Transcript Core-Shell Nanoparticle Generation Using Laser Ablation

Core-Shell Nanoparticle
Generation
Using Laser Ablation
Vanessa Coronado, Westside High School, Houston ISD
Dr. Sy-Bor Wen/ Assistant Professor and
YoungKyong Jo/ Ph.D. student
Dept. of Mechanical Engineering
http://www.istm.cnr.it/~ponti/NJC06.html
Dr. Sy-Bor Wen, Department of Mechanical
Engineering
• Ph.D. in Mechanical Engineering
@ University of California at Berkeley, CA
• M.S. and B.S. in Mechanical Engineering
@ National Taiwan University, Taipei, Taiwan
• Working on using lasers to ablate germanium and copper and
condense them together to form a nanoparticle core-shell
material that has superior optical and electromagnetic
properties.
If you will recall, our project….
• Uses 2 lasers to ablate a germanium and
copper sample a fraction of a second apart
• The second material (copper) condenses
onto first (germanium) to form core-shell
particle
• Particles deposit over time and are sent to
a SEM and/or a TEM for imaging
• If the particle is a core-shell
particle…party…. then determine the
properties of it.
What could my class do to cover
the TEKS and touch on some of
the cool stuff we’ve done in the
laboratory?
The main ideas that our research
project touched on were:
• Using lasers
• Creation of nanoparticles
• Experimental design
• Energy conversions and thermal
expansion
So, after MUCH deliberation….
I decided to use laser
light and
having the students design a project!
Why?
-Most realistic costs- after many hours pricing
items from internet
-Most concepts for kids to learn within the
physics TEKS
-Topic with the most design ideas
Physics TEKS Project Will Cover:
(8) Science concepts. The student knows the
characteristics and behavior of waves. The
student is expected to:
• (A) examine and describe a variety of waves
propagated in various types of media and describe
wave characteristics such as velocity, frequency,
amplitude, and behaviors such as reflection,
refraction, and interference;
• (B) identify the characteristics and behaviors of
sound and electromagnetic waves; and
• (C) interpret the role of wave characteristics and
behaviors found in medicinal and industrial
applications.
Or, the recently revised Physics TEKS:
(7) Science concepts. The student knows the characteristics and
behavior of waves. The student is expected to:
• (A) examine and describe oscillatory motion and wave
propagation in various types of media;
• (B) investigate and analyze characteristics of waves, including
velocity, frequency, amplitude, and wavelength, and calculate
using the relationship between wave speed, frequency, and
wavelength;
• (C) compare characteristics and behaviors of transverse waves,
including electromagnetic waves and the electromagnetic
spectrum, and characteristics and behaviors of longitudinal
waves, including sound waves;
• (D) investigate behaviors of waves, including reflection,
refraction, diffraction, interference, resonance, and the Doppler
effect;
• (E) describe and predict image formation as a consequence of
reflection from a plane mirror and refraction through a thin
convex lens; and
• (F) describe the role of wave characteristics and behaviors in
medical and industrial applications.
Focused L.A.S.E.R.s are used in….
(AKA “Mrs....why are we doing this?”)
Besides the fact that it’s cool:
• DVD and CD players
• LASIK eye surgery
• Metal working
• Etching
• Weaponry
• Microscopes
• Alignment
• Ablation
• And much, much more!
Safety First!
• Today, it is accepted that even low-power lasers
with only a few milliwatts of output power can be
hazardous to human eyesight, when the beam
from such a laser hits the eye directly or after
reflection from a shiny surface. At wavelengths
which the cornea and the lens can focus well, the
coherence and low divergence of laser light means
that it can be focused by the eye into an extremely
small spot on the retina, resulting in localized
burning and permanent damage in seconds or
even less time.
• Students will be signing a safety contract designed
for this project. (Even though our lasers aren’t high
powered.)
http://en.wikipedia.org/wiki/Laser
What will the kids be doing?
Their project sheet states the following:
*tentative
What will we be using?
·
·
A 7 beam laser box (have ordered 2)
A light meter -measures lux (ordered 1 so far)
-possibly probeware, depending on what the
school can do.
We will also be using….
6+ Mirrors
http://www.christianbook.com/Christian/Books/oversize?sku=754037
6+ Lenses
http://www.surplusshed.com/pages/item/l1875d.html
...different shapes and sizes of mirrors/lenses for purpose of
discovering which works best for their challenge activity
How will they be scored?
Example project
1 (57.5”)
2 (52.5”)
3 (34.2”)
4 (33.3”)
This project has 4 segments, the beam covers 177.5
cm (1.775m) and has 33% of the original intensity.
How would I calculate my score?
S = N * L * (I)2
n
(i)2
S = 4.0 *1.775m*(.33)2
1
( 1 )2
S = 4.0 *1.775 *0.11 = 0.78
I bet they can do much better than this! 
Other scores obtained on mission:
• Schematic Drawing
You will need to draw a schematic of your design that is to
scale. You may pick the scale (1:2, 1:10, 1:50, etc). When
you draw a schematic, you should include as many
dimensions as possible to give NASA an idea of how to
duplicate your project. See classroom example and rubric
for help.
• Team Interview and Presentation
You will need to know about all parts of your project for a
brief presentation and team interview. You will explain how
your project is solving the problem. The interview is very
brief, and consists of “why” and “how” type questions.
• Journal of Design Process
You will need to keep a ledger of your design process,
good/bad ideas our group had, who did what, etc. The more
detail you include, the better your grade- so be thorough.
You will also answer some questions given in class here as
well.
Pre-Test/Post-Test
Pre-Test/Post-Test
Project Timeline
• Day 1: Pre-Test ~25 min
Safety Lesson ~ 10 min
Q: difference between sci. & engr.? ~10 min
• Day 2: Engineering design lesson ~20 min
Assign project and groups of 3-4 ~20 min
Journaling questions ~ 10 min
• Day 3:
Vocabulary and demos ~15 min
Student design time ~30 min
During warm-ups and class time- journaling will occur.
Project Timeline
• Day 4: Student ocular discovery activity online ~15 min
http://www.glencoe.com/sites/common_assets/science/virtual_labs/E11/E11.html
Student design time with supplies ~30 min
• Day 5: Trials and redesign ~45 min
• Day 6: Final test and calculations ~45 min
• Day 7: Present projects ~5 min each group x 10
• Day 8: Post-Test ~25 min (catch-up time if needed ~20 min)
*During warm-ups and class time- journaling will occur.
Journaling (Interactive Notebook)
• Inventors, engineers, naturalists, and scientists
all keep written records of their work!
What is difference between science and
engineering?
Class info, notes, etc.
Engineering design flowchart
Results and discoveries
Vocabulary, concept maps
Targets “type B” kids
Any Questions?
Acknowledgements
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Texas A&M
National Science Foundation
E3 RET Program coordinators
Mechanical Engineering Dept
Dr Sy-Bor Wen and his team
And viewers like you