12 th Intersociety Conf. Thermal Phenomenon in Electronic Systems ; June 2-5, 2010, Las Vegas...

12th Intersociety Conf. Thermal Phenomenon in Electronic Systems ; June 2-5, 2010, Las Vegas

Thermophones by Quantum Mechanics

Thomas PrevenslikQED Radiations

Discovery Bay, Hong Kong

1


Introduction

Over a century ago, Stokes communicated to the Royal Society in 1880 the finding by Preece that

electrical wires produced sound.

In 1914, Rayleigh reported de Lange’s thermophone invention to the Royal Society

2


Theory

First presented by Arnold & Crandall in 1917. Classical heat transfer was used to determine the temperatures that cause the film vibrations that

produce sound from air pressure changes

3

dt

dTaCTa2)t(sinRI 22

0cdC;dt

dTaCTa2)t(sinRI p

22

C

f

r

RI

T2P

2

o

oorms


Modified TheoryIn 2008, Xiao et al. showed sound was produced in thin

films of CNTs. But the data could not be fit to the Arnold & Crandall theory. Modification allowed

additional heat loss Qo to the air.

4

0xoo x

)t,x(TQ

2

12

2

12

2

o

oorms f

f

f

f

f

f1

f

f

C

f

r

RI

T2P

dt

dTaCaQ2Ta2)t(sinRI oo

22


Problems with TheoryUltrasonic vibration of the film to produce pressure changes

was not found. Film temperature responds fast to cause pressure changes of colliding air molecules?

5

* “Thermally induced ultrasonic emission from porous silicon,” Letters to Nature, Vol. 400, 26 August 1999.

Shimoda et al.* previously questioned whether the film can even respond at ultrasonic frequencies.

“One might think the ultrasound generation by heat exchange is not possible, as the thermal conduction is too slow. But we

report here … an efficient ultrasound emitter”


Hypothesis

Thermophones by QM produce sound without vibration by emitting EM radiation that is

absorbed in the air surroundings

QM = Quantum Mechanics EM = Electromagnetic

6


Heat Capacity – Classical v. QM

0.00001

0.0001

0.001

0.01

0.1

1 10 100 1000

Wavelength - - microns

Pla

nck

Ene

rgy

- E -

eV

1

kT

hcexp

hc

E

7Nanoscale

kT 0.0258 eV

Classical

QM


Conservation of EM Energy

Recall from QM, QED photons of wavelength are created by supplying EM energy to a box having sides separated by / 2.

For thin film, = 2 d nr

Conservation proceeds by creating QED photons inside the nanostructure - by frequency up - conversion of absorbed EM energy to the fundamental resonance of the nanostructure.

QED = Quantum ElectroDynamics

8


QED Induced Heat Transfer

CondQEDAbsorb QQQ

9

dt

dNEQQED

Non Thermal Emission

E = Photon Planck Energy

dN/dt = Photon Rate

AbsorbQ

QEDQ

CondQ

T = 0


Classical heat transfer can not explain the reduced conductivity found in thin film experiments.

Explanations based on revisions to Fourier theory by phonons as quanta in the BTE are difficult to understand and

usually concluded by hand-waving

10

* See T. Prevenslik, “Heat Transfer in Thin Films,” Third Int. Conf. on Quantum, Nano and Micro Technologies, ICQNM 2009, February 1-6, Cancun, 2009: and

proceedings of MNHMT09 Micro/Nanoscale Heat and Mass Transfer International Conference, December 18-21, 2009, Shanghai.

Thermophones as Thin Films*


Thin Film – Reduced Conductivity

11

QED Heat Transfer QCond = QJoule - QQED ~ 0

Keff T = (QJoule- QQED) (df + dS ) / A T small, Keff ~ Bulk

QQED

QCond

T Current Approach

QCond = QJoule

Keff T = Qcond (df + dS )/AT large, Keff small

QJoule Effective Conductivity

Keff = [Kf / df + KS / dS ] / (df + dS )

Film

Substrate

df

dSKf

KS


Thin Film - QED Estimate

12

0

100

200

300

400

500

10 100 1000 10000

Film Thickeness - df - nm

The

rmal

Con

duct

ivity

- W

/ m

-K

.

0510152025303540

E(d

N/d

t) /

A (

T-T

o)

x10

9 W

/ m

2- K.

K - Keff Keff

QEDEmission

efff

QED KKd/TA

Q


Thermophones by QM

QED Emission

AirMoleculesSound

J oule Heat I 2R sin2t

W

d

L

Wall No Sound

13


Thermophone – QM Response

40

60

80

100

120

100 1000 10000 100000

Frequency - f - Hz

SP

L -

P -

dB

Xiao et al.

Arnold & Crandall

QED

nsr = 10x10-6

A = 0.15 B = 0.14

BfAf

f

r

RI

aMc

RrnP

20

2

o

*

rms s

14


Thermophone - Conclusions

Thermophones produce sound by the absorption of QED emission in the surrounding air.

Prompt QED emission allows sound at ultrasonic frequencies to be produced without temperature changes

or vibrations.

15


Questions & Papers

Email: [email protected]

http://www.nanoqed.org

16

http://www.nanoqed.org/

12 th Intersociety Conf. Thermal Phenomenon in Electronic Systems ; June 2-5, 2010, Las Vegas...

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Transcript of 12 th Intersociety Conf. Thermal Phenomenon in Electronic Systems ; June 2-5, 2010, Las Vegas...