THW - Transient Hot-Wire - A

Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions

A few words…

Time used to be measured by the change of the moon…
Now it is measured by the 2 ns between two sms!

Instruments and techniques have changed.. have been developed, evolved or
disappeared… new ones appear… faster, better… maybe more accurate, or not!

and computers have become so much faster…

In this section, we will walk through history
to see the evolution and development of the THW technique…
Not a thorough list of dates, numbers and equations
but through designs and drawings of instruments.

From Gases to Liquids, to Melts and Solids,
and it is Still Going Strong!

The section will include a typical selection of instruments in
order to demonstrate its evolution
and will certainly not include all investigators.

M.J. Assael, K.E. Antoniadis, W.A. Wakeham, Int. J. Thermophys. 31:1051-1072 (2010).
1/43 M.J. Assael, K.E. Antoniadis, Proc. 30th Int. Therm. Conduct. Conf. & 18th Int. Therm. Expansion Symp. 28 Aug. - 3 Sept. Pittsburg
(2009).


A few more words…

fluid Ideally, the thermal conductivity of the fluid is determined by observing
the rate at which the temperature of a very thin metallic wire increases
q (W/m) with time after a step change in voltage has been applied to it, thus
creating in the fluid a line source of essentially constant heat flux per
unit length.

Approximate analysis (Healy 1976)
wire
q
ln( 4kt )
of radius α q
ΔTid = ΔΤ
4πλ α2C ρCp? 4πλ

ΔTid = ΔΤw + Σ δTi
t

However today, It is much better,
and much more accurate, to solve ΔΤ
the full heat transfer equations for
the wire and the fluid by FEM. whole curve ρCp & λ

No approximations!
t

2/43 J.J. Healy, J.J. de Groot, and J. Kestin, Physica C, 82:392 (1976).


1780 - 1888
The early days

3/43


1780 J. Priestley GLNMS

Joseph Priestley was probably the first, to carry out experiments
to measure the gas' power to conduct heat
(i.e. the specific heat, which was unknown at that time…).

In 1780, Joseph Priestley became a minister in Birmingham. He continued his
scientific researches and also his theological ones. He expressed his views quite
forcibly, and, in 1785, his History of the Corruptions of Christianity was publicly
burned.

In 1791, Priestley was driven out of Birmingham by a mob who destroyed his
home. He had expressed support for the French Revolution, and so, on the
second anniversary of the storming of the Bastille, the mob burned down his
laboratory, which was at his home. He moved to USA.

4/43


1786 Count Rumford (Sir Benjamin Thomson) GLNMS

Count Rumford continued similar experiments examining
"the conductive power of artificial airs or gases" and while doing so
he stumbled on a completely new mode of heat transfer, convection.

In 1799
Count Rumford concluded that "a gas was unable to conduct heat"!!!
"Heat is incapable of passing through a mass of air, and that it is
to this circumstance that its non-conducting power is principally owing"
and because of his reputation, this conclusion was not challenged
for many years.

B. Thomson, Trans. Roy. Soc. London, 76:273-304 (1786).
5/43 B. Thomson, "Essays, Political Economical, and Philosophical”, 1 st Am. Ed. vol 2:457 (1799).
A.C. Burr, Isis, 21:169-186 (1934).


1804 Sir John Leslie GLNMS

Sir John Leslie in "An Experimental Inquiry into the
Nature and Propagation of Heat" (1804),
wrote about Count Rumford:
"A late ingenious experimenter, who by the
perspicuity and useful tendency of his writings, is
deservedly a favorite of the public, he advanced
the paradoxical conclusion that
fluids are non-conductors of heat …..
If the proposition, however, be taken in its strict
sense, it is more palpably erroneous.
Were fluids absolutely incapable of conducting heat,
how could they ever become heated?...
How could water, for instance, be heated by the
content of warm air?
But the question really deserves no serious
discussion“.

6/43 J. Leslie, "An Experimental Inquiry into the Nature and Propagation of Heat", Ist Ed, p.552 (1804).


1848 Sir William Robert Grove GLNMS

In a communication illustrated by an experiment, he showed, that a
platinum wire, rendered incandescent by a voltaic current, was cooled far
below the point of incandescence when immersed in an atmosphere
of hydrogen gas.

"This was found not to be due to specific heat, nor to the conducting
powers of the gases. Convection did not explain the fact; and
considerable difficulty was found, upon examination, to exist,
if it was attempted to refer it to the greater mobility of the particles
of hydrogen gas, the tightest known, than of either oxygen, nitrogen,
or carbonic acid. It was found that this peculiar property also belonged,
but to a less extent, to all the compounds of hydrogen and carbon".

NOTE : First experiments with heated wires...

7/43 W.R. Grove, Phil. Mag. Series 3, 27:442-446 (1845).
W.R. Grove, J. Franklin Institute, 46:358 (1848).


1861 Gustav Magnus GLNMS

Gustav Magnus reported in Poggendorf's Annalen, immediately being
translated into English and appearing in full in the Philosophical Magazine.

"A platinum wire is less strongly heated by a galvanic current
when surrounded by hydrogen than when it is in atmospheric air
or any other gas.

It cannot be doubted that hydrogen conducts heat,
and that in a higher degree than all other gases".

NOTE first experiments with heated wires….

G. Magnus, Phil. Mag. Series 4, 22:85-106 (1861).
8/43
G. Magnus, J. Franklin Institute, 72:130-132 (1861).


1863 John Tyndall GLNMS

John Tyndall in his book "Heat considered as a Mode of Motion" writes:
"The subject of gaseous conduction has been recently taken by Prof.
Magnus of Berlin, who considers that his experiments prove that
hydrogen gas conducts heat like a metal….

Beautiful and ingenious as these
experiments are (Magnus & Grove), I do
not think they conclusively establish the
conductivity of hydrogen…. Theories are
indispensable, but they sometimes act like
drugs upon the mind. Men grow fond of
them as they do of dram-drinking…"

Hot-wire employed by Tyndall

9/43 J. Tyndall, "Heat considered as a Mode of Motion", 1 st Ed. p.239 (1863)


1860 James Clerk Maxwell GLNMS

James Clerk Maxwell publishes his groundbreaking paper on the
dynamic theory of gases and he calculates a theoretical value of the
thermal conductivity of a gas and showed its dependence on
temperature and pressure.

1862
Rudolf Julius Emanuel Clausius backs up Maxwell, showing that
thermal conductivity increased with temperature and was independent
of pressure when the gas was ideal.

J. C. Maxwell, Phil. Mag. Series 4, 19:19-32 (1860).
J. C. Maxwell, Phil. Mag. Series 4, 20:21-37 (1860).
10/43 R.J.E. Clausius, Phil. Mag. Series 4, 23:417-435 (1862).
R.J.E. Clausius, Phil. Mag. Series 4, 23:512-534 (1862).


1872 Josef Stefan GLNMS

Josef Stefan with his experimental expertise (E=AT 4 law)
set out to defy Maxwell's words (Boltzmann was his
student).

He measured thermal conductivity of air with
diathermometer
(23.4 mW/mK - today's value is 26.3 mW/mK).

The diathermometer's principle was based on the energy
balance equation
-kA
T dr = dQ = mC dT
s
Δx

Rearranged to be expressed as a measure of pressures, as
Τ λA ΔΡ
Το = exp(- mC Δx t) = ΔP
s o

J. Stefan, Mathematische-Naturwissenschaftliche Classe Abteilung 2, 65:45-69 (1872).
11/43 J. Crepeau, Exper. Thermal & Fluid Sci., 31:795-803 (2007).


1888 August Schleiermacher GLNMS

August Schleiermacher following the work of Josef Stefan and
his predecessors set out to measure the thermal conductivity of gases
by using a Pt hot wire (probably first real application of Hot Wire)

Pt wire diameter 0.4 mm length 32 cm.
Glass diameter 2.4 cm.
Leads are soldered at A and B.
Temperature outside registered by
a wound resistance thermometer.
Inside by measuring the resistance
of wire. Equilibrium reached in minutes.
Measured up to 1000 oC.

When equilibrium is reached, measure I, V through wire and T1 and T2

Q
λ=Α A = ln(d2/d1)/(2πl) or by measuring known gas.
(T1-T2)

12/43 A. Schleiermacher, Annalen der Physik und Chemie, 270:623-646 (1888).
3/13


The early days…
1780 G First experiments in
conduction
(J. Priestley)
1786 G "Gases do not conduct"
(Count Rumford)
1804 G Can not be so..
(J. Leslie)
1848-61 G First experiments with
heated wires
(W.R. Grove & G. Magnus)
1863 G Still doubts about
conduction
(J. Tyndall)
1860-62 G Thermal conductivity
theory
(J.C. Maxwell & R.J.E. Clausius)
1872 G Thermal conductivity
measurement
(J. Stefan)
1888 G First hot wire - horizontal
4C
(A. Schleiermacher)

13/43


1888 - 1971
The evolution of
the Transient Hot-Wire

14/43


1917 Sophus Weber GLNMS

The sources of errors involved in the determination of the
thermal conductivity of gases by Schleiermacher’s method
are subjected to a critical analysis, and a modified form of
apparatus is described in which the errors due to convection
are greatly reduced.

Apparatus is placed vertically. With this improved form of
apparatus, measurements of the thermal conductivity of a
number of gases have been made.

Pt wire
The following values are recorded : 54.5 cm length,
@ 0 oC mW/m/K 0.40 mm diameter.
hydrogen. 174 168.4 internet
neon, 45.5 49.2 (25 oC)
Glass
helium, 144 155.3 (25 oC)
diameter 2.3 cm.
argon, 16.1 16.6 Ref.val.
nitrogen, 23.7 24.9 Ref.val.
oxygen, 24.1 25.5 Ref.val.
methane, 30.1 32.7 Ref.val.
CO2 16.4 16.3 Ref.val.
N2O 14.7 14.6 internet

15/43 S. Weber, Annalen der Physik, 21:325-356 (1917).
S. Weber, Annalen der Physik, 54:437-462 (1917).


1931 Bertil Stâlhane & Sven Pyk GLNMS

First transient hot wire.
Employed to measure thermal conductivity
of solids and powders (& liquids). They
investigated the relationship between time
and temperature rise, for a fine straight wire
subjected to a step change in the heat input
to the wire. They found that a short interval
after the initiation of the step change, the
following empirical relation holds:
2 A, B were found using fluids of
ΔΤ = Aq ln( ro + B)
λ t known thermal conductivity.

On the diagram above, the wire is placed in the middle of powder. The upper and lower
solids are kept at constant temperature. Temperatures are recorded by thermocouples.

The diagram on the right shows another sensor for powders with a thermometer in the
middle.

16/43 B. Stâlhane and S. Pyk, Teknisk Tidskrift, 61:389-398 (1931).


1938 A. Eucken & H. Eglert GLNMS

They designed an absolute THW for low temperatures.
The 0.1mm Pt wire is in the middle of the glass tube.
- two wires serve as potential leads, and
- two wires as supports.
Temperature obtained from the wire's resistance.

Thermal conductivities measured were:
- Benzene (0 to -78.5 oC),
- Glycerin (0 to -78.5 oC),
- Carbon dioxide (-103.9 oC),
- Ammonia (-103.9 oC).

17/43 A. Eucken and H. Englert, Zeitschrift fur die gesamte Kalte-Industrie, 45:109-118 (1938).


1949 E.F.M. van der Held & F.G. van Drunen (Rijksuniversiteit Utrecht) GLNMS

A Proved the empirical expression of Stâlhane & Pyk for the THW, by solving
the Fourier equation

q q
ΔΤ = [-Εi (- 4αt )] ΔΤ = [ln 4αt - 0.5772… ]
4πλ r2 4πλ ro2

This can further be simplified by taking the difference in temperatures at
two times as
ΔΤ
q t
ΔΤ1 - ΔΤ2 = ln 2 λ
4πλ t1

ln t

This way absolute measurements can be carried out.

E.F.M. van der Held and F.G. van Drunen, Physica, 15:865-881 (1949).
18/43 E.F.M. van der Held, J. Hardebol, and J. Kalshoven, Physica, 19:208-216 (1953).


1949 E.F.M. van der Held & F.G. van Drunen (Rijksuniversiteit Utrecht) GLNMS

B In order to develop a method for all liquids they used
- a 0.3 mm diameter Mn wire and
- a 0.1 mm diameter Copper/Constantan thermocouple
both placed in a narrow capillary with both ends fused into
the wall of a glass vessel. Liquid is placed between the
capillary and the glass vessel.
The glass vessel is placed in a Dewar flask for a steady
temperature.

They preferred to use thermocouple to record temperatures instead of
recording the resistance of the wire, as the later would involve high
temperature rises and complicated recorders and bridges.
They made many corrections for the wire thickness and the presence of
the glass and employed times in the region of 20-50 s.
Measured the thermal conductivity of many fluids (hydrocarbons,
alcohols, acids..) with a quoted uncertainty of ±2%.

E.F.M. van der Held and F.G. van Drunen, Physica, 15:865-881 (1949).
19/43 E.F.M. van der Held, J. Hardebol, and J. Kalshoven, Physica, 19:208-216 (1953).


1952 D.A. de Vries (Landbouwhogeschool Holland) GLNMS

De Vries employed a small modification of the original solution

q q
ΔΤ = [ln 4αt - 0.5772… ] ΔΤ = [d + ln(t + to ]
4πλ r2 4πλ

Heating wire 0.1 mm diameter enameled constantan folded and placed
inside the glass capillary of 0.4 mm outside diameter. Outside the capillary
there is a fine monel gauze forming a socket of 1.4 mm diameter.
The thermocouple wires are of enameled copper and constantan 0.1mm.
The thermocouple wires and the glass capillary are introduced into the gauge
cylinder, and the empty space is filled with paraffin wax. The whole sensor has
a length of 10 cm.

Resistance is measured with a sensitive D.C. Wheatstone bridge.
Times of 3 min were employed.

Daily trends in moisture content of soil reflected on the measurement of the
thermal conductivity.

20/43 D.A. de Vries, Soil Science, 73:83-89 (1952).


1955 D.G. Gillam, L. Romben, H.-E. Nissen, O.Lamm (Stockholm) GLNMS

They employed the ideas of Stâlhane & Pyk, and Eucken &
Englert to produce a simpler apparatus of lower uncertainty,
0.3% for liquids and solids (of low melting point - melted
solid, like liquid was poured into the glass and solidified
there).

They presented advances in the THW theory, and
discussed zero time determination and specific heat
capacity correction.
Temperature obtained from the wire's resistance.

Pt Wire of 0.1 mm diameter and 10 cm length.
Potential leads also welded Pt wires.
Optimized Kelvin bridge to record accurately the resistance change.
Times recorded between 1 - 60 s.

21/43 D.G. Gillam, L. Romben, H.-E. Nissen, and O. Lamm, Acta Chemica Scandinavica, 9:641-656 (1955).


1960 P. Grassman, W. Straumann (ETH Zurich) GLNMS

They employed a relative THW, i.e. two THW
one with a know thermal conductivity fluid, and
the other with the unknown, both placed in the
arms of a Wheatstone type bridge.

Heating lasted a few seconds, and the quoted
uncertainty was ±1%.

Pt Wire of 70 μm diameter and 15 cm length.
They registered resistance change from very low times
(interesting diagram) but only employed top part to obtain
the thermal conductivity.

22/43 P. Grassman, and W. Straumann, Int. J. Heat Mass Transfer, 1:50-54 (1960).


1960 W.E. Haupin (New Kensington) GLNMS

He determined the thermal conductivity by placing into the
specimen a line heat source consisting of a butt welded
thermocouple heated by alternating current. At the same
time, a filter network was used to eliminate the ac heating
specimen
current allowing the thermocouple emf to be measured.
The thermocouple served both as a heat source and a
thermometer.

Materials measured were high-fired, superduty, firebricks and furnace
insulation blocks.

23/43 W.E. Haupin, Am. Ceram. Soc. Bull., 39:139-141 (1960).


1961 A.G. Turnbull (Melbourne) GLNMS

He employed a THW to measure thermal conductivity of molten salts
both in liquid and solid state near their melting point (to confirm his theory
on molten salts).

Many salts like NaNO3, KNO3, NaCl, AgNO3, KHSO4, NH4HSO4, KCNS, ZnCl2, NaOH.

24/43 A.G. Turnbull, Aust. J. Appl. Sci., 12:325-329 (1961).


1963 J.K. Horrocks, E. McLaughlin (Imperial College, London) GLNMS

Four-terminal THW, for the measurement of the
thermal conductivity of liquids with an absolute
uncertainty 0.25%.
Full analysis of corrections a) finite wire diameter,
b) boundary medium, c) finite wire length, d) study
of convection and radiation.

1 cm diameter Glass cell.
60 μm Pt wire of 15 cm length, annealed for an hour.
Pt potential leads 1 cm from ends.
Pt spring at top (inside Pt strips) prevents wire sagging.
Measurements performed within 30s.
Temperature rise was calculated from the wire's resistance change.

25/43 J.K. Horrocks and E. McLaughlin, Proc. Roy. Soc. , A273:259-274 (1963).


1964 A. von Mittenbuhler GLNMS

The method employs a heating wire of one metal with a thermocouple
welded to the heating wire in the form of a cross. An ac or dc power suplly
can be employed, and the temperature rise generated by a known heating
power is used to determine the thermal conductivity.

The technique formed the basis for a German and a European
standard in use today.

A. von Mittenbuhler, Ber. Dtsch. Keram. Ges. 41:,15 (1964).
Deutsches Institut für Normung. 1976. Testing of Ceramic Materials: Determination of Thermal Conductivity up to 1600oC by the Hot-Wire Method.
Thermal Conductivity up to 2 W/m/K. DIN 51046.
26/43 European Committee for Standardization. 1998. Methods of Testing Dense Shaped Refractory Products. Part 14: Determination of Thermal Conductivity
by the Hot-Wire (Cross-Array) Method. EN 993-15.


1968 Harland L. Burge, Lawrence Baylor Robinson (California Univ.) GLNMS

Four-terminal
THW, for the
measurement of
the thermal
conductivity of
gases.

The line source consists of a 0.7 mm diameter, 20.6 cm length wire (alloy "evenohm"). Around it is tightly
wrapped a 0.02 mm nickel temperature sensing coil. A 3-element copper-constantan thermocouple
records gas temperature.
Resistance change is recorded by a camera attached to a Tetronik oscilloscope connected to a dc
resistance bridge. Times were limited to 0.27 s and temperature rise never exceed 10 oC.
Thermal conductivity of He, Ne, Ar and their mixtures was measured.

27/43 H.L. Burge, and L.B Robinson, J. Appl. Phys., 39:51-54 (1968).


1971 K. Hayashi, M. Fukui, I. Uei (Kyoto Tech. Univ.) GLNMS

Four-terminal THW, for solids
up to 1200 OC.

Wire:
0.3 mm diameter (constantan, alumel, Pt-Rh-13%)
combined with thermocouple (chromel-constantan, chromel-alumel, Pt-Pt Rh13%).

Measured thermal conductivity of fire clay brick, high alumina brick, chromite-magnesia brick. etc

28/43 K. Hayashi, M. Fukui, and I. Uei, Mem. Fac. Ind. Arts, Kyoto Tech. Univ. Sci. Tech., 81-103 (1971).


1971 E. McLaughlin, J.F.T. Pittman (Imperial College, London) GLNMS

A Four-terminal THW, for liquids,
100-450 K and up to 10 MPa.

Discussion on the ideal solution and following approximations:
a) temperature dependent fluid properties,
b) finite wire diameter,
c) finite conductivity wire,
d) wall effects,
e) interfacial thermal resistance,
f) time-dependent heat-source power,
g) end effects,
h) initial fluid temperature distribution.

29/43 E. McLaughlin, and J.F.T. Pittman, Phil. Trans. R. Soc. Lond., A 270:579-602 (1971).
E. McLaughlin, and J.F.T. Pittman, Phil. Trans. R. Soc. Lond., A 270:557-578 (1971).


1971 E. McLaughlin, J.F.T. Pittman (Imperial College, London) GLNMS

B Four-terminal THW, for liquids,
100-450 K and up to 10 MPa.

Cell:
1 cm diameter SS.

Wire:
25 μm diameter 15 cm length Pt.
1 cm from ends Pt potential leads.
Small weight at the bottom
ensures verticality.
Wire annealed for 15 min.

Elaborate temperature enclosure (heating and liquid nitrogen) with stability of
1mK/h.

Measurement time 1 - 20 s.
Instead of photographing galvanometer spots or using chart recorders, a digital
voltmeter is employed to record the change in voltage because of the change in
resistance. Temperature change is calculated from the wire's resistance.

30/43 E. McLaughlin, and J.F.T. Pittman, Phil. Trans. R. Soc. Lond., A 270:579-602 (1971).
E. McLaughlin, and J.F.T. Pittman, Phil. Trans. R. Soc. Lond., A 270:557-578 (1971).


1971 P.S. Davis, F. Theeuwes, R.J. Bearman, R.P. Gordon (Kansas Univ.) GLNMS

Four-terminal THW, for electrically conducting liquids and salts.

Wire:
6.2 μm diameter Pt wire of 1.3 cm length.
0.3 cm from ends Pt potential leads (T-shaped junction).

Measurement time 1 - 10 s.
Instead of photographing galvanometer spots or using chart recorders, a digital
voltmeter (HP 2402A, 40 measurements/s) is employed to record the change in
voltage because of the change in resistance, coupled to a precision frequency
generator. Temperature change is calculated from the wire's resistance.

For electrically conducting fluids they used a thin metal film evaporated on a quartz rod. The quartz
substrate rod was 1.25 mm long and had a diameter of 0.025 mm. The length of the sensing platinum film
was 0.51 mm. The film is in contact with both ends with gold plated portions of the quartz rod. The
resistance of the sensor was about 6 Ohm. This was employed as a relative instrument.

31/43 P.S. Davis, F. Theewesm R.J. Bearman, and R.P. Gordon, J. Chem. Phys., 55:4776-4783 (1971).


1971 J.W. Haarman (Delft) GLNMS

His equipment used an automatic Wheatstone bridge to measure the resistance
difference of two wires. The two wires were identical except for their length. Hence, end
effects were subtracted.
The bridge was also equipped with an electronic potential comparator. The bridge was
capable of measuring the time required for the resistance of the hot wire to reach six
predetermined values, with the aid of high-speed electronic switches and counters.
This new bridge made possible a ten-fold reduction in the duration of each
experimental run, eliminated completely the effects arising from convection and
reduced greatly other time-dependent errors.

J.W. Haarman, Physica, 52:605-619 (1971).
32/43 J.W. Haarman, Ph.D thesis, Technische Hogeschool Delft, Netherlands (1969).


The early days… & The evolution of the Transient Hot Wire
1780 G First experiments in 1952 STHW, 3 min, T=f (t/c)
conduction (D.A. de Vries)
(J. Priestley)
1955 LS THW, 1-60 s, T=f (R)
1786 G "Gases do not conduct" (D.G. Gillam, L. Romben, H.-E. Nissen, O.Lamm )
(Count Rumford)
1960 GL 2 THW in Wheatstone bridge, 1-20 s
1804 G Can not be so.. (P. Grassman & W. Sraumann)
(J. Leslie)
1960 S THW
1848-61 G First experiments with (W.E. Haupin)
heated wires
1961 MS THW
(W.R. Grove & G. Magnus)
(A.G. Turnbull)
1863 G Still doubts about
1963 L THW, analysis of errors, 30 s, T=f (R)
conduction
(J. Tyndall)
(J.K. Horrocks & E. McLaughlin)
1860-62 G Thermal conductivity
1964 STHW + t/c cross (basis for D & EU standards)
theory
(A. von Muttelbuhler)
(J.C. Maxwell & R.J.E. Clausius)
1968 G THW, 30 s, T=f (t/c)
1872 G Thermal conductivity
(H.L. Burge & L.B. Robinson)
measurement
(J. Stefan) 1971 STHW, up to 1200'C, T=f (t/c)
(K. Hayashi, M. Fukui, I. Uei)
1885 G First hot wire - horizontal
4C 1971 L THW, T=f (R), 20 s, Digital
(A. Schleiermacher) voltmeter
(E. McLaughlin & J.F.T. Pittman)
1917 G Vertical hot wire
(S. Weber) 1971 LSmall THW, 10 s, digital voltmeter
(P.S. Davis,F. Theewes,R.J. Bearman,R.P. Gordon)
1931 LS First transient hot wire, & theory
33/43 (B. Stâlhane & S. Pyk) 1971 L2 wires, new, much faster electronic bridge
(J.W. Haarman)
1938 GL Absolute THW, T=f (R)
(A. Eucken & H. Eglert)


1971 - today
Today's
Transient Hot-Wires

34/43


1971 today

The pioneering work of Haarman (use of 2 wires, faster electronic bridge, experimental
time of seconds) was the start of a new series of THW instruments developed after 1971,
most of them based theoretically in a paper by Healy in 1976.
Since the majority of these new groups cooperated through research projects, very
similar instruments appeared. Hence, they will be presented all together.

Most of the THW groups nowdays originated from, or were connected to,
- J. Kestin (Brown Univ., USA), or
- W.A. Wakeham (Imperial College & Southampton Univ., UK).
Such groups are:
- C.A. Nieto de Castro & J.M.N.A. Fareleira (Portugal),
- M.J. Assael (Aristotle Univ., Greece),
- R. Perkins (NIST, U.S.A.),
- A. Nagashima & Y. Nagasaka (Keio Univ., Japan).
and more recently
- J. Wu (Jiaotong Univ., China),
- E. Vogel (Rostock Univ., Germany).

In parallel, some more groups produced also excellent work, as
- S.E. Gustaffson (Chalmers Univ., Sweden),
- U. Hammerschmidt (PTB, Germany).

35/43 J.J. Healy, J.J. de Groot, and J. Kestin, Physica C, 82:392 (1976).


1971 today Development of THW Instruments for fluids GLNMS

(anodized)

Au

(a) (b) (c) (d) (e)
(a) J.J. de Groot, J. Kestin, and H. Sookiazian, Physica, 75:454-482 (1974).
C.A. Nieto de Castro, J.C.G. Calado, W.A. Wakeham, and M. Dix, J. Phys. E: Sci. Instrum., 9:1073-1080 (1976).
(b) J. Kestin, R. Paul, A.A. Clifford, and W.A. Wakeham, Physica, 100A:349-369 (1980).
M.J. Assael, M. Dix, A. Lucas, and W.A. Wakeham, J. Chem.Soc.,Faraday Trans. I, 77:439-464 (1981).
E.N. Haran, and W.A. Wakeham, J. Phys. E: Sci. Instrum.,15:839-842 (1982).
(c) J. Menashe, and W.A. Wakeham, Ber. Bunsenges. Phys. Chem., 85:340 (1981).
Y. Nagasaka, and A. Nagashima, J. Phys. E: Sci. Instrum., 14:1435-1440 (1981).
W.A. Wakeham, and M.Zalaf, Physica, 139:105 (1986).
E. Charitidou, M. Dix, C.A. Nieto de Castro, and W.A. Wakeham, Int. J. Thermophys., 8:511-519 (1987).
36/43 (d) S.H. Jawad, M.J. Dix, and W.A. Wakeham, Int. J. Thermophys., 20:45-54 (1999).
(e) M.J. Assael, C-F. Chen, I. Metaxa, and W.A. Wakeham, Int. J. Thermophys. 25:971-985 (2004) .


1971 today Development of THW Instruments for melts & solids GLNMS

(h)
(g)

(f)

(i)

(f) M.J. Assael, K.D. Antoniadis, K.E. Kakosimos, and I.N. Metaxa, Int. J. Thermophys., 29:445-456 (2008).
(g) M.V. Peralta-Martinez, M.J. Assael, M. Dix, L. Karagiannidis, and W.A. Wakeham, Int. J. Thermophys., 27:353-375 (2006).
37/43 (h) R. Model, R. Stosch, and U. Hammerschmidt, Int. J. Thermophys., 28:1447-1460 (2007).
(i) S.E. Gustafsson, Rev. Sci. Instrum., 62:797-804 (1991).


1971 today Development of THW automatic bridges GLNMS

Electronic bridges were developed tremendously following advances in electronics and
computers. An excellent series of bridges was developed in Imperial College by M. Dix,
and these are shown here as example.

(a) (b) (c)

(a) J.J. de Groot, J. Kestin, and H. Sookiazian, Physica, 75:454-482 (1974).
C.A. Nieto de Castro, J.C.G. Calado, W.A.Wakeham, and M. Dix, J. Phys. E: Sci. Instrum., 9:1073-1080 (1976).
J. Kestin, R. Paul, A.A. Clifford, and W.A. Wakeham, Physica, 100A:349-369 (1980).
M.J. Assael, M. Dix, A. Lucas, and W.A. Wakeham, J. Chem. Soc.,Faraday Trans. I, 77:439-464 (1981).
(b) G.C. Maitland, M. Mustafa, M. Ross, R.D. Trengove, W.A. Wakeham, and M. Zalaf, Int. J.Thermophys., 7:245-258 (1986).
38/43 M.J. Assael, E. Charitidou, G.P. Georgiades, and W.A. Wakeham, Ber.Bunsenges.Phys. Chem., 92:627-632 (1988).
(c) M.J. Assael, C-F. Chen, I. Metaxa, and W.A. Wakeham, Int. J. Thermophys., 25:971-985 (2004).


1971 today Measurement of the temperature rise GLNMS

As an example,
measurement of the thermal conductivity of BK7.

39/43 M.J. Assael, K.D. Antoniadis, and J. Wu, Int. J. Thermophys., 29:1257-1266 (2008).

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