Journal articles: 'Virtual soil'

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Scharenbroch, Bryant, John Galbraith, John Lawley, Chris Baxter, and Kris Osterloh. "Soil Judging Goes Virtual for 2021." CSA News 66, no. 8 (July 29, 2021): 38–39. http://dx.doi.org/10.1002/csan.20537.

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Karamanos, Rigas E., and Karen R. Cannon. "VIRTUAL SOIL TESTING: IS IT POSSIBLE?" Communications in Soil Science and Plant Analysis 33, no. 15-18 (November 2002): 2599–616. http://dx.doi.org/10.1081/css-120014467.

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Moraes, Diego Augusto de campos, and Anderson Antônio da Conceição Sartori. "AMOSTRAS VIRTUAIS DE ATRIBUTOS DO SOLO COMO SUBSÍDIO AO PLANEJAMENTO PARA ANÁLISE GEOESTATÍSTICA." ENERGIA NA AGRICULTURA 35, no. 3 (September 29, 2020): 426–36. http://dx.doi.org/10.17224/energagric.2020v35n3p426-436.

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AMOSTRAS VIRTUAIS DE ATRIBUTOS DO SOLO COMO SUBSÍDIO AO PLANEJAMENTO PARA ANÁLISE GEOESTATÍSTICA DIEGO AUGUSTO DE CAMPOS MORAES1, ANDERSON ANTÔNIO DA CONCEIÇÃO SARTORI2 1 Professor Doutor, Departamento de Análise e Desenvolvimento de Sistemas, Faculdade Eduvale de Avaré, Av. Prefeito Misael Eufrásio Leal, 347 - Centro, Avaré - SP, 18705-050, diego.moraes@ead.eduvaleavare.com.br. 2 Professor Doutor, Grupo de Estudos e Pesquisas Agrárias Georreferenciadas, Faculdade de Ciências Agronômicas de Botucatu – FCA/UNESP, Avenida Universitária, 3780, Altos do Paraíso, Botucatu – SP, 18610-034, sartori80@gmail.com. RESUMO: O objetivo deste artigo foi propor uma metodologia de amostragem virtual para atributos do solo em área agrícola, a qual pode subsidiar o planejamento para análise geoestatística. Foram selecionadas, aleatoriamente, 23 amostras de solo (profundidades de 0-20 cm e 20-40 cm) do conjunto de dados original, com o objetivo de realizar a validação externa. Foi aplicado o procedimento de polígonos de Thiessen com base nas demais amostras originais do solo (47 amostras) e, em seguida, foram inseridas, aleatoriamente, amostras virtuais (53 amostras). A análise do variograma, validação cruzada, krigagem ordinária e validação externa foram executadas com a finalidade de verificar a robustez da metodologia. A inserção de amostras virtuais mostrou-se promissora, uma vez que o GDE (Grau de Dependência Espacial) e a validação cruzada dos atributos do solo foram aprimorados, situação que não foi observada nos dados originalmente amostrados. A validação externa obteve bons resultados, indicando que a amostragem virtual pode ser utilizada unicamente no planejamento para análise geoestatística. Palavras-chaves: variograma, validação cruzada, solos. VIRTUAL SAMPLES OF SOIL ATTRIBUTES AS A SUBSIDY FOR GEOSTATISTICAL ANALYSIS PLANNING ABSTRACT: The aim of this article was to propose a virtual sampling methodology for soil attributes in an agricultural area, which can support planning for geostatistical analysis. Twenty-three soil samples (depths of 0-20 cm and 20-40 cm) from the original data set were selected randomly, for an external validation process. The Thiessen polygons procedure was applied based on the remaining original soil samples (47 samples), and then, virtual samples (53 samples) were randomly inserted. The analysis of the variogram, cross-validation, ordinary kriging and external validation were performed in order to verify the robustness of the methodology. The insertion of virtual samples was promising, since the GDE (Degree of Spatial Dependence) and the cross-validation of soil attributes were improved, which was not observed in the data originally sampled. The external validation obtained good results, indicating that the virtual sampling can be used only in the planning for geostatistical analysis. Keywords: variogram, cross-validation, soil.

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Arduino, Pedro, Augusto Op den Bosch, and Emir José Macari. "Geotechnical Triaxial Soil Testing within Virtual Environment." Journal of Computing in Civil Engineering 11, no. 1 (January 1997): 44–47. http://dx.doi.org/10.1061/(asce)0887-3801(1997)11:1(44).

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Takács, Péter, János Tamás, and Csaba Lénárd. "Virtual Soil Information Systems in the Bihar Subregion and at Tedej Corp." Acta Agraria Debreceniensis, no. 13 (May 4, 2004): 186–89. http://dx.doi.org/10.34101/actaagrar/13/3410.

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After evaluating the sample sites’ soils and environmental status, we built up 2 different soil information systems. The first relies on analog data (soil maps), and is based on a regional model; its sample site is the Bihar sub-region. The second is a complex, field scale virtual 3D system, based on several types of data sources. (Aerial photos, GPS, field samples, hyper and multispectral images, soil maps). In this paper, we analyze and evaluate these systems. The greatest advantage of the models is that, with their usage, we can reveal connections which cannot be made by analyzing the individual elements of our data sources. We discovered that with the help of our systems, the monitoring and evaluating of the processes taking place in the soil is more fast and simple.

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Naseri, Mahyar, Sascha C. Iden, and Wolfgang Durner. "Effective hydraulic properties of 3D virtual stony soils identified by inverse modeling." SOIL 8, no. 1 (February 9, 2022): 99–112. http://dx.doi.org/10.5194/soil-8-99-2022.

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Abstract. Stony soils that have a considerable amount of rock fragments (RFs) are widespread around the world. However, experiments to determine the effective soil hydraulic properties (SHPs) of stony soils, i.e., the water retention curve (WRC) and hydraulic conductivity curve (HCC), are challenging. Installation of measurement devices and sensors in these soils is difficult, and the data are less reliable because of their high local heterogeneity. Therefore, effective properties of stony soils especially under unsaturated hydraulic conditions are still not well understood. An alternative approach to evaluate the SHPs of these systems with internal structural heterogeneity is numerical simulation. We used the Hydrus 2D/3D software to create virtual stony soils in 3D and simulate water flow for different volumetric fractions of RFs, f. Stony soils with different values of f from 11 % to 37 % were created by placing impermeable spheres as RFs in a sandy loam soil. Time series of local pressure heads at various depths, mean water contents, and fluxes across the upper boundary were generated in a virtual evaporation experiment. Additionally, a multistep unit-gradient simulation was applied to determine effective values of hydraulic conductivity near saturation up to pF=2. The generated data were evaluated by inverse modeling, assuming a homogeneous system, and the effective hydraulic properties were identified. The effective properties were compared with predictions from available scaling models of SHPs for different values of f. Our results showed that scaling the WRC of the background soil based on only the value of f gives acceptable results in the case of impermeable RFs. However, the reduction in conductivity could not be simply scaled by the value of f. Predictions were highly improved by applying the Novák, Maxwell, and GEM models to scale the HCC. The Maxwell model matched the numerically identified HCC best.

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Lin, Yulong, Li Yang, Shourong Liu, Xueyan Zhao, Chao Cao, and Chunlin Li. "Virtual simulation technology based research on subsoiling process." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 233, no. 5 (May 25, 2018): 1493–503. http://dx.doi.org/10.1177/0954406218774358.

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A novel simulation method to research subsoiling process is proposed in this paper. The influence of changing depth of tines cutting soil caused by subsoiler’s structure, road roughness and excitation of tyre and road on subsoiling is investigated. Soil model is divided into three layers, the different characteristics of soil in different depths are also considered. Firstly, a 3D geometry model of tractor–subsoiler system is established. Secondly, road roughness test is designed to measure elevation data of a farmland, then its surface is reconstructed based on harmonic superposition theory. Thirdly, a virtual prototyping model of tractor–subsoiler system is developed, and the depth curves of tines cutting soil with time are obtained based on the reconstructed farmland. Finally, with the method of finite element method (FEM) and smoothed particle hydrodynamics (SPH) coupling, MAT147 (MAT_FHWA_SOIL) soil material model which is layered, and depth curves of tines cutting soil, the finite element dynamic analysis of tines cutting soil is simulated. With subsoiling resistance as verification index, the simulation data are compared with the field experimental data. Under subsoiler oscillatory operation, the error rate of simulation is 3.78%. Under subsoiler non-oscillatory operation, the error rate of simulation is 5.02%. The simulation results agree well with the experimental results, which proves that the proposed simulation method can be a good substitute for the subsoiling physical test.

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Narayanan, Anuja. "A Virtual and Comparative Study on Soil Features and its Managing Ability." Shanlax International Journal of Arts, Science and Humanities 9, no. 1 (July 1, 2021): 159–63. http://dx.doi.org/10.34293/sijash.v9i1.3808.

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The study is related to the comparison of soil characteristics in some areas from a depth of 1m, 1.2m, and 1.5m; physical and geotechnical properties of the soil samples are studied in the laboratory to develop a simple method to determine the type of soil on a site. The tests conducted are grain size analysis, specific gravity, and field density. Moreover, the research intends to validate the behavior of sieving systems for different types of soils and at various loading conditions. From work, a decision support system to facilitate a sieving system that integrates geological, geotechnical, and structural factors is developed. The study reveals that an increase in the plasticity index decreases the angle of internal friction. The empirical models developed with the help of regression analysis for the benefit of field engineers for predicting the geotechnical properties.

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Briend, R., P. Radziszewski, and D. Pasini. "Virtual soil calibration for wheel–soil interaction simulations using the discrete-element method." Canadian Aeronautics and Space Journal 57, no. 1 (April 2011): 59–64. http://dx.doi.org/10.5589/q11-009.

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Wang, Kui Hua, Wen Bing Wu, Deng Hui Wu, and Zhi Qing Zhang. "Study of the Influence of Sediment Properties on Complex Impedance at the Head of Rock-Socketed Pile." Advanced Materials Research 368-373 (October 2011): 2939–44. http://dx.doi.org/10.4028/www.scientific.net/amr.368-373.2939.

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Based on virtual soil pile model, the influence of sediment properties on complex impedance at the head of rock-socketed pile is theoretically investigated by virtue of Laplace transform technique and impedance function transfer method. Firstly, the sediment under pile toe is assumed to be virtual soil pile which the cross-section area is the same as the pile. The layered soils surrounding pile are described with plane strain model. Then, by means of initial conditions and boundary conditions of the soil-pile system, the complex impedance at rock-socketed pile head in frequency domain is derived at condition of arbitrary excitation on the pile head. At last, by using parametric study method, the influence of sediment properties on complex impedance at rock-socketed pile head is studied. It is shown that sediment properties have significant influence on complex impedance at the head of rock-socketed pile.

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Schlüter, Steffen, Hans-Jörg Vogel, Olaf Ippisch, Peter Bastian, Kurt Roth, Henrike Schelle, Wolfgang Durner, Roy Kasteel, and Jan Vanderborght. "Virtual Soils: Assessment of the Effects of Soil Structure on the Hydraulic Behavior of Cultivated Soils." Vadose Zone Journal 11, no. 4 (October 29, 2012): vzj2011.0174. http://dx.doi.org/10.2136/vzj2011.0174.

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Piovano, L., M. M. Brunello, I. Musso, L. Rocci, and V. Basso. "Virtual reality representation of Martian soil for space exploration." Pattern Recognition and Image Analysis 23, no. 1 (March 2013): 111–29. http://dx.doi.org/10.1134/s1054661812040141.

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Wu, Wen-bing, Kui-hua Wang, Shao-jun Ma, and Jian Leo Chin. "Longitudinal dynamic response of pile in layered soil based on virtual soil pile model." Journal of Central South University 19, no. 7 (July 2012): 1999–2007. http://dx.doi.org/10.1007/s11771-012-1237-5.

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14

Janzen, H. H., D. A. Angers, M. Boehm, M. Bolinder, R. L. Desjardins, J. Dyer, B. H. Ellert, et al. "A proposed approach to estimate and reduce net greenhouse gas emissions from whole farms." Canadian Journal of Soil Science 86, no. 3 (May 1, 2006): 401–18. http://dx.doi.org/10.4141/s05-101.

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Greenhouse gas emissions from farms can be suppressed in two ways: by curtailing the release of these gases (especially N2O and CH4), and by storing more carbon in soils, thereby removing atmospheric CO2. But most practices have multiple interactive effects on emissions throughout a farm. We describe an approach for identifying practices that best reduce net, whole-farm emissions. We propose to develop a “Virtual Farm”, a series of interconnected algorithms that predict net emissions from flows of carbon, nitrogen, and energy. The Virtual Farm would consist of three elements: descriptors, which characterize the farm; algorithms, which calculate emissions from components of the farm; and an integrator, which links the algorithms to each other and the descriptors, generating whole-farm estimates. Ideally, the Virtual Farm will be: boundary-explicit, with single farms as the fundamental unit; adaptable to diverse farm types; modular in design; simple and transparent; dependent on minimal, attainable inputs; internally consistent; compatible with models developed elsewhere; and dynamic (“seeing”into the past and the future). The Virtual Farm would be constructed via two parallel streams - measurement and modeling - conducted iteratively. The understanding built into the Virtual Farm may eventually be applied to issues beyond greenhouse gas mitigation. Key words: CO2, N2O, CH4, agroecosystems, models, climate change

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Smernik, R. J., J. O. Skjemstad, and J. M. Oades. "Virtual fractionation of charcoal from soil organic matter using solid state 13C NMR spectral editing." Soil Research 38, no. 3 (2000): 665. http://dx.doi.org/10.1071/sr99115.

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The solid state 13C NMR spectral editing technique proton spin relaxation editing (PSRE), which generates subspectra of components that have different proton relaxation rates and are spatially separated by at least 30–100 nm, was applied to hydrofluoric acid treated <53 m soil fractions from 8 Australian surface soils. Most of the aromatic signal was partitioned into the rapidly relaxing subspectrum, especially for the soils known to have high charcoal contents. However, the presence of other rapidly relaxing soil organic matter (SOM) components prevented a clean separation of charcoal from non-charcoal components. PSRE analysis was repeated after the samples had been treated with high energy ultraviolet photo-oxidation, which brings about the mineralisation of most SOM other than char. Excellent separation of the charcoal fraction by PSRE was achieved after photo-oxidation for 5 of the samples with the highest charcoal content. The rapidly relaxing subspectra for these samples also suggested that the charcoal present in soil contains significant carbonyl functionality, possibly as a result of in situ weathering. A new PSRE methodology is described, designed to best suit SOM samples. Data from inversion-recovery experiments were fitted to a model consisting of 2 components with different T1H relaxation rate constants, thus providing an objective best fit to the inversion-recovery data and avoiding the subjective judgements required in other PSRE methodologies.

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Sternagel, Alexander, Ralf Loritz, Brian Berkowitz, and Erwin Zehe. "Stepping beyond perfectly mixed conditions in soil hydrological modelling using a Lagrangian approach." Hydrology and Earth System Sciences 26, no. 6 (March 25, 2022): 1615–29. http://dx.doi.org/10.5194/hess-26-1615-2022.

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Abstract. A recent experiment of Bowers et al. (2020) revealed that diffusive mixing of water isotopes (δ2H and δ18O) over a fully saturated soil sample of a few centimetres in length required several days to equilibrate completely. In this study, we present an approach to simulate such time-delayed diffusive mixing processes, on the pore scale, beyond instantaneously and perfectly mixed conditions. The diffusive pore mixing (DIPMI) approach is based on a Lagrangian perspective on water particles moving by diffusion over the pore space of a soil volume and carrying concentrations of solutes or isotopes. The idea of DIPMI is to account for the self-diffusion of water particles across a characteristic length scale of the pore space using pore-size-dependent diffusion coefficients. The model parameters can be derived from the soil-specific water retention curve, and no further calibration is needed. We test our DIPMI approach by simulating diffusive mixing of water isotopes over the pore space of a saturated soil volume using the experimental data of Bowers et al. (2020). Simulation results show the feasibility of the DIPMI approach for reproducing the measured mixing times and concentrations of isotopes at different tensions over the pore space. This result corroborates the finding that diffusive mixing in soils depends on the pore size distribution and the specific soil water retention properties. Additionally, we perform a virtual experiment with the DIPMI approach by simulating mixing and leaching processes of a solute in a vertical, saturated soil column and compare the results against simulations with the common perfect mixing assumption. The results of this virtual experiment reveal that the frequently observed steep rise and long tailing of breakthrough curves, which are typically associated with non-uniform transport in heterogeneous soils, may also occur in homogeneous media as a result of imperfect subscale mixing in a macroscopically homogeneous soil matrix.

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Mamo, M., D. Namuth-Covert, A. Guru, G. Nugent, L. Phillips, L. Sandall, T. Kettler, and D. McCallister. "Avatars Go to Class: A Virtual Environment Soil Science Activity." Journal of Natural Resources and Life Sciences Education 40, no. 1 (2011): 114–21. http://dx.doi.org/10.4195/jnrlse.2010.0023u.

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Krzic, Maja, Rachel A. Strivelli, Emma Holmes, Stephanie Grand, Saeed Dyanatkar, Les M. Lavkulich, and Chris Crowley. "Virtual Soil Monoliths: Blending Traditional and Web-Based Educational Approaches." Natural Sciences Education 42, no. 1 (February 4, 2013): 1–8. http://dx.doi.org/10.4195/nse.2012.0014.

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Coenders-Gerrits, A. M. J., L. Hopp, H. H. G. Savenije, and L. Pfister. "The effect of spatial throughfall patterns on soil moisture patterns at the hillslope scale." Hydrology and Earth System Sciences 17, no. 5 (May 7, 2013): 1749–63. http://dx.doi.org/10.5194/hess-17-1749-2013.

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Abstract. Improving the understanding of the controls on subsurface stormflow generation has been the goal of numerous experimental and modeling studies. However, the effect of the spatial variability of throughfall on soil moisture patterns and subsurface stormflow (SSF) generation has not yet been studied in detail. The objectives of this study are three-fold: (1) to investigate the influence of a spatially variable throughfall pattern on soil moisture; (2) to investigate if soil moisture patterns reflect a balance between a throughfall and bedrock topography patterns; and (3) to investigate how this balance changes when soil depth, storm size and slope angle are varied. Virtual experiments are used to address these questions. A virtual experiment is a numerical experiment driven by collective field intelligence. It provides a learning tool to investigate the effect of individual processes in a complex system. In our virtual experiment we combined spatial throughfall data from the Huewelerbach catchment in Luxembourg with the topography of a well-studied hillslope within the Panola Mountain Research Watershed, Georgia, USA. We used HYDRUS-3D as a modeling platform. The virtual experiment shows that throughfall patterns influence soil moisture patterns, but only during and shortly after a storm. With a semi-variogram analysis we showed how the effective range of the soil moisture pattern (i.e., the main descriptor of a spatial pattern in case of a small nugget to sill ratio), is similar to the effective range of the throughfall pattern during the storm and gradually returns to the effective range of the bedrock topography after throughfall has ceased. The same analysis was carried out to investigate how this balance changes due to changes in storm size, soil depth, and slope. The analysis showed that the throughfall pattern is more important during large storms on gentle slopes. For steeper slopes the bedrock topography becomes more important.

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Hadi, Mohamed Saad, and Haider M. Mekkiyah. "The Behavior of the Al-Kadhim Minaret during Earthquakes: A Virtual Study." Journal of Engineering 29, no. 1 (January 1, 2023): 1–13. http://dx.doi.org/10.31026/j.eng.2023.01.01.

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The study focuses on the causes of minaret tilting as well as possible solutions. The major aims of this study are to improve knowledge of historical tall structure stability and rehabilitation operations using the finite element approach to model the soil and minaret (PLAXIS 3D 2020), a platform for computational soil investigation and modeling. The numerical analysis aims to identify stresses, settlement, and deformation of the soil and minaret in various scenarios like Earthquakes, explosions, and winds. The simulation of the problem by the PLAXIS 3D revealed that the greatest lateral displacement computed at the Top Minaret is 5.5 cm, and the greatest vertical movement is calculated to be 3 cm. Seismic settlement is the effect of earthquake shaking, causing densification of soil with lower relative density.

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Coenders-Gerrits, A. M. J., L. Hopp, H. H. G. Savenije, and L. Pfister. "The effect of spatial throughfall patterns on soil moisture patterns at the hillslope scale." Hydrology and Earth System Sciences Discussions 9, no. 7 (July 12, 2012): 8625–63. http://dx.doi.org/10.5194/hessd-9-8625-2012.

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Abstract. A better understanding of the controls on subsurface stormflow generation has been the focus of numerous experimental and modelling studies. However, the effect of the spatial variability of throughfall on soil moisture patterns and subsurface stormflow (SSF) generation has not yet been studied in detail. The objectives of this study are three-fold: (1) to investigate the influence of spatially variable throughfall on soil moisture; (2) to investigate if soil moisture patterns reflect a balance between throughfall and bedrock topography patterns; and (3) to investigate how this balance changes when soil depth, storm size and slope angle are varied. Virtual experiments are used to address these questions. A virtual experiment is a numerical experiment driven by collective field intelligence. It provides a learning tool to investigate the effect of separated processes in a complex system. In our virtual experiment we combined spatial throughfall data from the Huewelerbach catchment in Luxembourg with the topography characteristics of a well-studied hillslope within the Panola Mountain Research Watershed, Georgia, USA. We used HYDRUS-3D as a modeling platform. The virtual experiment shows that throughfall patterns influence soil moisture patterns, but only during and shortly after a storm. With a semi-variogram analysis we showed how the effective range of the soil moisture pattern (i.e. the main descriptor of a spatial pattern in case of a small nugget to sill ratio), has a similar effective range as the throughfall pattern during the storm and gradually returns to the effective range of the bedrock topography pattern after throughfall has ceased. The same analysis was carried out to investigate how this balance changes due to changes in storm size and hillslope controls. The analysis showed that the throughfall pattern is more important during large storms on gentle slopes. For steeper slopes the bedrock topography becomes more important.

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Schelle, Henrike, Wolfgang Durner, Steffen Schlüter, Hans-Jörg Vogel, and Jan Vanderborght. "Virtual Soils: Moisture Measurements and Their Interpretation by Inverse Modeling." Vadose Zone Journal 12, no. 3 (August 2013): vzj2012.0168. http://dx.doi.org/10.2136/vzj2012.0168.

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Gnusov, Maksim A., Michael V. Drapaluk, Denis Yu Druchinin, Michael N. Lysych, Evgeniy V. Pozdnyakov, and Alexander F. Petkov. "Simulation of dynamic processes when a soil-throwing drum meets an obstacle." Journal of Physics: Conference Series 2388, no. 1 (December 1, 2022): 012095. http://dx.doi.org/10.1088/1742-6596/2388/1/012095.

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Abstract The problem of combating forest fires is very relevant to this day. The development of machines designed to extinguish and prevent uncontrolled forest fires, especially in waterless areas, is the most important area of scientific research. The article presents scientific research on simulation modeling of the interaction of a soil-marking drum with obstacles of two types: stones and logging residues. For the study, a simulation method was used in the 3D-CAD environment of the SolidWorks Simulation system, which made it possible to conduct a virtual experiment of a solid model and determine the behavior under static and dynamic loads that occur in emergency situations. The purpose of the work was to develop a 3D model of a soil-throwing drum machine for extinguishing and preventing forest fires to conduct simulation studies on a virtual stand to determine the dynamic loads in contact with obstacles of the soil-throwing drum blades based on the created solid model. For the process of studying the soil-marking drum when encountering obstacles in the form of logging residues and stony inclusions, an imitation virtual stand was created. The paper presents the results of the analysis of data obtained on the basis of simulation modeling.

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MAGLIARI, M. "FREE SOIL, UNFREE LABOR." Pacific Historical Review 73, no. 3 (August 1, 2004): 349–90. http://dx.doi.org/10.1525/phr.2004.73.3.349.

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Although it prohibited chattel slavery, California permitted the virtual enslavement of Native Americans under the 1850 Act for the Government and Protection of Indians. Scholars have described some of the key components of the Indian Act, but none has provided a systematic examination of the law's labor provisions or examined how individual employers actually used the law. This article does both by offering a careful survey of the Indian Act, followed by a detailed case study focusing on Cave Couts, the owner of Rancho Guajome in San Diego County. The Couts example reveals that the 1850 Act did not simply legalize the exploitation of Indians as prisoners and indentured "apprentices." Perhaps more importantly, it also preserved the system of debt peonage that had �ourished in California under Mexican rule. Not until after the Civil War did California become a truly free state.

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Jones, David T., Homathevi Rahman, David E. Bignell, and Anggoro H. Prasetyo. "Forests on ultramafic-derived soils in Borneo have very depauperate termite assemblages." Journal of Tropical Ecology 26, no. 1 (December 8, 2009): 103–14. http://dx.doi.org/10.1017/s0266467409990356.

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Abstract:Previous studies in Sundaland (Borneo, Sumatra, Java and Peninsular Malaysia) have shown that termite assemblages in natural forests have a characteristic structure. These typical forest assemblages contain many soil-feeding species. However, this study investigated four natural forest sites in Borneo with depauperate termite assemblages, and compared their soils with soils from four other sites that have typical termite assemblages. In contrast to the typical assemblages, the four depauperate assemblages all have low species density (<35%), low relative abundance (<30%), a virtual absence of soil-feeders, significantly fewer wood-feeders, and a near-absence of species of Rhinotermitidae, Amitermes-group, Termes-group, Pericapritermes-group and Oriensubulitermes-group. The depauperate sites are on ultramafic-derived soils and have significantly higher concentrations of calcium, magnesium, nickel, chromium, cobalt, copper and zinc compared with the non-ultramafic soils at sites with typical assemblages. In addition, soil pH at the depauperate sites is significantly higher (>pH 5.4) compared with soils at the typical sites (which are all below pH 4.7). Possible mechanisms to explain the depauperate termite assemblages on ultramafic soils include metal toxicity, high pH disrupting gut physiology, and microbial interactions with metals.

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Zhao, Yanxi, Hai Zhang, Nan Xu, Youxin Wei, and Zhongxian Liu. "Scattering of Plane P1 Wave by an Inclusion in a Three-Dimension Poroelastic Half-Space." Mathematical Problems in Engineering 2020 (March 31, 2020): 1–16. http://dx.doi.org/10.1155/2020/6964171.

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Local inclusion topography has significant influence on seismic wave propagation, and the propagation characteristics of seismic waves in poroelastic soils are obviously different from those in single-phase media. Based on Biot’s theory, the scattering of plane P1 wave by inclusion in a three-dimensional poroelastic half-space is studied by using the indirect boundary element method (IBEM). The scattering field is constructed by introducing a virtual wave near the interface between inclusion and half-space and the surface of half-space, and the virtual wave density is obtained by establishing boundary integral equation based on the boundary conditions. The effects of the depth, geometric characteristics, boundary permeability, porosity, incident frequency, and incident angle of the inclusion on elastic wave scattering are systematically analyzed. The results show that due to the soil skeleton-pore water coupling effect, when the porosity is n = 0.3, the surface displacement amplitude of dry soil is larger than that of poroelastic soil. When the porosity is n = 0.36, the surface displacement amplitude of poroelastic soil is larger than that of dry soil. The surface displacement amplitude of poroelastic-drained condition is slightly larger than that of undrained condition. With the increase of inclusion depth, the scattering of elastic wave by inclusion decreases gradually. When P1 wave is incident, the surface displacement amplitude at the depth of H = 0.5 can be increased up to three times as much as that at the depth of H = 1.5. As the inclusion becomes narrower and flatter, the scattering of elastic waves by inclusion decreases gradually. When the ratio between height and length is S = 2/5, the surface displacement magnitude can reach up to 9.5.

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Childs, CW, and B. Clayden. "On the definition and identification of aquic soil moisture regimes." Soil Research 24, no. 2 (1986): 311. http://dx.doi.org/10.1071/sr9860311.

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The definition of an aquic soil moisture regime given in Soil Taxonomy is difficult to understand and, in places, ambiguous. The essence of the definition as written, however, is the requirement for reducing conditions. A soil which is saturated with groundwater or with capillary fringe water may, or may not, have an aquic moisture regime. Reducing conditions are defined in Soil Taxonomy in relation to the virtual absence of dissolved oxygen, though morphological criteria for the differentiation of soil classes are based on the reduction and segregation of iron. The absence of requirements relating to duration of reducing conditions, or to the thickness of reduced soil, suggests that the definition was intended to apply to soil material rather than to a pedon. The aquic moisture regime has a particular depth connotation only when it is applied to the differentiation of soil classes. A simple field test, based on the complexing agent �,�-dipyridyl, is useful for the identification of ferrous ions in soil solutions and hence is potentially useful in the recognition of aquic moisture regimes. The sensitivity of this test limits its usefulness to those soils which contain more than about 0.5% free iron (i.e. iron which can be solubilised as iron(II) under reducing conditions as measured by extraction with dithionite reagent).

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Cox, D. R., and Valerie Isham. "The virtual waiting-time and related processes." Advances in Applied Probability 18, no. 2 (June 1986): 558–73. http://dx.doi.org/10.2307/1427312.

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The virtual waiting-time process of Takács is one of the simplest examples of a stochastic process with a continuous state space in continuous time in which jump transitions interrupt periods of deterministic decay. Properties of the process are reviewed, and the transient behaviour examined in detail. Several generalizations of the process are studied. These include two-sided jumps, periodically varying ‘arrival’ rate and the presence of a state-dependent decay rate; the last case is motivated by the properties of soil moisture in hydrology. Throughout, the emphasis is on the derivation of simple interpretable results.

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Cox, D. R., and Valerie Isham. "The virtual waiting-time and related processes." Advances in Applied Probability 18, no. 02 (June 1986): 558–73. http://dx.doi.org/10.1017/s0001867800015883.

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The virtual waiting-time process of Takács is one of the simplest examples of a stochastic process with a continuous state space in continuous time in which jump transitions interrupt periods of deterministic decay. Properties of the process are reviewed, and the transient behaviour examined in detail. Several generalizations of the process are studied. These include two-sided jumps, periodically varying ‘arrival’ rate and the presence of a state-dependent decay rate; the last case is motivated by the properties of soil moisture in hydrology. Throughout, the emphasis is on the derivation of simple interpretable results.

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30

Grunwald, S., P. Barak, K. McSweeney, and B. Lowery. "SOIL LANDSCAPE MODELS AT DIFFERENT SCALES PORTRAYED IN VIRTUAL REALITY MODELING LANGUAGE." Soil Science 165, no. 8 (August 2000): 598–615. http://dx.doi.org/10.1097/00010694-200008000-00002.

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Hasan, Alsidqi, Ali Karrech, and Bruno Chareyre. "Evaluating Force Distributions within Virtual Uncemented Mine Backfill Using Discrete Element Method." International Journal of Geomechanics 17, no. 7 (July 2017): 06016042. http://dx.doi.org/10.1061/(asce)gm.1943-5622.0000850.

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32

Crisp, M. P., M. B. Jaksa, Y. L. Kuo, G. A. Fenton, and D. V. Griffiths. "A method for generating virtual soil profiles with complex, multi-layer stratigraphy." Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards 13, no. 2 (December 18, 2018): 154–63. http://dx.doi.org/10.1080/17499518.2018.1554817.

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Fang, Ying Guang, Jia Liu, and Zhi Liang Dong. "Soil Elastic-Plastic Rotation Gradient Theory Based on Grain Size Factor and its Finite Element Implementation." Advanced Materials Research 779-780 (September 2013): 420–24. http://dx.doi.org/10.4028/www.scientific.net/amr.779-780.420.

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Soil is the most common discontinuous granular material in the geotechnical engineering and its physical and mechanical properties have obvious grain size effect. In view of the insufficient of classical continuum mechanics and existing discrete mechanics, the matrix-reinforcing particles cell element model of soil introduces to account for the grain size effect and microstructure of the soil; then, based on the rotation gradient theory, the elastic-plastic stress-strain relations of soil with grain size factor obtains; finally, using the principle of virtual work establishes the corresponding finite element method.

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Wang, Xiang Qiu, Wen Tao Yang, and Yu Hong Zhang. "Study on the Stability Analysis Method of the Anchored Soil Slope Based on the Theory of Plasticity Limit." Applied Mechanics and Materials 204-208 (October 2012): 54–58. http://dx.doi.org/10.4028/www.scientific.net/amm.204-208.54.

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Based on the analysis theory of plasticity limit, a formula of virtual work and an energy equation are established for the stability analysis of anchored soil slope, in which the soil nails and anchors are regarded as the internal structure which consumes the external power in the soil slope engineering.In the meantime, based on the simplified method of circular slip, another formula which can consider many factors such as the self-weight of slope, earthquake force, pressure of pore water and the force of anchor, is established to analyse the whole stability of anchored soil slope. It has important values for perfecting the analysis method of soil slope.

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35

Sutarsyah, Sutarsyah, Rima Setiani, and Tupan Tupan. "Promosi Museum Tanah dan Pertanian Sebagai Penguatan Pusat Informasi dan Edukasi Pertanian Tematik." Media Pustakawan 29, no. 1 (April 30, 2022): 54–64. http://dx.doi.org/10.37014/medpus.v29i1.2694.

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Soil and Agriculture Museum as a center for information and education in agriculture which is managed by the Center for Library and Agricultural Technology Dissemination. In order to attract visitors, the museum needs to be managed creatively and attractively. This paper aims to provide information to users about the services and activities provided by the Museum of Soil and Agriculture (MTP). Services and activities carried out by libraries and museums to attract users during the COVID-19 pandemic are Virtual Tour MTP, Virtual Tour International Museum Day series, MTP Thematic Exhibition, Sundanese Cultural Creation Dance Competition, Illustration Drawing Competition. In addition to these activities, PUSTAKA also produced five videos which were posted on the Soil and Agriculture Museum Web. The results of activities and promotions carried out by PUSTAKA are then narrated descriptively. The results of the study show that after the promotion of services and activities in 2020 was held, the total visitors to the Soil and Agriculture Museum reached 13,844 people, both directly and via virtually, with students as the most visitors students. It can be concluded that the promotion and service activities carried out can increase the number of visits to the museum.

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Diveev, Aleks, and Gennadii Boldyrev. "Information systems in geotechnics." MATEC Web of Conferences 355 (2022): 02030. http://dx.doi.org/10.1051/matecconf/202235502030.

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The article considers the information modeling of buildings together with the foundation within the information system and the stages of its implementation. The workflow for building a 3D geotechnical model includes surface relief data, field and laboratory test data, soil lithology, geometric characteristics of the foundation structure and load. Automated systems with processing and interpretation of test data are used to determine the characteristics of soils. Mathematical modeling of the behavior of the foundations of the foundations with various input data is performed using analytical solutions and numerical methods. The natural heterogeneity of soil properties and its impact on the behavior of buildings is estimated by the sensitivity indicator of the foundation-foundation system by introducing virtual workings between the existing normative ones and the subsequent calculation of the precipitation and roll of the foundation.

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Crisp, M. P., M. B. Jaksa, and Y. L. Kuo. "Toward a generalized guideline to inform optimal site investigations for pile design." Canadian Geotechnical Journal 57, no. 8 (August 2020): 1119–29. http://dx.doi.org/10.1139/cgj-2019-0111.

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Insufficient or inappropriate soil testing can lead to a range of undesirable consequences, and yet there is no guideline for optimal investigation. This study analyses the influence of test type, number of boreholes, data interpretation, soil conditions, and structural configuration on site investigation performance. In addition to providing general recommendations, the relative sensitivity of these variables on performance is determined. Performance is assessed in terms of total expected project cost while implicitly incorporating the risk of damage from poor investigation. The framework for this study involves the use of randomly generated, variable, single layer virtual soils in a Monte Carlo analysis. It was found that optimal investigations can produce net savings in the order of several hundreds of thousands of Australian dollars, and key features of a future site investigation guideline are identified.

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Rodríguez-León, Carlos H., Clara P. Peña-Venegas, Armando Sterling, Herminton Muñoz-Ramirez, and Yeny R. Virguez-Díaz. "Changes in Soil-Borne Communities of Arbuscular Mycorrhizal Fungi during Natural Regrowth of Abandoned Cattle Pastures Are Indicative of Ecosystem Restoration." Agronomy 11, no. 12 (December 3, 2021): 2468. http://dx.doi.org/10.3390/agronomy11122468.

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Natural restoration of ecosystems includes the restoration of plant-microbial associations; however, few studies had documented those changes in tropical ecosystems. With the aim to contribute to understand soil microbial changes in a natural regrowth succession of degraded pastures that were left for natural restoration, we studied changes in arbuscular mycorrhizal (AM) fungal communities. Arbuscular mycorrhizal fungi (AMF) establish a mutualistic symbiosis with plants, improving plant nutrition. Amplification of the small subunit rRNA with specific primers and subsequent Illumina sequencing were used to search soil-borne AM fungal communities in four successional natural regrowth stages in two landscapes (hill and mountain) with soil differences, located in the Andean-Amazonian transition. Molecular results corroborated the results obtained previously by spores-dependent approaches. More abundance and virtual taxa of AMF exist in the soil of degraded pastures and early natural regrowth stages than in old-growth or mature forest soils. Although changes in AM fungal communities occurred similarly over the natural regrowth chronosequence, differences in soil texture between landscapes was an important soil feature differentiating AM fungal community composition and richness. Changes in soil-borne AM fungal communities reflect some signals of environmental restoration that had not been described before, such as the reduction of Glomus dominance and the increase of Paraglomus representativeness in the AM fungal community during the natural regrowth chronosequence.

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Shaherani, Natasya, Alfyananda Kurnia Putra, Djoko Soelistijo, and Batchuluun Yembuu. "The Development of Mobile Geography Virtual Laboratory for Rock and Soil Practicum Studies." International Journal of Interactive Mobile Technologies (iJIM) 16, no. 22 (November 29, 2022): 142–56. http://dx.doi.org/10.3991/ijim.v16i22.36163.

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The concept of concrete lithosphere material has limitations in being verbally stimulated by the teacher, so students have difficulty understanding the material. During the learning process, lithosphere material is rarely carried out in practicum activities due to the lack of media that can involve students directly. This study aims to produce, measure feasibility, and determine the effectiveness of mobile geography virtual laboratory learning media. This research was included in R&D research by adopting a 4-D development model. The results obtained, namely the Mobile Geography Virtual Laboratory media, are feasible and effectively used in rock and soil practicum activities. The results of this research can be an innovative solution for geography learning, especially in adequately supporting the implementation of practicum activities so that students can become more active and independent.

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Zhou, Wenqi, Chao Song, Xiaobo Sun, Ziming Liu, Xue Ni, Kangjia Shen, Yi Jia Wang, and Liquan Tian. "Design of High-Efficiency Soil-Returning Liquid Fertilizer Deep-Application Furrow Openers for Improving Furrowing Performance in Cold Regions of Northeast China." Agriculture 12, no. 9 (August 23, 2022): 1286. http://dx.doi.org/10.3390/agriculture12091286.

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Liquid-fertilizer deep-application techniques are techniques for applying fertilizers to the root system of crops, which can effectively improve the utilization rate of fertilizers and reduce application amounts. Due to the soil viscosity of soils in the cold region of Northeast China, the soil return rate of furrow openers for liquid-fertilizer deep applications is low, which can easily cause excessive volatilizations of liquid fertilizers. Therefore, aiming at the operational requirements of low soil disturbance for liquid-fertilizer furrowing and deep applications, an efficient soil-returning liquid-fertilizer deep-application furrow opener was innovatively designed based on soil characteristics during the inter-cultivation period in the cold region of Northeast China. The discrete element method (DEM) was used to analyze the operating performance of the high-efficiency soil-returning liquid-fertilizer deep-application furrow openers, which is determined by key operating parameters including width and slip cutting angle. The DEM Virtual Simulation Experiment results show that the optimal combination is the width of 37.52 mm and a slip cutting angle of 43.27°, and the test results show that the optimal performance of the high-efficiency soil-returning liquid-fertilizer deep-application furrow opener is that the soil disturbance rate is 51.81%, and the soil-returning depth is 52.1 mm. This paper clarifies the relationship between the width and the slip cutting angle in furrowing resistance and soil disturbance and the mechanism by which the width and slip cutting angle affect soil disturbance. Above all, this study provides a theoretical and practical reference for the design of liquid-fertilizer deep-application furrow openers.

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Cabrejos-Hurtado, J., S. Galindo Torres, and D. M. Pedroso. "Assessment of the Mechanical Behaviour of Granular Media by DEM-Based True Triaxial Tests." Applied Mechanics and Materials 846 (July 2016): 428–33. http://dx.doi.org/10.4028/www.scientific.net/amm.846.428.

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This study presents the numerical simulation of a true triaxial test by means of the discrete element method (DEM). Experimental results performed on Toyoura sand are employed as reference and the calibration methodology is explained. Physical aspects of the real soil, such as the grain size distribution and the relative density, are considered during the generation of the virtual sample. It is shown that the main aspects of the macro-mechanical behaviour of granular soils during compression loading can be fairly represented by the idealised simulations with particles.

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Wang, Qunming, Yijie Tang, Xiaohua Tong, and Peter M. Atkinson. "Virtual image pair-based spatio-temporal fusion." Remote Sensing of Environment 249 (November 2020): 112009. http://dx.doi.org/10.1016/j.rse.2020.112009.

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Xu, Bin, Manqing Xu, and Kang Li. "Dynamic Responses of the Pile-Saturated-Soil System to a Moving Load." Journal of Physics: Conference Series 2202, no. 1 (June 1, 2022): 012002. http://dx.doi.org/10.1088/1742-6596/2202/1/012002.

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Abstract According to the basic solution of viscoelastic and saturated soil subjected to moving load on the surface and circular uniform harmonic load on the inside, the integral equation of soil-pile interaction under moving load in frequency domain is established by using Muki virtual pile method, and then the time-space dynamic response characteristics of a single pile in viscoelastic saturated soil to moving load vibration source are analyzed by using inverse Fourier transform. The factors that affect the dynamic response of single pile, such as load speed, length of single pile, saturated soil parameters, vibration source properties, etc., are analyzed and compared with the known results in related literature.

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Winstone, Bethany C., Richard J. Heck, Lars J. Munkholm, and Bill Deen. "Characterization of soil aggregate structure by virtual erosion of X-ray CT imagery." Soil and Tillage Research 185 (January 2019): 70–76. http://dx.doi.org/10.1016/j.still.2018.09.001.

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Wang, Shengnian, Yue Li, Xinqun Gao, Qinpei Xue, Peng Zhang, and Zhijian Wu. "Influence of volumetric block proportion on mechanical properties of virtual soil-rock mixtures." Engineering Geology 278 (December 2020): 105850. http://dx.doi.org/10.1016/j.enggeo.2020.105850.

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Lin, Shan, Hong Zheng, Wei Jiang, Wei Li, and Guanhua Sun. "Investigation of the excavation of stony soil slopes using the virtual element method." Engineering Analysis with Boundary Elements 121 (December 2020): 76–90. http://dx.doi.org/10.1016/j.enganabound.2020.09.005.

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Miao, Zheng Jian, Deng Hua Zhong, Ming Chao Li, and Wei Gao. "Research on 3D Dredged Soil Visualization Analysis of Qinhuangdao Harbor Project." Advanced Materials Research 594-597 (November 2012): 2893–96. http://dx.doi.org/10.4028/www.scientific.net/amr.594-597.2893.

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In order to rapidly, accurately and vividly provide plenty of underwater soil analysis information for design and construction in dredging engineering, this paper took Qinhuangdao harbor project as an example, introducing a three-dimensional underwater soil modeling method and establishing the 3D unified soil solid model of Qinhuangdao harbor. The model has a small amount of data storage, high precision and is easy to operate graphical computing. Based on the model, and with 3D visualization technology, a series of soil visual analysis were conducted, including virtual digital drilling, arbitrary cutting analysis and water depth elevation analysis. Moreover, the model could quickly output scene graph, 2D cross-section and isoline map. Practical engineering applications indicate that 3D dredged soil visualization helps engineers to understand the space distribution of underwater soil. The proposed method can provide a convenient support tool for dredging engineering soil analysis.

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Allahem, Ali, Salah Boulaaras, Khaled Zennir, and Mohamed Haiour. "A New Mathematical Model of Heat Equations And its Application on the Agriculture Soil." European Journal of Pure and Applied Mathematics 11, no. 1 (January 30, 2018): 110. http://dx.doi.org/10.29020/nybg.ejpam.v11i1.3157.

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The goal of this paper is to provide a mathematical model which based on numerical simulation applied to heat equations and comparing the obtained results with virtual temperatures results for different depths of the homogeneous agricultural soil. The model was treated through this research that enable to know the degree of soil temperature homogeneous without recourse to tools of measuring physical expensive. The importance of this lies in the agricultural seed germination at temperatures suitable.

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Rosa-Gruszecka, Aleksandra, Dorota Hilszczańska, and Giovanni Pacioni. "Virtual Truffle Hunting—A New Method of Burgundy Truffle (Tuber aestivum Vittad.) Site Typing." Forests 12, no. 9 (September 13, 2021): 1239. http://dx.doi.org/10.3390/f12091239.

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The aim of this study was to enable searches for truffles (Tuber spp.), particularly the Burgundy truffle (T. aestivum Vittad.), to be carried out in forests based on a method that has been constantly developed since 2007 by the Forest Research Institute. The method is termed “Virtual Truffle Hunting” and it takes 12 parameters into account: bedrock, soil pH, Ca+ and CaCO3 content in soil, C/N ratio, soil structure, altitude of terrain, type of forest site, forest structure, the Burgundy truffle host trees, and the presence of particular species including orchids and insects. A simple “Virtual Truffle Hunting” software has also been developed, which makes the use of the method easy, fast, and effective. This method is to ascertain the truffle potential for all areas in which digital maps are not available. In 2015, the method was tested in 20 sites, representing forests in 5 Polish macroregions. Hunting for hypogeous fungi was conducted from June to October with the help of trained dogs. Thanks to this method, 14 new truffle sites were found. The knowledge of environmental conditions conducive to the Burgundy truffle growth enabled us to form an effective tool in order to identify new sites of truffle presence.

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Zhang, Wen, Bin Zhang, Wei Hong Zhang, Sheng Wei Li, Yan Zhen Luo, Xin Liu, Xiu Ling Ren, and Kai Wei. "Analysis and Calculation of Earth Pressure Based on Nonlinear Theory." Advanced Materials Research 1055 (November 2014): 109–13. http://dx.doi.org/10.4028/www.scientific.net/amr.1055.109.

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The results of the model test and field test which are proposed in soil pressure calculation indicate that soil pressure distribution is mostly non-linear. Using two models, the soil arching effect and horizontal unit by two theories of rigid retaining wall and non-linear soil pressure, combine with test material to calculate and analysis. The soil arching effect model calculated value on the upper part of retaining wall is higher than horizontal unit model, closer to the static soil pressure, which mainly relates to the upper part of the soil arching effect expresses in sufficiently. As the soil arching effect expresses in the lower part, its value is lower than horizontal unit model; both total soil pressure are the same; the resultant force point of the soil arching effect is higher than the horizontal unit model, the results of calculation and analyses are more well coincide to the virtual discipline. Basing on it, putting forward a kind of soil pressure calculation model which considers the space-time effect and reflects the soil pressure distribution is non-linear.

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Journal articles on the topic 'Virtual soil'

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