Soil, characteristics structure

The formation of characteristic structural aggregates vertic structure ) is an additional soil forming process in Vertisols. This typical structure may occur in most of the solum but has its strongest expression in the vertic horizon the grade of development and the sizes of peds change only gradually with depth. 

Soil characteristics and their influence on community structure... 

A new approach in the definition of "molecular structure" is introduced for natural humic substances and soil organic matter by proposing a model HA which represents a characteristic structural pattern for a large number of possible and likely structures. The crucial point is the adaptation, flexibility, and variability to decomposition and synthesis processes in the natural environment. 

The soil pH considerably affects soil characteristics. It is important for many soil-forming processes and it also affects the biological activity of soil organisms. The soil pH directly affects particularly the solubility of many substances, ion adsorption and desorption, coagulation and peptization of colloids and chemical reactions. By its action on the soil structure it also affects most of the physical properties of the soil. Thus, the soil pH is an important parameter of the soil fertility. 

Design considerations include the proximity to other metallic structures and existing CP systems, the type of grounding, the estimated remaining service life of the tank, the type and temperature of the stored product, the amount of product stored, the cycling rates, the method of tank bottom plate construction, the type of tank foundation, the type of secondary containment, if any, and the backfill soil characteristics. 

Normal probability and extreme value statistics have already been discussed as means of evaluating corrosion smd soil resistivity. Statistical methods have been applied to determine when steel tanks will fail [38]. Individual soil characteristics, such as resistivity, pH, and soluble ion content, are unsatisfactory methods of predicting the corrosion behavior of a structure in a particular soil. The statistical method is based on a regression analj is of all of the soil characteristics that affect corrosion as compared to actual corrosion of structures found in those soils. This method 5delds a mean time to corrosion failure (MTCF) as opposed to an actual corrosion rate. Its validity for structures other than steel tanks has not been demonstrated. 

Bushman, J. B. and Mehalick, T. E., "Statistical Analysis of Soil Characteristics to Predict Mean Time to Corrosion Failure of Underground Metallic Structures, Effects of Soil Characteristics on Corrosion, ASTM STP 1013, V. Chaker and J. D. Palmer, Eds., ASTM International, West Conshohocken, PA, 1989. 

Presented also was an application of PDD to soil-foundation-structure interaction problem for a bridge system and Earthquake-Soil-Structure (ESS) interaction effects were emphasized. The importance of the (miss-) matching of the ESS characteristics to the dynamic behavior of the bridge soil-structure system was shown on an example using same structure, two different earthquakes (one with short and one with long predominant periods) and two different subgrade soils (stiff sand and soft clay). 

The scope of the present study was to investigate the dynamic interaction between retaining walls, retained soil and retained structures. In all cases examined it was proven that the characteristics of the wall as well as the seismic excitation affect substantially the dynamic behaviour of the whole system. The rigid wall imposes a boundary that clearly alters the 1-D conditions of the backfill, while the flexible wall does not transform the model into 2-D. Furthermore, it has been shown that the amplification of the acceleration levels on the retained soil and structure depends also on the seismic motion. In addition, it has been presented that the existence of a retaining wall may alter considerably the dynamic response of a structure founded on the retained soil. Moreover, the distress of the wall may be affected significantly by the presence of retained structures. 

Key words soil texture, soil structure, soil characteristics, soil management, soil erosion. 

The main characteristic properties of a clay are its cohesive behaviour and the ability to hold water. Clay particles consist of metal silicates (Figure 9.1). Their structure is plate-like. These particles have strong cohesive properties, largely attributable to chemical forces acting between the grains on a small scale. The mineral structure of the clay particles enhances the absorption of organic material, which strongly affects the suitabihty of the soil in structural applications. 

Uptake, compartmentalization, and toxicity of metals in plants are important for exposure assessment of plant eating birds (21-25). Structures of plants, such as fruits, seeds, leaves and shoots, will accumulate metals at differing concentrations based on soil characteristics and air quality (12, 24, 25), thus controlling accessibility to herbivores. 

Other factors than the volume and composition that have to be taken into account for selecting a proper treatment process are similar to reverse osmosis (Squire et al., 2000 Ahmed et al., 2001) legal requirements such as permits and conditions cost of further treatment local factors such as the proximity and size of a wastewater treatment plant, the presence of surface water or open land, soil characteristics, and geological structure flexibility of the disposal method in case of an expansion of the existing plant and public acceptance. 

To promote the use of poor quality water for irrigation, a field research study was conducted in three semi-arid regions with water scarceness in Syria in order to define, under field conditions, the wheat yield response function to irrigation water salinity, the effect of soil texture and structural characteristics on the irrigation water salinity threshold, and to compare this value with the conventional threshold value. 

Soil Clay is the primary construction material for settling basins and waste treatment evaporation ponds. Since there is no single type of clay even within a given geographic area, the shrinkage, porosity absorption characteristics, and chemical resistance must be checked for each application. Geotextiles can be incorporated into basin and pond clay construction to improve the performance of the structure. 

A. Piccolo, S. Nardi, and G. Concheri, Structural characteristics of humic substances as related to nitrate uptake and growth regulation in plant systems. Soil Biol. Bio-chem. 24 313 (1992). 

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