Articoli di riviste: "Soils Analysis"

1

Williams, Stephen E. "A Review and Analysis of Rangeland and Wildland Soil Health". Sustainability 16, n. 7 (29 marzo 2024): 2867. http://dx.doi.org/10.3390/su16072867.

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Soil health is focused on intensively managed (IM) soils (often farmed soils), by-passing extensively managed (EM) soils (range lands, deserts, shrub lands, tundra). High economic value products are generated by IM systems. Many EM lands are of cultural, recreational, scenic, or scientific value. However, and despite the fact that they provide forage for domestic and wild animals, they are not always of high economic value. IM and EM soils are evaluated on the same health scales. The contention herein is all soils formed under soil state conditions under the absence of human interventions are inherently healthy. But a given soil has dynamic properties that determine its management as IM or EM. An EM sagebrush steppe soil may be deemed unhealthy as a result of low organic matter and short growing season. An IM grassland steppe soil is healthy as a result of high organic matter and a long growing season. The sagebrush soil, however, provides habitat for culturally important sage grouse. The grassland soil may provide, when plowed, habitat for economically important soybeans. Soil taxonomies can be used to establish inherent health of undisturbed soils. Determining a soil’s dynamic nature is a different construct. Here, four different sets of EM soils were evaluated to showcase their diversity, evaluate levels of health and display their often-unconventional dynamic characteristics. An argument is made that a soil’s health, an inherent condition, is not the same as its dynamic condition (potential to produce goods and services). Soil health changes are usually slowly driven by soil state factors but can be dramatically changed by humans. Otherwise, soil health can be viewed as a near constant ecosystem attribute. The dynamic nature of soils change according to needs placed by humans. EM soils may be healthy but lack attention since their dynamic nature is not traditional and often of low economic value. Evaluation of soil health and dynamic value on EM lands is often exacerbated by information absence. Strategies to circumvent this include sampling design, reference sites and standardized ways of EM soil health determination. A case is made that baselines of soil health can be taken from soil surveys, taxonomic names, and soil data from map units, where such information exists. Certified supplementary information is ambiguously available, but may be crucial. Outdoor living laboratories that feature inherent soil health and dynamic soil alternatives may help circumvent information voids.

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Cui, Jifei, Yanhao Jin, Yingjie Jing e Yu Lu. "Elastoplastic Solution of Cylindrical Cavity Expansion in Unsaturated Offshore Island Soil Considering Anisotropy". Journal of Marine Science and Engineering 12, n. 2 (9 febbraio 2024): 308. http://dx.doi.org/10.3390/jmse12020308.

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An elastoplastic analysis scheme for the cylindrical cavity expansion in offshore islands unsaturated soils considering anisotropy is established. The hydraulic properties and anisotropy caused by stress of unsaturated soils are coupled in an elastoplastic constitutive matrix for unsaturated soil to obtain the governing equations for the cylindrical cavity expansion problem, with an analytical solution that utilizes the original hydro-mechanical state of the soil as the initial conditions. Through a comparative analysis with other analytical solutions, the effectiveness of the new solution is verified. Moreover, the swelling response of the cylindrical cavity expansion in unsaturated soils is examined by systematically analyzing different parameters of the surrounding soil. The findings reveal that the development and rate of anisotropy in normal consolidated soil and over-consolidated soil exert a significant impact on the soil’s mechanical characteristics. Nevertheless, the alteration in the model constant h has little effect on the soil’s mechanical characteristics. The analytical solution introduces anisotropy and broadens the expansion theory of unsaturated soils to yield a more comprehensive theoretical framework for the comprehensive analysis of offshore islands’ unsaturated soils.

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Yang, Tai Hua, Huai Jian He e Xiang Chao Gong. "Analysis Again for Earth Pressure Calculation Theory Considering Displacement Effects". Advanced Materials Research 368-373 (ottobre 2011): 2755–59. http://dx.doi.org/10.4028/www.scientific.net/amr.368-373.2755.

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According to Moore-Coulomb strength theory, combined with the shear strength reduction method, assumed that the exerted value of the soil’s internal friction Angle and displacement were in nonlinear, and the exerted value of the soil’s cohesion and displacement were in linear, and then put forward a unified, continuous with displacement earth pressure calculation model, and this model could be used to calculate the active and passive earth pressure for cohesive soils and cohesionless soils in any nonlimited state and any movement mode. Through the analysis of the calculation model showed that: (1) The above assumptions were all reasonable from the two perspectives of the theoretical and the measuring; (2) The variation process of earth pressure acted on the retaining wall with displacement, could regard as the process of the soil’s shear strength parameters exerting gradually; (3) Given the physical meanings to the calculated parameters; (4) Analyzed the characteristics of the calculation model, and pointed out that there were calculation errors when the displacement of retaining wall was in (0, x0H) for the Rankine earth pressure theory.

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Le, Van Thao, Didier Marot, Abdul Rochim, Fateh Bendahmane e Hong Hai Nguyen. "Suffusion susceptibility investigation by energy-based method and statistical analysis". Canadian Geotechnical Journal 55, n. 1 (gennaio 2018): 57–68. http://dx.doi.org/10.1139/cgj-2017-0024.

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Internal erosion is one of the main causes of instabilities within hydraulic earth structures. Four internal erosion processes can be distinguished, and this study deals with the process of suffusion, which corresponds to the coupled processes of detachment–transport–filtration of the soil’s fine fraction between the coarse fraction. Because of the great length of earth structures and the heterogeneities of soils, it is very difficult to characterize the suffusion susceptibility of the different soils. Nevertheless, a statistical analysis can be performed to optimize the experimental campaign. By using a dedicated erodimeter, an experimental program was set up to study suffusion susceptibility of 31 specimens of nonplastic and low-plasticity soils. The suffusion susceptibility is determined by the erosion resistance index, which relates the total loss of mass with the total energy expended by the seepage flow. Fourteen physical parameters are selected, and a multi-variate statistical analysis leads to a correlation between the erosion resistance index and all these parameters. A statistical analysis is performed to identify the main parameters and to focus on those that can easily be measured on existing structures. By distinguishing gap-graded and widely graded soils, two correlations are proposed to estimate the erosion resistance index.

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Ivanyuk, Halyna. "Analysis of “Systematics of Polish Soils”". Visnyk of the Lviv University. Series Geography, n. 44 (28 novembre 2013): 122–32. http://dx.doi.org/10.30970/vgg.2013.44.1210.

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The “Systematics of Polish Soils” (SgP, 2011) is very close to WRB and “Soil Taxonomy”. The morphological characteristics of the soils, investigated in the field, rather than soil genesis are diagnostic criteria. The main provisions of the new “Systematics”, properties of soils of higher taxonomic levels have been reviewed. Some diagnostic horizons, which were not borrowed from other classifications, have been described. We tried to find equivalents in the Ukrainian classification for some soils names. The correlation of Poland soils and WRB has been analyzed. Key words: Systematics of Polish Soils, classification, order, soil type, diagnostic horizon, WRB.

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Chakravarthy, Thokala, e K. Shyam Chamberlin. "Fly ash and bagasse ash embankment in flexible pavements for the analysis and strengthening of black cotton soil’s strength stabilized properties". E3S Web of Conferences 391 (2023): 01005. http://dx.doi.org/10.1051/e3sconf/202339101005.

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Soil stabilization is necessary to increase the soil’s durability, volume stability, and engineering expansion strength. Expansive soils (also known as black cotton soil), a problem that affects the entire world and poses various challenges for civil engineers, are extremely hard while dry but completely lose their strength when wet. In this study, fly ash has been employed to stabilize the soil. Five, ten, twenty, and twenty-five percent of fly ash was used in the experiments. Bagasse ash is an easily accessible byproduct of the sugar cane refining process that has negative environmental effects. In this study, any potential pozzolanic benefits are evaluated while taking into account bagasse ash. material that stabilizes elongated soil In order to examine the soils’ geotechnical characteristics, the experimental investigation focuses on altering the fly ash content of the soils. The goal is to learn more about the characteristics of black cotton soil’s tensile strength. The primary goal of this research is to examine the effects of bagasse ash on the engineering expansive soil’s properties as revealed by various lab tests, and after improving the treated soil through embankment work at various civil engineering activities, such as roadways.

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Baldrian, P. "Microbial enzyme-catalyzed processes in soils and their analysis". Plant, Soil and Environment 55, No. 9 (14 ottobre 2009): 370–78. http://dx.doi.org/10.17221/134/2009-pse.

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Currently, measuring enzyme activities in soils or other lignocellulose-based materials is technically feasible; this measurement is particularly suitable for evaluating soil processes of biopolymer (cellulose, hemicelluloses, lignin, chitin and others) degradation by microbes and for assessing cycling and mobilization of principal nutrients including nitrogen, phosphorus and sulfur. With some considerations, assay methods can provide reliable information on the concentration of enzymes in soil or the rates of enzyme-catalyzed processes. Enzyme analyses in recent studies demonstrated a high level of spatial variability of soil enzyme activity both in depth and in space. The vertical gradients of enzyme activities are most developed in forest soils. Furthermore, enzyme activity in soils is regulated by seasonally-dependent variables such as temperature, moisture and the input of fresh litter. While several enzymes are widely produced by different groups of soil microorganisms, some of them can be used as indicators of the presence or activity of specific microbial taxa.

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8

Kaminski, P., M. Urlaub, J. Grabe e C. Berndt. "Geomechanical behaviour of gassy soils and implications for submarine slope stability: a literature analysis". Geological Society, London, Special Publications 500, n. 1 (19 dicembre 2019): 277–88. http://dx.doi.org/10.1144/sp500-2019-149.

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AbstractSubmarine slope failures pose a direct threat to seafloor installations and coastal communities. Here, we evaluate the influence of free gas on the soil's shear strength and submarine slope failures in areas with gassy soils based on an extensive literature review. We identify two potential destabilization mechanisms: gas bubbles in the pore space lead to a reduced shear strength of the soil and/or gas induces excess pore pressures that consequently reduce the effective stress in the soil. Our evaluation of the reported mechanical and hydraulic behaviour of gassy sediments indicates that the unfavourable impact of entrapped gas on a soil's shearing resistance is not sufficient to trigger large-scale slope failures. Liquefaction failure due to high gas pressures is, however, a viable scenario in coarse-grained soils. Transferring the gas influence on the soil mechanical behaviour to constitutive models is identified as the most important prerequisite for a successful future analysis of slope stability.

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9

Conte, Enrico. "Consolidation analysis for unsaturated soils". Canadian Geotechnical Journal 41, n. 4 (1 agosto 2004): 599–612. http://dx.doi.org/10.1139/t04-017.

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This paper deals with the multidimensional consolidation of unsaturated soils when both the air phase and water phase are continuous. Following the approach proposed by D.G. Fredlund and his coworkers, the differential equations governing the coupled and uncoupled consolidation are first derived and then solved numerically. The solution is achieved using a procedure that depends on the transformation of the field equations by using the Fourier transform. This transformation has the effect of reducing a two- or three-dimensional problem to a problem involving only a single spatial dimension. The transformed equations are solved using a finite element approximation that makes use of simple one-dimensional elements. Once the solution in the transformed domain is obtained, the actual solution is achieved by inversion of the Fourier transform. The time integration process is formulated in a stepwise form. Results are presented to point out some aspects of the consolidation in unsaturated soils. Moreover, it is shown that the results obtained using the simple uncoupled theory are of sufficient accuracy for practical purposes.Key words: coupled consolidation, uncoupled consolidation, unsaturated soils, Fourier transform.

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Najafi-Ghiri, M., e A. Abtahi. "Potassium fixation in soil size fractions of arid soils". Soil and Water Research 8, No. 2 (15 maggio 2013): 49–55. http://dx.doi.org/10.17221/52/2012-swr.

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Amounts of potassium (K) fixed in soil fractions of 10 calcareous soils of southern Iran were measured to evaluate the contributions of different soil size fractions to K fixation. Soil particles were fractionated after dispersion of the soils with an ultrasonic probe. Potassium fixation analysis was done by addition of 1000 mg K/kg samples. Mineralogy of the size fractions was determined by X-ray diffraction. The clay fractions were dominated by smectite, chlorite, mica, and palygorskite. Potassium fixation capacities ranged from 104 to 148 mg/kg for clay, from 102 to 155 mg/kg for silt, and from 96 to 187 mg/kg for sand fractions. A positive and significant relationship (P < 0.05) was obtained between K fixation capacity and smectite content for the clay fractions. High amounts of K fixed in the sand fraction may be explained by a larger diffusion path of fixed K out of the frayed edges of micaceous and smectitic minerals into the extracting solution, low cation exchange capacity (CEC) of the coarse fraction and thereby the high concentration gradient along solution and interlayers, physical entrapment of K ions in coarse aggregates cemented by carbonates, and by the presence of clay particles in coarse fractions due to incomplete dispersion of coarse aggregates.

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11

Rubio, Eduardo, María del Socorro Rubio-Alfaro e Martín Hernández-Marín. "Wetting Front Velocity Determination in Soil Infiltration Processes: An Experimental Sensitivity Analysis". Agronomy 12, n. 5 (10 maggio 2022): 1155. http://dx.doi.org/10.3390/agronomy12051155.

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An experimental approach for measuring the wetting front velocity in soils during water infiltration processes is presented. This experimental research is developed to test the sensitivity of the measurement technique in the detection of differences in the dynamics of the wetting front advancement in different soil testing scenarios. Experimental scenarios include undisturbed and artificially compacted soils, square and circular cross-sections of soil samples, water flowing in both directions downward and horizontal, and water infiltration in a block soil sample. The measurement technique is based on wetting front detection employing moisture sensors that measure the soil’s electrical conductivity. The technique was able to detect differences in wetting front in contrasting scenarios. Two-dimensional wetting front advancement experiments carried out on a block sample confirmed the results obtained for the one-dimensional case.

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Yu, Yiting, Huimin Peng e Jiangu Qian. "Numerical modeling bearing capacity in wetting unsaturated expansive soils". IOP Conference Series: Earth and Environmental Science 1330, n. 1 (1 maggio 2024): 012055. http://dx.doi.org/10.1088/1755-1315/1330/1/012055.

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Abstract To address the load-bearing deterioration of expansive soils uplift pile foundation after moisture absorption, a coupled seepage-soil deformation model for unsaturated expansive soils is implemented into ABAQUS. This modeling work consists primarily of two aspects: (1) The total strain of expansive soils has been decoupled into two parts, i.e., one caused by external loads and calculated by using Mohr-Coulomb plasticity model, and the other induced by wetting swelling and modeled by defining the moisture-swelling relation curve of expansive soils; (2) User-defined field subroutine (USDFLD) is developed by defining suction-dependent soil’s parameters (elastic modulus, cohesion and internal friction angle), and employed to simulate softening behaviors of expansive soils after moisture absorption. he above model is subsequently used to perform 3D finite element modeling and hydraulic-stress coupling analysis on the bearing capacity of pile in expansive soils before and after rainfall. Eventually, the proposed numerical method is validated by simulating a group of full-scale tests.

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Dmytruk, Y. M. "Ecological-evolutionary analysis of lithium content in soils". Fundamental and Applied Soil Science 17, n. 1-2 (9 gennaio 2018): 31–39. http://dx.doi.org/10.15421/041603.

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The point is that investigation of geochemistry and behavior of Lithium in Ukraine’s soils is been rather exceptional. We have analyzed the content of Lithium in soils: modern and buried under the ramparts of various ages. The research territory includes Prut-Dniester and Prut-Siret interfluvial. Most often there are Phaeozems (Luvic Phaeozem, or Mollic Gleysol or Eutric Gleysol) and Chernozems (Luvic Chernozem or Chernic Chernozem). Buried soils are located directly near the modern background soils, so the differences between them are the result of evolution of the background soils during burial (the screening) after the construction of ramparts. On the Podvirna site current landscapes are wood and meadow-steppe; in the past, subboreal stage, were probably closer to the steppe; buried soil – Chernozem typical with a little profile, in the modern of soil structure prevails Luvic Phaeozem. The sites Ridkivtsi and Grushivka are characterized forest landscapes and in the past on those areas dominated wood-meadow landscapes. At present prevailing types of soils are Phaeozems or Gleysol. Soil samples have taken for the genetic horizons. After drying and preparing of soils in them had performed analytical determination of total content (Nitrate extract, followed by evaporation of hydrogen peroxide) of Lithium and its mobile forms (ammonium acetate-extract with pH = 4,8). The results of analyzes had processed by using statistical and mathematical testing based on the program «Statistica 6.0». Our obtained results are indicating background of total Lithium content, which ranges from 8,70 to 33,5 mg∙kg-1 and its average amount was 22,3±6,01 mg∙kg-1; amplitude quantity of Lithium mobile forms is between 0,20 to 2,60 mg∙kg-1, with an average content of 0,60±0,57 mg∙kg-1. The mean of total Lithium content of all soils with buried soils in particular are decreased from Podvirna site (27,4 mg∙kg-1) to the site Ridkivtsi (22,8 and 26,3 mg∙kg-1, accordingly) and site Grushivka (20,0 and 19,1 mg∙kg-1, accordingly), while the number of mobile forms changed significantly from substantial Podvirne hospital (1,43 mg∙kg-1) to the hospital Grushivka (0,83 and 0,91 mg∙kg-1, respectively) and hospital Ridkivtsi (0,44 and 0,79 mg∙kg-1, appropriately). In the majority of background soils we had discovered humus-eluvial-illuvial redistribution, sometimes - eluvial-illuvial redistribution. It is important to know that we had not observed high Lithium content in the parent rock of soils (except for two sections of the site Ridkivtsi with discussion rather recognition of the parent rock of the profile). This is demonstrating the determining influence of pedogenesis on the redistribution of chemical elements in the of soils. Actually, Lithium has often accumulated in the upper humus horizons (as a result of the impact of organic matter and of soil biota as a whole) or in the horizons of clay accumulation. To crown it all pedogenesis fundamentally has changing features of the vertical distribution of Lithium content. Concerning future research is necessity of application of isotopic analysis to identify the characteristics of different ages soils.

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Kocaman, Kadir, Askin Ozocak, Tuncer B. Edil, Ertan Bol, Sedat Sert, Kurban Onturk e Mustafa Ozsagir. "Evaluation of Soil-Water Characteristic Curve and Pore-Size Distribution of Fine-Grained Soils". Water 14, n. 21 (29 ottobre 2022): 3445. http://dx.doi.org/10.3390/w14213445.

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A soil’s physical properties, mineral types, and pore structure significantly influence the shape and properties of the soil-water characteristic curve (SWCC). This study investigated the effects of the soil’s physical properties and mineral types on the SWCC and pore-size distribution (PSD). Eight different soils from an alluvial deposit in Istanbul and Adapazarı/Türkiye were used in the study. The test samples were prepared by compaction at optimum water content (OWC) and wet side of optimum water content (wet of OWC). The samples were prepared by consolidation from the slurry. The PSDs of the samples were calculated using the SWCCs and evaluated with scanning electron microscope (SEM) analysis. In addition, the mineral types of all soils were determined by X-ray diffraction analysis. The soil which contains illite-type minerals has higher matric suction than containing kaolin-type. The effect of the clay percentage is more pronounced in silty soils than in plasticity and activity. Soil suction increased with decreasing compaction water content in clayey soils. The air entry water contents rose as the void ratio, liquid limit, clay content, and plasticity increased. The compaction conditions affected the macropore structure more than the micropore structure. In addition, the ratio of macro-micro pore sizes increased with the rise of the compaction water content.

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Aubeny, Charles, Robert Lytton e Dina Tang. "Simplified Analysis of Unsteady Moisture Flow Through Unsaturated Soil". Transportation Research Record: Journal of the Transportation Research Board 1821, n. 1 (gennaio 2003): 75–82. http://dx.doi.org/10.3141/1821-09.

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The moisture diffusion properties of unsaturated soils control the rate of infiltration of surface moisture into the soil mass and hence are critical to a wide variety of civil structures, including pavements, structures, retaining walls, and slopes. Because of the dependence of permeability on suction and the nonlinearity of the suction–moisture relationship, the analytical formulation for flow through unsaturated soils is highly nonlinear. An approximate linear analysis of this problem, which was originally proposed by Peter Mitchell, was investigated. One advantage of this approximate analysis is that it can provide the practical basis for measuring soil moisture diffusion characteristics in laboratory tests. A second advantage is that the linear formulation provides an analytical tool accessible to practitioners. Mitchell originally based his formulation on a relatively restrictive assumption on the permeability-versus-suction relationship. An approach to circumventing that restriction is proposed. The findings of a laboratory test program that uses Mitchell’s formulation to estimate a soil’s moisture diffusion characteristics are presented. Finally, some simple analytical predictions demonstrate the practical significance of the soil moisture diffusion properties.

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Crisan, Vlad Emil, Lucian Constantin Dinca e Sorin Stefan Deca. "Analysis of Chemical Properties of Forest Soils from Bacau County". Revista de Chimie 71, n. 4 (5 maggio 2020): 81–86. http://dx.doi.org/10.37358/rc.20.4.8045.

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State forests are analyzed periodically, once every 10 years. This includes an analysis of forest soils. The present paperdescribes and interprets the chemical properties of forest soils from Bacau County focusing on the period 1983-2015. As such, 823 soil profiles and 2435 pedogenetic horizons were analysed taking into consideration the soil type, pH, humus content, nitrogen content, base saturation degree and the total cation exchange capacity. The most widespread types of soils are: eutriccambisol, luvisol, preluvisoland dystriccambisol. The dystriccambisols from Bacau County are strongly acid soils, while eutriccambisols and preluvisols are moderately acid. All forest soils from this area have a high cationic exchange capacity and are very well (dystriccambisol, eutriccambisol,luvisol) or well supplied (preluvisol, rendzina) with nitrogen. Knowing the chemical properties of soils is important for the analysis of stand variability and for adopting silvicultural methods adequate for the management of long-lasting forests.

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Miller, R., S. Jones e M. Lindaman. "Pulverizing Soils for Laboratory Analysis". Communications in Soil Science and Plant Analysis 43, n. 1-2 (gennaio 2012): 445–50. http://dx.doi.org/10.1080/00103624.2012.641831.

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Lim, B. F., e G. A. Siemens. "Unifying framework for modeling swelling soil behaviour". Canadian Geotechnical Journal 53, n. 9 (settembre 2016): 1495–509. http://dx.doi.org/10.1139/cgj-2015-0049.

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The destructive effect of expansive soils on infrastructure is one of the classical issues associated with unsaturated soils. Given the continuing challenges associated with swelling soils there is still a need for a practical analysis method. The swelling equilibrium limit (SEL) provides a concept for modeling expansive soil behaviour. The SEL is an upper bound swelling limit, which depends on the soil’s initial state and the boundary conditions upon wetting. The SEL is obtained experimentally from swelling tests performed by applying a range of swelling scenarios from rigid boundary condition to free swelling without confinement. In this paper, improvements to the triaxial swelling apparatus are reported, SELs for two new swelling soils are characterized, and a framework for SEL prediction is developed. The SEL framework is developed to relate SEL parameters to index properties as well as the soil’s initial volume. SEL parameters are correlated to liquid limit, plasticity index, free swell potential, and specific volume. The relationships are used to estimate the SEL for Regina clay, which is shown to agree with experimental data.

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Kim, Pyol, Myongchol Ri, Yonggun Kim, Gunhyang Ri e Hakbom Myong. "One-Dimensional Consolidation Analysis of Unsaturated Soils under Cyclic Loadings". Shock and Vibration 2020 (17 marzo 2020): 1–16. http://dx.doi.org/10.1155/2020/7285323.

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This paper presents analytical solutions to Fredlund and Hasan’s one-dimensional consolidation equations for unsaturated soils subjected to various cyclic loadings. Two new variables are introduced so that the governing equations for excess pore air and water pressures can be transformed to a set of conventional diffusion equations. Based on the general solutions for two introduced variables, the analytical solutions are derived for one-dimensional consolidation of unsaturated soils under trapezoidal, rectangular, triangular, and haversine cyclic loadings. It shows through the degeneration into the existing solutions for unsaturated and saturated soils that the proposed solutions are more general ones for one-dimensional consolidation of soils from unsaturated to saturated states. A comprehensive parametric study is conducted to investigate the effects of different parameters on one-dimensional consolidation of unsaturated soils under various cyclic loadings. The proposed solutions can be effectively utilized in the analysis of consolidation of unsaturated soils subjected to various cyclic loadings.

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Iqbal, Javed, John A. Thomasson, Johnie N. Jenkins, Phillip R. Owens e Frank D. Whisler. "Spatial Variability Analysis of Soil Physical Properties of Alluvial Soils". Soil Science Society of America Journal 69, n. 4 (luglio 2005): 1338–50. http://dx.doi.org/10.2136/sssaj2004.0154.

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Chien, Yi-Ju, Dar-Yuan Lee, Horng-Yuh Guo e Kun-Huang Houng. "GEOSTATISTICAL ANALYSIS OF SOIL PROPERTIES OF MID-WEST TAIWAN SOILS". Soil Science 162, n. 4 (aprile 1997): 291–98. http://dx.doi.org/10.1097/00010694-199704000-00007.

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Jinxi Ma e F. P. Dawlibi. "Analysis of grounding systems in soils with cylindrical soil volumes". IEEE Transactions on Power Delivery 15, n. 3 (luglio 2000): 913–18. http://dx.doi.org/10.1109/61.871352.

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Edmondson, Jill L., Zoe G. Davies, Sarah A. McCormack, Kevin J. Gaston e Jonathan R. Leake. "Are soils in urban ecosystems compacted? A citywide analysis". Biology Letters 7, n. 5 (20 aprile 2011): 771–74. http://dx.doi.org/10.1098/rsbl.2011.0260.

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Soil compaction adversely influences most terrestrial ecosystem services on which humans depend. This global problem, affecting over 68 million ha of agricultural land alone, is a major driver of soil erosion, increases flood frequency and reduces groundwater recharge. Agricultural soil compaction has been intensively studied, but there are no systematic studies investigating the extent of compaction in urban ecosystems, despite the repercussions for ecosystem function. Urban areas are the fastest growing land-use type globally, and are often assumed to have highly compacted soils with compromised functionality. Here, we use bulk density (BD) measurements, taken to 14 cm depth at a citywide scale, to compare the extent of surface soil compaction between different urban greenspace classes and agricultural soils. Urban soils had a wider BD range than agricultural soils, but were significantly less compacted, with 12 per cent lower mean BD to 7 cm depth. Urban soil BD was lowest under trees and shrubs and highest under herbaceous vegetation (e.g. lawns). BD values were similar to many semi-natural habitats, particularly those underlying woody vegetation. These results establish that, across a typical UK city, urban soils were in better physical condition than agricultural soils and can contribute to ecosystem service provision.

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Hofmann, E., T. Németh e A. Bidló. "Thermal analysis of soils formed on limestone in the Bükk Mountains, North Hungary". Agrokémia és Talajtan 67, n. 1 (giugno 2018): 5–22. http://dx.doi.org/10.1556/0088.2018.67.1.1.

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The present article discusses the applicability of thermoanalytical methods in the analysis of Hungarian soils formed on carbonate rocks. Up to now only limited mineralogical and soil chemical research has been done on these soils. Soils from the Bükk Mountains, the most varied limestone region in Hungary, were used for the investigations. The aim was to extend our incomplete knowledge on the mineral composition and formation processes of these soils and to demonstrate the possibilities and evaluation potential of thermoanalytical techniques. All the soils investigated were formed on limestone and had different surface soil thickness, influenced by the accumulation of silicate debris and the microterrain. The results of soil mineralogical analysis revealed an extraordinarily high proportion of quartz compared to that of other minerals (especially calcite), indicating that these soils could not have originated solely from the weathering of the limestone bedrock. The results also showed that thermoanalytical methods could complement classical chemical and instrumental (XRPD) methods in research on the genesis of soils formed on limestone.

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Abdulmazhidov, Khamzat. "Analysis of drainage canal defects and review of canal cleaner designs". E3S Web of Conferences 262 (2021): 01002. http://dx.doi.org/10.1051/e3sconf/202126201002.

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The drainage system elements, namely, the canals, lose their initial design characteristics over time. In general, the canals with unstable profiles are often in the reclamation construction. The problems of unstable profiles of the canals are, primarily, related to the physical and mechanical properties of soils, formation of internal mechanical, as well as chemical and biological processes occurring by the action of natural conditions. Maximum stability is characteristic for canals formed in cohesive organic soils, as well as in various kinds of peat with their thickness considerably exceeding the depth of the canal. With insignificant peat thickness above mineral soils, the stability of the drainage canal slopes will be rather insignificant. Wood peats are the most stable among organic soils. The canals laid in sapropelic soils characterized by the natural flow have rather low stability. That is why, the required stability in wet soils can be achieved by removing the excess moisture. The slopes of the canals made in various clays and loams with their large thickness considerably exceeding the depth of the canal have relatively high stability.

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Švec, O., L. Bílek, J. Remeš e Z. Vacek. "Analysis of operational approach during forest transformation in Klokočná Range, Central Bohemia". Journal of Forest Science 61, No. 4 (3 giugno 2016): 148–55. http://dx.doi.org/10.17221/102/2014-jfs.

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Afforestation of agricultural lands may be in many cases a positive step. Especially, it is a beneficial with waterlogged soils, stony soils or for soils which are for any other reason less fertile and unsuitable for farming. Even too in the agricultural landscape, afforestation can be very important by the breaking of large farm blocks by windbreakers and bio-corridors. The value, quality and fertility of soil can be assessed in different ways. The aim of this study is to determine the criteria for the identification of agricultural land suitable for afforestation. This evaluation process is based on Evaluated Soil Ecological Units (BPEJ) that are publicly available and already processed for all agricultural land. The results are represented by complete list of Evaluated Soil Ecological Units that are suitable for afforestation with stating the reason why they were chosen.

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27

Nemadodzi, Lufuno Ethel, Jacques Vervoort e Gerhard Prinsloo. "NMR-Based Metabolomic Analysis and Microbial Composition of Soil Supporting Burkea africana Growth". Metabolites 10, n. 10 (10 ottobre 2020): 402. http://dx.doi.org/10.3390/metabo10100402.

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Burkea africana is a leguminous tree used for medicinal purposes, growing in clusters, on soils impoverished from most nutrients. The study aimed to determine the factors responsible for successful reproduction and establishment of the B. africana trees in nature, as all efforts for commercial production has been proven unsuccessful. An investigation was carried out to determine the metabolomic profile, chemical composition, and microbial composition of the soils where B. africana grows (Burkea soil) versus the soil where it does not grow (non-Burkea soil). 1H-NMR metabolomic analysis showed different metabolites in the respective soils. Trehalose and betaine, as well as a choline-like and carnitine-like compound, were found to be in higher concentration in Burkea soils, whereas, acetate, lactate, and formate were concentrated in non-Burkea soils. Liquid Chromatography-Mass Spectrometry analysis revealed the presence of numerous amino acids such as aspartic acid and glutamine to be higher in Burkea soils. Since it was previously suggested that the soil microbial diversity is the major driver for establishment and survival of seedlings in nature, Deoxyribonucleic acid (DNA) was extracted and a BLAST analysis conducted for species identification. Penicillium species was found to be highly prevalent and discriminant between the two soils, associated with the Burkea soils. No differences in the bacterial composition of Burkea and non-Burkea soils were observed. The variances in fungal composition suggests that species supremacy play a role in development of B. africana trees and is responsible for creating a supporting environment for natural establishment and survival of seedlings.

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28

Widden, Paul. "Microfungal community structure from forest soils in southern Quebec, using discriminant function and factor analysis". Canadian Journal of Botany 64, n. 7 (1 luglio 1986): 1402–12. http://dx.doi.org/10.1139/b86-192.

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Abstract (sommario):

Fungal isolation data, from four forest soils, were analyzed using both discriminant analysis and factor analysis, to investigate the structure of fungal communities. The analyses indicated that the forest of origin was a major factor determining fungal community structure in these soils. Discriminant analysis separated the fungal communities of coniferous-forest soil samples from those of deciduous-forest soil samples. The pine-forest soil, which was in an early stage of invasion by hardwoods, had a fungal community intermediate in structure between the extremes. Of the microfungi isolated, Botryotrichum piluliferum, Farrowia seminuda, Geomyces pannorus, Mucor hiemalis, Penicillium janthinellum, Trichoderma polysporum, and Zygorrhynchus moelleri were associated with the coniferous sites, whereas an Acremonium species, Gliomastix murorum, Paecilomyces carneus, Pae. fumosoroseus, Penicillium spinulosum, and Pen. thomii characterized the deciduous-forest soils. Many pine-forest soil fungi were species abundant in the other soils, a possible reflection of the successional stage of the forest. Both factor analysis and discriminant analysis yielded similar interpretations of the data and indicated the importance of fungal interactions in determining community structure. The discriminant analyses also showed that fungal isolation data gave a better separation between the soils of the four forests than did abiotic data.

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29

Weindorf, David C., e Somsubhra Chakraborty. "Portable X-ray Fluorescence Spectrometry Analysis of Soils". Methods of Soil Analysis 1, n. 1 (2016): 0. http://dx.doi.org/10.2136/methods-soil.2015.0033.

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30

Tai, Tuo Ya, e Jin Sheng Wang. "Analysis of PFCs in Soil at Trace Levels Using UPLC/MS/MS". Advanced Materials Research 781-784 (settembre 2013): 2332–35. http://dx.doi.org/10.4028/www.scientific.net/amr.781-784.2332.

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Abstract (sommario):

Perfluorinated compounds (PFCs) have been detected in various environmental media in the world, and it is caused widespread concern because its persistence and dangers on the environment and the organism. However, little attention has been paid to their distribution in surface soils. Soils are the main sink for PFCs. In this study, a method was developed for the analysis of nine perfluorinated compounds in surface soils, including eight perfluorinated carboxylic acids and two perfluorinated sulfonic acids. Concentrations of perfluorinated compounds were determined using UPLC/MS/MS. The result shows that PFCs are widespread occurrence in surface soils in study areas.

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31

Yang, Xiuhan, e Sai Vanapalli. "Stability analysis of unsaturated soil slope considering softening and non-softening approach". E3S Web of Conferences 382 (2023): 13008. http://dx.doi.org/10.1051/e3sconf/202338213008.

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Abstract (sommario):

In conventional geotechnical engineering practice, peak shear strength parameters are widely used in the design of geo-structures constructed with or within unsaturated soils. However, a reduction inshear strength from the peak to the residual value is typically observed during the shear deformation in typical fine-grained unsaturated soils. Several geo-structures in unsaturated soils undergo a large shear deformation prior to reaching the failure condition. Thus, the factor of safety of such geo-structures will gradually but significantly decrease with the development of the shear deformation. For this reason, the strain-softening behaviour of unsaturated soils should be considered for reliable design of the geo-structuresin unsaturated soils. In this study, an unsaturated clay slope under 10 years rainfall infiltration were modelled using softening and non-softening approach using commercial finite element software SIGMA/W. The responses of the studied slope to the long-term rainfall infiltration were analysed. The results of the softening and non-softening analysis were compared. This study provides valuable information with respect to the significance of the strain-softening that are useful in the rational design of slopes in unsaturated soils.

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32

Liang, Fei Fei, Ren Wang Liang e Xing Hua Xiang. "Analysis of Effect Factors about the Ground Settlement during Foundation Pit Excavation". Advanced Materials Research 1065-1069 (dicembre 2014): 7–10. http://dx.doi.org/10.4028/www.scientific.net/amr.1065-1069.7.

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The excavation usually cause the settlement of surrounding soils, which will have a negative effect on the adjacent buildings. To find the effective measures to reduce the surface subsidence,a numerical model which is based on a project example is developed in this paper to analyze the settlement of surrounding soils during the excavation of a deep foundation pit by using FLAC3D.The influence of excavation on settlement outside the foundation pit is investigated when changing one of the factors which include reinjection pressures、waterproof curtain. The results show that: (1) The settlement of surrounding soils decreases gradually with the increase of reinjection pressures. Moreover ,the settlement with reinjection are around two times the value without reinjection.(2) The settlement of surrounding soils decreases gradually with the curtain depth increases. In the actual projects,we can decrease the settlement of surrounding soils by increasing the reinjection pressures and curtain depth.

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33

Lee, C. Y., e H. G. Poulos. "Cyclic analysis of axially loaded piles in calcareous soils". Canadian Geotechnical Journal 30, n. 1 (1 febbraio 1993): 82–95. http://dx.doi.org/10.1139/t93-008.

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Abstract (sommario):

This paper describes a simple nonlinear pile-soil interface model incorporated into a modified boundary element analysis to simulate the behaviour of piles in calcareous soils subjected to both static and cyclic loading. A shaft resistance degradation model and a cyclic secant soil modulus degradation model are proposed, and implemented in the nonlinear analysis. Parametric solutions are presented which examine the overall characteristics of axial pile response determined from the nonlinear analysis. Comparisons are made between the theoretical predictions and the measured results of laboratory model tests and published field tests of grouted piles in calcareous soils. These comparisons enable some conclusions to be drawn regarding the suitability of alternative nonlinear analyses. Key words : grouted piles, cyclic loading, calcareous soils, nonlinear analysis.

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34

Fu, Gui Hai, Li Min Wei e Hui Zhou. "Analysis of Single Pile Settlement in Layered Soils Based on Shear Displacement Method". Advanced Materials Research 368-373 (ottobre 2011): 2688–91. http://dx.doi.org/10.4028/www.scientific.net/amr.368-373.2688.

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Abstract (sommario):

Based on the theory of shear displacement method, the transfer matrix of pile in layered soils was deduced, so the analytical theory of settlement of single pile in layered soils is established, which can take into account the nonlinear influence of soils, and with which settlement, distribution of axial force, displacement and skin resistance of single pile along the depth in layered soils can be easily attained. By contrast with the practically measure data, it can be seen that the method proposed in this paper is simply and comparatively accurate in calculating the pile settlement under working load.

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35

Vlcek, Jozef, e Veronika Valaskova. "Analysis of Applicability of Clegg Impact Soil Tester for Clayey Soils". MATEC Web of Conferences 196 (2018): 02031. http://dx.doi.org/10.1051/matecconf/201819602031.

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Abstract (sommario):

Dynamic test methods are used in numerous civil engineering sections. Evaluation of the earthwork quality can be carried out effectively using these methods. Equipment utilized the dynamic methods, such as Clegg Impact Soil Tester, is portable and usable in cramped areas or difficult accessible places. Another benefit is that these apparatuses can be used for quick controlling of the subsoil layers during the subsoil improvement. Clegg Impact Soil Tester can substitute the common test equipment in terms of the earthworks assessment. However, boundary conditions of apparatus given by the manufacturer need to be taken into account to obtain results with sufficient reliability. Method is based on the impact effect of the test equipment on the ground. Thus, results have to be interpreted carefully considering the type and the physical state of the tested soil.

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36

Saleh Asheghabadi, Mohsen, e Mohammad Ali Rahgozar. "Finite Element Seismic Analysis of Soil–Tunnel Interactions in Clay Soils". Iranian Journal of Science and Technology, Transactions of Civil Engineering 43, n. 4 (3 dicembre 2018): 835–49. http://dx.doi.org/10.1007/s40996-018-0214-0.

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37

Fanti, Alessandro, Michele Spanu, Matteo Bruno Lodi, Francesco Desogus e Giuseppe Mazzarella. "Nonlinear Analysis of Soil Microwave Heating: Application to Agricultural Soils Disinfection". IEEE Journal on Multiscale and Multiphysics Computational Techniques 2 (2017): 105–14. http://dx.doi.org/10.1109/jmmct.2017.2723264.

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38

Benschoten, John E. Van, Mark R. Matsumoto e William H. Young. "Evaluation and Analysis of Soil Washing for Seven Lead-Contaminated Soils". Journal of Environmental Engineering 123, n. 3 (marzo 1997): 217–24. http://dx.doi.org/10.1061/(asce)0733-9372(1997)123:3(217).

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39

H. Abdul-Kareem, Ahmed. "ANALYSIS OF EMBANKMENT ON GYPSEOUS SOILS". Iraqi Journal of Civil Engineering 4, n. 8 (1 luglio 2007): 60–78. http://dx.doi.org/10.37650/ijce.2007.14140.

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40

Bigalke, Moritz, Montserrat Filella, Daniela Fischer, Anna Muntwyler, Michael Scheurer e Benjamin Watts. "Micro- and Nanoplastic Analysis in Soils". CHIMIA International Journal for Chemistry 72, n. 12 (19 dicembre 2018): 901. http://dx.doi.org/10.2533/chimia.2018.901.

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41

Wong, Coby S. C., e Xiangdong Li. "Analysis of Heavy Metal Contaminated Soils". Practice Periodical of Hazardous, Toxic, and Radioactive Waste Management 7, n. 1 (gennaio 2003): 12–18. http://dx.doi.org/10.1061/(asce)1090-025x(2003)7:1(12).

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42

Nagaraj, T. S., B. R. S. Murthy, A. Vatsala e R. C. Joshi. "Analysis of Compressibility of Sensitive Soils". Journal of Geotechnical Engineering 116, n. 1 (gennaio 1990): 105–18. http://dx.doi.org/10.1061/(asce)0733-9410(1990)116:1(105).

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43

Zhang, Weihua, e Chenggang Zhao. "Micromechanics analysis for unsaturated granular soils". Acta Mechanica Solida Sinica 24, n. 3 (giugno 2011): 273–81. http://dx.doi.org/10.1016/s0894-9166(11)60028-1.

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44

Steinwandter, H. "Contributions to residue analysis in soils". Fresenius' Journal of Analytical Chemistry 340, n. 6 (1991): 389–91. http://dx.doi.org/10.1007/bf00321588.

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45

Capote Rodriguez, G., R. Padilla Alvarez, G. Pérez Zayas, A. T. Hernández Rivero, M. C. López Reyes, S. Ribeiro Guevara e J. Molina Insfrán. "Neutron activation analysis of Cuban soils". Journal of Radioanalytical and Nuclear Chemistry 237, n. 1-2 (novembre 1998): 159–62. http://dx.doi.org/10.1007/bf02386682.

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46

Steinwandter, H. "Contributions to residue analysis in soils". Fresenius' Zeitschrift für analytische Chemie 327, n. 3-4 (gennaio 1987): 309–11. http://dx.doi.org/10.1007/bf00491834.

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47

Steinwandter, H. "Contributions to residue analysis in soils". Fresenius' Journal of Analytical Chemistry 339, n. 1 (1991): 30–33. http://dx.doi.org/10.1007/bf00324755.

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48

Garcia, J. M. P., H. F. Mothé Filho e L. V. Zuquete. "Study of soils by thermal analysis". Journal of Thermal Analysis and Calorimetry 93, n. 1 (luglio 2008): 253–56. http://dx.doi.org/10.1007/s10973-007-8808-y.

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49

Siriwardane, Hema J. "Numerical analysis of anchors in soils". International Journal for Numerical and Analytical Methods in Geomechanics 13, n. 4 (luglio 1989): 427–33. http://dx.doi.org/10.1002/nag.1610130406.

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50

Ruchika e Amar P. Garg. "Isolation and Identification of Microfungi from Diesel Oil Contaminated Soils and Their Physico-Chemical Analysis". International Journal of Environment and Climate Change 13, n. 10 (18 settembre 2023): 3476–87. http://dx.doi.org/10.9734/ijecc/2023/v13i103017.

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Abstract (sommario):

Diesel oil contaminated soils were collected and analyzed for various Physico-chemical properties that included moisture content, total carbon, total nitrogen and phosphorus using standard protocol and the data compared from normal uncontaminated soils. Analysis revealed that all 5 samples of diesel oil contaminated soils possessed higher percent of moisture content, greater amounts of total carbon, nitrogen and phosphorus in comparison to non-contaminated control soils. The diesel oil contaminated soils are not suitable for cultivation of agricultural crops. Though, several species of fungi were isolated from diesel contaminated soils but only 6 species of Aspergillus utilized diesel oil as sole carbon and nitrogen source as these grew well and sporulated normally on 2% agar that contained 10% of diesel oil only as nutrient. These included Aspergillus luchuensis, Aspergillus violaceofuscus, Aspergillus niveus, Aspergillus terreus, Aspergillus japonicus, Aspergillus ustus. which also grew well in broth containing 0.5% jaggery (for initial growth) supplemented with 10% diesel oil only which suggest that these species could utilize diesel oil as sole carbon and nitrogen source because no other nutrient other than diesel oil was added into the medium. The role of carbon, nitrogen and phosphorus is soils has been discussed in this paper.

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