78
REVIEW OF BELLUZZO
Doc.
6
Review
of
G. BELLUZZO,
"Principles
of
Graphic Thermodynamics"
("Principi
di termodinamica grafica," Il
Nuovo
Cimento
8
(1904):
196-222, 241-263)
[Beiblätter
zu
den
Annalen
der
Physik
29
(1905):
235]
which
is
obviously meant
for
engineers,
is
divided
into
four sections, the first
of
which
treats
graphically
the
changes
of
state
of
arbitrary fluids.
Thus,
the familiar areal construction of
the
work
performed
(L)
by
the
body,
of
the
energy
increase
(AE),
and of
the heat absorbed
(G)
are
given
in the
pv-plane
in
§3,
while in
§4
and
§5
the increase of
entropy
for
an
arbitrary
change
of state
is
presented
as an area
with
G
and
T
(the
absolute
temperature), and
with
G
and
1/T,
respectively,
as
coordinates.
This is followed
by
the
theory
of cyclic
processes
and
the definition of
reversibility
and
irreversibility
of
the
processes.
A
process
is considered
to
be
reversible
or
irreversible, respectively,
depending
on
whether the
pressure
exerted
on
the fluid
during
the
process
does
or
does not equal
the
inner
pressure
of
the fluid; this stipulation,
which,
by
the
way,
is
irrelevant
for
what
follows,
does not
make
sense,
because
then the
principle
of the equality
of
action
and
reaction
would
not be
satisfied
in
any
irreversible
process.
The
second
section
of
the article contains the
application
of the
theory
to
ideal
gases;
examined
are
the
changes
of state at
constant volume,
constant
pressure,
and constant
temperature,
as
well
as
the
and
polytropic
change
of state.
The
last section deals with
the
efflux
of
gases through pipes;
the
hypothesis
of
Saint-Venant
and Wantzel
is
replaced
by
known)
theoretical considerations.
The
third
and
fourth
sections of the article contain
the
theory
of
the saturated
and
the
superheated
water
vapor,
which
are
treated
in
a
corresponding
way,
with
special
consideration
given
to
the
theory
of the efflux
of water
vapor through
pipes
and to
the
theory
of
improving
the
efficiency of steam
engines
by
superheating.
For
the
equation
of state
for
water
vapor,
p(v+const.)
=
const.
T
is used,
following
Battelli
and
Tumlirz.
[1]
[2]
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