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Journal articles on the topic 'Uniform soil'

Author: Grafiati

Published: 28 June 2021

Last updated: 1 February 2022

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1

Zhou, Jizhong, Beicheng Xia, David S. Treves, L. Y. Wu, Terry L. Marsh, Robert V. O’Neill, Anthony V. Palumbo, and James M. Tiedje. "Spatial and Resource Factors Influencing High Microbial Diversity in Soil." Applied and Environmental Microbiology 68, no. 1 (January 2002): 326–34. http://dx.doi.org/10.1128/aem.68.1.326-334.2002.

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ABSTRACT To begin defining the key determinants that drive microbial community structure in soil, we examined 29 soil samples from four geographically distinct locations taken from the surface, vadose zone, and saturated subsurface using a small-subunit rRNA-based cloning approach. While microbial communities in low-carbon, saturated, subsurface soils showed dominance, microbial communities in low-carbon surface soils showed remarkably uniform distributions, and all species were equally abundant. Two diversity indices, the reciprocal of Simpson’s index (1/D) and the log series index, effectively distinguished between the dominant and uniform diversity patterns. For example, the uniform profiles characteristic of the surface communities had diversity index values that were 2 to 3 orders of magnitude greater than those for the high-dominance, saturated, subsurface communities. In a site richer in organic carbon, microbial communities consistently exhibited the uniform distribution pattern regardless of soil water content and depth. The uniform distribution implies that competition does not shape the structure of these microbial communities. Theoretical studies based on mathematical modeling suggested that spatial isolation could limit competition in surface soils, thereby supporting the high diversity and a uniform community structure. Carbon resource heterogeneity may explain the uniform diversity patterns observed in the high-carbon samples even in the saturated zone. Very high levels of chromium contamination (e.g., >20%) in the high-organic-matter soils did not greatly reduce the diversity. Understanding mechanisms that may control community structure, such as spatial isolation, has important implications for preservation of biodiversity, management of microbial communities for bioremediation, biocontrol of root diseases, and improved soil fertility.

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2

Simon, Steven L., and Leslie Fraley. "226Ra uptake by sagebrush from uniform and non-uniform soil amendments." Environmental and Experimental Botany 26, no. 1 (January 1986): 81–88. http://dx.doi.org/10.1016/0098-8472(86)90056-0.

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3

Al-Jabban, Wathiq, Jan Laue, Sven Knutsson, and Nadhir Al-Ansari. "Effect of Disintegration Times of the Homogeneity of Soil prior to Treatment." Applied Sciences 9, no. 22 (November 9, 2019): 4791. http://dx.doi.org/10.3390/app9224791.

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This paper presents an experimental study to investigate the effect of various disintegration times on the homogeneity of pre-treated natural soil before mixing with cementitious binders. Various disintegration times were applied, ranging from 10 s to 120 s. Four different soils were used with different characteristics from high, medium and low plasticity properties. Visual and sieving assessment were used to evaluate the best disintegration times to allow for a uniform distribution of water content and small-sized particles that would produce a uniform distribution of the binder around the soil particles. Results showed that a proper mixing time to homogenize and disintegrate the soil prior to treatment depended on several factors: soil type, water content and plasticity properties. For high plasticity soil, the disintegration time should be kept as short as possible. Increasing the disintegration time ha negative effects on the uniformity of distribution of the binder around soil particles. The homogenizing and disintegration time were less important for low plasticity soils with low water content than for medium to high plasticity soils. The findings could assist various construction projects that deal with soil improvement through preparation of soil before adding a cementitious binder to ensure uniformity of distribution of the binder around soil particles and obtain uniform soil–binder mixtures.

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Das, Angshuman, and Pradipta Chakrabortty. "ONE-DIMENSIONAL SEISMIC ENERGY TRANSMISSION ALONG HETEROGENEOUS LAYERED SOIL." International Journal of Students' Research in Technology & Management 4, no. 3 (December 2, 2016): 49. http://dx.doi.org/10.18510/ijsrtm.2016.432.

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In this present study an initiative has been taken to find out the modification in the seismic energy along distance its travel because of the soil heterogeneity. Soil heterogeneity is considered here in one dimensional analysis and analyses were performed using software DEEPSOIL. Both equivalent linear and nonlinear analyses were performed on homogenous and heterogeneous soil models: uniform loose sand, uniform soft clay and layered soil deposit of sandwiched clay layer between loose sandy soils. The performances of these soil models are compared here in terms of peak ground acceleration (PGA) value, and seismic energy migration in terms of Arias Intensity (AI) evolution along the depth inside the soil deposit. It is observed from the analysis that, less seismic energy and PGA is developed in the heterogeneous soil than that in homogeneous soil. This is because during earthquake more softening is taking place in the layered soil than that in uniform soil. Further in this paper the requirement of nonlinear analysis over the equivalent linear analysis is also presented.

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Li, Li, Na Dong, and Jianya Chen. "EM Wave Propagation in Non-uniform Soil." Information Technology Journal 12, no. 19 (September 15, 2013): 5011–16. http://dx.doi.org/10.3923/itj.2013.5011.5016.

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6

Masih, Rusk. "Foundation Uniform Pressure and Soil‐Structure Interaction." Journal of Geotechnical Engineering 120, no. 11 (November 1994): 2064–71. http://dx.doi.org/10.1061/(asce)0733-9410(1994)120:11(2064).

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7

Li, K. S. "Foundation Uniform Pressure and Soil-Structure Interaction." Journal of Geotechnical Engineering 121, no. 12 (December 1995): 912. http://dx.doi.org/10.1061/(asce)0733-9410(1995)121:12(912).

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8

Bukhartsev, V. N., and M. R. Petrichenko. "Nonsteady filtration in a uniform soil mass." Power Technology and Engineering 46, no. 3 (August 16, 2012): 198–200. http://dx.doi.org/10.1007/s10749-012-0331-z.

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9

Fredlund, Murray D., D. G. Fredlund, and G. Ward Wilson. "An equation to represent grain-size distribution." Canadian Geotechnical Journal 37, no. 4 (August 1, 2000): 817–27. http://dx.doi.org/10.1139/t00-015.

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The grain-size distribution is commonly used for soil classification; however, there is also potential to use the grain-size distribution as a basis for estimating soil behaviour. For example, much emphasis has recently been placed on the estimation of the soil-water characteristic curve. Many methods proposed in the literature use the grain-size distribution as a starting point to estimate the soil-water characteristic curve. Two mathematical forms are presented to represent grain-size distribution curves, namely, a unimodal form and a bimodal form. The proposed equations provide methods for accurately representing uniform, well-graded soils, and gap-graded soils. The five-parameter unimodal equation provides a closer fit than previous two-parameter, log-normal equations used to fit uniform and well-graded soils. The unimodal equation also improves representation of the silt- and clay-sized portions of the grain-size distribution curve.Key words: grain-size distribution, sieve analysis, hydrometer analysis, soil classification, probability density function.

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10

Jeremić, Boris, Guanzhou Jie, Matthias Preisig, and Nima Tafazzoli. "Time domain simulation of soil-foundation-structure interaction in non-uniform soils." Earthquake Engineering & Structural Dynamics 38, no. 5 (April 25, 2009): 699–718. http://dx.doi.org/10.1002/eqe.896.

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11

Siegrist, Robert, Paula Labieniec, and David Dzombak. "Editorial: The Need for Uniform Soil Cleanup Goals." Environmental Science & Technology 27, no. 5 (May 1993): 765–66. http://dx.doi.org/10.1021/es00042a607.

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12

Silvestri, Vincenzo, Ghassan Abou-Samra, and Christian Bravo-Jonard. "Shape Factors of Cylindrical Piezometers in Uniform Soil." Ground Water 50, no. 2 (August 17, 2011): 279–84. http://dx.doi.org/10.1111/j.1745-6584.2011.00845.x.

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13

Labieniec, Paula A., David A. Dzombak, and Robert L. Siegrist. "Risk Variability Due to Uniform Soil Remediation Goals." Journal of Environmental Engineering 122, no. 7 (July 1996): 612–21. http://dx.doi.org/10.1061/(asce)0733-9372(1996)122:7(612).

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14

Mylavarapu, R. S., and V. L. Quisenberry. "SPATIAL DISTRIBUTION OF DRAINAGE FROM UNIFORM SOIL COLUMNS." Soil Science 170, no. 1 (January 2005): 38–46. http://dx.doi.org/10.1097/00010694-200501000-00005.

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15

Hainsworth, J. M., and L. A. G. Aylmore. "Non-uniform soil water extaction by plant roots." Plant and Soil 113, no. 1 (January 1989): 121–24. http://dx.doi.org/10.1007/bf02181929.

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16

Huisz, Andrea. "The aggregate stability of the soil in respect to the uniform aggregate stability indicator." Acta Agraria Debreceniensis, no. 26 (July 16, 2007): 83–99. http://dx.doi.org/10.34101/actaagrar/26/3061.

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Soil structure and its quality are fundamental properties because they control many processes in soils. Tillage, crop and other factors influence soil structure. Efficient protection of it needs indication of changes in soil structure. A new Normalized Stability Index proposed by Six et al. (2000) tries to evaluate these changes, which was compared with some former used indices. The most common method (wet sieving) was modified to reduce the confounding effects of different particle size distribution of different soil types and method used to the investigation. Changes in soil structure caused by tillage and crop management therefore have been made quantitative and comparable. In this paper, we review the new method and Normalized Stability Index proposed by Six et al. (2000) and present the results of our investigations.

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17

Świtoniak, Marcin, Cezary Kabała, and Przemysław Charzyński. "Proposal of English equivalents for the soil taxa names in the Polish Soils Classification." Soil Science Annual 67, no. 3 (September 1, 2016): 103–16. http://dx.doi.org/10.1515/ssa-2016-0013.

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AbstractThe article presents proposed English translations of all names of soil units (orders, types and subtypes) listed by Polish Soils Classification, PSC (2011). The proposal has been elaborated based on the recent Polish and foreign literature, using uniform and consistent criteria. Due to the lack of soil names translation in the recent, fifth edition of PSC, the suggested English nomenclature was basically derived from the previous, fourth edition of PSC (1989). However, significant amendment and numerous additions to the latest version were proposed. A uniform and comprehensive system of soil taxa translations may help to avoid nomenclature chaos in the English papers of Polish authors, which intentionally base or refer to PSC.

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18

Zemke, Julian J., Joshua Pöhler, and Stephan Stegmann. "Modeling Runoff-Formation and Soil Erosion after Pumice Excavation at Forested Andosol-Sites in SW-Germany Using WEPP." Soil Systems 3, no. 3 (July 31, 2019): 48. http://dx.doi.org/10.3390/soilsystems3030048.

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This study investigates the effects of pumice excavation on runoff formation and soil erosion processes in a forested catchment in SW-Germany. The underlying questions are, if (a) backfilled soils have different properties concerning runoff generation and erodibility and if (b) clear-cutting prior to excavation triggers runoff and erosion. Four adjacent sub-areas were observed, which represented different pre- and post-excavation-stages. The basis of the investigation was a comprehensive field sampling that delivered the data for physical erosion modeling using the Water Erosion Prediction Project (WEPP). Modeling took place for standardized conditions (uniform slope geometry and/or uniform land management) and for actual slope geometry and land management. The results show that backfilled soils exhibited 53% increase of annual runoff and 70% increase of annual soil loss under standardized conditions. Storm runoff was increased by 6%, while storm soil loss was reduced by 9%. Land management changes also triggered shifts in annual runoff and soil erosion: Clear-cut (+1.796% runoff, +4.205% soil loss) and bare (+5.958% runoff, +21.055% soil loss) surfaces showed the most distinct changes when compared to undisturbed forest. While reforestation largely diminished post-excavation runoff and soil erosion, the standardized results statistically prove that soil erodibility and runoff generation remain increased after backfilling.

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19

Yang, Hong, Harianto Rahardjo, Eng-Choon Leong, and D. G. Fredlund. "Factors affecting drying and wetting soil-water characteristic curves of sandy soils." Canadian Geotechnical Journal 41, no. 5 (September 1, 2004): 908–20. http://dx.doi.org/10.1139/t04-042.

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Drying and wetting soil-water characteristic curves (SWCCs) for five sandy soils are investigated using a Tempe pressure cell and capillary rise open tube. The test data are fitted to two SWCC equations using a least-squares algorithm. The obtained fitting parameters and some hysteretic behaviour are discussed and correlated with grain-size distribution parameters. A concept of total hysteresis is proposed to quantify the hysteresis of SWCC. The measured SWCC for one soil is also compared with the SWCC estimated from its grain-size distribution. The SWCC was also obtained at a high dry density for one of the soils. The results show that the shapes of the SWCCs are similar to the grain-size distributions of the soils and are affected by the dry density of the soil. A coarse-grained soil has a lower air-entry value, residual matric suction, and water-entry value and less total hysteresis than a fine-grained soil. The residual matric suction and water-entry value tend to approach the same value when the effective grain size D10 of the soil is small, in the range of 3-6 mm. SWCCs of uniform soils have steeper slopes and less total hysteresis than those of less uniform soils. Soils with a low dry density have a lower air-entry value and residual matric suction than soils with a high dry density. The SWCC predicted from grain-size distribution is found to be sufficiently accurate.Key words: soil-water characteristic curve, water content, suction, hysteresis, grain size.

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20

Tang, Yangyang, Yingmin Li, Zongming Huang, Liping Liu, Yishun Ding, and Hui Zhu. "ANALYSIS OF LOCAL SITE EFFECTS ON SEISMIC RESPONSE OF FRAME STRUCTURES SUPPORTED BY FOUNDATIONS AT DIFFERENT ELEVATIONS." NED University Journal of Research 3, Special Issue on First SACEE'19 (December 12, 2019): 181–90. http://dx.doi.org/10.35453/nedjr-stmech-2019-0038.

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Frame structures supported by foundations with different elevations (such as a structure on the slope) undergo different ground motions because of the local site effect. Seismic response of the structure under non-uniform excitation of ground motion is different from that under uniform excitation on upper embedding end or lower embedding end. Sites with the same height difference and different soil conditions were set up in this paper to subject them to ground motions related to different positions and the seismic response of structures built on the sites under uniform and non-uniform strong seismic excitation were compared. The results show that the predominant period and amplitude of ground motions on upper embedding end and lower embedding end are different and affected by soil conditions. The extent and law of amplification of shear force, displacement and storey drift of structures under non-uniform excitation differ from those under uniform excitation when soil changes from soft to medium-hard soil. In addition, the position and degree of plastic hinges change under non-uniform excitation compared to uniform excitation. The uniform excitation using the ground motion on the upper embedding end is not always safe for the frame structure supported by foundations at different elevations.

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21

Bellairs, SM, NC Turner, PT Hick, and RCG Smith. "Plant and soil influences on estimating biomass of wheat in plant breeding plots using field spectral radiometers." Australian Journal of Agricultural Research 47, no. 7 (1996): 1017. http://dx.doi.org/10.1071/ar9961017.

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Field spectral radiometers were used to estimate the biomass of wheat at early growth stages, as wheat breeders require a rapid, non-destructive technique to rank wheat genotypes for early vigour. Under experimental conditions, good relationships were obtained between reflectance and biomass prior to the wheat crop achieving a green area index of 1.5. When used above different soil types, good results were achieved on very uniform dark and light soils under experimental conditions, but greater differentiation between plots differing in biomass was achieved on darker soils. Similarly, under operational conditions in wheat breeders' plots, the best results were achieved against a dark soil background. Structural differences between plants also influenced solar radiation reflectance. At the Merredin site with the dark soil background, where the best correlation between reflectance and biomass was achieved, the relationship was much stronger for the more uniform genotypes at the second stage of selection than for the more heterogeneous genotypes at the first stage of selection. On these plots, the vegetation spectral indices NDVI (normalised difference vegetation index) and TSAVI (transformed soil-adjusted vegetation index) had a coefficient of determination 90-95% as good as the best regression using two wavebands. To optimise the field spectroradiometry technique for estimating early biomass, it should be applied at a weed-free site, with a uniform dark soil background and on material that is relatively homogenous in structure. We conclude that, unless these precautions are taken, the technique will have limited utility in breeding programs.

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Chang, Kuang-Tsung, Kevin Zeh-Zon Lee, and Han-Yu Wu. "Internal Erosion Failure of Uniform Sands under Confinement and Constricted Seepage Exit." Water 12, no. 9 (August 28, 2020): 2417. http://dx.doi.org/10.3390/w12092417.

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Seepage water may move soil particles and cause internal erosion of soils, leading to sinkholes and the collapse of embankments and slopes. To account for the effects of confinement and constricted seepage exit, a test apparatus was developed to study the internal erosion of granular soils under various confining pressures, particle sizes, and sizes of the seepage exit opening. As indicated in the literature, the behavior of internal erosion has been largely studied by laboratory experiments and field investigations, and mechanical models that help describe the failure mechanism of internal erosion are less prevalent. A hydro-mechanical model that incorporates the fluid drag force and the shear strength of soil was therefore developed for quantifying the internal erosion experiments conducted in this study. The experimental results showed that the greater the confining pressure or the particle size, the greater the critical velocity; the greater the seepage exit opening, the smaller the critical velocity. The critical velocity predicted by the proposed hydro-mechanic model compares reasonably well with the experimental data. In addition to the confining pressure, particle size, and size of the seepage exit opening, the proposed model also showed that the friction angle and porosity of the soil are factors influencing the critical velocity, which is consistent with the experimental findings of this study.

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Smith, E. Lamar. "The Struggle for a Uniform Monitoring System." Arid Land Research and Management 17, no. 4 (January 2003): 347–58. http://dx.doi.org/10.1080/713936106.

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24

Morisawa, Masayuki, and Shinzo Muto. "Plastic Optical Fibre Sensing of Fuel Leakage in Soil." Journal of Sensors 2012 (2012): 1–6. http://dx.doi.org/10.1155/2012/247851.

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A basic operation of the very simple optical sensing system of fuel leakage in uniform sandy and clayey soils, which is consisting of a plastic optical fibre (POF) transmission line, the POF-type sensor heads, and a single LED photodiode pair, has been studied theoretically and experimentally. Its sensing principle is based on the POF structure change in the sensor head caused by fuels such as petrol. A scale-downed model prepared in the experimental room showed a possibility of optical detection of fuel leakage points in uniform soil. As this system operates without receiving the influence of water containing in fuels and soils, its application to fuel leak monitor around a filling station and oil tank can be expected.

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Meigooni, Fatemeh Soleiman, and Mohsen Tehranizadeh. "Uniform risk vs. uniform hazard spectral acceleration for different soil types in Alborze seismic zone." Asian Journal of Civil Engineering 21, no. 1 (September 24, 2019): 67–79. http://dx.doi.org/10.1007/s42107-019-00193-3.

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Alikonis, Antanas. "INFLUENCE OF CLAYEY SOIL STRUCTURE ON ITS MODULUS OF STIFFNESS." JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 5, no. 2 (April 30, 1999): 108–15. http://dx.doi.org/10.3846/13921525.1999.10531444.

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Disturbance of soil structure influences its density, strength and deformation properties. Among other cases soil structure could be disturbed by compacting it. It is possible to increase deformation properties of sand or gravel by compacting them. However, for clay soils deformation properties may increase if they are compacted. Differences of settlements of a building depends on the different deformation properties of the artificially placed and compacted soils beneath the foundations. Different values of stiffness modulus are used for the structural design of the buildings which are constructed on the soils with different compressibility. Coefficient of changeability of soil compression (1) was used. It may be calculated as a ratio of maximum and minimum values of deformation modulus, or according to the maximum and minimum values of coefficient of relative compressibility (3). Coefficient of the relative compressibility of soil can be calculated depending on the maximum and minimum values of tip resistence from CPT test (5). According to the coefficient of the relative compressibility we could estimate whether the soil is uniform, nonuniform or extremely non-uniform. It is important for the design of civil engineering structures. Mechanical properties of soils may be back-calculated using theoretical values of settlements and loads. Most frequently within the building layout area soils are natural and artificially compacted. For a compacted soil it is possible to draw compression curve in semi-logarithmic scale using compression curve of the same natural soil and the void ratio of the artificially placed and compacted soil. Thus we can determine compressibility of the soil with disturbed or undisturbed structure. Using parameters of soil compressibility, we can determine the coefficient of the relative compressibility, maximum and minimum values of settlement and modulus of stiffness.

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Shulaev, Nikolay S., Valeriya V. Pryanichnikova, Ramil R. Kadyrov, Inna V. Ovsyannikova, Nikolay A. Bykovsky, and Raisa M. Damineva. "Electrochemical cleaning of soils with different concentrations of oil pollution using a single source of electrical voltage." SCIENCE & TECHNOLOGIES OIL AND OIL PRODUCTS PIPELINE TRANSPORTATION 10, no. 6 (November 30, 2020): 674–80. http://dx.doi.org/10.28999/2541-9595-2020-10-6-674-680.

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The most essential scientifific and practical task in the area of ecological safety of pipelines operation is the development and improvement of methods of purifification and restoration of oil-contaminated soils. One of the most effificient and cost effective methods is electrochemical purifification, that does not require the use of expensive chemical reagents and soil excavation. However, the consideration of non-uniform contamination of various soil sections is required. The article examines the features of the organization and technological infrastructure for electrochemical purifification of non-uniformly contaminated soils when using a single electrical energy source, a method for calculating the design parameters of the corresponding installation is proposed. Effificient purifification of non-uniformly contaminated soil when using a specifified voltage is possible through the use of different-sized electrodes. For each soil type, the amount of transmitted electric charge required for soil purifification is determined by the concentration of the contaminant. Allocation of cathodes and anodes as parallel batteries and their connection using individual buses is an effective and energy-effificient solution, since an almost-uniform electric fifield is created in an inter-electrode space, thus allowing the reduction of the interelectrode resistance of the medium.

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Furbish, David Jon, Rina Schumer, and Amanda Keen-Zebert. "The rarefied (non-continuum) conditions of tracer particle transport in soils, with implications for assessing the intensity and depth dependence of mixing from geochronology." Earth Surface Dynamics 6, no. 4 (December 3, 2018): 1169–202. http://dx.doi.org/10.5194/esurf-6-1169-2018.

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Abstract. We formulate tracer particle transport and mixing in soils due to disturbance-driven particle motions in terms of the Fokker–Planck equation. The probabilistic basis of the formulation is suitable for rarefied particle conditions, and for parsing the mixing behavior of extensive and intensive properties belonging to the particles rather than to the bulk soil. The significance of the formulation is illustrated with the examples of vertical profiles of expected beryllium-10 (10Be) concentrations and optically stimulated luminescence (OSL) particle ages for the benchmark situation involving a one-dimensional mean upward soil motion with nominally steady surface erosion in the presence of either uniform or depth-dependent particle mixing, and varying mixing intensity. The analysis, together with Eulerian–Lagrangian numerical simulations of tracer particle motions, highlights the significance of calculating ensemble-expected values of extensive and intensive particle properties, including higher moments of particle OSL ages, rather than assuming de facto a continuum-like mixing behavior. The analysis and results offer guidance for field sampling and for describing the mixing behavior of other particle and soil properties. Profiles of expected 10Be concentrations and OSL ages systematically vary with mixing intensity as measured by a Péclet number involving the speed at which particles enter the soil, the soil thickness, and the particle diffusivity. Profiles associated with uniform mixing versus a linear decrease in mixing with depth are distinct for moderate mixing, but they become similar with either weak mixing or strong mixing; uniform profiles do not necessarily imply uniform mixing.

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Santos, D., A. J. M. Smucker, S. L. S. Murphy, H. Taubner, and R. Horn. "Uniform Separation of Concentric Surface Layers from Soil Aggregates." Soil Science Society of America Journal 61, no. 3 (May 1997): 720–24. http://dx.doi.org/10.2136/sssaj1997.03615995006100030003x.

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Loukidis, Dimitrios, George D. Bouckovalas, and Achilleas G. Papadimitriou. "Analysis of fault rupture propagation through uniform soil cover." Soil Dynamics and Earthquake Engineering 29, no. 11-12 (November 2009): 1389–404. http://dx.doi.org/10.1016/j.soildyn.2009.04.003.

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31

Shu-Tung Chu. "Modeling Infiltration into Tilled Soil during Non-Uniform Rainfall." Transactions of the ASAE 28, no. 4 (1985): 1226–29. http://dx.doi.org/10.13031/2013.32415.

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32

Porro, I., P. J. Wierenga, and R. G. Hills. "Solute transport through large uniform and layered soil columns." Water Resources Research 29, no. 4 (April 1993): 1321–30. http://dx.doi.org/10.1029/92wr02528.

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Stagnitti, F., M. B. Parlange, T. S. Steenhuis, and J. Y. Parlange. "Drainage From a Uniform Soil Layer on a Hillslope." Water Resources Research 22, no. 5 (May 1986): 631–34. http://dx.doi.org/10.1029/wr022i005p00631.

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34

Alharthi, Yasir M., and Adel M. Hanna. "Compaction Effort for Uniform Laboratory-Prepared Cohesionless Soil Bed." Geotechnical Testing Journal 42, no. 4 (September 13, 2018): 20180024. http://dx.doi.org/10.1520/gtj20180024.

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35

Labieniec, Paula A., David A. Dzombak, and Robert L. Siegrist. "Risk Variability from Uniform Soil Remediation Goals for PCBs." Journal of Environmental Engineering 120, no. 3 (May 1994): 495–512. http://dx.doi.org/10.1061/(asce)0733-9372(1994)120:3(495).

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36

Sulastri, Ni Nyoman, Sakae Shibusawa, and Masakazu Kodaira. "Soil Electrical Conductivity (Ec) Mapping Using Real-Time Soil Sensor." Jurnal Ilmiah Teknologi Pertanian Agrotechno 5, no. 1 (April 28, 2020): 9. http://dx.doi.org/10.24843/jitpa.2020.v05.i01.p02.

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The development of soil electrical conductivity (EC) recently to generate soil EC spatial variability map is increasingly attractive because of its application for site-specific crop management. Several commercial applications have been developed and marketed. The purpose of this paper is to compare soil EC spatial variability map produced by capacitance and spectroscopic sensors. The two sensors (capacitance and spectroscopic sensors) was mounted in a Real-time soil sensor. The spectrophotometer was used that has linearly arrayed photodiodes of 256 channels for 400 to 900 nm for visible (Vis) lights and 128 channels for 900 to 1700 nm for near infrared (NIR) lights. For two capacitance sensors were embedded in soil penetrator (front/ECF and side/ ECS), which its tip with a flat plane edge to make uniform soil cuts and the soil flattener behind produced a uniform surface texture. It was found that spectroscopic method performed better compared to capacitance sensor. Using linear regression, the spectroscopic method has shown a correlation of 0.75 with soil EC generated from laboratory analysis (ECL). While, the capacitance method shows significant different compared to soil ECL. The primary cause of the extreme differences between ECL, ECF and ECS values is likely related to the calibration of the capacitance sensor itself.

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El Assad, Hatim, Benaissa Kissi, Rhanim Hassan, Parron Vera Miguel Angel, Rubio Cintas Maria Dolores, Guemimi Chafik, and Mariem Kacem-Boureau. "Numerical Modeling of Soil Erosion with Three Wall Laws at the Soil-Water Interface." Civil Engineering Journal 7, no. 9 (September 1, 2021): 1546–56. http://dx.doi.org/10.28991/cej-2021-03091742.

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In the area of civil engineering and especially hydraulic structures, we find multiple anomalies that weakens mechanical characteristics of dikes, one of the most common anomalies is erosion phenomenon specifically pipe flow erosion which causes major damage to dam structures. This phenomenon is caused by a hole which is the result of the high pressure of water that facilitate the soil migration between the two sides of the dam. It becomes only a question of time until the diameter of the hole expands and causes destruction of the dam structure. This problem pushed physicist to perform many tests to quantify erosion kinetics, one of the most used tests to have logical and trusted results is the HET (hole erosion test). Meanwhile there is not much research regarding the models that govern these types of tests. Objectives: In this paper we modeled the HET using modeling software based on the Navier Stokes equations, this model tackles also the singularity of the interface structure/water using wall laws for a flow turbulence. Methods/Analysis: The studied soil in this paper is a clay soil, clay soil has the property of containing water more than most other soils. Three wall laws were applied on the soil / water interface to calculate the erosion rate in order to avoid the rupture of such a structure. The modlisitation was made on the ANSYS software. Findings: In this work, two-dimensional modeling was carried of the soil.in contrast of the early models which is one-dimensional model, the first one had shown that the wall-shear stress which is not uniform along the whole wall. Then using the linear erosion law to predict the non-uniform erosion along the whole length. The previous study found that the wall laws have a significant impact on the wall-shear stress, which affects the erosion interface in the fluid/soil, particularly at the hole's extremes. Our experiment revealed that the degraded profile is not uniform. Doi: 10.28991/cej-2021-03091742 Full Text: PDF

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38

Sharifi, A., and A. Mohsenimanesh. "Soil mechanical resistance measurement by an unique multi-cone tips horizontal sensor." International Agrophysics 26, no. 1 (February 1, 2012): 61–64. http://dx.doi.org/10.2478/v10247-012-0009-7.

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Soil mechanical resistance measurement by an unique multi-cone tips horizontal sensor Amulti-tips horizontal sensor was developed and mounted horizontally on a tine face by shafts. The length of shafts was reduced from top to down the tine. The developed system was evaluated in the controlled soil bin laboratory conditions with clay loam soil and uniform soil moisture content. The experiment was designed with soil compaction at three levels of uniform and non-uniform soil compaction in completely randomized block design with four replications. Vertical standard penetrometer was also used to compare with horizontal sensor data at whole working depth of 0 to 400 mm. The results indicated that there is a correlation with R2 = 0.86 between soil cone penetrometer values and the horizontal soil mechanical resistance measurement system data. It can be concluded that the idea of reducing the length of the tips from top to down the tine face would give promising results.

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39

Schouwenaars, J. M. "A simple method to estimate specific equilibrium soil-water content in a uniform soil." Journal of Hydrology 95, no. 1-2 (November 1987): 13–17. http://dx.doi.org/10.1016/0022-1694(87)90112-0.

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40

Purnomo, Heru, R. G. Raka Basmara Putra, R. Mochammad Syaifulloh, Iwan Sulistyawan, Essy Arijoeni Basoenondo, and Madsuri Satim. "Effect of Coconut Coir Uniformity on Strength of Unfired Soil Lime Bricks." Advanced Materials Research 887-888 (February 2014): 819–23. http://dx.doi.org/10.4028/www.scientific.net/amr.887-888.819.

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The paper discusses strength-time relation of unfired bricks reinforced with and without natural fibers. Untreated and treated coconut fibers with three different lengths (1 cm, 2.5 cm and 4 cm) were prepared for soil lime bricks reinforcements. The effects of 4% uniform 2.5 cm fiber reinforcement was compared to the effects of 4% non-uniform fiber reinforcement, which constitutes a fiber mix between 1/3 part each of 1 cm, 2.5 cm and 4 cm fiber length. Absorption of brick was also evaluated. Experimental investigations reveal that for all type of bricks, up to 90 days compressive strengths decrease a little but bending strengths rapidly decrease with time. The results show that unfired bricks added with uniform treated fiber resulted in better strength performances compared to those added with uniform untreated, non-uniform untreated and non-uniform treated fibers, and also to those without fibers.

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41

Ma, Qifu, Zed Rengel, and Kadambot H. M. Siddique. "Wheat and white lupin differ in root proliferation and phosphorus use efficiency under heterogeneous soil P supply." Crop and Pasture Science 62, no. 6 (2011): 467. http://dx.doi.org/10.1071/cp10386.

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Heterogeneity of soil nutrients, particularly phosphorus (P), is widespread in modern agriculture due to increased adoption of no-till farming, but P-use efficiency and related physiological processes in plants grown in soils with variable distribution of nutrients are not well documented. In a glasshouse column experiment, wheat (Triticum aestivum L.) and white lupin (Lupinus albus L.) were subjected to 50 mg P/kg at 7–10 cm depth (hotspot P) or 5 mg P/kg in the whole profile (uniform P), with both treatments receiving the same amount of P. Measurements were made of plant growth, gas exchange, P uptake, and root distribution. Plants with hotspot P supply had more biomass and P content than those with uniform P supply. The ratios of hotspot to uniform P supply for shoot parameters, but not for root parameters, were lower in L. albus than wheat, indicating that L. albus was better able than wheat to acquire and utilise P from low-P soil. Cluster roots in L. albus were enhanced by low shoot P concentration but suppressed by high shoot P concentration. Soil P supply decreased root thickness and the root-to-shoot ratio in wheat but had little effect on L. albus. The formation of cluster roots in low-P soil and greater proliferation and surface area of roots in the localised, P-enriched zone in L. albus than in wheat would increase plant P use in heterogeneous soils. L. albus also used proportionally less assimilated carbon than wheat for root growth in response to soil P deficiency. The comparative advantage of each strategy by wheat and L. albus for P-use efficiency under heterogeneous P supply may depend on the levels of P in the enriched v. low-P portions of the root-zone and other soil constraints such as water, nitrogen, or potassium supply.

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42

Gömöryová, Erika, Gabriela Barančíková, Erika Tobiašová, Ján Halás, Rastislav Skalský, Štefan Koco, and Dušan Gömöry. "Responses of soil microorganisms to land use in different soil types along the soil profiles." Soil and Water Research 15, No. 2 (March 11, 2020): 125–34. http://dx.doi.org/10.17221/20/2019-swr.

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The objective of this study was to find out how land use affects the soil microbial attributes in different soil types and to which depth. The study was performed in Slovakia (Europe) in three areas differing in soil type (Chernozem, Stagnosol, Cambisol). Within each area, three localities with different land use (forest, grassland, cropland), representing a gradient with different intensity of management, were chosen. The soil samples were taken along a single soil profile up to a depth of 1 m with 10 cm increments at each locality. In the soil samples, the basic soil chemical properties and microbial attributes were determined. The effect of the land use on the microbial biomass and basal respiration was mainly observed in the Chernozem in the top 30 cm, while in the Stagnosol, no difference in the trend in the microbial biomass between the different ecosystems along the soil profile was found. The N-mineralisation reflected the different management practices especially in the Cambisol in the top 20 cm. The most distinct differences in the catalase activity between the soils differing in land use were found in the Cambisol along the whole profile. The richness and diversity of the functional groups did not differ significantly between the soils with the different land use and also no uniform responses of the functional groups composition to the land use were observed. The microbial biomass and activity were mainly affected by the amount of the soil organic matter; the intensity of the impact differed according to the soil type.

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Miller, R. D. "Intrinsic Mesoscopic Spatial Variability in Macroscopically Uniform Soils." Soil Science Society of America Journal 58, no. 5 (September 1994): 1364–67. http://dx.doi.org/10.2136/sssaj1994.03615995005800050012x.

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44

Nassar, I. N., J. G. Benjamin, and R. Horton. "THERMALLY INDUCED WATER MOVEMENT IN UNIFORM CLAYEY SOIL1." Soil Science 161, no. 8 (August 1996): 471–79. http://dx.doi.org/10.1097/00010694-199608000-00001.

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45

Saye, Steven R., Bryan P. Kumm, and Alan J. Lutenegger. "Estimating overconsolidation ratio (OCR) in structured and unstructured cohesive soil with field vane tests referencing soil index properties." Canadian Geotechnical Journal 58, no. 1 (January 2021): 125–41. http://dx.doi.org/10.1139/cgj-2019-0414.

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Estimation of the preconsolidation stress and overconsolidation ratio (OCR) in uniform cohesive soils using a field vane is variably impacted by the combined effects of soil type and plasticity, geologic history, structured vs. unstructured behavior, and the presence of sand or organic matter. Published empirical correlations for cohesive soils consider the effects of soil type and plasticity, but significant variability can occur with changes in soil structure and organic matter content for specific instances. The adaption of the “stress history and normalized soil engineering properties” (SHANSEP) format improves the characterization of overconsolidated soils using field vane tests by applying a proposed empirical approach to identify structured soils from unstructured soils and updating the SHANSEP-based approach to separately evaluate structured and unstructured soils. Validation of the correlation coefficients for individual projects will be needed as the approach is applied to new geologic materials and with potentially different field vane equipment and laboratory testing procedures used to characterize the soils. This additional testing provides an opportunity to improve the correlations for specific conditions and reduce the variability in the OCR assessments.

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46

Krarti, M., D. E. Claridge, and J. F. Kreider. "Analytical Model to Predict Nonhomogeneous Soil Temperature Variation." Journal of Solar Energy Engineering 117, no. 2 (May 1, 1995): 100–107. http://dx.doi.org/10.1115/1.2870823.

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This paper presents an analytical model to predict the temperature variation within a multilayered soil. The soil surface temperature is assumed to have a sinusoidal time variation for both daily and annual time scales. The soil thermal properties in each layer are assumed to be uniform. The model is applied to two-layered, three-layered, and to nonhomogeneous soils. In case of two-layered soil, a detailed analysis of the thermal behavior of each layer is presented. It was found that as long as the order of magnitude of the thermal diffusivity of soil surface does not exceed three times that of deep soil; the soil temperature variation with depth can be predicted accurately by a simplified model that assumes that the soil has constant thermal properties.

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47

Popova, A. Yu, V. N. Rakitsky, T. A. Sinitskaya, G. M. Trukhina, and Irina P. Gromova. "URGENCY OF HYGIENIC RATING OF PESTICIDES IN THE SOIL." Hygiene and sanitation 97, no. 6 (June 15, 2018): 485–89. http://dx.doi.org/10.18821/0016-9900-2018-97-6-485-489.

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The requirement concerning the implementation of the research in the extreme soil-climatic conditions promoting the maximum migration in environments contacting to the soil (water, air, plants), and also providing most their intensive impact on processes of self-cleaning and a soil microbiocenosis is one of the basic provisions of the theory of hygienic rating of active ingredients of pesticides in the soil. For the creation of extreme conditions, the experiment is carried out on the sandy soil possessing the maximum filtering, minimal sorbing and absorbing ability. The observance of a principle of extremeness is provided with executing the research at microclimatic parameters (temperature, humidity, ultraviolet radiation), pesticides promoting the maximum migration on contacting media and the use in the experiment of plants concentrators creating a considerable margin of the safety in hygienic rating. All investigations are carried out in the standard and comparable soil and microclimatic conditions with the use of the uniform simulating standard modeling soil standard based on the constant granulometric and physical-chemical structure of the sandy soil and uniform microclimatic parameters. By analogy to a rating of active ingredients of pesticides in water of reservoirs, atmospheric air, etc., studies are carried out not in natural surroundings, but only in uniform comparable with experimental conditions on laboratory modeling installations. On the basis of the established threshold concentration on migratory water, migratory air, translocation and all-sanitary indices of harm there is chosen the limiting one, on which maximum concentration level is established. Established maximum concentration limits of active ingredients of pesticides in the soil are the uniform in size for any soil-climatic conditions. On the established uniform maximum concentration limit of active ingredient of pesticide in the soil if necessary it can be determined the regional maximum concentration limit for conditions of the concrete soil and climatic region. In the calculation of this size, there are considered leading factors: temperature, humidity of the soil, maintenance of a hummus, рН, porosity, bacterial load, etc. The factors characterizing the influence of these factors on processes of migration and a detoxication of active ingredients of pesticides were found on the basis of the research have been carried out on natural samples of the soil of this region.

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O'Brien, Bernard John. "The Use of Natural and Anthropogenic 14C to Investigate the Dynamics of Soil Organic Carbon." Radiocarbon 28, no. 2A (1986): 358–62. http://dx.doi.org/10.1017/s0033822200007463.

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Radiocarbon has been measured in two soil profiles, one of which has been covered by a building since 1956. A comparison of the Δ14C values in horizons of each profile gives an estimate of the total input of atom bomb 14C into the soil profile. From the Δ14C and carbon density profile data, the carbon input rates, respiration rates, and diffusivity are calculated. The lack of vegetation on one soil affects the mobility and the respiration rate of the soil carbon in that soil. The data from this soil profile are also used to check the assumption, used in previous analyses, that there is a uniform distribution of ‘old’ carbon down the soil profile. The input rate, turnover time, and diffusivity parameters determined from the Δ14C profiles in these soils are compared with other published data on pasture and forest soils.

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49

Norton, D. A. "Tree windthrow and forest soil turnover." Canadian Journal of Forest Research 19, no. 3 (March 1, 1989): 386–89. http://dx.doi.org/10.1139/x89-059.

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Soil turnover as a result of tree windthrow has an important influence on soil development and plant distribution in forests. Estimates of the time needed for soil turnover in a given area are often made, but unless these take into account the potential for reestablishment of canopy trees onto sites previously affected by windthrow, they are likely to substantially underestimate turnover time. Soil turnover is not a regular, uniform process, but rather results in a mosaic of soils with different turnover histories. Because soil turnover follows an exponential decay model, some area of soil will never be turned over. As it is therefore not possible to define the time when all the soil in an area has been turned over, it is proposed that soil turnover half-life (the time at which half the soil has been turned over) be used as a measure of soil turnover.

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Koudela, Pavel, Juraj Chalmovský, and Lumír Miča. "The Reinforcement of Sand by Fibres with a Non-Uniform Shape." Slovak Journal of Civil Engineering 29, no. 2 (June 1, 2021): 49–54. http://dx.doi.org/10.2478/sjce-2021-0013.

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Abstract The reinforcement of soil is used to improve its strength and stiffness. The standard method of soil reinforcement is an application of geosynthetics. Soil reinforcement by distributed discrete fibres represents an alternative to those techniques. Currently used fibres have a straight shape, uniform cross-section, and smooth surface, which is not optimal in terms of the fibre-soil interaction. In this study, fibres with a variable shape were utilized. The fibres were fabricated using a fused deposition modelling technology. Firstly, a brief theoretical background is presented. Then, the proposed shapes of the fibres and their manufacturing process are described. The mechanical properties of the soil-fibre composite were investigated through consolidated drained triaxial tests. Well-graded coarse sand and poorly-graded fine sand were used. A higher peak shear strength was observed in the case of fibres with a variable shape. The effect of the variable shape of the fibres on the peak shear strength was higher in the case of the coarse sand.

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