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Michael H Huang - One of the best experts on this subject based on the ideXlab platform.
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fabrication of truncated rhombic dodecahedral cu2o nanocages and nanoframes by Particle Aggregation and acidic etching
Journal of the American Chemical Society, 2008Co-Authors: Michael H HuangAbstract:We report a simple approach for the fabrication of cuprous oxide (Cu2O) nanocages and nanoframes possessing an unusual truncated rhombic dodecahedral structure. An aqueous solution containing CuCl2, sodium dodecyl sulfate (SDS) surfactant, NH2OH·HCl reductant, HCl, and NaOH was prepared, with the reagents introduced in the order listed. Rapid seed-Particle Aggregation and surface reconstruction of the intermediate structure resulted in the growth of type-I nanoframes, which have only {110} skeleton faces and empty {100} faces, 45 min after mixing the reagents. Continued crystal growth for additional 75 min produced nanocages with filled {100} faces. The nanocages have diameters of 350−400 nm, and their walls are thicker than those of the nanoframes. Selective acidic etching over the {110} faces of the nanocages by HCl via the addition of ethanol followed by sonication of the solution led to the formation of type-II nanoframes, which have elliptical pores on the {110} faces. The morphologies of these nanof...
Jurgen Blum - One of the best experts on this subject based on the ideXlab platform.
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cubesat Particle Aggregation collision experiment q pace design of a 3u cubesat mission to investigate planetesimal formation
Acta Astronautica, 2019Co-Authors: Stephanie Jarmak, Samir A. Rawashdeh, J Brisset, J E Colwell, A Dove, D Maukonen, Jurgen BlumAbstract:Abstract Observations of the collisional evolution of Particle ensembles in a microgravity environment are necessary to characterize the processes that lead to the formation of planetesimals, km-size and larger bodies, within the protoplanetary disk. The two current theories of planetesimal formation, namely growth through binary sticking collisions and gravitational instability within the protoplanetary disk, have difficulties in explaining how Particles grow beyond a centimeter in size. In this paper we describe the CubeSat Particle Aggregation and Collision Experiment (Q-PACE), a Low Earth Orbit 3U CubeSat mission that will provide a high-quality, long duration microgravity environment in which we will observe collisions between Particles under conditions relevant to planetesimal formation. We have designed a series of experiments involving a broad range of Particle size, density, surface properties, and collision velocities to observe collisional outcomes from bouncing to sticking as well as aggregate disruption in tens of thousands of collisions.
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cubesat Particle Aggregation collision experiment q pace design of a 3u cubesat mission to investigate planetesimal formation
Acta Astronautica, 2019Co-Authors: Stephanie Jarmak, Samir A. Rawashdeh, J Brisset, J E Colwell, A Dove, D Maukonen, Jurgen Blum, L RoeAbstract:Abstract Observations of the collisional evolution of Particle ensembles in a microgravity environment are necessary to characterize the processes that lead to the formation of planetesimals, km-size and larger bodies, within the protoplanetary disk. The two current theories of planetesimal formation, namely growth through binary sticking collisions and gravitational instability within the protoplanetary disk, have difficulties in explaining how Particles grow beyond a centimeter in size. In this paper we describe the CubeSat Particle Aggregation and Collision Experiment (Q-PACE), a Low Earth Orbit 3U CubeSat mission that will provide a high-quality, long duration microgravity environment in which we will observe collisions between Particles under conditions relevant to planetesimal formation. We have designed a series of experiments involving a broad range of Particle size, density, surface properties, and collision velocities to observe collisional outcomes from bouncing to sticking as well as aggregate disruption in tens of thousands of collisions.
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the suborbital Particle Aggregation and collision experiment space studying the collision behavior of submillimeter sized dust aggregates on the suborbital rocket flight rexus 12
Review of Scientific Instruments, 2013Co-Authors: J Brisset, Daniel Heiselmann, Stefan Kothe, Rene Weidling, Jurgen BlumAbstract:The Suborbital Particle Aggregation and Collision Experiment (SPACE) is a novel approach to study the collision properties of submillimeter-sized, highly porous dust aggregates. The experiment was designed, built, and carried out to increase our knowledge about the processes dominating the first phase of planet formation. During this phase, the growth of planetary precursors occurs by agglomeration of micrometer-sized dust grains into aggregates of at least millimeters to centimeters in size. However, the formation of larger bodies from the so-formed building blocks is not yet fully understood. Recent numerical models on dust growth lack a particular support by experimental studies in the size range of submillimeters, because these Particles are predicted to collide at very gentle relative velocities of below 1 cm/s that can only be achieved in a reduced-gravity environment. The SPACE experiment investigates the collision behavior of an ensemble of silicate-dust aggregates inside several evacuated glass c...
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the suborbital Particle Aggregation and collision experiment space studying the collision behavior of submillimeter sized dust aggregates on the suborbital rocket flight rexus 12
Review of Scientific Instruments, 2013Co-Authors: J Brisset, Daniel Heiselmann, Stefan Kothe, Rene Weidling, Jurgen BlumAbstract:The Suborbital Particle Aggregation and Collision Experiment (SPACE) is a novel approach to study the collision properties of submillimeter-sized, highly porous dust aggregates. The experiment was designed, built, and carried out to increase our knowledge about the processes dominating the first phase of planet formation. During this phase, the growth of planetary precursors occurs by agglomeration of micrometer-sized dust grains into aggregates of at least millimeters to centimeters in size. However, the formation of larger bodies from the so-formed building blocks is not yet fully understood. Recent numerical models on dust growth lack a particular support by experimental studies in the size range of submillimeters, because these Particles are predicted to collide at very gentle relative velocities of below 1 cm/s that can only be achieved in a reduced-gravity environment. The SPACE experiment investigates the collision behavior of an ensemble of silicate-dust aggregates inside several evacuated glass containers which are being agitated by a shaker to induce the desired collisions at chosen velocities. The dust aggregates are being observed by a high-speed camera, allowing for the determination of the collision properties of the protoplanetary dust analog material. The data obtained from the suborbital flight with the REXUS (Rocket Experiments for University Students) 12 rocket will be directly implemented into a state-of-the-art dust growth and collision model.
G G J Ernst - One of the best experts on this subject based on the ideXlab platform.
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volcanic Particle Aggregation in explosive eruption columns part i parameterization of the microphysics of hydrometeors and ash
Journal of Volcanology and Geothermal Research, 2006Co-Authors: Christiane Textor, Hansf Graf, Michael Herzog, Josef M Oberhuber, William I Rose, G G J ErnstAbstract:Abstract The Aggregation of volcanic ash Particles within the eruption column of explosive eruptions has been observed at many volcanoes. It influences the residence time of ash in the atmosphere and the radiative properties of the umbrella cloud. However, the information on the processes leading to aggregate formation are still either lacking or very incomplete. We examine the fate of ash Particles through numerical experiments with the plume model ATHAM (Active Tracer High resolution Atmospheric Model) in order to determine the conditions that promote ash Particle Aggregation. In this paper we describe the microphysics and parameterization of ash and hydrometeors. In a companion paper (this issue) we use this information in a series of numerical experiments. The parameterization includes the condensation of water vapor in the rising eruption column. The formation of liquid and solid hydrometeors and the effect of latent heat release on the eruption column dynamics are considered. The interactions of hydrometeors and volcanic ash within the eruption column that lead to aggregate formation are simulated for the first time within a rising eruption column. The microphysical parameterization follows a modal approach. The hydrometeors are described by two size classes, each of which is divided into a liquid and a frozen category. By analogy with the hydrometeor classification, we specify four categories of volcanic ash Particles. We imply that volcanic Particles are active as condensation nuclei for water and ice formation. Ash can be contained in all categories of hydrometeors, thus forming mixed Particles of any composition reaching from mud rain to accretionary lapilli. Collisions are caused by gravitational capture of Particles with different fall velocity. Coalescence of hydrometeor–ash aggregates is assumed to be a function of the hydrometeor mass fraction within the mixed Particles. The parameterization also includes simplified descriptions of electrostatics and salinity effects.
Brendan J Florio - One of the best experts on this subject based on the ideXlab platform.
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population balance modelling to describe the Particle Aggregation process a review
Powder Technology, 2018Co-Authors: Ricardo I Jeldres, P D Fawell, Brendan J FlorioAbstract:Abstract Unit operations used to achieve solid-liquid separation for fine Particle suspensions rely upon efficient aggregate formation. There is considerable potential for predictions from population balance models describing Particle Aggregation to help optimise full-scale processes. The vast majority of studies in this area make use of the classical coagulation equation of Smoluchowski, and while developed primarily for coalescence phenomena, it has been adapted and modified extensively to describe Particle Aggregation for many different substrates and procedures for inducing aggregate formation. This has resulted in a wide variety of mathematical expressions, some of which are highly sophisticated but can only be applied successfully to a limited range of conditions. For this reason, it is necessary for researchers to understand the main Aggregation mechanisms involved in the processes (coagulation, bridging flocculation) and how the system conditions (flow regime, Particle size, solids concentration) can then influence aggregate growth, breakage and the resulting structures. Such understanding is essential for the appropriate selection of mathematical equations to then obtain a successful model that can be solved at low computational cost. The main mathematical expressions developed for the different phenomena that occur during Particle Aggregation (i.e. collision frequency and efficiency, aggregate breakage rate and distribution, the structure formed and their potential for restructuring over time) by different mechanisms are reviewed. The main published studies are critically assessed, indicating their scope and the conditions under which the models can be usefully applied. Important challenges remain towards achieving wider practical applications, particularly in reducing reliance on empiricism. Particular emphasis is placed on research oportunities, focusing mainly on i) the incorporation of interaction forces for colloidal systems at submicron Particle; ii) importance of achieving more reliable representations of Aggregation behaviour at high solid concentration; and iii) incorporation of PBEs within computational fluid dynamics (CFD) models that describe industrial Aggregation processes as a powerful tool for full-scale unit design and process optimisation.
J Brisset - One of the best experts on this subject based on the ideXlab platform.
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cubesat Particle Aggregation collision experiment q pace design of a 3u cubesat mission to investigate planetesimal formation
Acta Astronautica, 2019Co-Authors: Stephanie Jarmak, Samir A. Rawashdeh, J Brisset, J E Colwell, A Dove, D Maukonen, Jurgen BlumAbstract:Abstract Observations of the collisional evolution of Particle ensembles in a microgravity environment are necessary to characterize the processes that lead to the formation of planetesimals, km-size and larger bodies, within the protoplanetary disk. The two current theories of planetesimal formation, namely growth through binary sticking collisions and gravitational instability within the protoplanetary disk, have difficulties in explaining how Particles grow beyond a centimeter in size. In this paper we describe the CubeSat Particle Aggregation and Collision Experiment (Q-PACE), a Low Earth Orbit 3U CubeSat mission that will provide a high-quality, long duration microgravity environment in which we will observe collisions between Particles under conditions relevant to planetesimal formation. We have designed a series of experiments involving a broad range of Particle size, density, surface properties, and collision velocities to observe collisional outcomes from bouncing to sticking as well as aggregate disruption in tens of thousands of collisions.
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cubesat Particle Aggregation collision experiment q pace design of a 3u cubesat mission to investigate planetesimal formation
Acta Astronautica, 2019Co-Authors: Stephanie Jarmak, Samir A. Rawashdeh, J Brisset, J E Colwell, A Dove, D Maukonen, Jurgen Blum, L RoeAbstract:Abstract Observations of the collisional evolution of Particle ensembles in a microgravity environment are necessary to characterize the processes that lead to the formation of planetesimals, km-size and larger bodies, within the protoplanetary disk. The two current theories of planetesimal formation, namely growth through binary sticking collisions and gravitational instability within the protoplanetary disk, have difficulties in explaining how Particles grow beyond a centimeter in size. In this paper we describe the CubeSat Particle Aggregation and Collision Experiment (Q-PACE), a Low Earth Orbit 3U CubeSat mission that will provide a high-quality, long duration microgravity environment in which we will observe collisions between Particles under conditions relevant to planetesimal formation. We have designed a series of experiments involving a broad range of Particle size, density, surface properties, and collision velocities to observe collisional outcomes from bouncing to sticking as well as aggregate disruption in tens of thousands of collisions.
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the suborbital Particle Aggregation and collision experiment space studying the collision behavior of submillimeter sized dust aggregates on the suborbital rocket flight rexus 12
Review of Scientific Instruments, 2013Co-Authors: J Brisset, Daniel Heiselmann, Stefan Kothe, Rene Weidling, Jurgen BlumAbstract:The Suborbital Particle Aggregation and Collision Experiment (SPACE) is a novel approach to study the collision properties of submillimeter-sized, highly porous dust aggregates. The experiment was designed, built, and carried out to increase our knowledge about the processes dominating the first phase of planet formation. During this phase, the growth of planetary precursors occurs by agglomeration of micrometer-sized dust grains into aggregates of at least millimeters to centimeters in size. However, the formation of larger bodies from the so-formed building blocks is not yet fully understood. Recent numerical models on dust growth lack a particular support by experimental studies in the size range of submillimeters, because these Particles are predicted to collide at very gentle relative velocities of below 1 cm/s that can only be achieved in a reduced-gravity environment. The SPACE experiment investigates the collision behavior of an ensemble of silicate-dust aggregates inside several evacuated glass c...
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the suborbital Particle Aggregation and collision experiment space studying the collision behavior of submillimeter sized dust aggregates on the suborbital rocket flight rexus 12
Review of Scientific Instruments, 2013Co-Authors: J Brisset, Daniel Heiselmann, Stefan Kothe, Rene Weidling, Jurgen BlumAbstract:The Suborbital Particle Aggregation and Collision Experiment (SPACE) is a novel approach to study the collision properties of submillimeter-sized, highly porous dust aggregates. The experiment was designed, built, and carried out to increase our knowledge about the processes dominating the first phase of planet formation. During this phase, the growth of planetary precursors occurs by agglomeration of micrometer-sized dust grains into aggregates of at least millimeters to centimeters in size. However, the formation of larger bodies from the so-formed building blocks is not yet fully understood. Recent numerical models on dust growth lack a particular support by experimental studies in the size range of submillimeters, because these Particles are predicted to collide at very gentle relative velocities of below 1 cm/s that can only be achieved in a reduced-gravity environment. The SPACE experiment investigates the collision behavior of an ensemble of silicate-dust aggregates inside several evacuated glass containers which are being agitated by a shaker to induce the desired collisions at chosen velocities. The dust aggregates are being observed by a high-speed camera, allowing for the determination of the collision properties of the protoplanetary dust analog material. The data obtained from the suborbital flight with the REXUS (Rocket Experiments for University Students) 12 rocket will be directly implemented into a state-of-the-art dust growth and collision model.