Soil Characterization

More sophisticated methods that actually measure volumetric water content can also be used, such as time domain reflectometry (TDR). In Figure 14, an example of TDR results is presented. Both the calculated and measured (i.e., TDR) volumetric water contents provide a similar picture of the profile water status by depth with time. Proper soil characterization data, such as those shown in Table 6, are necessary for these calculations and improve understanding of the test system. The determination of water-holding capacity (WHC) at 0.03 MPa field capacity (FC) and 1.5 MPa... 

Table 6 Soil characterization results used in water balance calculations and data interpretations...

Immature soil samples have S Te values that are indistinguishable from lunar rocks, whereas submature and mature soils have 5 Fe values that are greater than those of lunar rocks, and S Te values are positively correlated with Ig/FeO values (Fig. 12). Lunar regolith samples in general tend to have heavy isotopic compositions as compared to lunar rock samples, as demonstrated by isotopic analyses of O, Si, S, Mg, K, Ca, and Cd (Epstein and Taylor 1971 Clayton et al. 1974 Russell et al. 1977 Esat and Taylor 1992 Humayun and Clayton 1995 Sands et al. 2001 Thode 1976). The origin of isotopic compositions that are enriched in the heavy isotopes has been presumed to reflect sputtering by solar wind and vaporization, where preferential loss of the lighter isotope to space occurs. In contrast to previous isotopic studies, the Fe isotope compositions measured in the Lunar Soil Characterization Consortium samples can be related to a specific phase based on the positive correlation in Ig/FeO and 5 Fe values (Fig. 12). 

Figure 12. Plot of I/FeO versus 5 Fe values of lunar regolith samples from the Lunar Soil Characterization Consortium. The sub-scripted numbers after the sample numbers are the I,/FeO values measured for the <250 pm sized fraction. All analyses are for bulk samples of the different sized fractions error bars are 2a as calculated from 2 or more complete Fe isotope analyses. Modified from Wiesli et al. (2003a).

Ponnamperuma EN. 1985. Chemical kinetics of wetland rice soils relative to soil fertility. In Wetland Soils Characterization, Classification and Utilization. Manila International Rice Research Institute, 71-89. 

Akhter, H., Cartledge, F.K., Miller, J. and McLearn, M. (2000) Treatment of arsenic-contaminated soils. I soil characterization. Journal of Environmental Engineering, 126(11), 999-1003. 

Field Locations. For each field test location a variety of information is collected and recorded in addition to the samples which are collected. Seven general categories of information can be defined. Three simple ones are 1) test design or plot plan, 2) location and 3) field use history for several years. Field soil characterization 4) includes screen analysis (soil type), pH measurement, and organic matter content. Weather information 5) includes daily temperatures and rainfall and/or irrigations during the test. Application related data 6) consists of dates, application modes, weather conditions at application, calculations and calibrations. Harvest information 7) includes crop name, part, amount, date, and collector. 

Mukeijee, S., W.D. Ellenson, R.G. Lewis, R.K. Stevens, M.C. Somerville, D.S. Shadwick and R.D. Willis (1997). Soil characterizations conducted in the lower Rio Grande Valley of Texas, m. Residential microenvironmental measurements with applications for regional and temporal-based exposure assessments. Environ. Int., 23, 657-673. 

A lowering of the interaction temperature increased the adsorption tendency of most of the soils studied (Table 3). Such exothermicity can be reconciled with a physical adsorption mechanism [ 16 ]. The retention mechanism appeared to be slightly endothermic on GI, a soil characterized by a very high sand content, a low pH, and a very low organic matter content. It seemed possible that, once... 

Surface and subsurface soils investigations to assess the location and extent of contamination from each significant constituent. In many cases, the prior mixing of the wastes with the soil makes the soil characterization a critical aspect of defining the source strength and extent. 

Spodosol. A soil characterized by a whitish-grey, highly leached A horizon, and a B spodic horizon that is significantly enriched in organic matter. These soils develop in cool-temperate to temperate, humid climates under coniferous or mixed coniferous and deciduous forests. In the current soil taxonomic system, most Podzol soils (an older classification) are Spodosols. 

TABLE 4. Warynski major contaminant soil characterization by depth. 

The above-listed parameters are included in the Nernst equation to describe the Eh of a system. For example, pH and temperature have an inverse relationship with Eh. Similarly, an increase in electron donor supply (organic matter) will decrease Eh values, while an increase in electron acceptor supply (oxidants) will increase Eh values. Considering these factors, Eh can be used as an operational parameter to characterize soil anaerobiosis. It is a simple parameter, and because of its ease of measurement, it can be included in routine monitoring of soil quality and soil characterization. The Eh parameter by itself may have little value when it is related to the soil conditions at the time of measurement. 

Crockett, A. B., A. Prop, and T. Kunes. 1986. Soil characterization study of former herbicide storage site at Johnson Island. Govt. Rep. Announce. Index (U.S.) 87(19), Abstr. No. 743, p. 346 Chem. Abstr. CA 708(17) 145271a. 

A - Lithoid formations or homogeneous soils characterized by a value of is the velocity of... 

C Deposits of non cohesive soils, with or without inserts of soft cohesive soils, characterized by values of Vs increasing with depth without marked discontinuities, starting from Fs > 150 m s (NSPT > 10) at the depth of 20 m. 

The uranium content in soil can be determined directly by some analytical methods that are mainly based on nuclear techniques (variations of neutron activation analysis, gamma spectrometry, x-ray fluorescence, or laser-ablation ICPMS), but the common, popular, and more accurate methods require digestion and dissolution of the entire soil sample or at least rely on leaching the uranium out of the sample matrix. In principle, the methods used for assaying uranium in minerals (see Chapter 2) are also suitable for soil characterization, but uranium is usually present in the latter only as a low-level impurity, usually below 100 pg U g. We shall first overview the procedures deployed for the treatment of soil samples prior to analysis and refer to the analytical devices used for the measuranent of the uranium content and isotopic composition in these studies. 

Specific surface area determination is most commonly conducted by positive adsorption studies (Section 7.6.4.2), and here the election of the probe molecule is very important. The most traditional and widely used method is N2 adsorption at 77 K, using the BET isotherm to evaluate monolayer coverage (Section 7.6.4.2) sometimes other inert gases, such as argon, are employed in the same conditions (Sposito 1984). In soil characterization, other substances are also used in the BET... 

The number of geotechnical investigations to be carried out can be based on the potential consequences of the site related hazards. For all classes of research reactors, soil characterization may involve borehole drillings in sufficient number and depth, depending on soil conditions. At least one borehole should be drilled for every safety related building at the site. However, drUhng may not be necessary for competent rock sites where the rock formation continues to a sufficient depth. 

Soil characterization results are reported in Table 1. As it can be observed this soil is classified as a Low plasticity Clay (CL), then it will no exhibit a great volume change during experimentation also, clay and silt content indicate that this is a low permeability sod. 

Moraci, N., 1992. The Filter Action of Geotextiles on Contact with Granular Soils Characterization, Interaction and ModeUing (Ph.D. thesis). University of Padova, Italy (in Italian). 

Most of the results presented above are related to solute transport in saturated heterogeneous media. In the vadose zone, the variability in water saturation usually contributes to enhance the variability in water velocity, and therefore solute spreading (Russo, 1998). However, it has been shown that macrodispersion coefficients for solute transport in unsaturated soils characterized by strong stratification are usually smaller than saturated values, especially at low water content (Harter and Zhang, 1999). 

The characterization of the soil overburden at SRS as a fairly uniform sand to sand/clay layer of about 1000 feet thickness and having a shear wave velocity slightly larger than 1000 fps is consistent with the data collected at the site. This descriptiuii is also consistent with the geologic history of the area. As discussed in Section 6.1.5, a soils characterization program has been initiated to further document the near surface material properties at the rector site. 

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