3D Thermal Cloaking

1
00:00:03,536 --> 00:00:04,704
This is the Discovery

2
00:00:04,704 --> 00:00:05,438
Files podcast

3
00:00:05,438 --> 00:00:06,172
from the U.S.

4
00:00:06,172 --> 00:00:06,940
National Science

5
00:00:06,940 --> 00:00:09,943
Foundation.

6
00:00:10,143 --> 00:00:10,910
Investments

7
00:00:10,910 --> 00:00:11,544
in developing

8
00:00:11,544 --> 00:00:12,078
and advanced

9
00:00:12,078 --> 00:00:12,779
technologies

10
00:00:12,779 --> 00:00:13,313
and the

11
00:00:13,313 --> 00:00:14,280
foundational research

12
00:00:14,280 --> 00:00:15,181
that lead to them

13
00:00:15,181 --> 00:00:15,915
transform

14
00:00:15,915 --> 00:00:17,350
industry, society

15
00:00:17,350 --> 00:00:18,852
and result in products

16
00:00:18,852 --> 00:00:19,819
that improve people's

17
00:00:19,819 --> 00:00:20,987
lives and strengthen

18
00:00:20,987 --> 00:00:22,455
the national economy.

19
00:00:22,455 --> 00:00:23,256
We're joined today

20
00:00:23,256 --> 00:00:24,290
by Shelly Zhang,

21
00:00:24,290 --> 00:00:25,091
an NSF

22
00:00:25,091 --> 00:00:25,992
supported researcher

23
00:00:25,992 --> 00:00:26,860
whose group is using

24
00:00:26,860 --> 00:00:28,061
additive manufacturing

25
00:00:28,061 --> 00:00:29,029
and topology

26
00:00:29,029 --> 00:00:30,230
optimization to

27
00:00:30,230 --> 00:00:31,297
create new structures,

28
00:00:31,297 --> 00:00:32,332
including a 3D

29
00:00:32,332 --> 00:00:33,833
thermal cloaking device.

30
00:00:33,833 --> 00:00:34,667
Professor Zhang,

31
00:00:34,667 --> 00:00:35,201
thank you so much

32
00:00:35,201 --> 00:00:36,202
for joining me today.

33
00:00:36,202 --> 00:00:36,736
Thank you.

34
00:00:36,736 --> 00:00:37,037
Nate,

35
00:00:37,037 --> 00:00:37,270
for the

36
00:00:37,270 --> 00:00:38,104
great opportunity

37
00:00:38,104 --> 00:00:38,838
to speak.

38
00:00:38,838 --> 00:00:39,672
So I'm excited

39
00:00:39,672 --> 00:00:40,240
to speak to you

40
00:00:40,240 --> 00:00:40,874
about some

41
00:00:40,874 --> 00:00:41,741
very interesting work

42
00:00:41,741 --> 00:00:42,242
you have coming

43
00:00:42,242 --> 00:00:42,976
out of your lab.

44
00:00:42,976 --> 00:00:43,510
But I would

45
00:00:43,510 --> 00:00:44,077
like to start

46
00:00:44,077 --> 00:00:45,078
with kind of

47
00:00:45,078 --> 00:00:46,746
a concept definition.

48
00:00:46,746 --> 00:00:47,881
What is

49
00:00:47,881 --> 00:00:49,082
thermal cloaking?

50
00:00:49,082 --> 00:00:50,016
The thermal cloak

51
00:00:50,016 --> 00:00:51,051
is essentially about

52
00:00:51,051 --> 00:00:52,118
controlling the path

53
00:00:52,118 --> 00:00:52,952
of the heat.

54
00:00:52,952 --> 00:00:54,254
So if we imagine

55
00:00:54,254 --> 00:00:55,522
placing an object

56
00:00:55,522 --> 00:00:56,923
in a uniform material

57
00:00:56,923 --> 00:00:58,858
and we heat on one side,

58
00:00:58,858 --> 00:00:59,592
that object

59
00:00:59,592 --> 00:01:00,660
has a different

60
00:01:00,660 --> 00:01:01,694
thermal property

61
00:01:01,694 --> 00:01:03,029
from its surrounding,

62
00:01:03,029 --> 00:01:04,230
it will disturb

63
00:01:04,230 --> 00:01:05,432
the heat flow.

64
00:01:05,432 --> 00:01:06,499
So the temperature

65
00:01:06,499 --> 00:01:08,201
contour around

66
00:01:08,201 --> 00:01:09,669
it will bend.

67
00:01:09,669 --> 00:01:10,937
And that's how we know

68
00:01:10,937 --> 00:01:11,771
that there is

69
00:01:11,771 --> 00:01:12,539
something there

70
00:01:12,539 --> 00:01:13,139
if we use a

71
00:01:13,139 --> 00:01:14,674
thermal camera.

72
00:01:14,674 --> 00:01:15,875
A thermal cloak

73
00:01:15,875 --> 00:01:16,776
will do something

74
00:01:16,776 --> 00:01:17,811
that's very different.

75
00:01:17,811 --> 00:01:19,145
So basically

76
00:01:19,145 --> 00:01:20,780
it will guide the heat

77
00:01:20,780 --> 00:01:21,314
around the

78
00:01:21,314 --> 00:01:22,282
protective region

79
00:01:22,282 --> 00:01:23,316
and then allow

80
00:01:23,316 --> 00:01:24,250
the heat to

81
00:01:24,250 --> 00:01:25,652
come back together

82
00:01:25,652 --> 00:01:27,020
at the other side.

83
00:01:27,020 --> 00:01:29,355
So inside the cloak

84
00:01:29,355 --> 00:01:30,423
the temperature field

85
00:01:30,423 --> 00:01:31,891
will look almost as if

86
00:01:31,891 --> 00:01:33,093
the object

87
00:01:33,093 --> 00:01:34,427
is never there.

88
00:01:34,427 --> 00:01:35,028
In this case,

89
00:01:35,028 --> 00:01:35,428
I would like

90
00:01:35,428 --> 00:01:36,162
to describe it

91
00:01:36,162 --> 00:01:36,996
as a building,

92
00:01:36,996 --> 00:01:39,666
a contour for the heat.

93
00:01:39,666 --> 00:01:41,201
And there are three

94
00:01:41,201 --> 00:01:42,635
very important features

95
00:01:42,635 --> 00:01:44,971
for this cloak to work.

96
00:01:44,971 --> 00:01:46,539
So the first thing is.

97
00:01:46,539 --> 00:01:48,074
So if we think about

98
00:01:48,074 --> 00:01:48,575
there are

99
00:01:48,575 --> 00:01:49,542
two geometries.

100
00:01:49,542 --> 00:01:51,144
One is the object

101
00:01:51,144 --> 00:01:52,011
being protected.

102
00:01:52,011 --> 00:01:52,946
The other one is

103
00:01:52,946 --> 00:01:53,680
the outside

104
00:01:53,680 --> 00:01:55,315
of the thermal cloak.

105
00:01:55,315 --> 00:01:56,349
The first feature

106
00:01:56,349 --> 00:01:57,650
that's important is

107
00:01:57,650 --> 00:01:59,152
we are redirecting heat

108
00:01:59,152 --> 00:02:00,520
such that outside

109
00:02:00,520 --> 00:02:01,921
of the cloak region,

110
00:02:01,921 --> 00:02:02,555
if we use a

111
00:02:02,555 --> 00:02:03,623
thermal camera,

112
00:02:03,623 --> 00:02:05,358
will now be able to see

113
00:02:05,358 --> 00:02:05,959
there is an

114
00:02:05,959 --> 00:02:07,160
object inside

115
00:02:07,160 --> 00:02:07,694
in the sense

116
00:02:07,694 --> 00:02:09,362
that the thermal contour

117
00:02:09,362 --> 00:02:10,697
is purely uniform.

118
00:02:10,697 --> 00:02:11,898
So that's the one thing

119
00:02:11,898 --> 00:02:12,699
it serves

120
00:02:12,699 --> 00:02:13,700
as a protecting

121
00:02:13,700 --> 00:02:14,334
the object

122
00:02:14,334 --> 00:02:15,101
being detected

123
00:02:15,101 --> 00:02:16,236
thermally.

124
00:02:16,236 --> 00:02:17,270
The second feature

125
00:02:17,270 --> 00:02:18,638
is inside

126
00:02:18,638 --> 00:02:20,240
this cloak region.

127
00:02:20,240 --> 00:02:21,174
The temperature

128
00:02:21,174 --> 00:02:23,143
gradient is very uniform

129
00:02:23,143 --> 00:02:24,344
and it's

130
00:02:24,344 --> 00:02:24,911
the temperature

131
00:02:24,911 --> 00:02:26,146
is very constant

132
00:02:26,146 --> 00:02:27,380
and undisturbed.

133
00:02:27,380 --> 00:02:29,082
So in this case

134
00:02:29,082 --> 00:02:29,949
it serves as

135
00:02:29,949 --> 00:02:31,718
a capability to protect

136
00:02:31,718 --> 00:02:32,919
whatever inside

137
00:02:32,919 --> 00:02:33,953
from being influenced

138
00:02:33,953 --> 00:02:35,355
by the external extreme

139
00:02:35,355 --> 00:02:37,457
heat or damage.

140
00:02:37,457 --> 00:02:38,758
The third feature

141
00:02:38,758 --> 00:02:40,660
is that a real cloak

142
00:02:40,660 --> 00:02:42,162
has to be a cloak

143
00:02:42,162 --> 00:02:43,263
that works.

144
00:02:43,263 --> 00:02:43,863
Doesn't matter

145
00:02:43,863 --> 00:02:44,430
where the heat

146
00:02:44,430 --> 00:02:45,031
comes from

147
00:02:45,031 --> 00:02:46,533
is a universal cloak

148
00:02:46,533 --> 00:02:47,133
that works

149
00:02:47,133 --> 00:02:49,002
for infinite direction

150
00:02:49,002 --> 00:02:49,802
for the heat.

151
00:02:49,802 --> 00:02:51,137
So those three features

152
00:02:51,137 --> 00:02:53,273
come up with an actual

153
00:02:53,273 --> 00:02:53,973
thermal cloak.

154
00:02:53,973 --> 00:02:55,642
So I think for the idea,

155
00:02:55,642 --> 00:02:56,242
a lot of us

156
00:02:56,242 --> 00:02:57,510
have seen media

157
00:02:57,510 --> 00:02:58,178
such as movies

158
00:02:58,178 --> 00:02:58,745
over the years

159
00:02:58,745 --> 00:02:59,479
where maybe it's

160
00:02:59,479 --> 00:03:00,947
in military applications

161
00:03:00,947 --> 00:03:01,948
and they're using it to

162
00:03:01,948 --> 00:03:02,682
see, like

163
00:03:02,682 --> 00:03:03,416
the people that are

164
00:03:03,416 --> 00:03:03,983
in a building,

165
00:03:03,983 --> 00:03:04,751
let's say.

166
00:03:04,751 --> 00:03:05,518
So if you

167
00:03:05,518 --> 00:03:06,352
had your cloak,

168
00:03:06,352 --> 00:03:07,120
instead of being able

169
00:03:07,120 --> 00:03:07,820
to see the outline

170
00:03:07,820 --> 00:03:08,354
of the person

171
00:03:08,354 --> 00:03:09,322
in the building,

172
00:03:09,322 --> 00:03:10,790
it might just be it

173
00:03:10,790 --> 00:03:11,958
dissipates the heat

174
00:03:11,958 --> 00:03:12,292
in a way

175
00:03:12,292 --> 00:03:12,892
that they wouldn't

176
00:03:12,892 --> 00:03:13,193
be able

177
00:03:13,193 --> 00:03:14,661
to see that source.

178
00:03:14,661 --> 00:03:15,361
Exactly.

179
00:03:15,361 --> 00:03:16,963
So a very

180
00:03:16,963 --> 00:03:18,264
interesting point

181
00:03:18,264 --> 00:03:18,831
that you make

182
00:03:18,831 --> 00:03:20,333
is about the heat.

183
00:03:20,333 --> 00:03:21,034
So actually

184
00:03:21,034 --> 00:03:23,236
we are not

185
00:03:23,236 --> 00:03:24,337
eliminating the heat.

186
00:03:24,337 --> 00:03:25,438
The heat is still there.

187
00:03:25,438 --> 00:03:26,673
So the energy

188
00:03:26,673 --> 00:03:28,041
is still conserved,

189
00:03:28,041 --> 00:03:29,375
but we are steering it

190
00:03:29,375 --> 00:03:30,443
around the region.

191
00:03:30,443 --> 00:03:32,111
And then we repair

192
00:03:32,111 --> 00:03:33,947
it afterwards

193
00:03:33,947 --> 00:03:34,614
so that the

194
00:03:34,614 --> 00:03:35,982
temperature field

195
00:03:35,982 --> 00:03:38,985
are not being influenced

196
00:03:39,185 --> 00:03:39,852
outside of the

197
00:03:39,852 --> 00:03:40,787
cloak region.

198
00:03:40,787 --> 00:03:41,454
And then

199
00:03:41,454 --> 00:03:42,121
you showed

200
00:03:42,121 --> 00:03:43,256
the example there

201
00:03:43,256 --> 00:03:43,990
where you have

202
00:03:43,990 --> 00:03:45,458
the 3D printed.

203
00:03:45,458 --> 00:03:46,626
So what you've

204
00:03:46,626 --> 00:03:47,694
really accomplished

205
00:03:47,694 --> 00:03:48,595
is being able

206
00:03:48,595 --> 00:03:49,662
to demonstrate

207
00:03:49,662 --> 00:03:51,197
how to do this idea.

208
00:03:51,197 --> 00:03:51,698
So can you

209
00:03:51,698 --> 00:03:52,298
talk a little bit

210
00:03:52,298 --> 00:03:53,499
about this project

211
00:03:53,499 --> 00:03:54,200
you have coming

212
00:03:54,200 --> 00:03:55,068
out of your lab?

213
00:03:55,068 --> 00:03:56,669
So in my lab

214
00:03:56,669 --> 00:03:57,503
at the Department

215
00:03:57,503 --> 00:03:58,271
of Civil

216
00:03:58,271 --> 00:03:58,972
and Environmental

217
00:03:58,972 --> 00:03:59,539
Engineering

218
00:03:59,539 --> 00:04:00,573
at the Grainger College

219
00:04:00,573 --> 00:04:01,674
of Engineering

220
00:04:01,674 --> 00:04:02,542
at University

221
00:04:02,542 --> 00:04:03,142
of Illinois,

222
00:04:03,142 --> 00:04:04,210
Urbana-Champaign.

223
00:04:04,210 --> 00:04:04,744
We have

224
00:04:04,744 --> 00:04:05,878
worked in this project

225
00:04:05,878 --> 00:04:06,879
a couple of years

226
00:04:06,879 --> 00:04:08,715
and actually is built

227
00:04:08,715 --> 00:04:10,350
upon a very important

228
00:04:10,350 --> 00:04:11,117
theory called

229
00:04:11,117 --> 00:04:12,385
transformation theory.

230
00:04:12,385 --> 00:04:13,753
So what happened

231
00:04:13,753 --> 00:04:15,154
is this transformation

232
00:04:15,154 --> 00:04:15,922
theory

233
00:04:15,922 --> 00:04:17,757
can already calculate

234
00:04:17,757 --> 00:04:19,025
and tell us

235
00:04:19,025 --> 00:04:19,792
in order to

236
00:04:19,792 --> 00:04:21,160
make a perfect cloak,

237
00:04:21,160 --> 00:04:21,828
what is the

238
00:04:21,828 --> 00:04:23,229
thermal conductivity

239
00:04:23,229 --> 00:04:24,130
that we need

240
00:04:24,130 --> 00:04:25,265
at each point

241
00:04:25,265 --> 00:04:26,332
of the space.

242
00:04:26,332 --> 00:04:27,467
But the problem is

243
00:04:27,467 --> 00:04:29,335
that this required

244
00:04:29,335 --> 00:04:30,303
the thermal conductivity

245
00:04:30,303 --> 00:04:31,504
or the thermal property

246
00:04:31,504 --> 00:04:32,438
that is different

247
00:04:32,438 --> 00:04:34,540
at each different point.

248
00:04:34,540 --> 00:04:36,175
It's almost impossible

249
00:04:36,175 --> 00:04:36,876
to realize

250
00:04:36,876 --> 00:04:37,543
by any

251
00:04:37,543 --> 00:04:39,145
commercial material.

252
00:04:39,145 --> 00:04:40,346
The problem is that

253
00:04:40,346 --> 00:04:42,015
the property is very

254
00:04:42,015 --> 00:04:43,416
directionally dependent,

255
00:04:43,416 --> 00:04:44,717
and from one point

256
00:04:44,717 --> 00:04:45,418
to the other point,

257
00:04:45,418 --> 00:04:46,552
it also becomes

258
00:04:46,552 --> 00:04:47,820
very drastically

259
00:04:47,820 --> 00:04:48,955
different.

260
00:04:48,955 --> 00:04:51,224
So we can not simply buy

261
00:04:51,224 --> 00:04:52,625
that type of material

262
00:04:52,625 --> 00:04:54,294
anywhere.

263
00:04:54,294 --> 00:04:55,228
So we then

264
00:04:55,228 --> 00:04:56,029
ask ourselves

265
00:04:56,029 --> 00:04:56,896
a question,

266
00:04:56,896 --> 00:04:57,897
can we create

267
00:04:57,897 --> 00:04:58,731
those properties

268
00:04:58,731 --> 00:05:00,300
using structures

269
00:05:00,300 --> 00:05:01,334
or geometry

270
00:05:01,334 --> 00:05:01,934
rather than

271
00:05:01,934 --> 00:05:03,136
using chemistry

272
00:05:03,136 --> 00:05:04,170
where you maintain

273
00:05:04,170 --> 00:05:04,737
a new

274
00:05:04,737 --> 00:05:05,338
chemically

275
00:05:05,338 --> 00:05:06,272
made material.

276
00:05:06,272 --> 00:05:07,907
So in this case

277
00:05:07,907 --> 00:05:08,908
we make

278
00:05:08,908 --> 00:05:09,776
use of a three

279
00:05:09,776 --> 00:05:11,177
dimensional lattice.

280
00:05:11,177 --> 00:05:12,011
So the idea

281
00:05:12,011 --> 00:05:12,712
of this lattice

282
00:05:12,712 --> 00:05:14,314
is that locally

283
00:05:14,314 --> 00:05:15,381
this lattice

284
00:05:15,381 --> 00:05:16,883
if you observe

285
00:05:16,883 --> 00:05:18,551
we can have full control

286
00:05:18,551 --> 00:05:19,319
on these three

287
00:05:19,319 --> 00:05:20,453
perpendicular

288
00:05:20,453 --> 00:05:21,788
lattice numbers.

289
00:05:21,788 --> 00:05:23,189
And by changing

290
00:05:23,189 --> 00:05:24,624
their thickness

291
00:05:24,624 --> 00:05:26,092
and the orientation

292
00:05:26,092 --> 00:05:27,193
from one point to

293
00:05:27,193 --> 00:05:27,894
another point,

294
00:05:27,894 --> 00:05:30,096
we can then engineer

295
00:05:30,096 --> 00:05:31,631
or tailor different

296
00:05:31,631 --> 00:05:32,465
effective

297
00:05:32,465 --> 00:05:34,033
thermal conductivity

298
00:05:34,033 --> 00:05:35,401
in different direction.

299
00:05:35,401 --> 00:05:36,402
Because if

300
00:05:36,402 --> 00:05:37,270
to realize this

301
00:05:37,270 --> 00:05:39,172
in the real 3D world

302
00:05:39,172 --> 00:05:39,906
is extremely

303
00:05:39,906 --> 00:05:41,074
challenging.

304
00:05:41,074 --> 00:05:42,041
And then,

305
00:05:42,041 --> 00:05:43,176
that's the first thing

306
00:05:43,176 --> 00:05:43,943
that we use

307
00:05:43,943 --> 00:05:44,344
is the three

308
00:05:44,344 --> 00:05:45,411
dimensional lattice.

309
00:05:45,411 --> 00:05:46,813
Another very

310
00:05:46,813 --> 00:05:47,613
difficult problem

311
00:05:47,613 --> 00:05:48,381
is that

312
00:05:48,381 --> 00:05:50,416
how do we connect

313
00:05:50,416 --> 00:05:51,317
these hundreds

314
00:05:51,317 --> 00:05:52,652
or thousands of lattice

315
00:05:52,652 --> 00:05:53,519
together,

316
00:05:53,519 --> 00:05:54,554
naturally, in the way

317
00:05:54,554 --> 00:05:55,121
that we can

318
00:05:55,121 --> 00:05:56,656
fabricate them easily?

319
00:05:56,656 --> 00:05:57,390
In this case,

320
00:05:57,390 --> 00:05:58,257
we make

321
00:05:58,257 --> 00:05:59,459
use of our

322
00:05:59,459 --> 00:06:01,227
dehomogenization methods

323
00:06:01,227 --> 00:06:03,363
to naturally translate

324
00:06:03,363 --> 00:06:04,130
the desired

325
00:06:04,130 --> 00:06:05,498
material property

326
00:06:05,498 --> 00:06:07,033
into this, a

327
00:06:07,033 --> 00:06:08,668
smoothly connected

328
00:06:08,668 --> 00:06:09,602
global lattice

329
00:06:09,602 --> 00:06:10,203
that you can see

330
00:06:10,203 --> 00:06:10,703
from here.

331
00:06:10,703 --> 00:06:12,038
So every node,

332
00:06:12,038 --> 00:06:12,872
every lattice

333
00:06:12,872 --> 00:06:13,573
is connected

334
00:06:13,573 --> 00:06:14,774
with one another

335
00:06:14,774 --> 00:06:16,142
in a very elegant

336
00:06:16,142 --> 00:06:17,477
and natural way.

337
00:06:17,477 --> 00:06:19,412
So this is an essential

338
00:06:19,412 --> 00:06:20,480
for us to be able

339
00:06:20,480 --> 00:06:21,948
to fabricate this

340
00:06:21,948 --> 00:06:23,483
in real life.

341
00:06:23,483 --> 00:06:24,751
The next component is

342
00:06:24,751 --> 00:06:25,985
how do we actually

343
00:06:25,985 --> 00:06:26,986
physically make it.

344
00:06:26,986 --> 00:06:28,187
So in this case

345
00:06:28,187 --> 00:06:29,522
we make use of a

346
00:06:29,522 --> 00:06:30,690
two materials,

347
00:06:30,690 --> 00:06:32,091
the aluminum material

348
00:06:32,091 --> 00:06:33,960
and a type of

349
00:06:33,960 --> 00:06:35,695
elastomer called PDMS.

350
00:06:35,695 --> 00:06:37,196
The idea is that we need

351
00:06:37,196 --> 00:06:38,464
one that is

352
00:06:38,464 --> 00:06:39,465
highly conductive

353
00:06:39,465 --> 00:06:40,600
and another one

354
00:06:40,600 --> 00:06:41,901
is not conductive

355
00:06:41,901 --> 00:06:42,602
at all.

356
00:06:42,602 --> 00:06:43,836
So in that case,

357
00:06:43,836 --> 00:06:44,537
we create

358
00:06:44,537 --> 00:06:46,305
a huge designable space

359
00:06:46,305 --> 00:06:47,240
for us

360
00:06:47,240 --> 00:06:47,940
where it's

361
00:06:47,940 --> 00:06:48,841
a huge space

362
00:06:48,841 --> 00:06:51,077
with a big variation

363
00:06:51,077 --> 00:06:51,310
of the

364
00:06:51,310 --> 00:06:52,512
thermal conductivity

365
00:06:52,512 --> 00:06:53,212
that allows us

366
00:06:53,212 --> 00:06:53,813
to realize

367
00:06:53,813 --> 00:06:55,882
almost any effective

368
00:06:55,882 --> 00:06:57,083
thermal conductivity

369
00:06:57,083 --> 00:06:59,719
that the theory asks.

370
00:06:59,719 --> 00:07:01,020
And then by

371
00:07:01,020 --> 00:07:02,321
choosing this material

372
00:07:02,321 --> 00:07:03,122
and then using

373
00:07:03,122 --> 00:07:03,923
our technique

374
00:07:03,923 --> 00:07:05,458
to generate,

375
00:07:05,458 --> 00:07:06,993
to create, derive

376
00:07:06,993 --> 00:07:07,894
the geometry

377
00:07:07,894 --> 00:07:08,895
of the lattice,

378
00:07:08,895 --> 00:07:09,429
we use

379
00:07:09,429 --> 00:07:10,930
the commercial metal

380
00:07:10,930 --> 00:07:12,031
3D printing

381
00:07:12,031 --> 00:07:13,132
to print

382
00:07:13,132 --> 00:07:14,734
the aluminum lattice.

383
00:07:14,734 --> 00:07:16,402
And then we cast them

384
00:07:16,402 --> 00:07:17,236
with the

385
00:07:17,236 --> 00:07:18,237
low conductivity

386
00:07:18,237 --> 00:07:19,672
material here,

387
00:07:19,672 --> 00:07:20,673
for example

388
00:07:20,673 --> 00:07:22,175
with the PDMS

389
00:07:22,175 --> 00:07:23,743
and then we put the

390
00:07:23,743 --> 00:07:25,011
surrounding medium

391
00:07:25,011 --> 00:07:25,878
around it.

392
00:07:25,878 --> 00:07:26,379
And then

393
00:07:26,379 --> 00:07:27,280
we apply the heat

394
00:07:27,280 --> 00:07:28,714
in different directions

395
00:07:28,714 --> 00:07:30,550
to experimentally show

396
00:07:30,550 --> 00:07:31,884
that if we use

397
00:07:31,884 --> 00:07:32,952
the thermal camera,

398
00:07:32,952 --> 00:07:34,220
we are able to

399
00:07:34,220 --> 00:07:35,254
thermally hide

400
00:07:35,254 --> 00:07:36,422
the object

401
00:07:36,422 --> 00:07:38,458
inside the cloak region.

402
00:07:38,458 --> 00:07:39,392
And the one thing

403
00:07:39,392 --> 00:07:40,593
that we explore,

404
00:07:40,593 --> 00:07:41,260
but that's very

405
00:07:41,260 --> 00:07:42,595
interesting, is

406
00:07:42,595 --> 00:07:44,464
we are trying to hide

407
00:07:44,464 --> 00:07:46,098
an apple shaped

408
00:07:46,098 --> 00:07:48,301
object from a pear

409
00:07:48,301 --> 00:07:49,502
shaped cloak.

410
00:07:49,502 --> 00:07:50,336
And another,

411
00:07:50,336 --> 00:07:51,170
that interesting thing

412
00:07:51,170 --> 00:07:52,071
that we also

413
00:07:52,071 --> 00:07:53,039
ask ourselves to do

414
00:07:53,039 --> 00:07:53,706
is to increase

415
00:07:53,706 --> 00:07:54,474
the complexity

416
00:07:54,474 --> 00:07:55,708
of the geometry

417
00:07:55,708 --> 00:07:58,144
by trying to hide

418
00:07:58,144 --> 00:07:59,078
a human face

419
00:07:59,078 --> 00:08:00,480
object from another

420
00:08:00,480 --> 00:08:01,180
very complex

421
00:08:01,180 --> 00:08:02,515
human faced object,

422
00:08:02,515 --> 00:08:03,983
and we physically show

423
00:08:03,983 --> 00:08:05,785
that they can be created

424
00:08:05,785 --> 00:08:07,320
and they can be realized

425
00:08:07,320 --> 00:08:07,787
in the three

426
00:08:07,787 --> 00:08:08,654
dimensional world.

427
00:08:08,654 --> 00:08:09,188
So I want

428
00:08:09,188 --> 00:08:09,822
to take those

429
00:08:09,822 --> 00:08:10,656
three dimensions

430
00:08:10,656 --> 00:08:11,357
in the shapes

431
00:08:11,357 --> 00:08:12,492
and thinking

432
00:08:12,492 --> 00:08:13,092
about more

433
00:08:13,092 --> 00:08:14,160
complex shapes.

434
00:08:14,160 --> 00:08:15,661
Can I ask you

435
00:08:15,661 --> 00:08:16,762
where you imagine

436
00:08:16,762 --> 00:08:17,396
this going

437
00:08:17,396 --> 00:08:17,730
in terms

438
00:08:17,730 --> 00:08:18,431
of possible

439
00:08:18,431 --> 00:08:19,232
applications?

440
00:08:19,232 --> 00:08:19,599
Like,

441
00:08:19,599 --> 00:08:21,300
I could imagine

442
00:08:21,300 --> 00:08:22,435
maybe using it for heat

443
00:08:22,435 --> 00:08:23,803
shielding and computers.

444
00:08:23,803 --> 00:08:24,704
Maybe it would

445
00:08:24,704 --> 00:08:25,238
circle back

446
00:08:25,238 --> 00:08:26,105
to some military

447
00:08:26,105 --> 00:08:27,740
applications eventually.

448
00:08:27,740 --> 00:08:28,174
Can you talk

449
00:08:28,174 --> 00:08:28,975
a little bit about where

450
00:08:28,975 --> 00:08:29,709
you might see

451
00:08:29,709 --> 00:08:30,743
this headed?

452
00:08:30,743 --> 00:08:32,078
Yes. Yes, definitely.

453
00:08:32,078 --> 00:08:32,879
So in terms

454
00:08:32,879 --> 00:08:33,713
of application,

455
00:08:33,713 --> 00:08:34,614
if we think about

456
00:08:34,614 --> 00:08:36,115
the thermal cloak,

457
00:08:36,115 --> 00:08:37,416
it can definitely

458
00:08:37,416 --> 00:08:38,618
be used to protect

459
00:08:38,618 --> 00:08:39,452
for example

460
00:08:39,452 --> 00:08:40,520
some sensitive

461
00:08:40,520 --> 00:08:41,654
electronic devices

462
00:08:41,654 --> 00:08:42,855
from being influenced

463
00:08:42,855 --> 00:08:44,023
by extreme

464
00:08:44,023 --> 00:08:45,024
external heat.

465
00:08:45,024 --> 00:08:47,059
It can also be used to

466
00:08:47,059 --> 00:08:47,894
thermally hide

467
00:08:47,894 --> 00:08:49,262
some important

468
00:08:49,262 --> 00:08:50,096
or highly

469
00:08:50,096 --> 00:08:51,631
valuable devices

470
00:08:51,631 --> 00:08:52,899
from being detected.

471
00:08:52,899 --> 00:08:53,399
And one thing

472
00:08:53,399 --> 00:08:54,834
I wanted to add is that

473
00:08:54,834 --> 00:08:55,601
I think there is

474
00:08:55,601 --> 00:08:56,502
a much larger

475
00:08:56,502 --> 00:08:57,970
opportunities beyond

476
00:08:57,970 --> 00:08:59,372
just a thermal cloak.

477
00:08:59,372 --> 00:09:00,439
This object,

478
00:09:00,439 --> 00:09:01,173
for example,

479
00:09:01,173 --> 00:09:02,875
I think the capability

480
00:09:02,875 --> 00:09:03,643
that we gain in

481
00:09:03,643 --> 00:09:04,143
this work

482
00:09:04,143 --> 00:09:05,311
is the capability

483
00:09:05,311 --> 00:09:06,913
that we can control

484
00:09:06,913 --> 00:09:07,480
the heat

485
00:09:07,480 --> 00:09:08,381
and manipulate

486
00:09:08,381 --> 00:09:09,682
the heat in this complex

487
00:09:09,682 --> 00:09:10,416
3D world,

488
00:09:10,416 --> 00:09:12,118
this 3D environment.

489
00:09:12,118 --> 00:09:13,419
So in this case,

490
00:09:13,419 --> 00:09:14,186
cloaking is

491
00:09:14,186 --> 00:09:15,421
just one function,

492
00:09:15,421 --> 00:09:17,056
as we just discussed

493
00:09:17,056 --> 00:09:18,357
the same idea

494
00:09:18,357 --> 00:09:19,292
of transformation

495
00:09:19,292 --> 00:09:19,659
thermal.

496
00:09:19,659 --> 00:09:21,294
This can also be used

497
00:09:21,294 --> 00:09:22,295
to create

498
00:09:22,295 --> 00:09:23,095
the device

499
00:09:23,095 --> 00:09:25,464
that not only just hide

500
00:09:25,464 --> 00:09:26,432
the object,

501
00:09:26,432 --> 00:09:26,899
basically

502
00:09:26,899 --> 00:09:27,833
creating uniform

503
00:09:27,833 --> 00:09:28,834
temperature distribution

504
00:09:28,834 --> 00:09:29,468
on the

505
00:09:29,468 --> 00:09:30,703
outside of the region.

506
00:09:30,703 --> 00:09:32,071
It can also be used

507
00:09:32,071 --> 00:09:33,506
to manipulate the heat

508
00:09:33,506 --> 00:09:35,708
inside the cloak region.

509
00:09:35,708 --> 00:09:36,509
So for example,

510
00:09:36,509 --> 00:09:37,076
if there are

511
00:09:37,076 --> 00:09:38,210
some devices

512
00:09:38,210 --> 00:09:39,011
or equipment

513
00:09:39,011 --> 00:09:40,112
that require

514
00:09:40,112 --> 00:09:41,147
the concentrating

515
00:09:41,147 --> 00:09:41,981
of the heat,

516
00:09:41,981 --> 00:09:43,583
dilution of the heat,

517
00:09:43,583 --> 00:09:44,717
or rotating

518
00:09:44,717 --> 00:09:45,585
the heat flow,

519
00:09:45,585 --> 00:09:46,218
we can use

520
00:09:46,218 --> 00:09:47,153
the same idea,

521
00:09:47,153 --> 00:09:47,553
the same

522
00:09:47,553 --> 00:09:48,921
transformation thermal

523
00:09:48,921 --> 00:09:50,423
to construct

524
00:09:50,423 --> 00:09:51,190
the lattice,

525
00:09:51,190 --> 00:09:51,991
the architecture

526
00:09:51,991 --> 00:09:52,758
of the material

527
00:09:52,758 --> 00:09:53,659
in order to

528
00:09:53,659 --> 00:09:54,994
manipulate the heat

529
00:09:54,994 --> 00:09:56,596
according to the

530
00:09:56,596 --> 00:09:57,663
specific demand

531
00:09:57,663 --> 00:09:59,498
of this subject,

532
00:09:59,498 --> 00:10:00,266
according to different

533
00:10:00,266 --> 00:10:01,701
applications. Very cool.

534
00:10:01,701 --> 00:10:02,902
So taking the heat

535
00:10:02,902 --> 00:10:03,903
both on the outside

536
00:10:03,903 --> 00:10:04,971
and dissipating it

537
00:10:04,971 --> 00:10:05,571
in different ways,

538
00:10:05,571 --> 00:10:06,238
or directing it

539
00:10:06,238 --> 00:10:06,872
in different ways,

540
00:10:06,872 --> 00:10:07,573
and being able

541
00:10:07,573 --> 00:10:08,841
to do it on the inside,

542
00:10:08,841 --> 00:10:09,842
that might be totally

543
00:10:09,842 --> 00:10:10,843
different ways.

544
00:10:10,843 --> 00:10:11,811
So this kind of builds

545
00:10:11,811 --> 00:10:12,311
on where

546
00:10:12,311 --> 00:10:13,512
I want to go next

547
00:10:13,512 --> 00:10:14,113
for thinking

548
00:10:14,113 --> 00:10:15,281
about topology.

549
00:10:15,281 --> 00:10:15,748
Like you've done

550
00:10:15,748 --> 00:10:16,115
a lot of

551
00:10:16,115 --> 00:10:16,782
different versions

552
00:10:16,782 --> 00:10:17,216
of these,

553
00:10:17,216 --> 00:10:18,150
as you mentioned,

554
00:10:18,150 --> 00:10:19,118
leading up to this

555
00:10:19,118 --> 00:10:19,986
and some of

556
00:10:19,986 --> 00:10:21,253
your earlier works

557
00:10:21,253 --> 00:10:21,954
was really dealing

558
00:10:21,954 --> 00:10:22,822
with different shapes

559
00:10:22,822 --> 00:10:24,423
and some of

560
00:10:24,423 --> 00:10:25,391
that control mechanism.

561
00:10:25,391 --> 00:10:25,791
So thinking

562
00:10:25,791 --> 00:10:26,859
about rotation

563
00:10:26,859 --> 00:10:27,293
and the

564
00:10:27,293 --> 00:10:28,060
concentration

565
00:10:28,060 --> 00:10:28,561
attributes,

566
00:10:28,561 --> 00:10:28,961
can you talk

567
00:10:28,961 --> 00:10:29,295
a little bit

568
00:10:29,295 --> 00:10:30,896
about how these

569
00:10:30,896 --> 00:10:31,597
kind of interact

570
00:10:31,597 --> 00:10:32,098
with each other

571
00:10:32,098 --> 00:10:33,032
to get you to

572
00:10:33,032 --> 00:10:33,866
this successful

573
00:10:33,866 --> 00:10:34,900
device here.

574
00:10:34,900 --> 00:10:35,601
A couple of things

575
00:10:35,601 --> 00:10:36,268
you hit there,

576
00:10:36,268 --> 00:10:37,303
I would like to

577
00:10:37,303 --> 00:10:37,837
follow up

578
00:10:37,837 --> 00:10:39,372
on these several points.

579
00:10:39,372 --> 00:10:40,139
The first one is

580
00:10:40,139 --> 00:10:41,040
about the geometry.

581
00:10:41,040 --> 00:10:42,141
I think the geometry

582
00:10:42,141 --> 00:10:43,075
and topology

583
00:10:43,075 --> 00:10:43,876
plays a

584
00:10:43,876 --> 00:10:45,277
very important role

585
00:10:45,277 --> 00:10:46,145
in this work.

586
00:10:46,145 --> 00:10:47,079
So there are

587
00:10:47,079 --> 00:10:47,813
I would say

588
00:10:47,813 --> 00:10:48,948
in terms of this

589
00:10:48,948 --> 00:10:50,082
thermal cloud project

590
00:10:50,082 --> 00:10:50,683
we are working

591
00:10:50,683 --> 00:10:51,584
on, there are

592
00:10:51,584 --> 00:10:52,518
two geometries

593
00:10:52,518 --> 00:10:53,819
that are important.

594
00:10:53,819 --> 00:10:55,321
One is the geometry

595
00:10:55,321 --> 00:10:56,522
of the object

596
00:10:56,522 --> 00:10:58,090
that we want to conceal.

597
00:10:58,090 --> 00:10:59,759
The other geometry is

598
00:10:59,759 --> 00:11:00,893
what is the cloaking

599
00:11:00,893 --> 00:11:02,895
region, the geometry

600
00:11:02,895 --> 00:11:04,096
we wanted to consider.

601
00:11:04,096 --> 00:11:06,399
And the difference

602
00:11:06,399 --> 00:11:07,266
between these two

603
00:11:07,266 --> 00:11:09,502
geometry is the design

604
00:11:09,502 --> 00:11:10,703
space is the space

605
00:11:10,703 --> 00:11:11,504
that we will need

606
00:11:11,504 --> 00:11:12,571
to create

607
00:11:12,571 --> 00:11:14,106
the architecture

608
00:11:14,106 --> 00:11:15,307
material in order to

609
00:11:15,307 --> 00:11:16,742
manipulate the heat.

610
00:11:16,742 --> 00:11:18,077
So in this case,

611
00:11:18,077 --> 00:11:18,811
this is why

612
00:11:18,811 --> 00:11:20,546
the 3D geometry and also

613
00:11:20,546 --> 00:11:21,981
the arbitrary geometry

614
00:11:21,981 --> 00:11:22,581
is such a

615
00:11:22,581 --> 00:11:23,716
difficult problem

616
00:11:23,716 --> 00:11:25,651
because the architecture

617
00:11:25,651 --> 00:11:26,052
has to

618
00:11:26,052 --> 00:11:27,386
continuously change

619
00:11:27,386 --> 00:11:28,120
its thickness

620
00:11:28,120 --> 00:11:29,055
and orientation

621
00:11:29,055 --> 00:11:31,057
and at the same time

622
00:11:31,057 --> 00:11:31,657
remain

623
00:11:31,657 --> 00:11:32,992
globally connected.

624
00:11:32,992 --> 00:11:34,260
So for

625
00:11:34,260 --> 00:11:35,661
extremely complicated

626
00:11:35,661 --> 00:11:36,262
geometry,

627
00:11:36,262 --> 00:11:37,263
such as the human

628
00:11:37,263 --> 00:11:38,297
face example.

629
00:11:38,297 --> 00:11:39,231
So for this type

630
00:11:39,231 --> 00:11:40,099
of a complicated

631
00:11:40,099 --> 00:11:41,000
geometry

632
00:11:41,000 --> 00:11:41,634
we make

633
00:11:41,634 --> 00:11:43,135
use of the spherical

634
00:11:43,135 --> 00:11:44,036
harmonics.

635
00:11:44,036 --> 00:11:44,970
Basically

636
00:11:44,970 --> 00:11:45,771
it's a

637
00:11:45,771 --> 00:11:47,506
mathematical description

638
00:11:47,506 --> 00:11:48,474
or Fourier

639
00:11:48,474 --> 00:11:49,475
representation of

640
00:11:49,475 --> 00:11:50,276
a sphere.

641
00:11:50,276 --> 00:11:51,877
Basically to translate

642
00:11:51,877 --> 00:11:53,312
the complicated

643
00:11:53,312 --> 00:11:54,947
human face and geometry

644
00:11:54,947 --> 00:11:56,716
into a mathematical form

645
00:11:56,716 --> 00:11:58,751
that our transformation

646
00:11:58,751 --> 00:12:00,219
theory can use.

647
00:12:00,219 --> 00:12:02,221
So this also connects

648
00:12:02,221 --> 00:12:02,822
naturally

649
00:12:02,822 --> 00:12:03,856
with our earlier work

650
00:12:03,856 --> 00:12:05,491
with the other thermal

651
00:12:05,491 --> 00:12:06,225
devices,

652
00:12:06,225 --> 00:12:07,426
the metal devices,

653
00:12:07,426 --> 00:12:08,160
for example,

654
00:12:08,160 --> 00:12:09,428
the cloak

655
00:12:09,428 --> 00:12:11,897
that can rotate the heat

656
00:12:11,897 --> 00:12:12,732
and concentrate

657
00:12:12,732 --> 00:12:13,332
the heat.

658
00:12:13,332 --> 00:12:14,400
So I would say that

659
00:12:14,400 --> 00:12:15,701
the geometry plays

660
00:12:15,701 --> 00:12:17,103
a very important role

661
00:12:17,103 --> 00:12:17,937
because for

662
00:12:17,937 --> 00:12:18,704
each different

663
00:12:18,704 --> 00:12:19,739
types of capability,

664
00:12:19,739 --> 00:12:21,140
we want to realize

665
00:12:21,140 --> 00:12:22,241
either a cloak

666
00:12:22,241 --> 00:12:23,642
or concentrator

667
00:12:23,642 --> 00:12:24,810
or rotator,

668
00:12:24,810 --> 00:12:26,746
the resulting

669
00:12:26,746 --> 00:12:27,580
architected

670
00:12:27,580 --> 00:12:28,280
lattice will

671
00:12:28,280 --> 00:12:29,482
be completely different.

672
00:12:29,482 --> 00:12:30,116
In addition

673
00:12:30,116 --> 00:12:31,383
to hiding this object

674
00:12:31,383 --> 00:12:31,851
from being

675
00:12:31,851 --> 00:12:32,752
thermally detected,

676
00:12:32,752 --> 00:12:33,853
we can also

677
00:12:33,853 --> 00:12:35,454
concentrate the heat

678
00:12:35,454 --> 00:12:36,589
inside this region,

679
00:12:36,589 --> 00:12:38,224
and in this case

680
00:12:38,224 --> 00:12:40,059
it is a thermal rotator.

681
00:12:40,059 --> 00:12:41,293
So in addition

682
00:12:41,293 --> 00:12:43,596
to thermally hide

683
00:12:43,596 --> 00:12:44,363
or conceal

684
00:12:44,363 --> 00:12:45,264
this object

685
00:12:45,264 --> 00:12:46,265
being detected

686
00:12:46,265 --> 00:12:48,334
from outside a camera,

687
00:12:48,334 --> 00:12:50,236
it can also redirect

688
00:12:50,236 --> 00:12:52,304
the heat from,

689
00:12:52,304 --> 00:12:53,472
for example,

690
00:12:53,472 --> 00:12:55,241
90 degree to 45 degree

691
00:12:55,241 --> 00:12:56,041
and so on.

692
00:12:56,041 --> 00:12:56,642
So in

693
00:12:56,642 --> 00:12:57,510
all of these cases,

694
00:12:57,510 --> 00:12:58,144
the geometry

695
00:12:58,144 --> 00:12:59,345
and topology plays

696
00:12:59,345 --> 00:13:00,713
a huge role.

697
00:13:00,713 --> 00:13:02,414
But the underlying

698
00:13:02,414 --> 00:13:04,316
theory and mathematical

699
00:13:04,316 --> 00:13:05,017
descriptions

700
00:13:05,017 --> 00:13:06,252
are universal.

701
00:13:06,252 --> 00:13:07,019
So really thinking

702
00:13:07,019 --> 00:13:07,987
about how you want

703
00:13:07,987 --> 00:13:08,988
to manifest

704
00:13:08,988 --> 00:13:09,822
the technique

705
00:13:09,822 --> 00:13:11,557
or the capability

706
00:13:11,557 --> 00:13:13,192
of different forms

707
00:13:13,192 --> 00:13:13,592
to get to

708
00:13:13,592 --> 00:13:14,160
where you're going

709
00:13:14,160 --> 00:13:15,795
there, you mentioned

710
00:13:15,795 --> 00:13:16,495
that it's

711
00:13:16,495 --> 00:13:17,663
that the materials

712
00:13:17,663 --> 00:13:18,097
a little bit.

713
00:13:18,097 --> 00:13:19,265
And I wanted to ask you

714
00:13:19,265 --> 00:13:20,733
about the importance

715
00:13:20,733 --> 00:13:21,433
of materials,

716
00:13:21,433 --> 00:13:22,802
thinking about aluminum

717
00:13:22,802 --> 00:13:24,970
for the lattice there.

718
00:13:24,970 --> 00:13:26,739
How important is it

719
00:13:26,739 --> 00:13:27,106
that it's

720
00:13:27,106 --> 00:13:27,973
aluminum versus

721
00:13:27,973 --> 00:13:28,908
other kinds of metals

722
00:13:28,908 --> 00:13:29,575
or other kinds

723
00:13:29,575 --> 00:13:30,276
of polymers

724
00:13:30,276 --> 00:13:31,377
or something like,

725
00:13:31,377 --> 00:13:32,311
what impact does

726
00:13:32,311 --> 00:13:33,512
that have specifically?

727
00:13:33,512 --> 00:13:34,113
So a couple

728
00:13:34,113 --> 00:13:35,147
of consideration

729
00:13:35,147 --> 00:13:35,714
of why

730
00:13:35,714 --> 00:13:37,183
we pick up aluminum

731
00:13:37,183 --> 00:13:38,217
as one of the materials.

732
00:13:38,217 --> 00:13:39,752
So in fact,

733
00:13:39,752 --> 00:13:40,452
in order to make

734
00:13:40,452 --> 00:13:41,353
an effective

735
00:13:41,353 --> 00:13:42,121
thermal cloak

736
00:13:42,121 --> 00:13:42,822
we will need

737
00:13:42,822 --> 00:13:44,056
two types of materials.

738
00:13:44,056 --> 00:13:45,090
One is the highly

739
00:13:45,090 --> 00:13:46,225
thermally conductive.

740
00:13:46,225 --> 00:13:47,426
The other one is a

741
00:13:47,426 --> 00:13:48,294
not as

742
00:13:48,294 --> 00:13:49,862
a high conductivity.

743
00:13:49,862 --> 00:13:50,896
So in terms of

744
00:13:50,896 --> 00:13:51,797
the aluminum

745
00:13:51,797 --> 00:13:53,032
is the one that we use

746
00:13:53,032 --> 00:13:53,899
for the highly

747
00:13:53,899 --> 00:13:55,501
conductive material.

748
00:13:55,501 --> 00:13:56,468
And the reason

749
00:13:56,468 --> 00:13:57,336
we choose aluminum

750
00:13:57,336 --> 00:13:58,037
is because it's

751
00:13:58,037 --> 00:13:58,904
highly conductive

752
00:13:58,904 --> 00:14:00,039
and it is

753
00:14:00,039 --> 00:14:01,173
easily accessible

754
00:14:01,173 --> 00:14:02,441
at the same time, it's

755
00:14:02,441 --> 00:14:03,509
a fully compatible

756
00:14:03,509 --> 00:14:05,377
with the metal additive

757
00:14:05,377 --> 00:14:06,345
manufacturing that

758
00:14:06,345 --> 00:14:07,346
we wanted to use

759
00:14:07,346 --> 00:14:08,013
to fabricate

760
00:14:08,013 --> 00:14:08,814
this lattice.

761
00:14:08,814 --> 00:14:11,350
So in principle,

762
00:14:11,350 --> 00:14:12,451
any type of

763
00:14:12,451 --> 00:14:14,053
highly conductive metal,

764
00:14:14,053 --> 00:14:14,787
metallic

765
00:14:14,787 --> 00:14:15,454
or some other

766
00:14:15,454 --> 00:14:16,589
type of material

767
00:14:16,589 --> 00:14:17,389
can be used

768
00:14:17,389 --> 00:14:18,190
as this highly

769
00:14:18,190 --> 00:14:20,059
conductive material.

770
00:14:20,059 --> 00:14:21,060
The architecture

771
00:14:21,060 --> 00:14:22,027
actually it's

772
00:14:22,027 --> 00:14:22,862
more important

773
00:14:22,862 --> 00:14:23,796
than the specific

774
00:14:23,796 --> 00:14:24,864
material itself.

775
00:14:24,864 --> 00:14:26,198
So in another study

776
00:14:26,198 --> 00:14:26,999
we actually make

777
00:14:26,999 --> 00:14:28,300
use of stainless steel

778
00:14:28,300 --> 00:14:30,135
instead of the aluminum.

779
00:14:30,135 --> 00:14:31,737
So the common

780
00:14:31,737 --> 00:14:32,471
feature between

781
00:14:32,471 --> 00:14:33,672
these two materials are

782
00:14:33,672 --> 00:14:34,740
they're both

783
00:14:34,740 --> 00:14:35,741
easily accessible.

784
00:14:35,741 --> 00:14:36,342
And they are

785
00:14:36,342 --> 00:14:37,142
manufacturable

786
00:14:37,142 --> 00:14:38,744
using metal 3D printing.

787
00:14:38,744 --> 00:14:40,679
And at the same time

788
00:14:40,679 --> 00:14:42,081
they also have high

789
00:14:42,081 --> 00:14:43,282
thermal conductivity.

790
00:14:43,282 --> 00:14:45,050
Now if we wanted to

791
00:14:45,050 --> 00:14:46,852
use this device towards

792
00:14:46,852 --> 00:14:47,653
higher

793
00:14:47,653 --> 00:14:49,021
temperature distribution

794
00:14:49,021 --> 00:14:51,056
or extreme temperature,

795
00:14:51,056 --> 00:14:52,591
to give us an idea,

796
00:14:52,591 --> 00:14:53,392
the aluminum

797
00:14:53,392 --> 00:14:54,159
usually works

798
00:14:54,159 --> 00:14:57,162
around 115°C.

799
00:14:57,463 --> 00:14:58,898
If we want to make

800
00:14:58,898 --> 00:14:59,698
an object

801
00:14:59,698 --> 00:15:00,332
or device

802
00:15:00,332 --> 00:15:01,233
that operates

803
00:15:01,233 --> 00:15:02,501
at a much higher

804
00:15:02,501 --> 00:15:03,736
extreme temperature,

805
00:15:03,736 --> 00:15:04,637
then we would

806
00:15:04,637 --> 00:15:05,905
like to use

807
00:15:05,905 --> 00:15:06,872
even more

808
00:15:06,872 --> 00:15:08,173
thermally conducted

809
00:15:08,173 --> 00:15:09,475
metallic material

810
00:15:09,475 --> 00:15:10,943
instead of the aluminum.

811
00:15:10,943 --> 00:15:11,710
So it's

812
00:15:11,710 --> 00:15:12,344
really a question

813
00:15:12,344 --> 00:15:13,479
of what makes sense

814
00:15:13,479 --> 00:15:14,146
for the project

815
00:15:14,146 --> 00:15:14,880
you're working on.

816
00:15:14,880 --> 00:15:17,182
And it speaks to in

817
00:15:17,182 --> 00:15:17,583
I think

818
00:15:17,583 --> 00:15:18,384
in fundamental

819
00:15:18,384 --> 00:15:19,351
research in general,

820
00:15:19,351 --> 00:15:20,619
you want to get to

821
00:15:20,619 --> 00:15:20,953
where you're

822
00:15:20,953 --> 00:15:21,553
working with things

823
00:15:21,553 --> 00:15:22,021
that you can

824
00:15:22,021 --> 00:15:23,122
actually get access to

825
00:15:23,122 --> 00:15:23,722
that could

826
00:15:23,722 --> 00:15:24,423
actually be used

827
00:15:24,423 --> 00:15:25,291
for manufacturing.

828
00:15:25,291 --> 00:15:25,758
If this is

829
00:15:25,758 --> 00:15:26,792
moving up into

830
00:15:26,792 --> 00:15:27,559
some commercial

831
00:15:27,559 --> 00:15:28,193
application

832
00:15:28,193 --> 00:15:28,827
where they can get

833
00:15:28,827 --> 00:15:29,428
the materials

834
00:15:29,428 --> 00:15:30,429
to do this.

835
00:15:30,429 --> 00:15:31,864
Yes, exactly.

836
00:15:31,864 --> 00:15:32,865
So thinking of

837
00:15:32,865 --> 00:15:33,432
that commercial

838
00:15:33,432 --> 00:15:34,533
application, I guess,

839
00:15:34,533 --> 00:15:36,135
what is the pathway

840
00:15:36,135 --> 00:15:37,970
to translate this study

841
00:15:37,970 --> 00:15:38,837
into something

842
00:15:38,837 --> 00:15:40,072
that might be used

843
00:15:40,072 --> 00:15:41,073
out in the world?

844
00:15:41,073 --> 00:15:41,740
So I think

845
00:15:41,740 --> 00:15:42,675
there are various

846
00:15:42,675 --> 00:15:43,442
applications

847
00:15:43,442 --> 00:15:44,677
considerations

848
00:15:44,677 --> 00:15:45,744
when we think about

849
00:15:45,744 --> 00:15:47,479
how do we scale it

850
00:15:47,479 --> 00:15:48,380
towards the

851
00:15:48,380 --> 00:15:49,682
commercial applications

852
00:15:49,682 --> 00:15:50,149
for different

853
00:15:50,149 --> 00:15:51,150
applications.

854
00:15:51,150 --> 00:15:52,051
The positive

855
00:15:52,051 --> 00:15:53,218
and encouraging part

856
00:15:53,218 --> 00:15:54,653
is that in our work,

857
00:15:54,653 --> 00:15:55,988
we have already

858
00:15:55,988 --> 00:15:56,922
incorporates

859
00:15:56,922 --> 00:15:58,457
the manufacturing

860
00:15:58,457 --> 00:15:59,224
constraints.

861
00:15:59,224 --> 00:16:00,259
Because of the fact

862
00:16:00,259 --> 00:16:01,293
that we make use

863
00:16:01,293 --> 00:16:02,561
of our dehomogenization

864
00:16:02,561 --> 00:16:03,462
technique.

865
00:16:03,462 --> 00:16:04,897
All the lattices are

866
00:16:04,897 --> 00:16:05,931
naturally connected

867
00:16:05,931 --> 00:16:06,665
with each other,

868
00:16:06,665 --> 00:16:07,633
and that's something

869
00:16:07,633 --> 00:16:09,301
that we also find it

870
00:16:09,301 --> 00:16:11,236
extremely surprising

871
00:16:11,236 --> 00:16:12,371
and satisfactory

872
00:16:12,371 --> 00:16:14,873
is the ideal cloak.

873
00:16:14,873 --> 00:16:15,908
The almost ideal cloak

874
00:16:15,908 --> 00:16:16,442
is actually

875
00:16:16,442 --> 00:16:17,242
made of something

876
00:16:17,242 --> 00:16:18,711
that is so simple

877
00:16:18,711 --> 00:16:19,578
and elegant

878
00:16:19,578 --> 00:16:20,112
and can be

879
00:16:20,112 --> 00:16:22,147
directly manufactured.

880
00:16:22,147 --> 00:16:23,515
I think if we want

881
00:16:23,515 --> 00:16:24,550
to scale it up,

882
00:16:24,550 --> 00:16:25,718
there are three things

883
00:16:25,718 --> 00:16:26,251
that we will

884
00:16:26,251 --> 00:16:27,386
need to consider.

885
00:16:27,386 --> 00:16:28,387
So they are

886
00:16:28,387 --> 00:16:29,755
scaling up in three

887
00:16:29,755 --> 00:16:31,557
different dimensions.

888
00:16:31,557 --> 00:16:33,192
The first one is to

889
00:16:33,192 --> 00:16:34,626
when we want to scale up

890
00:16:34,626 --> 00:16:36,362
in terms of size,

891
00:16:36,362 --> 00:16:37,096
in this case

892
00:16:37,096 --> 00:16:37,830
the theory

893
00:16:37,830 --> 00:16:39,598
as well as the framework

894
00:16:39,598 --> 00:16:40,399
that we propose

895
00:16:40,399 --> 00:16:41,300
in this work.

896
00:16:41,300 --> 00:16:42,468
It's applicable

897
00:16:42,468 --> 00:16:43,402
and directly

898
00:16:43,402 --> 00:16:44,236
generalizable

899
00:16:44,236 --> 00:16:45,537
for any size.

900
00:16:45,537 --> 00:16:46,338
So so it's

901
00:16:46,338 --> 00:16:47,373
size independent.

902
00:16:47,373 --> 00:16:48,540
And if we want to,

903
00:16:48,540 --> 00:16:49,041
for example,

904
00:16:49,041 --> 00:16:49,908
increase this

905
00:16:49,908 --> 00:16:51,377
size of the object

906
00:16:51,377 --> 00:16:53,012
to ten times bigger,

907
00:16:53,012 --> 00:16:53,946
all we need to do

908
00:16:53,946 --> 00:16:54,947
is to

909
00:16:54,947 --> 00:16:56,882
recreate this

910
00:16:56,882 --> 00:16:58,517
lattice distribution

911
00:16:58,517 --> 00:17:00,352
to redirect the heat.

912
00:17:00,352 --> 00:17:01,620
It will not be simply

913
00:17:01,620 --> 00:17:03,055
to increase the size

914
00:17:03,055 --> 00:17:03,922
by ten times.

915
00:17:03,922 --> 00:17:04,990
It will require

916
00:17:04,990 --> 00:17:05,657
some different

917
00:17:05,657 --> 00:17:06,859
calculations,

918
00:17:06,859 --> 00:17:08,460
but the procedure

919
00:17:08,460 --> 00:17:09,194
will be exactly

920
00:17:09,194 --> 00:17:09,561
the same.

921
00:17:09,561 --> 00:17:10,863
So that part is

922
00:17:10,863 --> 00:17:12,297
really general

923
00:17:12,297 --> 00:17:13,499
in terms of size.

924
00:17:13,499 --> 00:17:14,333
The second part

925
00:17:14,333 --> 00:17:15,000
is, as

926
00:17:15,000 --> 00:17:16,101
we just discussed,

927
00:17:16,101 --> 00:17:18,103
if we wanted this device

928
00:17:18,103 --> 00:17:20,072
to work under different

929
00:17:20,072 --> 00:17:21,306
operating temperature.

930
00:17:21,306 --> 00:17:22,374
In that case,

931
00:17:22,374 --> 00:17:24,176
instead of the aluminum,

932
00:17:24,176 --> 00:17:25,310
we probably wanted

933
00:17:25,310 --> 00:17:26,412
to use some material

934
00:17:26,412 --> 00:17:27,513
that is more

935
00:17:27,513 --> 00:17:28,614
thermally conductive.

936
00:17:28,614 --> 00:17:29,715
So in that case,

937
00:17:29,715 --> 00:17:30,516
we will find

938
00:17:30,516 --> 00:17:31,116
a different set

939
00:17:31,116 --> 00:17:32,618
of material combinations

940
00:17:32,618 --> 00:17:33,919
to create the cloak.

941
00:17:33,919 --> 00:17:35,120
So that's in terms of

942
00:17:35,120 --> 00:17:36,155
the temperature

943
00:17:36,155 --> 00:17:37,356
or the operating

944
00:17:37,356 --> 00:17:38,524
temperature range.

945
00:17:38,524 --> 00:17:39,491
The third part

946
00:17:39,491 --> 00:17:40,392
I think

947
00:17:40,392 --> 00:17:41,226
that's very important

948
00:17:41,226 --> 00:17:41,860
for commercial

949
00:17:41,860 --> 00:17:42,761
applications

950
00:17:42,761 --> 00:17:43,495
is whether

951
00:17:43,495 --> 00:17:44,196
they can

952
00:17:44,196 --> 00:17:46,031
massively produce

953
00:17:46,031 --> 00:17:48,534
massively fabricated

954
00:17:48,534 --> 00:17:50,035
as well as in terms

955
00:17:50,035 --> 00:17:50,803
of the cost

956
00:17:50,803 --> 00:17:52,037
of fabrication.

957
00:17:52,037 --> 00:17:53,639
And in this aspect,

958
00:17:53,639 --> 00:17:54,440
I think

959
00:17:54,440 --> 00:17:55,641
in this current work,

960
00:17:55,641 --> 00:17:56,375
we use the metal

961
00:17:56,375 --> 00:17:57,576
3D printing

962
00:17:57,576 --> 00:17:58,010
in terms

963
00:17:58,010 --> 00:18:00,145
of massive fabrication.

964
00:18:00,145 --> 00:18:00,712
I think

965
00:18:00,712 --> 00:18:01,914
both the improvement,

966
00:18:01,914 --> 00:18:02,714
further development

967
00:18:02,714 --> 00:18:03,215
and research

968
00:18:03,215 --> 00:18:03,816
on the metal

969
00:18:03,816 --> 00:18:04,516
3D printing,

970
00:18:04,516 --> 00:18:05,617
as well as considering

971
00:18:05,617 --> 00:18:07,719
some other type of metal

972
00:18:07,719 --> 00:18:08,987
fabrication technique

973
00:18:08,987 --> 00:18:10,155
like forming,

974
00:18:10,155 --> 00:18:10,856
milling

975
00:18:10,856 --> 00:18:11,857
or stamping,

976
00:18:11,857 --> 00:18:12,691
will be

977
00:18:12,691 --> 00:18:13,492
a very good,

978
00:18:13,492 --> 00:18:14,660
promising technique

979
00:18:14,660 --> 00:18:16,295
to massively produce

980
00:18:16,295 --> 00:18:17,663
the thermal cloak.

981
00:18:17,663 --> 00:18:19,298
In terms of the cost,

982
00:18:19,298 --> 00:18:20,666
I think it's related to

983
00:18:20,666 --> 00:18:21,800
both the type

984
00:18:21,800 --> 00:18:23,535
of fabrication technique

985
00:18:23,535 --> 00:18:24,837
as well as the materials

986
00:18:24,837 --> 00:18:26,305
and the materials

987
00:18:26,305 --> 00:18:27,039
that we pick.

988
00:18:27,039 --> 00:18:27,639
For example,

989
00:18:27,639 --> 00:18:28,540
the aluminum is

990
00:18:28,540 --> 00:18:29,374
a good example

991
00:18:29,374 --> 00:18:30,342
of a commonly

992
00:18:30,342 --> 00:18:30,976
used material

993
00:18:30,976 --> 00:18:31,310
that is

994
00:18:31,310 --> 00:18:32,211
easily accessible

995
00:18:32,211 --> 00:18:33,512
and affordable.

996
00:18:33,512 --> 00:18:34,980
So now I mentioned

997
00:18:34,980 --> 00:18:36,348
a lot of consideration

998
00:18:36,348 --> 00:18:37,382
about being able

999
00:18:37,382 --> 00:18:39,418
to scale this up

1000
00:18:39,418 --> 00:18:40,719
or scale this

1001
00:18:40,719 --> 00:18:41,787
to toward more

1002
00:18:41,787 --> 00:18:43,589
general application.

1003
00:18:43,589 --> 00:18:45,390
Another consideration

1004
00:18:45,390 --> 00:18:46,425
or further development

1005
00:18:46,425 --> 00:18:47,626
needed for the thermal

1006
00:18:47,626 --> 00:18:48,093
cloak, for

1007
00:18:48,093 --> 00:18:48,961
example,

1008
00:18:48,961 --> 00:18:50,562
is to adapt it

1009
00:18:50,562 --> 00:18:52,030
for the real world

1010
00:18:52,030 --> 00:18:52,798
consideration,

1011
00:18:52,798 --> 00:18:54,633
because if we wanted to

1012
00:18:54,633 --> 00:18:55,267
actually make

1013
00:18:55,267 --> 00:18:55,901
use of this

1014
00:18:55,901 --> 00:18:56,869
in real world,

1015
00:18:56,869 --> 00:18:58,137
we also need to consider

1016
00:18:58,137 --> 00:18:59,705
some additional physics.

1017
00:18:59,705 --> 00:19:00,472
For example,

1018
00:19:00,472 --> 00:19:01,507
the convection,

1019
00:19:01,507 --> 00:19:02,908
the radiation,

1020
00:19:02,908 --> 00:19:05,077
as well as some other

1021
00:19:05,077 --> 00:19:05,577
different type

1022
00:19:05,577 --> 00:19:06,111
of physics

1023
00:19:06,111 --> 00:19:07,146
that has not

1024
00:19:07,146 --> 00:19:08,180
been incorporated

1025
00:19:08,180 --> 00:19:09,348
in the current work.

1026
00:19:09,348 --> 00:19:09,948
For example,

1027
00:19:09,948 --> 00:19:10,749
if we wanted to

1028
00:19:10,749 --> 00:19:13,051
thermally hide a person,

1029
00:19:13,051 --> 00:19:14,019
then we will need

1030
00:19:14,019 --> 00:19:14,753
to consider

1031
00:19:14,753 --> 00:19:15,787
that the person

1032
00:19:15,787 --> 00:19:16,722
can generate

1033
00:19:16,722 --> 00:19:17,589
its own heat

1034
00:19:17,589 --> 00:19:18,657
and at the same time

1035
00:19:18,657 --> 00:19:19,091
the person

1036
00:19:19,091 --> 00:19:20,225
can also move.

1037
00:19:20,225 --> 00:19:21,760
So consideration

1038
00:19:21,760 --> 00:19:22,427
of the time,

1039
00:19:22,427 --> 00:19:24,096
the transient property,

1040
00:19:24,096 --> 00:19:25,697
as well as the heat

1041
00:19:25,697 --> 00:19:26,298
radiation

1042
00:19:26,298 --> 00:19:27,132
would be something

1043
00:19:27,132 --> 00:19:27,833
very interesting

1044
00:19:27,833 --> 00:19:28,534
to consider

1045
00:19:28,534 --> 00:19:29,801
for the real world

1046
00:19:29,801 --> 00:19:30,802
application, right?

1047
00:19:30,802 --> 00:19:31,203
Might be

1048
00:19:31,203 --> 00:19:32,104
a little complicated

1049
00:19:32,104 --> 00:19:33,872
to get it to move

1050
00:19:33,872 --> 00:19:34,339
when it's

1051
00:19:34,339 --> 00:19:35,774
a solid structure,

1052
00:19:35,774 --> 00:19:37,075
and to address

1053
00:19:37,075 --> 00:19:38,110
some of the issues

1054
00:19:38,110 --> 00:19:38,510
you're thinking

1055
00:19:38,510 --> 00:19:38,810
about there,

1056
00:19:38,810 --> 00:19:39,411
you might have to

1057
00:19:39,411 --> 00:19:39,745
do some

1058
00:19:39,745 --> 00:19:41,113
sort of surface over it

1059
00:19:41,113 --> 00:19:42,314
that isn't currently

1060
00:19:42,314 --> 00:19:43,515
part of the design.

1061
00:19:43,515 --> 00:19:44,316
Yes, exactly.

1062
00:19:44,316 --> 00:19:45,784
So I also want to

1063
00:19:45,784 --> 00:19:46,185
ask you,

1064
00:19:46,185 --> 00:19:46,785
while we're here

1065
00:19:46,785 --> 00:19:49,021
about the impact of

1066
00:19:49,021 --> 00:19:50,422
NSF support,

1067
00:19:50,422 --> 00:19:51,356
you have a career award.

1068
00:19:51,356 --> 00:19:52,858
You've been a Co-PI

1069
00:19:52,858 --> 00:19:53,825
or PI on a couple

1070
00:19:53,825 --> 00:19:54,893
other awards.

1071
00:19:54,893 --> 00:19:56,028
I want to ask you,

1072
00:19:56,028 --> 00:19:56,862
what difference has

1073
00:19:56,862 --> 00:19:58,630
that made to your work?

1074
00:19:58,630 --> 00:19:59,264
I think

1075
00:19:59,264 --> 00:20:01,033
NSF has been

1076
00:20:01,033 --> 00:20:02,701
really fundamental

1077
00:20:02,701 --> 00:20:03,702
to the trajectory

1078
00:20:03,702 --> 00:20:05,470
of my research

1079
00:20:05,470 --> 00:20:06,572
and including this

1080
00:20:06,572 --> 00:20:08,140
cloak research.

1081
00:20:08,140 --> 00:20:09,541
The impact goes

1082
00:20:09,541 --> 00:20:10,509
way beyond

1083
00:20:10,509 --> 00:20:11,610
supporting this

1084
00:20:11,610 --> 00:20:12,711
one publication

1085
00:20:12,711 --> 00:20:13,378
or just a few

1086
00:20:13,378 --> 00:20:14,546
publications.

1087
00:20:14,546 --> 00:20:16,982
I think it actually

1088
00:20:16,982 --> 00:20:17,950
enables us

1089
00:20:17,950 --> 00:20:18,951
the a

1090
00:20:18,951 --> 00:20:19,985
true intellectual

1091
00:20:19,985 --> 00:20:20,419
freedom.

1092
00:20:20,419 --> 00:20:21,987
And that's the core

1093
00:20:21,987 --> 00:20:23,789
essence of the NSF.

1094
00:20:23,789 --> 00:20:24,890
So it allows us

1095
00:20:24,890 --> 00:20:25,824
to explore

1096
00:20:25,824 --> 00:20:26,858
very fundamental

1097
00:20:26,858 --> 00:20:27,693
questions

1098
00:20:27,693 --> 00:20:28,994
like in this case,

1099
00:20:28,994 --> 00:20:30,762
can we physically create

1100
00:20:30,762 --> 00:20:32,497
the material property

1101
00:20:32,497 --> 00:20:33,665
that allows us to

1102
00:20:33,665 --> 00:20:34,733
freely manipulate

1103
00:20:34,733 --> 00:20:36,902
the heat in space?

1104
00:20:36,902 --> 00:20:38,837
So that's one example.

1105
00:20:38,837 --> 00:20:40,772
I feel like this NSF

1106
00:20:40,772 --> 00:20:41,273
support

1107
00:20:41,273 --> 00:20:42,708
is really fundamental

1108
00:20:42,708 --> 00:20:43,909
to support us

1109
00:20:43,909 --> 00:20:44,676
of exploring

1110
00:20:44,676 --> 00:20:45,577
these questions

1111
00:20:45,577 --> 00:20:47,179
that are so fundamental

1112
00:20:47,179 --> 00:20:48,614
but so important.

1113
00:20:48,614 --> 00:20:49,581
And I also

1114
00:20:49,581 --> 00:20:50,315
want to mention

1115
00:20:50,315 --> 00:20:51,383
that there are

1116
00:20:51,383 --> 00:20:52,451
numerous examples

1117
00:20:52,451 --> 00:20:54,853
that NSF has supported

1118
00:20:54,853 --> 00:20:55,988
in the past

1119
00:20:55,988 --> 00:20:56,788
that led

1120
00:20:56,788 --> 00:20:58,557
to extraordinary

1121
00:20:58,557 --> 00:20:59,491
technologies.

1122
00:20:59,491 --> 00:21:01,460
And I think NSF

1123
00:21:01,460 --> 00:21:02,894
making a huge impact

1124
00:21:02,894 --> 00:21:04,229
on also

1125
00:21:04,229 --> 00:21:05,797
the future technology,

1126
00:21:05,797 --> 00:21:06,431
that is going

1127
00:21:06,431 --> 00:21:07,599
to be very exciting

1128
00:21:07,599 --> 00:21:08,867
for the society.

1129
00:21:08,867 --> 00:21:10,335
So for my last question

1130
00:21:10,335 --> 00:21:10,936
today,

1131
00:21:10,936 --> 00:21:11,536
I want to think

1132
00:21:11,536 --> 00:21:12,437
about the future

1133
00:21:12,437 --> 00:21:14,039
and what you are excited

1134
00:21:14,039 --> 00:21:15,140
to work on over

1135
00:21:15,140 --> 00:21:16,642
the next few years.

1136
00:21:16,642 --> 00:21:17,709
Particularly in

1137
00:21:17,709 --> 00:21:18,377
this direction

1138
00:21:18,377 --> 00:21:19,711
of the thermal

1139
00:21:19,711 --> 00:21:21,313
cloaking capability.

1140
00:21:21,313 --> 00:21:22,147
One thing that

1141
00:21:22,147 --> 00:21:23,181
we wanted to

1142
00:21:23,181 --> 00:21:23,782
move forward

1143
00:21:23,782 --> 00:21:25,617
is to develop

1144
00:21:25,617 --> 00:21:26,718
these devices

1145
00:21:26,718 --> 00:21:27,352
that can

1146
00:21:27,352 --> 00:21:28,620
actively manipulate

1147
00:21:28,620 --> 00:21:30,455
the heat, for example,

1148
00:21:30,455 --> 00:21:32,257
where we can specify

1149
00:21:32,257 --> 00:21:33,625
where we want the heat

1150
00:21:33,625 --> 00:21:34,860
to be concentrated,

1151
00:21:34,860 --> 00:21:35,560
where it want it

1152
00:21:35,560 --> 00:21:36,795
to be redirected,

1153
00:21:36,795 --> 00:21:37,562
where we want it

1154
00:21:37,562 --> 00:21:38,897
to be protected,

1155
00:21:38,897 --> 00:21:39,998
and how do

1156
00:21:39,998 --> 00:21:41,099
we want to distribute it

1157
00:21:41,099 --> 00:21:42,034
between different

1158
00:21:42,034 --> 00:21:43,068
regions?

1159
00:21:43,068 --> 00:21:44,469
Another direction

1160
00:21:44,469 --> 00:21:45,537
I'm thinking that is

1161
00:21:45,537 --> 00:21:46,371
correlated is

1162
00:21:46,371 --> 00:21:48,173
how do we make this

1163
00:21:48,173 --> 00:21:49,174
a cloak

1164
00:21:49,174 --> 00:21:50,275
to be dynamic

1165
00:21:50,275 --> 00:21:51,710
and to accommodate

1166
00:21:51,710 --> 00:21:52,911
the transient behavior

1167
00:21:52,911 --> 00:21:54,579
that comes in for time.

1168
00:21:54,579 --> 00:21:55,314
Currently,

1169
00:21:55,314 --> 00:21:56,014
the cloak

1170
00:21:56,014 --> 00:21:56,948
that we are designing

1171
00:21:56,948 --> 00:21:58,383
are mainly the steady

1172
00:21:58,383 --> 00:21:59,217
state cloak

1173
00:21:59,217 --> 00:22:00,786
that basically requires

1174
00:22:00,786 --> 00:22:01,320
some time

1175
00:22:01,320 --> 00:22:02,054
for the heat

1176
00:22:02,054 --> 00:22:03,588
to become

1177
00:22:03,588 --> 00:22:05,190
a stable over time.

1178
00:22:05,190 --> 00:22:06,491
So incorporating

1179
00:22:06,491 --> 00:22:06,992
the time

1180
00:22:06,992 --> 00:22:08,226
would be very important

1181
00:22:08,226 --> 00:22:08,627
because

1182
00:22:08,627 --> 00:22:09,761
we also recognize

1183
00:22:09,761 --> 00:22:11,363
that in the real world

1184
00:22:11,363 --> 00:22:11,997
application,

1185
00:22:11,997 --> 00:22:12,731
the temperature

1186
00:22:12,731 --> 00:22:13,999
are taking with time,

1187
00:22:13,999 --> 00:22:16,001
and the object itself

1188
00:22:16,001 --> 00:22:16,868
can also

1189
00:22:16,868 --> 00:22:18,704
moves with time.

1190
00:22:18,704 --> 00:22:19,571
The third direction

1191
00:22:19,571 --> 00:22:21,573
I wanted to move forward

1192
00:22:21,573 --> 00:22:22,507
is to move

1193
00:22:22,507 --> 00:22:23,442
beyond the heat.

1194
00:22:23,442 --> 00:22:24,343
So basically

1195
00:22:24,343 --> 00:22:25,911
we can in addition

1196
00:22:25,911 --> 00:22:26,912
to manipulating

1197
00:22:26,912 --> 00:22:27,412
the heat,

1198
00:22:27,412 --> 00:22:27,946
we also

1199
00:22:27,946 --> 00:22:28,814
wanted to develop

1200
00:22:28,814 --> 00:22:30,182
the capability to,

1201
00:22:30,182 --> 00:22:31,216
for example,

1202
00:22:31,216 --> 00:22:32,417
manipulate

1203
00:22:32,417 --> 00:22:33,385
the electrical

1204
00:22:33,385 --> 00:22:35,253
conduction or pressure

1205
00:22:35,253 --> 00:22:36,121
driven flow

1206
00:22:36,121 --> 00:22:37,122
such as

1207
00:22:37,122 --> 00:22:38,757
the fluid application.

1208
00:22:38,757 --> 00:22:39,991
And in this case,

1209
00:22:39,991 --> 00:22:41,693
a lot of other physics

1210
00:22:41,693 --> 00:22:42,761
has to be

1211
00:22:42,761 --> 00:22:43,962
put into consideration,

1212
00:22:43,962 --> 00:22:45,297
but the underlying

1213
00:22:45,297 --> 00:22:47,132
mathematical relations

1214
00:22:47,132 --> 00:22:48,734
will be applicable

1215
00:22:48,734 --> 00:22:49,401
as well.

1216
00:22:49,401 --> 00:22:49,868
Special

1217
00:22:49,868 --> 00:22:50,936
thanks to Shelly Zhang.

1218
00:22:50,936 --> 00:22:51,670
For the Discovery

1219
00:22:51,670 --> 00:22:52,938
Files, I'm Nate Pottker.

1220
00:22:52,938 --> 00:22:53,839
Watch video versions

1221
00:22:53,839 --> 00:22:54,873
of these conversations

1222
00:22:54,873 --> 00:22:56,174
on our NSF science

1223
00:22:56,174 --> 00:22:57,075
YouTube channel.

1224
00:22:57,075 --> 00:22:57,776
Please subscribe

1225
00:22:57,776 --> 00:22:58,243
wherever you

1226
00:22:58,243 --> 00:22:58,977
get podcasts

1227
00:22:58,977 --> 00:22:59,778
and if you like

1228
00:22:59,778 --> 00:23:00,545
our program, share

1229
00:23:00,545 --> 00:23:01,380
with a friend

1230
00:23:01,380 --> 00:23:02,013
and consider

1231
00:23:02,013 --> 00:23:03,115
leaving a review.

1232
00:23:04,616 --> 00:23:05,550
Discover how the U.S.

1233
00:23:05,550 --> 00:23:06,184
National Science

1234
00:23:06,184 --> 00:23:07,252
Foundation is advancing

1235
00:23:07,252 --> 00:23:09,221
research at NSF.gov.