Impact of random soil properties on stress–strain response

2004 ◽  
Vol 41 (2) ◽  
pp. 351-355 ◽  
Author(s):  
Dieter Stolle ◽  
Peijun Guo ◽  
Gabriel Sedran
Keyword(s):  
Soil Properties ◽  
Constitutive Modelling ◽  
Soil Parameters ◽  
Strain Response ◽  
Constitutive Behaviour ◽  
Stress Strain ◽  
Deterministic Analysis ◽  
Model Predictions ◽  
Random Variability ◽  
The Impact

This paper analyzes the impact of natural random variation of soil properties on the constitutive modelling of geomaterial behaviour. A theoretical framework for accommodating variation in soil properties is presented. The framework is then used to examine the consequence of parameter variability on stress–strain relations. An important observation is that average soil parameters from a series of tests on small specimens, in which density of the specimens varies randomly, do not necessarily reflect the average constitutive behaviour of soil. Model predictions are shown to be consistent with the experimental data.Key words: random variability, deterministic analysis, soil parameters, constitutive model.

The thermomechanical stress-strain response of intumescent mat materials through experiments and strain decomposition

2002 ◽  
Vol 37 (3) ◽  
pp. 187-199 ◽  
Author(s):  
H. J Kim ◽  
J. S Kim ◽  
M. E Walter ◽  
J. K Lee
Keyword(s):  
Constitutive Modelling ◽  
Load Control ◽  
Strain Response ◽  
Stress Strain ◽  
Dead Weight ◽  
Transient Stress ◽  
Thermomechanical Stress ◽  
Decomposition Procedure ◽  
Property Changes ◽  
Strain Responses

Intumescent mat materials in catalytic converters undergo chemical reactions that lead to material property changes and volume expansion during heating processes. Dead weight (load control) and displacement control compression experiments have been performed to explore static and transient stress-strain responses. The apparatus and methods for both experiments are described. The experimental results together with a strain decomposition procedure yield a master curve that can be employed for constitutive modelling.

scholarly journals Changes in Soil Hydro-Physical Properties and SOM Due to Pine Afforestation and Grazing in Andean Environments Cannot Be Generalized

Forests ◽  
2018 ◽  
Vol 10 (1) ◽  
pp. 17 ◽  
Author(s):  
Franklin Marín ◽  
Carlos Dahik ◽  
Giovanny Mosquera ◽  
Jan Feyen ◽  
Pedro Cisneros ◽  
...  
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Physical Properties ◽  
Soil Properties ◽  
Water Retention ◽  
Soil Parameters ◽  
Water Retention Capacity ◽  
Sampling Depth ◽  
Site Specific ◽  
The Impact

Andean ecosystems provide important ecosystem services including streamflow regulation and carbon sequestration, services that are controlled by the water retention properties of the soils. Even though these soils have been historically altered by pine afforestation and grazing, little research has been dedicated to the assessment of such impacts at local or regional scales. To partially fill this knowledge gap, we present an evaluation of the impacts of pine plantations and grazing on the soil hydro-physical properties and soil organic matter (SOM) of high montane forests and páramo in southern Ecuador, at elevations varying between 2705 and 3766 m a.s.l. In total, seven study sites were selected and each one was parceled into undisturbed and altered plots with pine plantation and grazing. Soil properties were characterized at two depths, 0–10 and 10–25 cm, and differences in soil parameters between undisturbed and disturbed plots were analyzed versus factors such as ecosystem type, sampling depth, soil type, elevation, and past/present land management. The main soil properties affected by land use change are the saturated hydraulic conductivity (Ksat), the water retention capacity (pF 0 to 2.52), and SOM. The impacts of pine afforestation are dependent on sampling depth, ecosystem type, plantation characteristics, and previous land use, while the impacts of grazing are primarily dependent on sampling depth and land use management (grazing intensity and tilling activities). The site-specific nature of the found relations suggests that extension of findings in response to changes in land use in montane Andean ecosystems is risky; therefore, future evaluations of the impact of land use change on soil parameters should take into consideration that responses are or can be site specific.

Nucleation of Recrystallization in Mg Alloys during and after Hot Working

2012 ◽  
Vol 715-716 ◽  
pp. 96-101 ◽  
Author(s):  
Matthew R. Barnett ◽  
Aiden G. Beer
Keyword(s):  
Dynamic Recrystallization ◽  
Hot Working ◽  
Mg Alloys ◽  
Strain Response ◽  
Stress Strain ◽  
Local Texture ◽  
The Impact

Recrystallization nucleates at heterogeneities. The impact of this on local texture and stress-strain response in hot worked magnesium is considered in the present paper. Two aspects of bulge nucleation during dynamic recrystallization are considered.

scholarly journals Description of stress-strain response and evaluation of the formability for Al-Cu-Mg alloy under the impact hydroforming

2020 ◽  
Vol 967 ◽  
pp. 012028
Author(s):  
Da-Yong Chen ◽  
Shi-Hong Zhang ◽  
Yong Xu ◽  
Yan Ma ◽  
Hong-Wu Song ◽  
...  
Keyword(s):  
Mg Alloy ◽  
Strain Response ◽  
Stress Strain ◽  
The Impact

Geoinformation in support of sustainable soils’ management to strengthen resilience under the pressure of climate change

2021 ◽  
Author(s):  
Christina Lekka ◽  
George P. Petropoulos ◽  
Dimitrios Triantakonstantis ◽  
Spyros Detsikas ◽  
Christos Chalkias
Keyword(s):  
Climate Change ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Properties ◽  
Satellite Imagery ◽  
Anthropogenic Activities ◽  
Soil Salinization ◽  
Soil Parameters ◽  
Alkaline Soils ◽  
The Impact

<p><strong>Abstract</strong></p><p>The National Map of Saline – Alkaline Soils of Greece was recently developed within the initiative of the European Soil Partnership (ESP) of FAO. The technique combines between other MODIS satellite imagery, spatial interpolation methods and ground surveying to derive at 1 km spatial resolution maps of soil’s salinity (SS) and soil organic carbon (SOC).</p><p>The present study investigates for the first time the development of higher resolution maps of these soil properties adopting the aforementioned methodology. Furthermore, this study attempted to estimate the Carbon sequestration (SOC) using Remote Sensing and geostatistic methods of spatial analysis, a concern that is eminent today due to its effect on climate change mitigation.</p><p>As a case study the island of Mytilene in Greece is used, for which detailed information on soil properties as well as climatic, geomorphological, geological and soil data was available from previous studies. An MCDA (Multiple Criteria Decision Analysis) method was applied in a GIS environment using Landsat satellite imagery for the composition of a Saline - Alkaline map. Between the key soil parameters estimated spatially included the Electrical Conductivity (EC), Exchangeable Sodium Percentage (ESP) and pH. Geospatial data analysis methods were implemented to visualize all the derived parameters related for the study area and to analyze the final products in the spatial domain.</p><p>Finding suggests that climate change and soil directly affect one another. The impact of environmental and climate change in addition to unsustainable agricultural practices seems to be linked to salinity increase, soil erosion and loss of organic matter.  In addition, when land degradation as well as erosion and loss of vegetation occur, SOC emissions increase. Under these conditions, soil cannot absorb enough amounts of CO2, especially when soil salinization and sodicity exists; inputs are further limited due to declines in vegetation health. The role of geoinformation technologies in support of sustainable agricultural production under the pressure of both climate change and anthropogenic activities is also discussed within the present study framework.  </p><p><strong>KEYWORDS:</strong> geoinformation, soil, pH, salinity, soil organic carbon, geostatistics, earth observation, GIS, Greece</p>

scholarly journals Tree species distribution and its impact on soil properties, and nitrogen and phosphorus mineralization in a humid subtropical forest ecosystem of northeastern India

2009 ◽  
Vol 39 (1) ◽  
pp. 36-47 ◽  
Author(s):  
Jenpuiru Kamei ◽  
H. N. Pandey ◽  
S. K. Barik
Keyword(s):  
Soil Properties ◽  
Tree Species ◽  
Soil Parameters ◽  
Organic Carbon Content ◽  
Nitrogen And Phosphorus ◽  
Total N ◽  
Species Dominance ◽  
Northeastern India ◽  
P Mineralization ◽  
The Impact

The impact of tree species on net N and P mineralization, and soil properties beneath their canopy were studied in a subtropical evergreen broad-leaved forest of northeastern India. Four types of experimental plots were identified based on tree species dominance. The first plot was dominated by Myrica esculenta Buch.-Ham. ex D. Don., the second by Rhododendron arboreum Sm., the third by Neolitsea cassia Koster., and the fourth was a mixed-species plot. Organic carbon content (3.11%) and NH4+-N concentration (11.40 μg·g–1) in the Rhododendron plot, pH (4.64) and total N content (0.89%) in the mixed plot, available P (5.16 μg·g–1) and NO3–-N (8.63 μg·g–1) concentrations in the Neolitsea plot were significantly higher (p < 0.001) than the other plots. All these soil parameters were lowest in the Myrica plot. The net N and P mineralization rates in an annual cycle across different plots ranged between 18.83 and 22.14 μg·g–1·month–1 and between 4.54 and 5.87 μg·g–1·month–1, respectively. The flux varied significantly (p < 0.001) among the plots, the lowest and highest being in the Myrica plot and mixed plots, respectively. The differences in soil properties and in net N and P mineralization among different species plots were related to litter quality and yield of the respective species as well as soil microenvironment.

scholarly journals Laboratory device to analyse the impact of soil properties on electrical and thermal conductivity

2017 ◽  
Vol 31 (2) ◽  
pp. 157-166 ◽  
Author(s):  
David Bertermann ◽  
Hans Schwarz
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
Soil Properties ◽  
Bulk Density ◽  
Test Sequence ◽  
Soil Parameters ◽  
Geothermal Systems ◽  
Laboratory Setup ◽  
Huge Impact ◽  
The Impact

Abstract Gathering information about soil properties in an efficient way is essential for many soil applications also for very shallow geothermal systems (e.g. collector systems or heat baskets). In the field, electrical resistivity tomogramphy measurements enable non-invasive and extensive analyses regarding the determination of soil properties. For a better understanding of measured electrical resistivity values in relation to soil properties within this study, a laboratory setup was developed. The structure of this laboratory setup is geared to gather electrical resistivity or rather electrical conductivity values which are directly comparable to data measured in the field. Within this setup grain size distribution, moisture content, and bulk density, which are the most important soil parameters affecting the electrical resistivity, can be adjusted. In terms of a better estimation of the geothermal capability of soil, thermal conductivity measurements were also implemented within the laboratory test sequence. The generated data reveals the serious influence of the water content and also provides a huge impact of the bulk density on the electrical as well as on the thermal conductivity. Furthermore, different behaviour patterns of electrical and thermal conductivity in their particular relation to the different soil parameters could be identified.

Usage of visual and near-infrared spectroscopy to predict soil properties in forest stands

2020 ◽  
Author(s):  
Felix Thomas ◽  
Rainer Petzold ◽  
Carina Becker ◽  
Ulrike Werban
Keyword(s):  
Soil Properties ◽  
Near Infrared ◽  
Soil Survey ◽  
Soil Conditions ◽  
Soil Parameters ◽  
Forest Conversion ◽  
Electromagnetic Spectrum ◽  
Forest Stands ◽  
Site Mapping ◽  
The Impact

&lt;p&gt;There is a high demand for information about soil conditions in forests stands as it is crucial to ensure sustainable management, to maintain ecosystem services, to preserve timber production and establish proper pest management. Nowadays, the main drivers for changes in soil conditions are element input, forest conversion, subsoil liming and changing climate. These drivers influence nutrients and water availability and are challenging current site mapping methods. However, for impact assessment high-resolution and up-to-date information is needed. As laboratory analysis is time consuming and expensive, alternative approaches are preferred.&lt;/p&gt;&lt;p&gt;The project DIGI-Humus uses methods of reflectance spectroscopy in the visual and near-infrared-region of the electromagnetic spectrum for indirect measurement and prediction of physical and chemical soil properties in forest stands. For this purpose, spectral data were collected under laboratory conditions to build a database of forest soils. We used retained samples from Saxony soil survey, measuring both Oh and Ah horizons. To ensure data quality, we developed our own protocol based on literature review and self-conducted test measurements. The data has been used to successfully calibrate regression models based on different forest types and soil horizons to predict the soil parameters C and N content, C/N ratio and pH-value.&lt;/p&gt;&lt;p&gt;To improve model performance and test its generalization capability, the created library has been extended with new samples from a field campaign conducted in 2019 at an additional local test site. Using this data, the impact of adding new information to the modelling process and the robustness of the models could be evaluated.&lt;/p&gt;&lt;p&gt;The results of this research will be used to assess forest sites regarding nutrients availability, as basis for the development of site specific management strategies and to enhance and improve current methods of periodic site mapping of forest stands.&lt;/p&gt;

Experimental Characterization of Mechanical Behavior of Cord-Rubber Composites

1982 ◽  
Vol 10 (1) ◽  
pp. 37-54 ◽  
Author(s):  
M. Kumar ◽  
C. W. Bert
Keyword(s):  
Response Characteristic ◽  
Cord Compression ◽  
Complete Characterization ◽  
Strain Response ◽  
Strain Gages ◽  
Experimental Characterization ◽  
Rubber Composites ◽  
Stress Strain ◽  
Strain Data

Abstract Unidirectional cord-rubber specimens in the form of tensile coupons and sandwich beams were used. Using specimens with the cords oriented at 0°, 45°, and 90° to the loading direction and appropriate data reduction, we were able to obtain complete characterization for the in-plane stress-strain response of single-ply, unidirectional cord-rubber composites. All strains were measured by means of liquid mercury strain gages, for which the nonlinear strain response characteristic was obtained by calibration. Stress-strain data were obtained for the cases of both cord tension and cord compression. Materials investigated were aramid-rubber, polyester-rubber, and steel-rubber.

scholarly journals From the Ground Up: Prairies on Reclaimed Mine Land—Impacts on Soil and Vegetation

Land ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 455
Author(s):  
Rebecca M. Swab ◽  
Nicola Lorenz ◽  
Nathan R. Lee ◽  
Steven W. Culman ◽  
Richard P. Dick
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Properties ◽  
Plant Community ◽  
Prairie Restoration ◽  
Native Plant ◽  
Soil Microbial ◽  
Prairie Restorations ◽  
Mine Lands ◽  
The Impact

After strip mining, soils typically suffer from compaction, low nutrient availability, loss of soil organic carbon, and a compromised soil microbial community. Prairie restorations can improve ecosystem services on former agricultural lands, but prairie restorations on mine lands are relatively under-studied. This study investigated the impact of prairie restoration on mine lands, focusing on the plant community and soil properties. In southeast Ohio, 305 ha within a ~2000 ha area of former mine land was converted to native prairie through herbicide and planting between 1999–2016. Soil and vegetation sampling occurred from 2016–2018. Plant community composition shifted with prairie age, with highest native cover in the oldest prairie areas. Prairie plants were more abundant in older prairies. The oldest prairies had significantly more soil fungal biomass and higher soil microbial biomass. However, many soil properties (e.g., soil nutrients, β-glucosoidase activity, and soil organic carbon), as well as plant species diversity and richness trended higher in prairies, but were not significantly different from baseline cool-season grasslands. Overall, restoration with prairie plant communities slowly shifted soil properties, but mining disturbance was still the most significant driver in controlling soil properties. Prairie restoration on reclaimed mine land was effective in establishing a native plant community, with the associated ecosystem benefits.

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