Reasons of Blooming on Light Clinker Paving Bricks

2019 ◽  
Vol 974 ◽  
pp. 75-82
Author(s):  
V.D. Kotlyar ◽  
Yurii V. Popov ◽  
Anton V. Kotlyar ◽  
Yulia V. Terekhina ◽  
Roman A. Yashchenko
Keyword(s):  
Soil Water ◽  
Sulfur Content ◽  
Mineralogical Composition ◽  
Iron Hydroxides ◽  
Surface Evaporation ◽  
Base Materials ◽  
Clinker Brick ◽  
Iron Sulphates ◽  
Permeable Sand ◽  
Crystalline Hydrates

The paper presents the results of the research for the reasons of the formation of a brownish bloom on a light clinker brick during its operation. In the work course, the clinker bricks, their mineralogical composition, the nature of the secondary brick coloring and the base materials were tested during bricklaying. It was established that 2 factors caused incrustation. Firstly, the site on which the clinker brick was laid was characterized by a level of alkali soil water close to the surface, and the surface evaporation prevailed over the soil absorption in the warm period of the year. That is all soil water-dissolved salts migrated to the surface of the brick along well-permeable sand joints between the bricks. Secondly, ferrous minerals, including hematite, which was subjected to hydration with the formation of iron hydroxides, and also reacted with sulphates of groundwater with the formation of iron sulphates, were found in the foundation under the brick. This confirms the higher sulfur content in incrustation areas and the presence of a film similar to crystalline hydrates. The analysis of the research allowed us to develop the recommendations for the performance of paving various types of sites with clinker bricks, to develop measures to eliminate an existing bloom, and also to defend the “honor and dignity” of light bricks.

Evaluation of Surface Evaporation Considering the Effect of Soil Water Gradient

2021 ◽  
Vol 26 (8) ◽  
pp. 04021026
Author(s):  
Tiehang Wang ◽  
Jingjing Guo ◽  
Zaikun Zhao ◽  
Yanzhou Hao
Keyword(s):  
Soil Water ◽  
Surface Evaporation ◽  
Water Gradient

scholarly journals An application of GLEAM to estimating global evaporation

2011 ◽  
Vol 8 (1) ◽  
pp. 1-27 ◽  
Author(s):  
D. G. Miralles ◽  
R. A. M. De Jeu ◽  
J. H. Gash ◽  
T. R. H. Holmes ◽  
A. J. Dolman
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Land Surface ◽  
Root Zone ◽  
Rainfall Interception ◽  
Running Water ◽  
Surface Evaporation ◽  
Continental Scale ◽  
Wide Range ◽  
Global Land

Abstract. A physics-based methodology is applied to estimate global land-surface evaporation from multi-satellite observations. GLEAM (Global Land-surface Evaporation: the Amsterdam Methodology) combines a wide range of remotely sensed observations within a Priestley and Taylor-based framework. Daily actual evaporation is derived at quarter degree resolution over the world's land surface. A running water balance of the vertical profile of soil moisture in the root zone is used to estimate the effect of soil water stress on transpiration. Forest rainfall interception, evaporation from bare soil, transpiration and snow sublimation are calculated independently. The inclusion of soil moisture deficit and forest rainfall interception – by means of the Gash analytical model – leads to an improved representation of the magnitude and distribution of the latent heat flux over semiarid and forested regions. Analyses of the global results show that interception loss plays an important role in the partition of the precipitation into evaporation and water available for runoff at a continental scale. The global distribution of evaporation and its different components is analysed to understand the relative magnitude of each component over different ecosystems. This study gives new insights into the relative importance of precipitation and net radiation in driving evaporation, and how the seasonal influence of these controls varies over the different regions of the world. Precipitation is recognised as an important factor driving evaporation, not only in areas that have limited soil water availability, but also in areas of high rainfall interception and low available energy.

scholarly journals Composition of Mineral Phases of the Ghidirim Diatomite

2007 ◽  
Vol 2 (1) ◽  
pp. 63-66
Author(s):  
Vasile Rusu ◽  
Aliona Vrînceanu ◽  
Igor Polevoi
Keyword(s):  
Clay Minerals ◽  
Amorphous Material ◽  
Clay Fraction ◽  
Mineralogical Composition ◽  
Iron Hydroxides ◽  
Liquid Media ◽  
Mineral Phase ◽  
Accurate Identification ◽  
Mineral Phases

Studies of the mineralogical composition of diatomite from the Ghidirim location of RM, as well as of the extracted clay phase are presented. The mineral phase of the diatomite contains a number of clay minerals, like montmorillonite (in a mixture with insignificant quantities of slightly chloritized montmorillonite), illite and kaolinite. Diatomite contains also non-clay components as fine-dispersed quartz and amorphous material, the more probable sources of which are opal, amorphous alumosilicates, aluminum and iron hydroxides. The applied procedure for separation of clay fractions by sizing settling in liquid media proves to be very useful, enabling possibilities for more accurate identification of the clay constituents of diatomic material. Procedure allows to separate very clean clay fraction especially rich in montmorillonite, which can be utilized itself as mineral adsorbent for practical purposes.

scholarly journals Magnitude and variability of land evaporation and its components at the global scale

2011 ◽  
Vol 15 (3) ◽  
pp. 967-981 ◽  
Author(s):  
D. G. Miralles ◽  
R. A. M. De Jeu ◽  
J. H. Gash ◽  
T. R. H. Holmes ◽  
A. J. Dolman
Keyword(s):  
Soil Water ◽  
Land Surface ◽  
Root Zone ◽  
Bare Soil ◽  
Global Scale ◽  
Relative Importance ◽  
Rainfall Interception ◽  
Surface Evaporation ◽  
Continental Scale ◽  
Wide Range

Abstract. A process-based methodology is applied to estimate land-surface evaporation from multi-satellite information. GLEAM (Global Land-surface Evaporation: the Amsterdam Methodology) combines a wide range of remotely-sensed observations to derive daily actual evaporation and its different components. Soil water stress conditions are defined from a root-zone profile of soil moisture and used to estimate transpiration based on a Priestley and Taylor equation. The methodology also derives evaporationfrom bare soil and snow sublimation. Tall vegetation rainfall interception is independently estimated by means of the Gash analytical model. Here, GLEAM is applied daily, at global scale and a quarter degree resolution. Triple collocation is used to calculate the error structure of the evaporation estimates and test the relative merits of two different precipitation inputs. The spatial distribution of evaporation – and its different components – is analysed to understand the relative importance of each component over different ecosystems. Annual land evaporation is estimated as 67.9 × 103 km3, 80% corresponding to transpiration, 11% to interception loss, 7% to bare soil evaporation and 2% snow sublimation. Results show that rainfall interception plays an important role in the partition of precipitation into evaporation and water available for runoff at a continental scale. This study gives insights into the relative importance of precipitation and net radiation in driving evaporation, and how the seasonal influence of these controls varies over different regions. Precipitation is recognised as an important factor driving evaporation, not only in areas that have limited soil water availability, but also in areas of high rainfall interception and low available energy.

Applications of SEM/EDXA in cement clinker investigation

1990 ◽  
Vol 48 (4) ◽  
pp. 870-871
Author(s):  
Arezki Tagnit-Hamou ◽  
Shondeep L. Sarkar
Keyword(s):  
Mineralogical Composition ◽  
Physicochemical Characteristics ◽  
Cement Clinker ◽  
Accurate Information ◽  
Phase Identification ◽  
History Of ◽  
Bulk Chemical ◽  
Resolution Imaging ◽  
Proven Method ◽  
Instantaneous Chemical

All the desired properties of cement primarily depend on the physicochemical characteristics of clinker from which the cement is produced. The mineralogical composition of the clinker forms the most important parameter influencing these properties.Optical microscopy provides reasonably accurate information pertaining to the thermal history of the clinker, while XRDA still remains the proven method of phase identification, and bulk chemical composition of the clinker can be readily obtained from XRFA. Nevertheless, all these microanalytical techniques are somewhat limited in their applications, and SEM/EDXA combination fills this gap uniquely by virtue of its high resolution imaging capability and possibility of instantaneous chemical analysis of individual phases.Inhomogeneities and impurities in the raw meal, influence of kiln conditions such as sintering and cooling rate being directly related to the microstructure can be effectively determined by SEM/EDXA. In addition, several physical characteristics of cement, such as rhcology, grindability and hydraulicity also depend on the clinker microstructure.

Influence of technology parameters of free-cutting steel continuous casting on the billet internal structure

2020 ◽  
Vol 76 (2) ◽  
pp. 139-142
Author(s):  
A. T. Kunakbaeva ◽  
A. M. Stolyarov ◽  
M. V. Potapova
Keyword(s):  
Regression Analysis ◽  
Continuous Casting ◽  
Internal Structure ◽  
Sulfur Content ◽  
Manganese Content ◽  
High Quality ◽  
Correlation And Regression Analysis ◽  
Cutting Steel ◽  
Continuously Cast

Free-cutting steel gains specific working properties thanks to the high content of sulfur and phosphorus. These elements, especially sulfur, have a rather high tendency to segregation. Therefore, segregation defects in free-cutting steel continuously cast billets can be significantly developed. The aim of the work was to study the influence of the chemical composition of freecutting steel and casting technological parameters on the quality of the macrostructure of continuously cast billets. A metallographic assessment of the internal structure of cast metal made of free-cutting steel and data processing by application of correlation and regression analysis were the research methods. The array of production data of 43 heats of free-cutting steel of grade A12 was studied. Steel casting on a five-strand radial type continuous casting machine was carried out by various methods of metal pouring from tundish into the molds. Metal of 19 heats was poured with an open stream, and 24 heats – by a closed stream through submerged nozzles with a vertical hole. High-quality billets had a cross-sectional size of 150×150 mm. The macrostructure of high-quality square billets made of free-cutting steel of A12 grade is characterized by the presence of central porosity, axial segregation and peripheral point contamination, the degree of development of which was in the range from 1.5 to 2.0 points, segregation cracks and strips – about 1.0 points. In the course of casting with an open stream, almost all of these defects are more developed comparing with the casting by a closed stream. As a result of correlation and regression analysis, linear dependences of the development degree of segregation cracks and strips both axial and angular on the sulfur content in steel and on the ratio of manganese content to sulfur content were established. The degree of these defects development increases with growing of sulfur content in steel of A12 grade. These defects had especially strong development when sulfur content in steel was of more than 0.10%. To improve the quality of cast metal, it is necessary to have the ratio of the manganese content to the sulfur content in the metal more than eight.

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