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Joseph L. Cecchia - One of the best experts on this subject based on the ideXlab platform.
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Investigation of the Kinetics of Tungsten Chemical Mechanical Polishing in Potassium Iodate‐Based Slurries: II. Roles of Colloid Species and Slurry Chemistry
Journal of The Electrochemical Society, 1999Co-Authors: David J. Stein, Dale L. Hetherington, Joseph L. CecchiaAbstract:We investigated the role of Colloid species and slurry chemistry in tungsten chemical mechanical polishing. Specifically, we measured polish rate and process temperature in potassium iodate-based slurries as a function of Colloid species and concentration, slurry pH, and potassium iodate concentration, as well as polish pressure and polish rotation rate. We investigated slurries containing yttrium-, zirconium-, cerium-, and aluminum-based oxide and hydroxide Colloids. We found that the Colloid species had a large effect on polish rate and process temperature. The Colloids showed two orders of magnitude in the polish rate range from ∼15 to ∼1975 A min -1 under otherwise identical experimental conditions (same polisher, pad, slurry chemistry, pressure, and rotation rates). Colloids of the same metal species from different sources also showed a large range in polish rates. Process temperature was a function of Colloid species, however, the trend in polish rate did not always follow that of process temperature. Both polish rate and process temperature were dependent on potassium iodate concentration and slurry pH (controlled with a buffer). We also introduce a heuristic polish mechanism to investigate the role of the Colloid surface chemistry and its interaction with the tungsten surface. The data indicate that the surface characteristics of the Colloid and how this surface interacts with the tungsten surface play a significant role in the mechanism of tungsten removal during polish.
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investigation of the kinetics of tungsten chemical mechanical polishing in potassium iodate based slurries ii roles of Colloid species and slurry chemistry
Journal of The Electrochemical Society, 1999Co-Authors: David J. Stein, Dale L. Hetherington, Joseph L. CecchiaAbstract:We investigated the role of Colloid species and slurry chemistry in tungsten chemical mechanical polishing. Specifically, we measured polish rate and process temperature in potassium iodate-based slurries as a function of Colloid species and concentration, slurry pH, and potassium iodate concentration, as well as polish pressure and polish rotation rate. We investigated slurries containing yttrium-, zirconium-, cerium-, and aluminum-based oxide and hydroxide Colloids. We found that the Colloid species had a large effect on polish rate and process temperature. The Colloids showed two orders of magnitude in the polish rate range from ∼15 to ∼1975 A min -1 under otherwise identical experimental conditions (same polisher, pad, slurry chemistry, pressure, and rotation rates). Colloids of the same metal species from different sources also showed a large range in polish rates. Process temperature was a function of Colloid species, however, the trend in polish rate did not always follow that of process temperature. Both polish rate and process temperature were dependent on potassium iodate concentration and slurry pH (controlled with a buffer). We also introduce a heuristic polish mechanism to investigate the role of the Colloid surface chemistry and its interaction with the tungsten surface. The data indicate that the surface characteristics of the Colloid and how this surface interacts with the tungsten surface play a significant role in the mechanism of tungsten removal during polish.
David J. Stein - One of the best experts on this subject based on the ideXlab platform.
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Investigation of the Kinetics of Tungsten Chemical Mechanical Polishing in Potassium Iodate‐Based Slurries: II. Roles of Colloid Species and Slurry Chemistry
Journal of The Electrochemical Society, 1999Co-Authors: David J. Stein, Dale L. Hetherington, Joseph L. CecchiaAbstract:We investigated the role of Colloid species and slurry chemistry in tungsten chemical mechanical polishing. Specifically, we measured polish rate and process temperature in potassium iodate-based slurries as a function of Colloid species and concentration, slurry pH, and potassium iodate concentration, as well as polish pressure and polish rotation rate. We investigated slurries containing yttrium-, zirconium-, cerium-, and aluminum-based oxide and hydroxide Colloids. We found that the Colloid species had a large effect on polish rate and process temperature. The Colloids showed two orders of magnitude in the polish rate range from ∼15 to ∼1975 A min -1 under otherwise identical experimental conditions (same polisher, pad, slurry chemistry, pressure, and rotation rates). Colloids of the same metal species from different sources also showed a large range in polish rates. Process temperature was a function of Colloid species, however, the trend in polish rate did not always follow that of process temperature. Both polish rate and process temperature were dependent on potassium iodate concentration and slurry pH (controlled with a buffer). We also introduce a heuristic polish mechanism to investigate the role of the Colloid surface chemistry and its interaction with the tungsten surface. The data indicate that the surface characteristics of the Colloid and how this surface interacts with the tungsten surface play a significant role in the mechanism of tungsten removal during polish.
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investigation of the kinetics of tungsten chemical mechanical polishing in potassium iodate based slurries ii roles of Colloid species and slurry chemistry
Journal of The Electrochemical Society, 1999Co-Authors: David J. Stein, Dale L. Hetherington, Joseph L. CecchiaAbstract:We investigated the role of Colloid species and slurry chemistry in tungsten chemical mechanical polishing. Specifically, we measured polish rate and process temperature in potassium iodate-based slurries as a function of Colloid species and concentration, slurry pH, and potassium iodate concentration, as well as polish pressure and polish rotation rate. We investigated slurries containing yttrium-, zirconium-, cerium-, and aluminum-based oxide and hydroxide Colloids. We found that the Colloid species had a large effect on polish rate and process temperature. The Colloids showed two orders of magnitude in the polish rate range from ∼15 to ∼1975 A min -1 under otherwise identical experimental conditions (same polisher, pad, slurry chemistry, pressure, and rotation rates). Colloids of the same metal species from different sources also showed a large range in polish rates. Process temperature was a function of Colloid species, however, the trend in polish rate did not always follow that of process temperature. Both polish rate and process temperature were dependent on potassium iodate concentration and slurry pH (controlled with a buffer). We also introduce a heuristic polish mechanism to investigate the role of the Colloid surface chemistry and its interaction with the tungsten surface. The data indicate that the surface characteristics of the Colloid and how this surface interacts with the tungsten surface play a significant role in the mechanism of tungsten removal during polish.
Tammo S. Steenhuis - One of the best experts on this subject based on the ideXlab platform.
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impact of dissolved organic matter on Colloid transport in the vadose zone deterministic approximation of transport deposition coefficients from polymeric coating characteristics
Water Research, 2011Co-Authors: Verónica L. Morales, Wei Zhang, Bin Gao, Leonard W Lion, James J Bisogni, Brendan A Mcdonough, Tammo S. SteenhuisAbstract:Abstract Although numerous studies have been conducted to discern Colloid transport and stability processes, the mechanistic understanding of how dissolved organic matter (DOM) affects Colloid fate in unsaturated soils (i.e., the vadose zone) remains unclear. This study aims to bridge the gap between the physicochemical responses of Colloid complexes and porous media interfaces to solution chemistry, and the effect these changes have on Colloid transport and fate. Measurements of adsorbed layer thickness, density, and charge of DOM-Colloid complexes and transport experiments with tandem internal process visualization were conducted for key constituents of DOM, humic (HA) and fulvic acids (FA), at acidic, neutral and basic pH and two CaCl 2 concentrations. Polymeric characteristics reveal that, of the two tested DOM constituents, only HA electrosterically stabilizes Colloids. This stabilization is highly dependent on solution pH which controls DOM polymer adsorption affinity, and on the presence of Ca +2 which promotes charge neutralization and inter-particle bridging. Transport experiments indicate that HA improved Colloid transport significantly, while FA only marginally affected transport despite having a large effect on particle charge. A transport model with deposition and pore-exclusion parameters fit experimental breakthrough curves well. Trends in deposition coefficients are correlated to the changes in Colloid surface potential for bare Colloids, but must include adsorbed layer thickness and density for sterically stabilized Colloids. Additionally, internal process observations with bright field microscopy reveal that, under optimal conditions for retention, experiments with FA or no DOM promoted Colloid retention at solid-water interfaces, while experiments with HA enhanced Colloid retention at air-water interfaces, presumably due to partitioning of HA at the air-water interface and/or increased hydrophobic characteristics of HA-Colloid complexes.
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Colloid Transport and Retention in Unsaturated Porous Media: Effect of Colloid Input Concentration
Environmental science & technology, 2010Co-Authors: Wei Zhang, M. Ekrem Cakmak, Verónica L. Morales, Anthony E. Salvucci, Larry D. Geohring, Anthony G. Hay, Jean-yves Parlange, Tammo S. SteenhuisAbstract:Colloids play an important role in facilitating transport of adsorbed contaminants in soils. Recent studies showed that under saturated conditions Colloid retention was a function of its concentration. It is unknown if this is the case under unsaturated conditions. In this study, the effect of Colloid concentration on Colloid retention was investigated in unsaturated columns by increasing concentrations of Colloid influents with varying ionic strength. Colloid retention was observed in situ by bright field microscopy and quantified by measuring Colloid breakthrough curves. In our unsaturated experiments, greater input concentrations resulted in increased Colloid retention at ionic strength above 0.1 mM, but not in deionized water (i.e., 0 mM ionic strength). Bright field microscope images showed that Colloid retention mainly occurred at the solid-water interface and wedge-shaped air-water-solid interfaces, whereas the retention at the grain-grain contacts was minor. Some Colloids at the air-water-solid interfaces were rotating and oscillating and thus trapped. Computational hydrodynamic simulation confirmed that the wedge-shaped air-water-solid interface could form a "hydrodynamic trap" by retaining Colloids in its low velocity vortices. Direct visualization also revealed that Colloids once retained acted as new retention sites for other suspended Colloids at ionic strength greater than 0.1 mM and thereby could explain the greater retention with increased input concentrations. Derjaguin-Landau-Verwey-Overbeek (DLVO) energy calculations support this concept. Finally, the results of unsaturated experiments were in agreement with limited saturated experiments under otherwise the same conditions.
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Pore Scale Simulation of Colloid Deposition
Modelling and Simulation, 2008Co-Authors: M. Ekrem Cakmak, Bin Gao, John L. Nieber, Tammo S. SteenhuisAbstract:Mobile subsurface Colloids have received considerable attention because the migration of Colloids and Colloid-contaminant complexes through the solid matrix substantially increase the risk of groundwater pollution. Typically defined as suspended particulate matter with diameter less than 10μm, Colloids include both organic and inorganic materials such as microorganisms, humic substances, clay minerals and metal oxides. Accurate prediction of the fate of Colloids is important to predict Colloid facilitated transport of pollutants, and the transport of bioColloids such as viruses and bacteria. In Colloid transport studies Colloid deposition, that is, the capture of Colloids by grain surfaces, is considered as the primary mechanism controlling the transport of Colloids in groundwater (Ryan & Elimelech; 1996). The role of electrostatic and hydrodynamic forces in controlling Colloid deposition behavior of Colloids has been afforded detailed investigation in the field of Colloid science to gain more understanding about Colloid-surface interaction processes. The study of deposition rates of Colloids onto model collectors has provided substantial information on the electrostatic and hydrodynamic forces involved in the transport of Colloids (Elimelech et al., 1995; Tien & Ramarao, 2007). Most of these studies have focused on Colloid transport under saturated conditions (Yao et al., 1971; Rajagopalan & Tien, 1976; Ryan & Elimelech, 1996; Keller & Auset, 2007). However, there is not much information available on Colloid behavior under unsaturated conditions due to the complexity of the conditions involved (DeNovio et al., 2004; Keller & Sirivithayapakorn, 2004; Auset & Keller; 2004; Crist et al., 2005; Zevi et al., 2005; Keller & Auset, 2007). Most of the experimental and modeling studies on Colloid transport under unsaturated conditions have focused primarily on Colloid concentration in drainage water with very little emphasis on the precise mechanisms retaining the Colloids in the pores (Corapcioglu & Choi, 1996; Lenhart & Saiers, 2002; DeNovio et al., 2004). Generally, the approaches used to simulate Colloid transport can be classified into two types, Lagrangian or Eulerian. The Lagrangian approach focuses on the movement of distinct particles and tracks particle position in a moving fluid (Rajagopalan & Tien, 1976; Ryan and Elimelech, 1996). In contrast, the Eulerian approach considers the concentration distribution of particles in a porous media (Yao et al., 1971; Tufenkji & Elimelech, 2004). The Eulerian approach has advantages over the Lagrangian approach, in that it does not require high computational performance, and it is easy to incorporate Brownian motion (Ryan and Elimelech, 1996; Nelson & Ginn, 2005).
François Quentel - One of the best experts on this subject based on the ideXlab platform.
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Particle size and mineralogical composition of inorganic Colloids in waters draining the adit of an abandoned mine, Goesdorf, Luxembourg
Applied Geochemistry, 2009Co-Authors: Montserrat Filella, Vincent Chanudet, Simon Philippo, François QuentelAbstract:Particle size distributions and the mineralogy of inorganic Colloids in waters draining the adit of an abandoned mine (Goesdorf, Luxembourg) were quantified by single particle counting based on light scattering (100 nm–2 μm) combined with transmission electronic microscopy coupled with energy dispersive spectroscopy and selected area electron diffraction. This water system was chosen as a surrogate for groundwaters. The dependence of the Colloid number concentration on Colloid diameters can be described by a power-law distribution in all cases. Power-law slopes ranged from −3.30 to −4.44, depending on water ionic strength and flow conditions. The same main mineral types were found in the different samples: 2:1 phyllosilicates (illite and mica), chlorite, feldspars (albite and orthoclase), calcite and quartz; with a variable number of Fe oxide particles. The Colloid mineralogical composition closely resembles the composition of the parent rock. Spatial variations in the structure and composition of the rock in contact with the waters, i.e. fissured rock versus shear joints, are reflected in the Colloid composition. The properties of the study Colloids, as well as the processes influencing them, can be considered as representative of the Colloids present in groundwaters.
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Particle size and mineralogical composition of inorganic Colloids in draining waters of the adit of an old antimony mine, Goesdorf, Luxembourg.
Applied Geochemistry, 2009Co-Authors: Montserrat Filella, Vincent Chanudet, Simon Philippo, François QuentelAbstract:Particle size distributions and the mineralogy of inorganic Colloids in waters draining the adit of an abandoned mine (Goesdorf, Luxembourg) were quantified by single particle counting based on light scattering (100 nm–2 lm) combined with transmission electronic microscopy coupled with energy dispersive spectroscopy and selected area electron diffraction. This water system was chosen as a surrogate for groundwaters. The dependence of the Colloid number concentration on Colloid diameters can be described by a power-law distribution in all cases. Power-law slopes ranged from 3.30 to 4.44, depending on water ionic strength and flow conditions. The same main mineral types were found in the different samples: 2:1 phyllosilicates (illite and mica), chlorite, feldspars (albite and orthoclase), calcite and quartz; with a variable number of Fe oxide particles. The Colloid mineralogical composition closely resembles the composition of the parent rock. Spatial variations in the structure and composition of the rock in contact with the waters, i.e. fissured rock versus shear joints, are reflected in the Colloid composition. The properties of the study Colloids, as well as the processes influencing them, can be considered as representative of the Colloids present in groundwaters.
Dale L. Hetherington - One of the best experts on this subject based on the ideXlab platform.
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Investigation of the Kinetics of Tungsten Chemical Mechanical Polishing in Potassium Iodate‐Based Slurries: II. Roles of Colloid Species and Slurry Chemistry
Journal of The Electrochemical Society, 1999Co-Authors: David J. Stein, Dale L. Hetherington, Joseph L. CecchiaAbstract:We investigated the role of Colloid species and slurry chemistry in tungsten chemical mechanical polishing. Specifically, we measured polish rate and process temperature in potassium iodate-based slurries as a function of Colloid species and concentration, slurry pH, and potassium iodate concentration, as well as polish pressure and polish rotation rate. We investigated slurries containing yttrium-, zirconium-, cerium-, and aluminum-based oxide and hydroxide Colloids. We found that the Colloid species had a large effect on polish rate and process temperature. The Colloids showed two orders of magnitude in the polish rate range from ∼15 to ∼1975 A min -1 under otherwise identical experimental conditions (same polisher, pad, slurry chemistry, pressure, and rotation rates). Colloids of the same metal species from different sources also showed a large range in polish rates. Process temperature was a function of Colloid species, however, the trend in polish rate did not always follow that of process temperature. Both polish rate and process temperature were dependent on potassium iodate concentration and slurry pH (controlled with a buffer). We also introduce a heuristic polish mechanism to investigate the role of the Colloid surface chemistry and its interaction with the tungsten surface. The data indicate that the surface characteristics of the Colloid and how this surface interacts with the tungsten surface play a significant role in the mechanism of tungsten removal during polish.
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investigation of the kinetics of tungsten chemical mechanical polishing in potassium iodate based slurries ii roles of Colloid species and slurry chemistry
Journal of The Electrochemical Society, 1999Co-Authors: David J. Stein, Dale L. Hetherington, Joseph L. CecchiaAbstract:We investigated the role of Colloid species and slurry chemistry in tungsten chemical mechanical polishing. Specifically, we measured polish rate and process temperature in potassium iodate-based slurries as a function of Colloid species and concentration, slurry pH, and potassium iodate concentration, as well as polish pressure and polish rotation rate. We investigated slurries containing yttrium-, zirconium-, cerium-, and aluminum-based oxide and hydroxide Colloids. We found that the Colloid species had a large effect on polish rate and process temperature. The Colloids showed two orders of magnitude in the polish rate range from ∼15 to ∼1975 A min -1 under otherwise identical experimental conditions (same polisher, pad, slurry chemistry, pressure, and rotation rates). Colloids of the same metal species from different sources also showed a large range in polish rates. Process temperature was a function of Colloid species, however, the trend in polish rate did not always follow that of process temperature. Both polish rate and process temperature were dependent on potassium iodate concentration and slurry pH (controlled with a buffer). We also introduce a heuristic polish mechanism to investigate the role of the Colloid surface chemistry and its interaction with the tungsten surface. The data indicate that the surface characteristics of the Colloid and how this surface interacts with the tungsten surface play a significant role in the mechanism of tungsten removal during polish.