Can You Heat Me
Now?
Brie Frame
Sandra Gonzalez
Angela Tong
Chenny Zhu
Department of Materials Science • 3.082 • Advisor: Hao Wang •
March 4, 2004
Outline of Presentation
Objective
 Updated Design
 Potential Materials
 Proposed Schedule

Objective

Design and fabricate a heat therapy
device for lower back pain with a future
use for transdermal drug delivery.
Single Component vs. Hybrid
Portability
Low Cost
Modular
Temp.
Regulation
Compact
Long Heat
Reusability
Chemical
Electrical
Hybrid
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Components of Device
Battery
High Insulating Layer
Heating Core
Outer Covering
Body
Battery
Device Placement
Heating Device
Heating Core

Potential Materials


Tetradecanol
Ethylene Carbonate

2,6-Di-tert-butylphenol

Cis-Cyclohexane-1,2dicarboylic anydride

Benzylideneacetone

Sodium Acetate
Insulating Material
Potential Materials
 COHRlastic Solid Silicone Rubber
 Thermally Conductive R10404



Low Thermal Conductivity 0.0037W/mK
Very Thin
R10480


Low Thermal Conductivity
Flexible
 Cotton
 Low Thermal Conductivity 0.03 W/mK
 Neoprene
 Insulwrap Quilts from American
Acoustical Products
Battery

Sanyo Batteries
 Lithium Polymer: UPF574199
 high energy density both by volume and by weight, flat
and flexible
 not as much total energy available per battery
 Li-ion Rechargeable: UR18650H, UR18650F
 highest energy densities of the fifteen batteries surveyed
 less total energy than lithium polymer, round casing

Saft Batteries
 Li-ion Rechargeable: MP176065 and others
 highest total energy available per battery, flat casing
 big and bulky, rigid casing, low energy density
Switch

Potential Switches
 Polymer Thermal Switch
 Polymer matrix with conductive particles interspersed
 When cooled, matrix becomes compact, particles touch
and form electrically connected network
 When heated, matrix expands, connected network breaks
 Bi-metallic Switch
 Two metals with different expansion coefficients laminated
together
 When heated, one expands more than the other, which
causes it to bend and either open or close the circuit
 Integrated Circuit – Programmable Thermostatic
Switch

Circuit where temperature setting can be controlled by
adding resistors
Wire Tensile Testing
 Ni80Cr20
 Ni60Cr40
 High Resistance
 Strong
 Cross-sectional area =
1.26x10-3 sq. in.
Wire Tensile Results for Ni60-Cr40
Stre ss-Strain Curve for Ni60-Cr40 Wire
120000
Stress (psi)
100000
80000
60000
40000
20000
0
0
0.1
0.2
0.4
0.3
0.5
0.6
0.7
Strain
Ultimate force withstood: 135 pounds
Ultimate Tensile Strength (UTS): 107,432 psi
Elastic Modulus= (61,674-15,915) psi / (.1388-.1042) = 1,322.5 ksi
Total Elongation=1.9 in.
Wire Tensile Results for Ni80-Cr20
Stress-Strain NiCr 80:20
140000
120000
100000
Stress
80000
60000
40000
20000
0
0
0.1
0.2
0.3
0.4
0.5
Strain
Ultimate force withstood: 160 pounds
Ultimate Tensile Strength (UTS): 127,300 psi
Total Elongation=2.6 in.
0.6
0.7
0.8
0.9
1
Proposed Schedule
Feb 2004
ID
Task Name
Start
2/1
1
Formal Design Review Presentation
2
Obtaining Materials
3/11/2004
3/11/2004
2/5/2004
3/18/2004
3
Wires
3/2/2004
3/4/2004
4
PCM
3/2/2004
3/11/2004
5
Thermal Switch
3/9/2004
3/11/2004
6
Polymer Gel
3/9/2004
3/11/2004
7
Insulating Material
3/9/2004
3/16/2004
8
Battery
3/9/2004
3/16/2004
9
Outside Material
3/9/2004
3/16/2004
Wire Coating
3/9/2004
3/16/2004
3/9/2004
3/18/2004
10
11
Processing
12
Polymer Gels
3/11/2004
3/18/2004
13
Wire Coating
3/11/2004
3/18/2004
3/2/2004
4/1/2004
14
Testing Materials
Mar 2004
Apr 2004
May 2004
Finish
15
Wire
3/2/2004
3/9/2004
16
PCM
3/4/2004
3/18/2004
17
Thermal Switch
3/16/2004
3/25/2004
18
Polymer Gel
3/18/2004
4/1/2004
3/18/2004
4/6/2004
19
Prototype Assembly
20
Initial Prototypes
4/6/2004
4/6/2004
21
Testing and Troubleshooting Prototype
4/6/2004
5/6/2004
22
Last Day of Lab Work
5/6/2004
5/6/2004
23
Final Presentation/Posters Due
5/13/2004
5/13/2004
2/8
2/15
2/22
2/29
3/7
3/14
3/21
3/28
4/4
4/11
4/18
4/25
5/2
5/9
5/16