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Yangkook Sun - One of the best experts on this subject based on the ideXlab platform.
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optimization of layered cathode material with full concentration gradient for lithium ion batteries
Journal of Physical Chemistry C, 2014Co-Authors: Eungju Lee, Chong Seung Yoon, Seungtaek Myung, Yangkook SunAbstract:Li[NixCoyMn1–x–y]O2 cathode materials were synthesized with varying concentration gradients of Ni and Co ions from the Particle Center (0.62–0.74 mol % for Ni and 0.05 mol % for Co) to the surface (0.48–0.62 mol % for Ni and 0.18 mol % for Co), i.e., full concentration gradient (FCG) with fixed Mn concentrations. In particular, the Mn concentration (20, 25, and 33 mol %) was controlled to optimize electrode performance. The average chemical compositions of lithiated products were Li[NixCo0.16Mn0.84–x]O2 (x = 0.64, 0.59, 0.51). These cathode materials with concentration gradients followed the general performance trend of conventional layered materials; an increase in Ni content improved the capacity, whereas a higher amount of Mn delivered better capacity retention and thermal properties at the expense of capacity. As a result, we determined an optimal level of Mn concentration among the tested FCG cathodes, which maximized the discharge capacity of 188 mAh g–1 and had an excellent capacity retention of 96...
Musunuri, Naga Aditya - One of the best experts on this subject based on the ideXlab platform.
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Study on the dispersion of Particles at a fluid-liquid interface and its application in hydrophilous pollination
Digital Commons @ NJIT, 2017Co-Authors: Musunuri, Naga AdityaAbstract:This dissertation work describes the physics of Particle adsorption and the spontaneous dispersion of powders that occurs when they come in contact with a fluid-liquid interface and its application in hydrophilous pollination of Ruppia Maritima, an aquatic plant. The dispersion of Particles can occur so quickly that it appears explosive, especially for small Particles on the surface of mobile liquids like water. PIV (Particle Image Velocimetry) measurements show that the adsorption of a spherical Particle at the interface causes an axisymmetric streaming flow about the vertical line passing through the Particle Center. The fluid directly below the Particle rises upward, and near the surface, it moves away from the Particle. The flow, which develops within a fraction of a second after the adsorption of the Particle, persists for several seconds. The flow strength, and the volume over which it extends, decrease with decreasing Particle size. The streaming flow induced by the adsorption of two or more Particles is a combination of the flows which they induce individually. The flow causes Particles sprinkled together onto a liquid surface to disperse, as well as to hydrodynamic stresses which is extensional in the plane tangential to the interface and compressive in the normal direction. The stresses can cause the breakup of Particle agglomerates when they are adsorbed on a liquid surface
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Study on the dispersion of Particles at a fluid-liquid interface and its application in hydrophilous pollination
Digital Commons @ NJIT, 2017Co-Authors: Musunuri, Naga AdityaAbstract:This dissertation work describes the physics of Particle adsorption and the spontaneous dispersion of powders that occurs when they come in contact with a fluid-liquid interface and its application in hydrophilous pollination of Ruppia Maritima, an aquatic plant. The dispersion of Particles can occur so quickly that it appears explosive, especially for small Particles on the surface of mobile liquids like water. PIV (Particle Image Velocimetry) measurements show that the adsorption of a spherical Particle at the interface causes an axisymmetric streaming flow about the vertical line passing through the Particle Center. The fluid directly below the Particle rises upward, and near the surface, it moves away from the Particle. The flow, which develops within a fraction of a second after the adsorption of the Particle, persists for several seconds. The flow strength, and the volume over which it extends, decrease with decreasing Particle size. The streaming flow induced by the adsorption of two or more Particles is a combination of the flows which they induce individually. The flow causes Particles sprinkled together onto a liquid surface to disperse, as well as to hydrodynamic stresses which is extensional in the plane tangential to the interface and compressive in the normal direction. The stresses can cause the breakup of Particle agglomerates when they are adsorbed on a liquid surface. The physics underlying the mechanisms of two-dimensional aquatic pollen dispersal, known as hydrophily is also studied and presented here. The aquatic pollination has evolved in several genera of aquatic plants, including Halodule, Halophila, Lepilaena, and Ruppia. Ruppia maritima, which is native to salt and brackish waters circumglobally, is selected for this study. Two mechanisms are observed, by which the pollen released from male inflorescences of Ruppia is adsorbed on a water surface: 1) inflorescences rise above the water surface and after they mature their pollen mass falls onto the surface as clumps and disperses as it comes in contact with the surface; 2) inflorescences remain below the surface and produce air bubbles which carry pollen mass to the surface where it disperses. In both cases dispersed pollen masses combined with others under the action of lateral capillary forces to form pollen rafts. The formation of porous pollen rafts increases the probability of pollination since the attractive capillary force on a pollen raft toward a stigma is much larger than on a single pollen grain. The presence of a trace amount of surfactant can disrupt the pollination process as the pollen is not captured or transported on the water surface
Eungju Lee - One of the best experts on this subject based on the ideXlab platform.
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optimization of layered cathode material with full concentration gradient for lithium ion batteries
Journal of Physical Chemistry C, 2014Co-Authors: Eungju Lee, Chong Seung Yoon, Seungtaek Myung, Yangkook SunAbstract:Li[NixCoyMn1–x–y]O2 cathode materials were synthesized with varying concentration gradients of Ni and Co ions from the Particle Center (0.62–0.74 mol % for Ni and 0.05 mol % for Co) to the surface (0.48–0.62 mol % for Ni and 0.18 mol % for Co), i.e., full concentration gradient (FCG) with fixed Mn concentrations. In particular, the Mn concentration (20, 25, and 33 mol %) was controlled to optimize electrode performance. The average chemical compositions of lithiated products were Li[NixCo0.16Mn0.84–x]O2 (x = 0.64, 0.59, 0.51). These cathode materials with concentration gradients followed the general performance trend of conventional layered materials; an increase in Ni content improved the capacity, whereas a higher amount of Mn delivered better capacity retention and thermal properties at the expense of capacity. As a result, we determined an optimal level of Mn concentration among the tested FCG cathodes, which maximized the discharge capacity of 188 mAh g–1 and had an excellent capacity retention of 96...
Vasilije Manovic - One of the best experts on this subject based on the ideXlab platform.
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modeling the temperature in coal char Particle during fluidized bed combustion
Fuel, 2008Co-Authors: Vasilije Manovic, Mirko KomatinaAbstract:Abstract The temperatures of a coal char Particle in hot bubbling fluidized bed (FB) were analyzed by a model of combustion. The unsteady model includes phenomena of heat and mass transfer through a porous char Particle, as well as heterogeneous reaction at the interior char surface and homogeneous reaction in the pores. The parametric analysis of the model has shown that above 550 °C combustion occurs under the regime limited by diffusion. The experimental results of temperature measurements by thermocouple in the Particle Center during FB combustion at temperatures in the range 590–710 °C were compared with the model predictions. Two coals of different rank were used: lignite and brown coal, with Particle size in the range 5–10 mm. The comparisons have shown that the model can adequately predict the histories of temperatures in char Particles during combustion in FB. In the first order, the model predicts the influence of the Particle size, coal rank (via porosity), and oxygen concentration in its surroundings.
Haoxiang Luo - One of the best experts on this subject based on the ideXlab platform.
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Effect of surface slip on Stokes flow past a spherical Particle in infinite fluid and near a plane wall
2015Co-Authors: C. Pozrikidis, Haoxiang LuoAbstract:Abstract The motion of a spherical Particle in infinite linear flow and near a plane wall, subject to the slip bound-ary condition on both the Particle surface and the wall, is studied in the limit of zero Reynolds number. In the case of infinite flow, an exact solution is derived using the singularity representation, and analytical expressions for the force, torque, and stresslet are derived in terms of slip coefficients generalizing the Stokes–Basset–Einstein law. The slip velocity reduces the drag force, torque, and the effective viscosity of a dilute suspension. In the case of wall-bounded flow, advantage is taken of the axial symmetry of the boundaries of the flow with respect to the axis that is normal to the wall and passes through the Particle Center to formulate the problem in terms of a system of one-dimensional integral equations for the first sine and cosine Fourier coefficients of the unknown traction and velocity along the boundary contour in a meridional plane. Numerical solutions furnish accurate predictions for (a) the force and torque exerted on a Particle translating parallel to the wall in a quiescent fluid, (b) the force and torque exerted on a Particle rotating about an axis that is parallel to the wall in a quiescent fluid, and (c) the translational and angular velocities of a freely suspended Particle in simple shear flow parallel to the wall. For certain combinations of the wall and Particle slip coefficients, a Particle moving under the influence of a tangential force translates parallel to the wall without rotation, and a Particle moving under the influence of a tangential torque rotates about an axis that is parallel to the wall without translation. For a Particle convected in simple shear flow, minimum translationa