Biologically and ecologically the member viruses are extremely diverse. In searching for further bases for making comparisons of these agents, the nature of host cell infection, both in vivo and in cultured cells, has been explored by thin-section electron microscopy.

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