Kristin Brodie
Jeff Colton
Colin Galbraith
Bushra Makiya
Tiffany Santos

Fabrication of Microspheres
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Used protocol learned at beginning of semester to fabricate PLGA microspheres
Homogenizer speed:
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Paraffin: 3.5, 5
Octadecane: 4, 5
Pipette used to separate water and paraffin
Filter used for octadecane (0.22
 m)

SEM of Microspheres
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Paraffin Wax
Homogenizer speed 5
Average size: 150  m
Range: 50 – 300  m

SEM of Microspheres (2)
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Paraffin Wax
Homogenizer speed 3.5
Average size: 200  m
Range: 50 – 400  m

DSC for Octadecane and PEG

Octadecane  PEG

Heat Flow Model for a Finger
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Finger assumed to be a cylinder
Power = 2

 rLq = 2  L(T
1
-T
3
)/R
R = Fabric Resistance + BL Resistance

FR = 1/k c
BLR = 1/(r
* ln (r c
/r w
)
 c
*h) h = 1.22*(  T/D)^( 1 /
4
Approximating values:
) for a horizontal pipe
 h~10 W/m 2 K

Power~2.5 W
A hand can be assumed to be a cylinder
 r hand
= 2*r finger

Heat Transfer Through Gloves
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Heating element in the glove (73cm)
Thermistor in and out of the glove
Power: 3.6V
Current: 0.55A
Weight to reduce air flow into glove

Heat Flow Results
Event T [in] T [out]
1
2
3
4
109.9
71.5
112.4
71.9
112.6
71.6
112.5
71.1
5
6
112.2
112.1
71.6
71.7
Avg 111.95 71.57
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I*V/A = h (T[in] – T[out])
I = 0.55A
V = 3.6V
A = 0.05m
2
T[in] = 317.42K
T[out] = 294.98K
 h = 1.765 W/m 2 K

Data for Heating Element Wires
Starting Diameter
(mm)
Area of Wire (in 2 )
Ni:Cr
80:20wt%
0.41
0.00807
Suggested Stress (kpsi) 120
Length of Graph (in)
Extension (in)
19.5
1.95
Max Load (lbs) 24.2
Calculated Stress (kpsi) 121
Ni:Cr:Fe
60:16:24 wt%
0.40
1.192e-4
74-130
21.7
2.17
21
107.8
Stainless Steel Fe:Cr:Ni
70:19:11 wt%
0.375
1.7e-4
~95
35
3.5
17.5
102.2

Curve for Ni:Cr 80:20wt%
Ni:Cr 80:20wt%
30
25
20
15
10
5
0
1 3 5 7 9 11 13 15 17 19 21 23 25 27
Distance (inch)

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Ni:Cr 80:20wt% chosen for large elastic region
Octadecane preferred over PEG for Heat of crystallization properties
Experimental thermal coefficient is similar to theoretical value

What Will We Do Next?
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Phase Change Material

Test integrity of PVA
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Fabricate microspheres of PEG
Incorporation of phase change material into fabric
DSC of microspheres
Heating Elements
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Test battery with Prof Ceder
Incorporation of thermal switch
Choose a fabric to get specific thermal properties