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Sylke Boyd, PhD Assistant
Professor, Physics |
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SB’s Work schedule for Fall semester
2009 UMM Student Research in Physics UMM Undergraduate
Research Symposium Information
for students with children
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Current
Courses:
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Electromagnetism (Phys4101) |
SB
will be on maternity leave from September 27, 2009, and return on November 9,
2009.
Courses
taught recently:
Phys1101
General Physics 1,(sping 2009), Phys3501 Statistical Physics (spring
2009), Computer Modeling of
Materials (spring 2008), , Physics of Weather (fall 2007) , Classical Mechanics (fall 2006), FYS Bottomdwellers in an
ocean of air (fall 2006), Physics of Sound and Music (fall 2005)
Courses
developed, but not offered yet:
Atmospheric Physics Phys2104 (emphasis
on atmospheric thermodynamics and fluid dynamics, offered in Spring 2010)
Alles
klommt vom Bergwerk her – A journey to the roots of modern science (3-weeks
summer abroad program, offered again in Summer 2011)
Research Group:
Johanna Martin: Water
droplet formation in clouds (MAP 2008/9)
Anna Schliep: Dislocations
in RDX (GIA, URS 2007 poster)
Sound
generation by wind in Strings (UROP, finished, presented as poster at MAAPT
Fall 2006 meeting, URS 2007 poster)
Sam Geller: Monte
Carlo Simulations of Vacancies in a
Matt Gravelle: Point
defects in RDX (UROP and GIA, finished, presented posters at URS and
CCTCC, coauthor of publication)
If you are interested
in any way to collaborate in a research project please do not hesitate to stop
by or drop a line by e-mail.
Research Interests:
My research interest is in computer simulations of
materials, including force field development, molecular dynamics and
- The physics of the problem: The question must
be relevant, aspects of it not answerable by other means, and backed up
with sufficient experimental data.
- The software: the success of the model is
constrained by computing efficiency. The faster the algorithm, the larger
the model, and the longer the times the model can access. A typical
molecular dynamics simulation can span a few nanoseconds with sample sizes
of a few nanometers. However, many physical problems involve processes on
larger time and length scales – limits that need to be pushed. It is
crucial to implement parallel computing if helpful, as well as employ
other means of pushing these limits, for example by employing a multi-scale
approach.
- The hardware: All simulations are performed on
a Beowulf cluster
with currently 32 CPUs, dedicated exclusively to this purpose. For really extensive (and tested) model
runs, one can search for computing time in other places, such as the
supercomputing center in Argonne National Lab or the UofM Supercomputing
Institute.
Current Projects:
- Interfaces
under normal and shear stress. Friction is a dissipative phenomenon that has
relevance in very many applications as well as in various environmental
problems. Static friction is the force which keeps surfaces in contact
under stress from sliding relative to each other, while dynamic friction
sets in when the surfaces actually move. The transition from static to
dynamic friction occurs when the shear stress increases beyond a critical
point, detachment occurs, and the contacting surfaces start to slip past
each other. The subsequent sliding will easily be maintained by a much
lower shear force. Applications in robotics, construction and engineering
fields, even processes in geological systems face the challenge of the
unpredictability of the onset of sliding. During my research leave in Fall
2008, I am working to develop a comprehensive, multi-scale computer model
of frictional processes in order to study the physical processes
surrounding the so-called stick-slip transition. I expect that students
can work on this project beginning in the spring semester of 2009. This
project has ties to the group of Thomas Frauenheim at the
- Water
droplet formation in clouds. Water droplets form if the partial pressure of
water in the air supersedes the saturation pressure. However, the
mechanisms of initial condensation is more complicated and involves
nucleation. After the initial droplets are formed, they grow either by
continued condensation on their surface, or by merging with other droplets
– so-called coalescence. However, in warm cumulus clouds there often is
not much time between the initial formation of the cloud and the onset of
precipitation, which means that those large rain drops must have formed
very fast. The problem is, that the speed of droplet growth in cumulus
clouds can not be explained by either one of the two mechanisms above
alone. This makes the prediction of the onset and type of precipitation
from these clouds difficult – there must be mechanisms beyond condensation
and coalescence. Questions of turbulence surrounding a droplet appear to
play a role as mechanisms for delivery of additional moisture for
condensation. There is a very active area of research, focused on the
fluid dynamics involved furthering or limiting droplet growth. This
project is developing a computer model for constant-pressure
constant-temperature molecular dynamics simulations of water droplets embedded in an air
atmosphere. We are studying questions of nucleation, growth rates and
coalescence. The model is based on a Lennard-Jones model of water,
embedded in a soft hard-sphere fluid (air). This allows to includes the dissipative
influence of the air, as well as to study the effect of a droplet with
terminal speed onto this medium.
Animations: NPT simulation of a water droplet of 4000 water
molecules at 275 K and 1 atm, water particles shown only.
- Molecular
solid RDX: This is a powerful explosive with the caveat
of a high sensitivity. The project originates from an initiative from
Lawrence Livermore National Lab, trying to solve the problem of stockpile
of weapons from the cold-war era. The weapons are aging, and need to be
dealt with. Rather than experiment with these stockpiles, a computational
initiative has been started to model the materials and their behavior, hence
helping to decide the best course of action. In addition, RDX is a
material of choice for terrorists due to its large energetic density. Its
was used by the shoe
bomber Michael Reid in the infamous 2001 air plane incident, but also
in the attack
on the Marriot hotel in Islamabad, Pakistan, in September 2008. It is
important to find inconspicuous methods of detection for such chemicals,
and one possibility is the use of Terahertz spectroscopy. This method
analyses the spectrum of long-wave infrared radiation in a part of the
spectrum that is associated with thermal vibrations of the crystal
lattices in conjunction with molecular modes of motion. Our computer model is one of only very few that is
able to investigate such coupled modes and predictively model and explain
the vibrational spectrum of the substance. Currently my work focuses on
the vibrational properties of the substance under various circumstances,
such as the presence of large defects and an electric field. In addition,
defects in the crystalline lattice provide places at which detonations seem
to originate due to their energetically predisposed position.
Experimentally, the crystals are produced from solution, and often defects
are incorporated during the crystal growth. Limiting the amount of defects
can help lower the sensitivity, hence our model studied how the defects
are formed, which geometry they have, how easily they heal or diffuse, and
how growth conditions influence their concentration. Work has been done on
point defects in the molecular solid RDX, voids and dislocations. The
project is a collaboration with the group of Peter Politzer at the
Recent publications and presentations:
Sylke
Boyd and Kevin J Boyd, A computational
analysis of the interaction of lattice and intramolecular vibrational modes in
crystalline alpha-RDX, J. Chem. Phys. 129, 134502 (2008).
S.
Boyd, K. J. Boyd, Vibrational
properties of RDX, presented as poster at the 16th
Conference on Current Trends in Computational Chemnistry (CCTCC) in
S.
Boyd, M. Gravelle, Computer
Simulations Of Point Defects In Crystalline RDX, presented as
poster at the 2006 Gordon Research Conference on Energetic Materials in
Sylke Boyd, Matthew Gravelle, and Peter Politzer, Nonreactive
molecular dynamics force field for crystalline hexahydro-1,3,5-trinitro-1,3,5
triazine, , J. Chem. Phys. 124, 104508 (2006).
M. Gravelle, S. Boyd, A computer
study of point defects in the RDX crystal, presented as poster at
the 14th Conference on Current Trends in Computational Chemistry
(CCTCC) in
Outreach
activities:
Super Saturday Science: a science experience for
girls 5-8th grade (activity:
Air pressure)
Plan-It-Green:
Activity “Are greenhouse
gases really green?”
Miscellaneous stuff:
My take on creativity and perseverance
Just in case you were wondering what a Nischel is…
Intersection
of Math, physics and computer: Ave verum
corpus by Wolfgang Amadeus Mozart and the Mathematica notebook that produced it
Personal stuff
Any views and opinions in this page have not been
reviewed by a campus committee.
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