scholarly journals Improved Packing Model for Functionally Graded Sand-Fines Mixtures—Incorporation of Fines Cohesive Packing Behavior

2020 ◽  
Vol 10 (2) ◽  
pp. 562
Author(s):  
Ammar El-Husseiny
Keyword(s):  
Fine Particles ◽  
Current Model ◽  
Functionally Graded ◽  
Analytical Models ◽  
Dry Density ◽  
Published Data ◽  
Fine Silt ◽  
Packing Model ◽  
Cohesive Particles ◽  
Mixed Soils

Binary soil mixture, containing large silica particles (sand) mixed with variable content of very fine silt or clay, is an example of a functionally graded material that is important for several science and engineering applications. Predicting the porosity (or void ratio), which is a fundamental quantity that affects other physical properties, of such material as function of fines (clay or silt) fraction can be significant for sediment research and material design optimization. Existing analytical models for porosity prediction work well for binary mixed soils containing multi-sized non-cohesive particles with no clay, while such models frequently underestimate the porosity of sand-clay mixtures. This study aims to present an analytical model that accurately predicts the porosity of mixed granular materials or soils containing sand and very fine silt or clay (cohesive particles). It is demonstrated that accounting for the cohesive nature of very fine particles, which exists due to the effect of inter-particle forces, is a major missing aspect in existing packing models for mixed soils. Consequently, a previously developed linear packing model is modified so that it accounts for fines cohesive packing in sand-fines mixtures. The model prediction is validated using various experimental published data sets for the porosity of sand-fines mixtures. Improvement in the prediction of permeability and maximum packing dry density when incorporating cohesive packing behavior is discussed. The current model also provides important insights on the conditions under which, the lowest permeability and maximum packing state are expected.

scholarly journals Unified Packing Model for Improved Prediction of Porosity and Hydraulic Conductivity of Binary Mixed Soils

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 455
Author(s):  
Ammar El-Husseiny
Keyword(s):  
Hydraulic Conductivity ◽  
Current Model ◽  
Fine Sand ◽  
Coarse Sand ◽  
Published Data ◽  
Soil Mixing ◽  
Packing Model ◽  
Wide Range ◽  
The Impact ◽  
Mixed Soils

Binary mixed soils, containing coarse sand particles mixed with variable content of fines (fine sand, silt, or clay) are important for several environmental and engineering applications. The packing state (or porosity) of such sand-fines mixtures controls several important physical properties such as hydraulic conductivity. Therefore, developing an analytical packing model to predict porosity of binary mixed soils, based on properties of pure unmixed sand and fines (endmembers), can contribute to predicting hydraulic conductivity for the mixtures without the need for extensive laboratory measurements. Toward this goal, this study presents a unified packing model for the purpose of predicting the porosity and hydraulic conductivity of binary mixed soils as function of fines fraction. The current model modifies an existing packing model developed for coarse binary mixed soils to achieve three main improvements: (1) being inclusive of wide range of binary mixed soils covering the whole range particle sizes, (2) incorporating the impact of cohesive packing behavior of the fines on binary mixture porosity, and (3) accounting for the impact of clay swelling. The presented model is the first of its kind incorporating the combined impact of all three factors: particle size ratio, fines cohesive packing and swelling, on binary mixtures porosity. The predictions of the modified model are validated using experimental published data for the porosity of sand-fines mixtures from 24 different studies. The model shows significant improvement in predicting porosity compared to existing packing models that frequently underestimate the porosity. By using the predicted porosity as an input in Kozeny–Carman formulation, the absolute mean error in predicting hydraulic conductivity, as function of fines fraction for 16 different binary mixed soils, is reduced by 50% when compared to the use of the previous packing model. The current model provides insights about the endmembers properties (porosity, hydraulic conductivity, and grain size) and fines content required to achieve a certain target desirable porosity and hydraulic conductivity of the mixed soils. This can assist the optimization of soil mixing design for various applications.

scholarly journals An Improved Mathematical Model for Accurate Prediction of the Heavy Oil Production Rate during the SAGD Process

Processes ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 235
Author(s):  
Aria Rahimbakhsh ◽  
Morteza Sabeti ◽  
Farshid Torabi
Keyword(s):  
Production Rate ◽  
Penetration Depth ◽  
Oil Recovery ◽  
Current Model ◽  
Oil Production ◽  
Exponential Model ◽  
Analytical Models ◽  
Test Facility ◽  
Drainage Rate ◽  
Heat Penetration

Steam-assisted gravity drainage (SAGD) is one of the most successful thermal enhanced oil recovery (EOR) methods for cold viscose oils. Several analytical and semi-analytical models have been theorized, yet the process needs more studies to be conducted to improve quick production rate predictions. Following the exponential geometry theory developed for finding the oil production rate, an upgraded predictive model is presented in this study. Unlike the exponential model, the current model divides the steam-oil interface into several segments, and then the heat and mass balances are applied to each of the segments. By manipulating the basic equations, the required formulas for estimating the oil drainage rate, location of interface, heat penetration depth of steam ahead of the interface, and the steam required for the operation are obtained theoretically. The output of the proposed theory, afterwards, is validated with experimental data, and then finalized with data from the real SAGD process in phase B of the underground test facility (UTF) project. According to the results, the model with a suitable heat penetration depth correlation can produce fairly accurate outputs, so the idea of using this model in field operations is convincing.

scholarly journals Investigation of porosity effect on flexural analysis of doubly curved FGM conoids

2019 ◽  
Vol 26 (1) ◽  
pp. 435-448
Author(s):  
Md Irfan Ansari ◽  
Ajay Kumar ◽  
Danuta Barnat-Hunek ◽  
Zbigniew Suchorab ◽  
Bartłomiej Kwiatkowski
Keyword(s):  
Mathematical Model ◽  
Shear Strain ◽  
Transverse Shear ◽  
Volume Fraction ◽  
Current Model ◽  
Lower Surface ◽  
Functionally Graded ◽  
Transverse Shear Strain ◽  
Flexural Analysis ◽  
Doubly Curved

AbstractThe flexural analysis of doubly curved functionally graded porous conoids was performed in the present paper. The porosities inside functionally graded materials (FGMs) can occur during the fabrication and lead to the occurrence of micro-voids in the materials. The mathematical model includes expansion of Taylor’s series up to the third degree in thickness coordinate and normal curvatures in in-plane displacement fields. Since there is a parabolic variation in transverse shear strain deformation across the thickness coordinate, the shear correction factor is not necessary. The condition of zero-transverse shear strain at upper and lower surface of conoidal shell is implemented in the present model. The improvement in the 2D mathematical model enables to solve problems of moderately thick FGM porous conoids. The distinguishing feature of the present shell from the other shells is that maximum transverse deflection does not occur at its centre. The improved mathematical model was implemented in finite element code written in FORTRAN. The obtained numerical results were compared with the results available in the literature. Once validated, the current model was employed to study the effect of porosity, boundary condition, volume fraction index, loading pattern and others geometric parameters.

Effect of Impoundment and Diversion on the Sediment Budget and Nearshore Sedimentation of Southern Indian Lake

1984 ◽  
Vol 41 (4) ◽  
pp. 567-578 ◽  
Author(s):  
R. E. Hecky ◽  
G. K. McCullough
Keyword(s):  
Fine Particles ◽  
Suspended Load ◽  
Constituent Particle ◽  
Shoreline Erosion ◽  
Bed Load ◽  
Particle Sizes ◽  
Fine Silt ◽  
Load Transport ◽  
Bed Load Transport ◽  
Clay Aggregates

Shoreline erosion added an annual average of 4 × 106 t of mineral sediment per year to Southern Indian Lake (postimpoundment area, 2391 km2) during the first 3 yr of impoundment. This erosion increased sedimentary input to the lake by a factor of 20. The lake retained 90% of this eroded material within its basin, and 80–90% of the retained material was deposited nearshore. Despite the production of extremely fine constituent particle sizes, eroding shorelines generated predominantly large clay aggregates, initially transported offshore as bed load. During bed load transport, abrasion of clay aggregates produced fine particles that became suspended. Over 80% of the suspended load is lost to outflows from the lake because the suspended load is primarily fine silt and clay-sized particles, most of which do not settle even under winter ice cover. The extensive nearshore clay aggregate deposits are temporary, and net deposition in these areas will change to net erosion when input of sediment from eroding shorelines ceases. The effects of shoreline erosion on the lake's sediment regime will persist for decades.

Multiple Surface Cracking and Its Effect on Interface Cracks in Functionally Graded Thermal Barrier Coatings Under Thermal Shock

2003 ◽  
Vol 70 (2) ◽  
pp. 234-245 ◽  
Author(s):  
S. Rangaraj ◽  
K. Kokini
Keyword(s):  
Thermal Shock ◽  
Thermal Barrier Coatings ◽  
Architectural Design ◽  
Effective Properties ◽  
Mean Field ◽  
Functionally Graded ◽  
Analytical Models ◽  
Thermal Barrier ◽  
Thermal Fracture ◽  
Barrier Coatings

The thermal fracture behavior in functionally graded yttria stabilized zirconia–NiCoCrAlY bond coat alloy thermal barrier coatings was studied using analytical models. The response of three coating architectures of similar thermal resistance to laser thermal shock tests was considered. Mean field micromechanics models were used to predict the effective thermoelastic and time-dependent (viscoplastic) properties of the individual layers of the graded thermal barrier coatings (TBCs). These effective properties were then utilized in fracture mechanics analyses to study the role of coating architecture on the initiation of surface cracks. The effect of the surface crack morphology and coating architecture on the propensity for propagation of horizontal delamination cracks was then assessed. The results of the analyses are correlated with previously reported experimental results. Potential implications of the findings on architectural design of these material systems for enhanced thermal fracture resistance are discussed.

scholarly journals Dynamic Analysis of Functionally Graded Timoshenko Beams in Thermal Environment Using a Higher-Order Hierarchical Beam Element

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Dinh Kien Nguyen ◽  
Van Tuyen Bui
Keyword(s):  
Dynamic Behaviour ◽  
Thermal Environment ◽  
Beam Element ◽  
Higher Order ◽  
Functionally Graded ◽  
Published Data ◽  
Timoshenko Beams ◽  
Material Inhomogeneity ◽  
Forced Vibration Analysis ◽  
Loading Parameter

A higher-order finite beam element for free and forced vibration analysis of functionally graded Timoshenko beams in thermal environment is formulated by using hierarchical functions to interpolate the kinematic variables. The shear strain is constrained to constant to improve the efficiency of the element. The effect of environmental temperature is taken into account in the element derivation by considering that the material properties are temperature-dependent and the temperature is nonlinear distribution in the beam thickness. The accuracy of the derived formulation is confirmed by comparing the results obtained in the present work with the published data. Numerical investigations show that the formulated element is efficient, and it is capable of giving accurate vibration characteristics by a small number of elements. A parametric study is carried out to highlight the effect of the material inhomogeneity, temperature rise, and loading parameter on the dynamic behaviour of the beams. The influence of the aspect ratio on the dynamic behaviour of the beam is also examined and highlighted.

scholarly journals Geotechnical Properties of Clayey Soil Contaminated with Copper

2019 ◽  
Vol 26 (1) ◽  
pp. 74-80
Author(s):  
Mahdi O. Karkush ◽  
Shahad D. Ali
Keyword(s):  
Copper Sulfate ◽  
Fine Particles ◽  
Clayey Soil ◽  
Physical And Mechanical Properties ◽  
Cohesive Soil ◽  
Geotechnical Properties ◽  
Oil Field ◽  
Dry Density ◽  
Unconfined Compression Test ◽  
Intact Soil

In this research, the effectsof coppersulfate contamination on the chemical, physical and mechanical properties of cohesive soil have been studied and compared with the properties of intact soil. Soil sampleswere obtained from Al-Ahdab oil field in Wasit governorate, located in the east of Iraq. In the laboratory, the soil specimens were contaminated artificiallywith three quantities of copper sulfate) CuSO4.5H2O) (100, 200 and 400) gm. The contaminantwas dissolved in 10 liters of distilled water and then added to the intact soil. The intact soil samplekept soaked with the contaminantfor 30 days. Several tests were conducted onthe soil samples (intact and contaminated) to measure the effects of copper sulfate on the geotechnical properties of clayey soil. The results of tests showed significant effectsfor copper on the studied soil properties. The copper sulfate causesdecreasing the percentage of fine particles in the soil, Atterberg s limits, permeability and optimum water content. Inaddition, the copper sulfate causes increasing thespecific gravity andmaximum dry density of soil. The shear strength parameters of soil are measured by using direct shear test, unconfined compression test and unconsolidated undrained triaxial test are decreased with increasing the concentration of copper sulfate in soil. Also, its noted increasing the initial void ratio, the compression index and recompression index with increasing concentration of contaminant in soil.

Experimental Study of Influence Factors in Unsaturated Soil Infiltration Rate

2013 ◽  
Vol 477-478 ◽  
pp. 472-475
Author(s):  
Ling Cao ◽  
Xin Zhe Li
Keyword(s):  
Water Content ◽  
Unsaturated Soil ◽  
Infiltration Rate ◽  
Water Infiltration ◽  
Dry Density ◽  
Initial Water Content ◽  
Soil Infiltration ◽  
Initial Water ◽  
Cohesive Particles ◽  
Soil Infiltration Rate

Based on the unsaturated soil ponding water infiltration test in laboratory, the influences of cohesive particles content, dry density and initial water content on infiltration rate are analyzed. Soil infiltration rate decreased with the increase of cohesive particles content and dry density; with the decrease of initial water content at low dry density, and with the increase of initial water content at high dry density.

Design of Functionally Graded Beam of Aluminium Foam for Civil Structural Application

2016 ◽  
Vol 710 ◽  
pp. 65-70 ◽  
Author(s):  
Gianpaolo Perrella ◽  
Diana Faiella ◽  
Giuseppe Brandonisio ◽  
Massimiliano Fraldi ◽  
Elena Mele
Keyword(s):  
Metal Foam ◽  
Functionally Graded ◽  
Aluminium Foam ◽  
Analytical Models ◽  
Metallic Foam ◽  
High Tech ◽  
Functionally Graded Beam ◽  
Structural Application ◽  
Flexural Response ◽  
Parametric Analyses

Sandwich foam beams, made of solid skins and aluminium foam core, are usually applied in high-tech engineering field while they are not yet adopted in civil structures. An initial, explorative study on the structural application of metal foam is presented in this paper. The potentials of sandwich foam beams are studied through analytical models and parametric analyses; the sensitivity of the flexural response of the media to the total amount of pores and their spatial distribution are investigated. An analytical tool able to design functionally graded beams of metallic foam is presented and applied with reference some commercial aluminium foams. An experimental campaign is being planned to validate the presented results.

Research of the Particle Gradation Technology of Components in PBX Explosive Based on CPM Model

2015 ◽  
Vol 727-728 ◽  
pp. 366-369
Author(s):  
Qiu An Huang ◽  
Geng Guang Xu ◽  
Jian Yu Chen
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Relative Error ◽  
Fine Particles ◽  
Raw Materials ◽  
Maximum Value ◽  
Packing Model ◽  
Packing Efficiency ◽  
Compressible Packing Model

Basedon the assumption of related parameters in compressible packing model, thecompressible packing model was used for the calculation of the explosivespacking efficiency. The accuracy of the calculation was verified by experimentsand the relative error was 2.49%. Besides, the influence of content offineparticles and particle size distribution in explosives on stacking efficiencywas discussed. The results show that the stacking efficiency was increasingwith the particle size distribution increasing from 0~300μm to 0~700μm. Thepacking efficiency reached it’s maximum value when we only increased thecontent of fine particles to 40%. Therefore, the packing efficiency has arelation with particle size distribution of raw materials.

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