MAAPT SPRING Meeting 2005
APRIL 30,
BETHEL UNIVERSITY, ST. PAUL
This MAAPT
meeting will be held in room AC246 of the Academic Center (AC), Bethel
University, St. Paul, Minnesota. A
campus map, driving directions to Bethel University, and a list of local hotels
can be found at http://www.bethel.edu/special-events/campus_map.htm.
The Academic
Center is building #2 on the campus map.
Attendees should park in the West Parking Lot (#6 on the map), enter the
Community Life Center (building #1) and go up the main stairway into the
adjoining Academic Center building.
Signs will be posted inside the buildings.
The regular
lunch will be $5 per person, but is limited to the first 24 people to buy
tickets from Steven Ratliff at the meeting. The Bethel physics department has kindly picked up half the
cost to keep the price down for meeting attendees. There is a grill and sandwich shop and Caribou Coffee next
door so if necessary, one could buy lunch there and bring it into the room
where the lunch and business meeting will be held.
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MAAPT PROGRAM
7:30
– 8:00 Coffee
and Registration
8:00 – 8:20 Modeling movement of electric charges within dielectric
materials
Erik
Dahlman and Brian Beecken, Bethel University
8:20 – 8:40 Optimization of the genetic algorithm for ultrafast pulse
shaping
Anastasiya
S. Vershenya, Hamline University
8:40 – 9:00 Sonoluminescence studies at Hamline University
Christopher
Visker, Hamline University
9:00
– 9:20 Implementation,
Analysis, and Assessment of On-Line Teaching Evaluations
Jerry
L. Artz, Andrew R. Rundquist, Hamline University.
9:20 – 9:40 Modern Physics at Hamline University
Andy
Rundquist, Hamline University
9:40
– 10:00 A
new twist in the double slit experiment and Rayleigh Criterion on
resolution
R.
C. Misra, Warren Menough, and Mukti Aryal, Minnesota State University, Mankato
10:00
– 10:30 Coffee
Break and poster session
Variations
in the Correlation Coefficients of SiO Masers
Amanda
Hyde and Gordon McIntosh, University of Minnesota, Morris
Using
Autocorrelation Functions to Examine the Pumping of Silicon
Monoxide
Masers
Bill
Cox and Gordon McIntosh, University of Minnesota, Morris
Performance
of Computer Generated Zone Plates
Ryan
Johnson, Minnesota State University Moorhead
10:30
– 10:50 CCD
Photometry of the Open Cluster NGC 7789*
Jessica
L. Windschitl, Saint Mary's University
10:50
– 11:10 Introductory
physics through inquiry-based labs
Brian
Batell and Bradley McCoy, University of Minnesota, Twin Cities
11:10 – 11:30 Applications of Radial Distribution Functions to Biological
Systems
Josh
Jacobson and Brendan Johnston, Gustavus Adolphus College
11:30 – 11:50 Is more really better? The connection between student success in
introductory
physics and the number of demonstrations.
Brian
Andersson, University of Minnesota, Twin Cities
11:50
– 12:10 Using
AC Magnetic Susceptometry to Probe Exchange Anisotropy in
Antiferromagnetic/Ferromagnetic
Bilayers
Richard
A. Thomas, David Caven, and E. Dan Dahlberg, University of
Minnesota
12:10
– 12:20 Update
on the Minnesota Planetarium
Parke
Kunkle, President, Minnesota Planetarium Society
12:20
– 1:30 Lunch
and Business Meeting
MAAPT PROGRAM ABSTRACTS
SPRING
Meeting 2005
APRIL 30,
BETHEL UNIVERSITY, ST. PAUL
Modeling movement of
electric charges within dielectric materials
Erik Dahlman and
Brian Beecken, Bethel University
An
algorithm modeling the motion of electrons and holes within dielectric
materials under bombardment by high-energy electrons has been developed. The
three-step cyclical algorithm calculates the number densities of both electrons
and holes, then the electric field and finally the current density at
incremental positions within the dielectric. The algorithm is relevant to
spacecraft discharging because it utilizes two earlier algorithms to create a
dosage profile for energy deposited by incident electrons.
Optimization of the
genetic algorithm for ultrafast pulse shaping
Anastasiya S.
Vershenya, Hamline University
Sponsored by Andy
Rundquist
The idea of the genetic
algorithm, which models natural selection, has never been customized for the
study of ultrafast pulse shaping. Through application of the algorithm to
ultrafast pulses, we will maximize signal levels for a simple case of nonlinear
optimization. By increasing the ratio of blue to red light through algorithm
controlled voltage variations, we can converge to the shortest possible pulse
and derive best-input parameters and methods of evaluation in ultrafast
context.
Sonoluminescence
studies at Hamline University
Christopher Visker,
Hamline University
Sponsored by Andy
Rundquist
Sonoluminescence
(SL) is a phenomenon in which short light pulses are produced by acoustically
trapping an air bubble in a liquid filled resonance chamber. Sonic pressure
places a large force on the bubble, causing it to collapse on itself. The
bubble then expands and contracts in a time scale measured in picoseconds. As
the bubble contracts, it begins to emit photons. This phenomenon can be
inexpensively produced in any modern physics laboratory with standard
equipment.
Implementation,
Analysis, and Assessment of On-Line Teaching Evaluations
Jerry L.
Artz, Andrew R. Rundquist, Hamline University.
This
two-year project involved the introduction of a new, on-line teaching
evaluation that enables students to anonymously assess their teachers and
courses via computer. A pilot
program, during fall 2003, involved 14 faculty volunteers. Resulting in moderate to strong
success, the pilot program was then extended to include the entire College of
Liberal Arts of Hamline University during the spring and fall of 2004. The evaluation instrument, student
compliance, analysis of data, and assessment will be discussed.
Modern Physics at
Hamline University
Andy Rundquist,
Hamline University
Restricted
by resources from actually performing the "standard labs" (like
Millikan, Compton etc.) in our modern physics course, we require a major report
on one of the labs where the student must present the software required for
both collecting and analyzing data.
We provide the "data" to be analyzed. A major benefit is that students are
spared the pitfalls of actual data collection and can focus on data analysis,
something often incomplete in other projects.
A new
twist in the double slit experiment and Rayleigh Criterion on resolution
R. C.
Misra, Warren Menough, and Mukti Aryal, Minnesota State University, Mankato
We have
studied the Rayleigh Criterion for the resolution of two neighboring objects.
Its 81% requirement on combined intensity is translated to a center-to-center
separation of 1.9s, where s is the standard deviation of the ÒjustÓ resolved
Gaussians. To realize this with a
ÒvariableÓ double slit on an optical bench, we attempted to change d, center-to-center
separation of the two slits, to obtain ÒonlyÓ the equivalent single-slit
diffraction. Results will be
presented.
CCD
Photometry of the Open Cluster NGC 7789*
Jessica
L. Windschitl, Saint Mary's University
Sponsored
by Paul J. Nienaber
The rich
and relatively nearby open cluster NGC 7789 has been chosen as a potential
standard (or fundamental) cluster.
This presentation details some broad-band photometry measurements of the
cluster to determine its fundamental parameters. Observations were made during 2004 June using the WIYN 0.9 m
telescope. Reddening and
metallicity were determined from color-color diagrams. The distance modulus and age were
derived by applying the Yale-Yonsei isochrones.
*Part of the greater WIYN
Open Cluster Study (WOCS), a collaboration between the University of Wisconsin,
Indiana University, Yale University, and the National Optical Astronomical
Observatory (NOAO), and supported by NSF Grant AST-1039617 (REU).
Introductory
physics through inquiry-based labs
Brian
Batell and Bradley McCoy, University of Minnesota, Twin Cities
Typical
introductory physics labs require students to follow a set of instructions. We
present an alternative method we have developed for Honors students at the
University of Minnesota. Students design all aspects of their experiments from
concept to conclusion. We will discuss the benefits and limitations of these
inquiry-based labs.
Applications of
Radial Distribution Functions to Biological Systems
Josh Jacobson and
Brendan Johnston, Gustavus Adolphus College
Sponsored by Paul
Sauliner
Aggregations
of Brine shrimp and Ostracods were analyzed to determine the Radial
Distribution Function of each species. Based on these Radial Distribution
Functions, the behavior of each species was analyzed quantitatively allowing
conclusions to be drawn about the behavior of the individuals comprising the
aggregation of each species.
Is more really
better? The connection between
student success in introductory physics and the number of demonstrations.
Brian
Andersson, University of Minnesota, Twin Cities
Students
often comment that they find lecture demonstrations interesting. But, do these
"interesting" demonstrations help students understand physics, or are
they just something cool to see?
Using readily available data, can we determine any connection linking
the number of lecture demonstrations used to student success? In this talk, I will discuss my search
for relationships between different measures of student understanding and the
use of standard lecture demonstrations in large introductory physics classes.
Using AC
Magnetic Susceptometry to Probe Exchange Anisotropy in
Antiferromagnetic/Ferromagnetic Bilayers
Richard
A. Thomas, David Caven, and E. Dan Dahlberg, University of Minnesota, Twin Cities
The direct
exchange coupling between ferromagnetic and antiferromagnetic layers can pin
the ferromagnetic layer magnetization in a certain direction; the most common
manifestation of this effect, known as exchange anisotropy, is a shift in the
hysteresis loop. In order to
further explore this technologically important phenomenon, we used AC
susceptibility measurements to probe the strength of the interactions between
these layers and developed a simple model to explain the results.
Update
on the Minnesota Planetarium
Parke
Kunkle, President, Minnesota Planetarium Society
The city of
Minneapolis has now been granted bonding money for the new Minnesota
Planetarium. Where will it be
located, what will it look like, and what are the next steps?
Posters:
Variations in the Correlation
Coefficients of SiO Masers
Amanda Hyde and Gordon McIntosh,
University of Minnesota, Morris
Correlation
coefficients of maser spectra can be used to determine properties of the source. Over the past four years,
the silicon monoxide masers of Mira
(v=1; J=1-0) and R Cassiopeia (v=1; J=1-0 and v=2; J=1-0) have been monitored remotely via the Haystack
Radio Telescope in Westford, MA. The
observations did not agree with the expectations. The graphs show a complicated pattern indicating possible
periodicities and longer
correlation times than expected.
Using Autocorrelation
Functions to Examine the Pumping of Silicon Monoxide Masers
Bill Cox and Gordon
McIntosh,
University of Minnesota, Morris
A
current theory suggests that the predominant mechanism pumping stellar silicon
monoxide masers is periodic shocks through the region in which the masers
originate. To examine this theory,
we have measured the widths of maser features in spectra taken from the long
period variable stars Mira and R Cassiopeia. The width of a maser feature is affected by the velocity
field present in the originating region, so the passage of the stellar shocks
may be apparent due to a disruption of the velocity field and a discontinuity
in the maser widths. In our
spectra, the maser features are blended making it impossible to determine the
width of an individual feature.
Instead, an autocorrelation function is generated from each
spectrum. An autocorrelation
function measures the correlation between points a given width apart in the
spectrum. Thus, the
autocorrelation function can be used to characterize the widths of all features
in the spectrum. Our data provide
no evidence that would support the theory that stellar shocks are the
predominant pumping mechanism.
Performance
of Computer Generated Zone Plates
Ryan
Johnson, Minnesota State University Moorhead
Sponsored
by Matt Craig
One method
of generating a Fresnel zone plate is to draw or print the zone plate at large
scale and photograph it on slide film. Another method is to generate a digital
zone plate that is printed directly to a slide. A comparison of zone plates
made both ways is made, with an emphasis on the location of focal points and
images due to Moire-like patterns generated as the size of individual zones
approaches the pixel size of a digital zone plate. A computer-generated model
of the zone plate images is used to understand why anomalous focal points
exist.