Angelica Palomino | University of Tennessee Knoxville (original) (raw)

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Papers by Angelica Palomino

$Research paper thumbnail of Shale particle interactions with organic and inorganic hydraulic fracturing additives$

Applied Geochemistry, 2021

$Research paper thumbnail of Comparison of Hydrometer Analysis and Laser Diffraction Method for Measuring Particle and Floc Size Distribution Applied to Fine Coal Refuse$

Geotechnical Testing Journal, 2020

Traditional grain size distribution measurement techniques assume that the measured particle diam... more Traditional grain size distribution measurement techniques assume that the measured particle diameters are of individual grains. However, for suspended particulate materials, particles may be dispersed or associated in flocs. Further, particle-level associations depend on the surrounding fluid chemistry, which may change over time. The purpose of this study is to compare two different methods of grain size analysis for detecting particle and floc sizes in suspensions of fine coal refuse (FCR): hydrometer analysis, the well-known traditional method, and laser diffraction, a lesser known method. The influence of background solution—flocculant, dispersant, or distilled water—on the apparent grain size of FCR was also investigated. Analogous slurry suspensions made from a well-characterized kaolin were analyzed for comparison. Results from the grain/floc size analysis indicate that there are several advantages of laser diffraction over hydrometer analysis including a short measurement period, small sample size requirement, and the ability to measure a wide range of particle sizes in the same analysis. Moreover, this study highlights the ability of the particle size analyzer (PSA) to accurately measure changes in apparent particle size over time for the same suspension and thereby indicate the presence of flocs. Finally, the PSA has the capability of capturing dynamic particle interactions—flocculation and deflocculation— in real time.

Canadian Geotechnical Journal

“Tunable” clay–polymer composites have the potential to improve the engineering properties of cla... more “Tunable” clay–polymer composites have the potential to improve the engineering properties of clay materials. The importance of these materials derives from the ability of the responsive polymer to adopt various conformations (coiled, partially extended or extended), which in turn impacts the mesoscale properties of the material. However, the influence of polymer molecule conformation on particle arrangement and overall composite behavior is not well understood. The purpose of this study is to understand the fabric development due to the conformational behavior of the polymer, and thus the clay–polymer composite, over a wide range of solids content and stress levels. The polymer molecule conformation was controlled using selected fluid pH and ionic concentrations. Results show that the polymer conformation significantly influences clay fabric formation. When the polymer molecules are likely to have extended conformation, the dominant fabric mode is face-to-face and particle mobilization increases. Both face-to-face and edge-to-edge fabric formation dominate the behavior of the composite when coiled conformation is likely, resulting in a decrease in interparticle movement. Thus, the polymer conformation can be used to manipulate both the interparticle spacing between particles and (or) aggregates and arrangement of particles.

Earth Surface Processes and Landforms

Applied Clay Science, 2014

International Journal of Pavement Engineering, 2008

GeoCongress 2008, 2008

The objective of this study is to identify mechanical and physical geogrid properties critical to... more The objective of this study is to identify mechanical and physical geogrid properties critical to performance in geogrid‐reinforced pavements. Properties such as aperture size, wide‐width tensile strength, and junction strength of several geogrid types are determined from ...

GeoCongress 2008, 2008

ABSTRACT This paper describes a pit-scale experimental study aimed at quantifying and evaluating ... more ABSTRACT This paper describes a pit-scale experimental study aimed at quantifying and evaluating geogrid reinforcement in flexible pavements. Two sets of pavement sections are constructed on two different subgrades and trafficked using a Model Mobile Load Simulator (MMLS3). Each set of test sections consists of the same pavement materials and structure except for the geogrid type used for stabilizing the subgrade. Rutting of all sections are measured using a profilometer at various trafficking stages. Geogrid reinforcement effectiveness is found to be related to the difference in geogrids properties. Test results show that the geogrid reinforcement enhances the pavement performance with respect to rutting resistance compared to a non-reinforced system.

ABSTRACT Instrumentation embedded in pavements is increasingly being used to measure the critical... more ABSTRACT Instrumentation embedded in pavements is increasingly being used to measure the critical responses and monitor performance of specially-constructed experimental pavement sections or in-service pavements under controlled wheel loading or live traffic. On the other hand, nondestructive tests (NDT), such as falling weight deflectometer (FWD) testing, are routinely performed to evaluate pavement layer structural properties based on deflections measured on the surface of the pavements. In cases where measurements from the pavement surface only are not sufficient to infer pavement layer modulus values, e.g. rolling wheel deflectometer (RWD) tests typically with only one deflection measurement or complex geometries, a procedure that combines measurements from the embedded instruments and surface deflections would provide an alternative to the traditional backcalculation of pavement layer moduli. This study presents an inverse analysis procedure integrating finite element (FE) models and a population-based optimization technique, Covariance Matrix Adaptation Evolution Strategy (CMA-ES), to determine the pavement layer structural properties. Tests using a lightweight deflectometer (LWD) were conducted on instrumented three-layer scaled flexible pavement test sections. The time histories of the LWD load, surface deflection underneath the LWD load, subgrade deflection and vertical stress were recorded and used in the inverse analysis. While the common practice in backcalculating pavement layer properties still assumes a static FWD load and makes use of only peak values of the load and deflections, dynamic analysis was conducted to simulate the impulse LWD load. Results of the inverse analysis show that consistent pavement layer properties can be obtained based on the LWD surface deflection data and measurements of the embedded instrumentation.