scholarly journals Numerical Characterization of Cohesive and Non-Cohesive ‘Sediments’ under Different Consolidation States Using 3D DEM Triaxial Experiments

Processes ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 1252
Author(s):  
Hadar Elyashiv ◽  
Revital Bookman ◽  
Lennart Siemann ◽  
Uri ten Brink ◽  
Katrin Huhn
Keyword(s):  
Mechanical Response ◽  
Burial Depth ◽  
Cohesive Sediments ◽  
Third Order ◽  
First Order ◽  
Numerical Characterization ◽  
Response To Stress ◽  
Bond Strengths ◽  
Individual Bond

The Discrete Element Method has been widely used to simulate geo-materials due to time and scale limitations met in the field and laboratories. While cohesionless geo-materials were the focus of many previous studies, the deformation of cohesive geo-materials in 3D remained poorly characterized. Here, we aimed to generate a range of numerical ‘sediments’, assess their mechanical response to stress and compare their response with laboratory tests, focusing on differences between the micro- and macro-material properties. We simulated two endmembers—clay (cohesive) and sand (cohesionless). The materials were tested in a 3D triaxial numerical setup, under different simulated burial stresses and consolidation states. Variations in particle contact or individual bond strengths generate first order influence on the stress–strain response, i.e., a different deformation style of the numerical sand or clay. Increased burial depth generates a second order influence, elevating peak shear strength. Loose and dense consolidation states generate a third order influence of the endmember level. The results replicate a range of sediment compositions, empirical behaviors and conditions. We propose a procedure to characterize sediments numerically. The numerical ‘sediments’ can be applied to simulate processes in sediments exhibiting variations in strength due to post-seismic consolidation, bioturbation or variations in sedimentation rates.

scholarly journals CARACTERIZAÇÃO MORFOMÉTRICA DA MICROBACIA HIDROGRÁFICA DO CÓRREGO DA FAZENDA GLÓRIA, MUNICÍPIO DE TAQUARITINGA, SP.

Irriga ◽  
2008 ◽  
Vol 13 (3) ◽  
pp. 310-322 ◽  
Author(s):  
Flávia Mazzer Rodrigues ◽  
Teresa Cristina Tarlé Pissara ◽  
Sérgio Campos
Keyword(s):  
Remote Sensing ◽  
Fourth Order ◽  
Land Development ◽  
Morphometric Characteristics ◽  
Third Order ◽  
First Order ◽  
The Relationship ◽  
Number Of Segments ◽  
Morphometric Characterization

Caracterização morfométrica da microbacia hidrográfica do córrego da Fazenda Glória, Município de Taquaritinga, SP.  Flavia Mazzer Rodrigues1; Teresa Cristina Tarlé Pissarra1; Sérgio Campos2 1Departamento de Engenharia Rural, Faculdade de Ciências Agronômicas e Veterinária, Universidade Estadual Paulista, Jaboticabal, SP, [email protected] de Engenharia Rural, Faculdade de Ciências Agronômicas, Universidade Estadual Paulista, Botucatu, SP   1 RESUMO  Com a análise das características morfométricas, procura-se entender a relação solo-superfície, em decorrência dos processos erosivos sobre estruturas e litologias variadas. Neste trabalho, objetivou-se caracterizar, no período de 1983 e 2000, as características morfométricas na Microbacia Hidrográfica do Córrego da Fazenda Glória, de 4a ordem de magnitude, Município de Taquaritinga - SP. Esta microbacia hidrográfica foi dividida em 7 microbacias hidrográficas de 2a ordem e 2 microbacias hidrográficas de 3a ordem. As características morfométricas demonstraram que ocorreu uma redução do número de segmentos de rios de 1.a ordem e comprimento da rede de drenagem ao longo do período analisado, estando relacionadas às diversas influências que a evolução do modelado sofreu, tendo em vista o uso e ocupação do solo, indicando comportamento hidrológico desigual. Os resultados permitiram inferir que o comprimento do segmento de rio de 4a ordem se manteve constante ao longo do período analisado. UNITERMOS: sensoriamento remoto, análise morfométrica, microbacias hidrográficas.  RODRIGUES, F. M.; PISSARRA, T. C. T.; CAMPOS, S. Morphometric characterization of Glória FARM Watershed, Taquaritinga, state of São Paulo, brazil.  2 ABSTRACT The analysis of morphometric characteristics is used to understand the relationship between soil and surface as a result of erosive processes on different structures and lithologies. The objective of this study was to study the morphometric characteristics of Fazenda Gloria watershed from 1983 to2000, afourth-order watershed in  TaquaritingaMunicipality,São PauloState. The study was based on photointerpretation techniques. Drainage net and the respective watersheds were selected and the morphometric variables were determined. The watersheds consisted of 7 second-order watersheds and 2 third-order watersheds. The morphometric characteristics showed a reduction in the number of segments of first-order rivers and in the length of the drainage net during the study period. These findings could be related to several influences on land development considering the occupation and use of land. A different hydrological behavior could also be observed. The analysis of Fazenda Glória Watershed showed that the length of the segment of fourth order river remained constant during the study period. KEY WORDS: remote sensing, morphometric analysis, watershed.

Numerical Characterization of a High Flux Solar Simulator Using Forward and Inverse Methods

2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Mostafa Abuseada ◽  
Nesrin Ozalp
Keyword(s):  
Heat Flux ◽  
Ray Tracing ◽  
Focal Plane ◽  
High Flux ◽  
Solar Simulator ◽  
New Approach ◽  
First Order ◽  
Numerical Characterization ◽  
Tracing Method

Abstract The numerical characterization of a 10 kWe xenon arc high flux solar simulator is thoroughly presented and performed using two approaches: a forward Monte Carlo ray tracing (MCRT) method and an inverse ray tracing method. Experimental characterization was previously performed for the solar simulator using an indirect flux mapping technique, where the experimental heat flux distribution was obtained at the focal plane and additional 12 planes away from the simulator. For the first numerical characterization method, an in-house MCRT code was used to determine the shape of the xenon arc to best model the simulator. It was determined that an isotropic volumetric source consisting of a hemisphere of 1 mm radius that is attached to a cylinder of 1 mm in radius and 10 mm in length well described the experimental results obtained. The in-house code was then used to generate heat flux maps similar to that obtained experimentally and determine the intensity at the focal plane to be used by the inverse ray tracing method presented for its validation. For the inverse method, intensity interpolation schemes of zeroth and first-order were examined in addition to different solution strategies. It is shown that a first-order interpolation scheme unnecessary complicates the inverse problem, leading to larger errors. In addition, a new approach of constraining the formulated system of equations with an equality constraint that works by eliminating intensity values not tracing back to the ellipsoidal reflector is proposed. This new approach provided intensity values with reduced percentage errors.

scholarly journals Application of instrumented nanoindentation in preformulation studies of pharmaceutical active ingredients and excipients

2016 ◽  
Vol 66 (3) ◽  
pp. 303-330 ◽  
Author(s):  
Mateja Egart ◽  
Biljana Janković ◽  
Stane Srčič
Keyword(s):  
Mechanical Response ◽  
Active Ingredients ◽  
Force Microscopy ◽  
Atomic Force ◽  
Accuracy And Precision ◽  
Response To Stress ◽  
Preformulation Studies ◽  
Elastic And Plastic Deformation

Abstract Nanoindentation allows quantitative determination of a material’s response to stress such as elastic and plastic deformation or fracture tendency. Key instruments that have enabled great advances in nanomechanical studies are the instrumented nanoindenter and atomic force microscopy. The versatility of these instruments lies in their capability to measure local mechanical response, in very small volumes and depths, while monitoring time, displacement and force with high accuracy and precision. This review highlights the application of nanoindentation for mechanical characterization of pharmaceutical materials in the preformulation phase (primary investigation of crystalline active ingredients and excipients). With nanoindentation, mechanical response can be assessed with respect to crystal structure. The technique is valuable for mechanical screening of a material at an early development phase in order to predict and better control the processes in which a material is exposed to stress such as milling and compression.

Construction of plastic contact deformation maps on ceramics: a case study on aluminum nitride

1996 ◽  
Vol 54 ◽  
pp. 636-637
Author(s):  
D. L. Callahan
Keyword(s):  
Plastic Deformation ◽  
Aluminum Nitride ◽  
Mechanical Response ◽  
Three Dimensional ◽  
Bright Field Image ◽  
Perfectly Plastic ◽  
Contrast Analysis ◽  
Deformation Patterns

Modern polishing, precision machining and microindentation techniques allow the processing and mechanical characterization of ceramics at nanometric scales and within entirely plastic deformation regimes. The mechanical response of most ceramics to such highly constrained contact is not predictable from macroscopic properties and the microstructural deformation patterns have proven difficult to characterize by the application of any individual technique. In this study, TEM techniques of contrast analysis and CBED are combined with stereographic analysis to construct a three-dimensional microstructure deformation map of the surface of a perfectly plastic microindentation on macroscopically brittle aluminum nitride.The bright field image in Figure 1 shows a lg Vickers microindentation contained within a single AlN grain far from any boundaries. High densities of dislocations are evident, particularly near facet edges but are not individually resolvable. The prominent bend contours also indicate the severity of plastic deformation. Figure 2 is a selected area diffraction pattern covering the entire indentation area.

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