Jonathan Drew Perry
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- School: Texas A&M University
- Campus: College Station
- Department: Physics
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College Station, TX - Dates at Texas A&M University: -
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Biography
Texas A&M University College Station - Physics
Experience
Texas A&M University
Lecturer
Jonathan Drew worked at Texas A&M University as a Lecturer
Texas A&M University
Graduate Assistant
Jonathan Drew worked at Texas A&M University as a Graduate Assistant
University of Texas at Austin
Assistant Professor of Instruction
Jonathan Drew worked at University of Texas at Austin as a Assistant Professor of Instruction
University of Texas at Austin
Course Coordinator
Jonathan Drew worked at University of Texas at Austin as a Course Coordinator
Education
Texas A&M University
Doctor of Philosophy - PhD
Physics
Completed a doctorate degree in Physics Education Research (PER) studying the impact of introductory physics on engineering majors at Texas A&M University.Texas A&M University
Lecturer
Texas A&M University
Graduate Assistant
Baylor University
Master of Science - MS
Physics
Conducted research into the microphysical interactions of dust grains in astrophysical environments. Used numerical simulations to model magnetic and electromagnetic interactions of (sub)micron sized grains.Baylor University
Bachelor's degree
Physics
Publications
The Influence of Monomer Shape on Aggregate Morphology
Astronomy & Astrophysics
Context. The coagulation of dust particles is the initial step in planetary formation, with the precursors to planetesimals believed to form via the collisions of micron and submicron sized dust particles in the disk surrounding a newly formed protostar. One of the usual assumptions in numerical models of aggregation is that of spherical monomers. However, the polarization of light in the interstellar medium (ISM) indicates that dust particles may not necessarily be spherical. Aims. This study investigates the influence of monomer shape (ellipsoidal vs. spherical) on the morphology of aggregates. The ellipsoidal grains used are prolate with an axis ratio of 3: 1: 1, which current evidence suggests as a possible shape for instellar dust grains. Methods. Populations of aggregates are built from ellipsoidal monomers and spherical monomers using both particle-cluster aggregation (PCA) and cluster-cluster aggregation (CCA) regimes incorporating the rotation of particles. The morphology of the resulting aggregates is compared using the maximum radius, porosity, fractal dimension, compactness factor and friction time. The last two factors indicate how the dynamics of a population of dust may be altered depending on monomer shape. Results. The results of this study indicate that monomer shape plays an important role in determining the final morphology of aggregates. Comparing ellipsoid grains with 3: 1: 1 axis ratio to spheres, the greatest difference is seen in compactness factors: (similar to 18%) for the PCA regime, reaching a maximum of (similar to 80%) for the CCA regime. The influence on porosity is also appreciable, (similar to 8%) and (similar to 15%) for PCA and CCA regimes respectively. The resulting differences for the friction times depend on the collision regime employed, yet show a marked difference for the different monomer shapes, (similar to 12%) for PCA and (> 50%) for CCA at large sizes.
The Influence of Monomer Shape on Aggregate Morphology
Astronomy & Astrophysics
Context. The coagulation of dust particles is the initial step in planetary formation, with the precursors to planetesimals believed to form via the collisions of micron and submicron sized dust particles in the disk surrounding a newly formed protostar. One of the usual assumptions in numerical models of aggregation is that of spherical monomers. However, the polarization of light in the interstellar medium (ISM) indicates that dust particles may not necessarily be spherical. Aims. This study investigates the influence of monomer shape (ellipsoidal vs. spherical) on the morphology of aggregates. The ellipsoidal grains used are prolate with an axis ratio of 3: 1: 1, which current evidence suggests as a possible shape for instellar dust grains. Methods. Populations of aggregates are built from ellipsoidal monomers and spherical monomers using both particle-cluster aggregation (PCA) and cluster-cluster aggregation (CCA) regimes incorporating the rotation of particles. The morphology of the resulting aggregates is compared using the maximum radius, porosity, fractal dimension, compactness factor and friction time. The last two factors indicate how the dynamics of a population of dust may be altered depending on monomer shape. Results. The results of this study indicate that monomer shape plays an important role in determining the final morphology of aggregates. Comparing ellipsoid grains with 3: 1: 1 axis ratio to spheres, the greatest difference is seen in compactness factors: (similar to 18%) for the PCA regime, reaching a maximum of (similar to 80%) for the CCA regime. The influence on porosity is also appreciable, (similar to 8%) and (similar to 15%) for PCA and CCA regimes respectively. The resulting differences for the friction times depend on the collision regime employed, yet show a marked difference for the different monomer shapes, (similar to 12%) for PCA and (> 50%) for CCA at large sizes.
New Video Resource for Calculus-based Introductory Physics, Development & Assessment I. Electricity & Magnetism
American Journal of Physics
Under review
The Influence of Monomer Shape on Aggregate Morphology
Astronomy & Astrophysics
Context. The coagulation of dust particles is the initial step in planetary formation, with the precursors to planetesimals believed to form via the collisions of micron and submicron sized dust particles in the disk surrounding a newly formed protostar. One of the usual assumptions in numerical models of aggregation is that of spherical monomers. However, the polarization of light in the interstellar medium (ISM) indicates that dust particles may not necessarily be spherical. Aims. This study investigates the influence of monomer shape (ellipsoidal vs. spherical) on the morphology of aggregates. The ellipsoidal grains used are prolate with an axis ratio of 3: 1: 1, which current evidence suggests as a possible shape for instellar dust grains. Methods. Populations of aggregates are built from ellipsoidal monomers and spherical monomers using both particle-cluster aggregation (PCA) and cluster-cluster aggregation (CCA) regimes incorporating the rotation of particles. The morphology of the resulting aggregates is compared using the maximum radius, porosity, fractal dimension, compactness factor and friction time. The last two factors indicate how the dynamics of a population of dust may be altered depending on monomer shape. Results. The results of this study indicate that monomer shape plays an important role in determining the final morphology of aggregates. Comparing ellipsoid grains with 3: 1: 1 axis ratio to spheres, the greatest difference is seen in compactness factors: (similar to 18%) for the PCA regime, reaching a maximum of (similar to 80%) for the CCA regime. The influence on porosity is also appreciable, (similar to 8%) and (similar to 15%) for PCA and CCA regimes respectively. The resulting differences for the friction times depend on the collision regime employed, yet show a marked difference for the different monomer shapes, (similar to 12%) for PCA and (> 50%) for CCA at large sizes.
New Video Resource for Calculus-based Introductory Physics, Development & Assessment I. Electricity & Magnetism
American Journal of Physics
Under review
Effects of Monomer Shape on the Formation of Fractal Aggregates Under a Power Law Mass Distribution
New Journal of Physics
The coagulation of dust aggregates is an important process in many physical systems such as the Earth's upper atmosphere, comet tails and protoplanetary discs. Numerical models which study the aggregation in these systems typically involve spherical monomers. There is evidence, however, via the polarization of sunlight in the interstellar medium, as well as optical and LIDAR observations of high-altitude particles in Earth's atmosphere (70–100 km), which indicate that dust monomers may not necessarily be spherical. This study investigates the influence of different ellipsoidal monomer shapes on the morphology of aggregates given various distributions of monomer sizes. Populations of aggregates are grown from a single monomer using a combination of ballistic particle–cluster aggregation and ballistic cluster–cluster aggregation regimes incorporating the rotation of monomers and aggregates. The resulting structures of the aggregates are then compared via the compactness factor, geometric cross-section and friction time.
The Influence of Monomer Shape on Aggregate Morphology
Astronomy & Astrophysics
Context. The coagulation of dust particles is the initial step in planetary formation, with the precursors to planetesimals believed to form via the collisions of micron and submicron sized dust particles in the disk surrounding a newly formed protostar. One of the usual assumptions in numerical models of aggregation is that of spherical monomers. However, the polarization of light in the interstellar medium (ISM) indicates that dust particles may not necessarily be spherical. Aims. This study investigates the influence of monomer shape (ellipsoidal vs. spherical) on the morphology of aggregates. The ellipsoidal grains used are prolate with an axis ratio of 3: 1: 1, which current evidence suggests as a possible shape for instellar dust grains. Methods. Populations of aggregates are built from ellipsoidal monomers and spherical monomers using both particle-cluster aggregation (PCA) and cluster-cluster aggregation (CCA) regimes incorporating the rotation of particles. The morphology of the resulting aggregates is compared using the maximum radius, porosity, fractal dimension, compactness factor and friction time. The last two factors indicate how the dynamics of a population of dust may be altered depending on monomer shape. Results. The results of this study indicate that monomer shape plays an important role in determining the final morphology of aggregates. Comparing ellipsoid grains with 3: 1: 1 axis ratio to spheres, the greatest difference is seen in compactness factors: (similar to 18%) for the PCA regime, reaching a maximum of (similar to 80%) for the CCA regime. The influence on porosity is also appreciable, (similar to 8%) and (similar to 15%) for PCA and CCA regimes respectively. The resulting differences for the friction times depend on the collision regime employed, yet show a marked difference for the different monomer shapes, (similar to 12%) for PCA and (> 50%) for CCA at large sizes.
New Video Resource for Calculus-based Introductory Physics, Development & Assessment I. Electricity & Magnetism
American Journal of Physics
Under review
Effects of Monomer Shape on the Formation of Fractal Aggregates Under a Power Law Mass Distribution
New Journal of Physics
The coagulation of dust aggregates is an important process in many physical systems such as the Earth's upper atmosphere, comet tails and protoplanetary discs. Numerical models which study the aggregation in these systems typically involve spherical monomers. There is evidence, however, via the polarization of sunlight in the interstellar medium, as well as optical and LIDAR observations of high-altitude particles in Earth's atmosphere (70–100 km), which indicate that dust monomers may not necessarily be spherical. This study investigates the influence of different ellipsoidal monomer shapes on the morphology of aggregates given various distributions of monomer sizes. Populations of aggregates are grown from a single monomer using a combination of ballistic particle–cluster aggregation and ballistic cluster–cluster aggregation regimes incorporating the rotation of monomers and aggregates. The resulting structures of the aggregates are then compared via the compactness factor, geometric cross-section and friction time.
Dipole-Dipole Interactions of Charged-Magnetic Grains
IEEE Transactions on Plasma Science
The interaction between dust grains is an important process in fields as diverse as planetesimal formation or the plasma processing of silicon wafers into computer chips. This interaction depends in large part on the material properties of the grains, for example whether the grains are conducting, non-conducting, ferrous or non-ferrous. This work considers the effects that electrostatic and magnetic forces, alone or in combination, can have on the coagulation of dust in various environments. A numerical model is used to simulate the coagulation of charged, charged-magnetic and magnetic dust aggregates formed from ferrous material and the results are compared to each other as well as to those from uncharged, non-magnetic material. The interactions between extended dust aggregates are also examined, specifically looking at how the arrangement of charge over the aggregate surface or the inclusion of magnetic material produces dipole-dipole interactions. It will be shown that these dipole-dipole interactions can affect the orientation and structural formation of aggregates as they collide and stick. Analysis of the resulting dust populations will also demonstrate the impact that grain composition and/or charge can have on the structure of the aggregate as characterized by the resulting fractal dimension.