Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 30 for “"particle packing"”.
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Development and analysis of a gravity-simulated particle-packing algorithm for modeling optimized rocket propellants
… require an accurate description of the packing arrangement in order to correctly model the complex geometric effects that stem from the random morphology. A new and novel computational packing algorithm was invented, implemented, and analyzed using various particle starting arrangements. …
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A study of the influence of aggregate grading on concrete penetrability
… properties of hardened concrete. The aggregate particle size distribution is usually selected so as to achieve a particle packing density that is equal to or near the maximum, which is seen as optimal for strength and durability. However, the influence of aggregate grading on durability apart …
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Optimization and behavior of high-performance concrete in structural applications
… journals. The first paper investigates a particle packing model for determination of the optimal proportions of materials for high performance concrete. Since concrete with higher strength and durability will have a higher packing density, this research used particle packing to optimize a …
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Asphalt Mixture Design Concepts to Develop Aggregate Interlock
… that utilize aggregate interlock and aggregate packing to develop an aggregate blend that meets volumetric criteria and provides adequate compaction characteristics. The presented concepts rely on coarse aggregate for the skeleton of the mixture with the proper amount of fine aggregate to …
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Experimental and numerical investigation of steady-state and transient ultrasound directed self-assembly of spherical particles in a viscous medium
… a standing ultrasound wave field to organize particles dispersed in a fluid medium into specific patterns. The ability to tailor the organization and packing density of spherical particles using ultrasound DSA in a viscous fluid medium is crucial in the context of (additive) manufacturing of …
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Simulation of packed column jigging
… finely disseminated particulate materials. The packing materials in the jig divide the column into a large number of virtual cells. Each cell performs the similar separation action. A model about the movement of a particle in the packed column jig was derived to interpret the separation …
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Compositional Effects on the Chemorheological Properties and Forming Behavior of Aqueous Alumina-Poly(vinyl Alcohol) Gelcasting Suspensions
… Free-fomied Al2O3 components exhibited uniform particle packing and had minimal macro-defects (e.g., slumping or stair casing) and no detectable micro-defects (e.g., bubbles or cracking).
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The Influence of Amorphous, Sub-Micrometer Silica Particles in Cement Pastes and Mortars with Very Low Water-to-Cement Ratios (Ultra-High Performance Concrete)
… influence of amorphous, sub-micrometer silica particles in UHPCs. The present literature is equivocal about whether silica enhances clinker hydration due to its dissolution and subsequent pozzolanic reaction to calcium–silicate–hydrate phases (C–S–H phases) and/or due to a heterogeneous …
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On Local Order in Particle Packings
A great many physical systems take the form of a particle packing. The structure of such systems is often characterized through the study of local order. The current thesis makes progress towards a formal understanding of this physical phenomenon. It is demonstrated that particle packings cannot …
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Modeling the relation between suction, effective stress and shear strength in partially saturated granular media
… stress and soil suction for uniform, spherical particles, at low water contents. The model includes the analytical formulation of water geometry and forces at the micro-scale. The change in effective stress due to soil suction is estimated from this particle contact scale, taking account of the …
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Improvised explosive device crater repair for enduring route remediation
… the selected product was optimized using particle packing theory. The laboratory testing program was performed on the optimized mix to determine the effectiveness of the optimization. Through laboratory tests, a pre-blended rapid hardening material was recommended for crater repairs that …
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Improving the Sustainability of Performance-Based Concrete Overlay Mix Design made with Rounded Aggregate
… the Power 45 and Tarantula curves to improve particle packing and concrete cohesiveness. Concrete mixtures were designed with three types of cement, Type I/II, Type IL, and calcium sulfoaluminate cement with polymer (CSAP), and evaluated at two water-to-cement ratios (0.35 and 0.40). The …
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Colloidal properties of sugar particle dispersions in food oils with relevance to chocolate processing
… on the interactions between fine sugar particles dispersed in different triglyceride oils has been investigated at a range of volume fractions. Four techniques were applied: rheology. sedimentation, light microscopy and adsorption. Eight different types of food oil were used: sunflower …
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Computational Modeling and Simulation of Viscoelastic Granular Packings
… of two dimensional (2D) viscoelastic granular packings, aiming to unravel the complex relationship between particle-level properties and macroscopic responses. We perform a suite of finite element simulations under rate-dependent uniaxial compaction. The study commences with an analysis of a …
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Powder packing optimisation for clinker reduction in concrete
… The optimisation of powder (materials < 125 µm) packing, using filler materials with varying fineness, was identified to potentially increase clinker efficiency. The optimisation undertaken was the maximisation of powder packing density but without adversely affecting workability. The …
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Near-Net Shaping and Additive Manufacturing of Ultra-High Temperature Ceramics via Colloidal Processing
… into the role of interaction forces between particles, solvents, and polymeric additives in the rheology, particle packing, and strength of a ceramic green body. For difficult-to-densify ceramics such as the UHTCs, which find their place in extreme environment applications, precise control of …
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Dynamic simulation of particulate and molecular systems
… OF MISSOURI AT AUTHOR'S REQUEST.] Granular packing of millimeter-scale and micrometer-scale particles with three different size distributions (monosize, bimodal and Gaussian) are studied using the Distinct Element Method (DEM). The dissipative forces including viscoelastic and frictional …
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Understanding bulk behavior of particulate materials from particle scale simulations
… bulk behaviors of particulate materials from particle scale simulations. Packing properties of assembly of particles are investigated first, focusing on the effects of particle size, surface energy, and aspect ratio on the coordination number, porosity, and packing structures. The simulation …
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Study of micro-sized particle deposition using DEM, CFD-DEM and SPH approach
Self-assembly and packing of colloids and micro or nano scale particles has become a subject of great interest due to widespread advancement of micro-scale technologies. In this thesis, several numerical analyses are performed to study the packing or self-assembly of micro or nano sized particles …
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Scale-up of Using Novel Dewatering Aids
… removal of free water from the surface of fine particles is difficult and costly, and often the results are less than desirable. Fine particles inherently have very large surface areas, and hence retain large amounts of water. Increased amounts of fines also cause denser particle packing, which …
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