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Godfrey, Kneeland, Jr. (ed.) / The Wisconsin engineer
Volume 59, Number 4 (January 1955)

Burnard, Carl
Science highlights,   pp. 46-49


Page 46


i     by Cr Ed                EE
Edited by Carl Burnard, CiE'57
   STUDY OF SOAP BUBBLES TO
   AID METAL DEVELOPMENT
   Studyv of soap l)ul))les l)y scieni-
tists ill the Cenieral Electric Re-
searclhI al)oratorv at Schenectady,
N. Y., may aiul in the development
of metals that are stronger than-}
thlos(e  n1o\w  in  Isc  a111nd   that  have
oti  cr.  iii l)lrove(l  I)roperties.  Sucll
l)til)l)]es  are  helping  to  explain
fmndamllelntal data on the behavior
of metals.
   Tle soap  l)1il)l)les resemble in
1ManyV respects the crystals or grains
of  \wh]licll  all  metals  are  mad(e.  JIl
p)artielllar, it leas l)een found that
the  w\ay that little l)ul)bles grow
into bigr ones is closely analogous
to tht(e growthl of metallic graills.
  Neitlher  tihe  bubbles  noir  the
(gr1aints ever grow by the coalescence
of twvo simaller units into a larger
one, it sai(l. Instead, when a htlb-
ble or lgrain gets bigger, its botn-
daries expand  at the expense of
adjacent ones which contract and
filially (lisappear.
  Ihe l)eulbl)les to be studied not
l)lowvil ill tite open air , l)ut ill spe
cial glass cells, about five inches
ill diamiieter anl half anl inch thick.
Each cell is lialf-filled with a spe-
eial soap solution. It consists of a
liqmiiidl solol in toy stores for mak-
ing bubbles, to  whiichi other chem-
icals hlave beenel added to improve
tihe perforimnce. The n the air is
pumI)e(l out of thie cell and tihe
space above   the liquid  becomnes
filled  mainlyv  with  Nv\ater vapor.
Tlhe tuibe to the vactiuum  pump is
sealed off so the exhatisted cell mav
be handled.
  Wlheni tihe cell is shiaken) vigor-
olisiv and thene laid oin a flat Stir-
face, thommsands of tiny\ bubbles
appear above the liquid. After it
has been allowed to stand a little
while (ten or fifteen minutes) the
bubbles are larger and fewer. At
this stage their continued growth
may easily be observed.
  The bubbles have varying num-
l)ers of sides, but when there are
only three sides on a bubble, it
starts to disappear. The three sides
shrink, while the vapor inside mi-
grates through the walls into adja-
cent bubbles, which are enlarged
accordingly.
  In a single metal grain the atoms
are lined tip like bricks in a wall.
So are the atoms in a grain next-
cloor, but the rows in one grain do
not line up with those in the other.
The line of discontinuity is the
boundary between the grains.
  When a metal is heated, some
of the grains enlarge, while others
shrink and disappear, just as in the
soap bubbles. As the boundary of
a grain passes an atom, the atom
shifts its position a little to get
into line with the rows in the ex-
panding crystal.
  Many metallurgical applications,
such as the steel used in electrical
transformers, depend on accurate
knowledge and control of metal
grains. Hence, studies of their
behavior, by the buble technique
and other means, is expected to
lead to new knowledge which may
greatly improve the performance
of metallic structures.
        NEW BORE GAGE
  Two engine blocks per minute!
That's the rated capacity at 100%
efficiency of the latest model auto-
motive cylinlder bore gaging and
classifying machine designed and
manufactured by the Sheffield Cor-
poration, Dayton 1, Ohio.
  This unique machine is used to
simultaneously measure and clas--
sify bore diameters in a six cylinder
engine block, to inspect out-of-
roundness and taper, and to stamp
the classification of each bore on
the block. Bores are divided into
10 classes with a .0003 difference
between  each class. Classifying
bore diameters in this manner per-
mits selective matching of pistons
to bores during assembly.
  Six air spindles, each having two
diametrically opposed air jets at
four positions along its length, are
motorized for rapid travel into and
out of the block. They explore the
lbores to full depth. Each pair of
air jets is connected to a glass
column in the 24 column Precision-
aire. The position of the floats in
the Precisionaire instantly indicates
any taper, out-of-roundness or de-
viation in diameter.
    RADAR ON WINDSHIELDS
  Interceptor aircraft eventually
may have radar information dis-
played directly on the cockpit
windshield. An electrical firm has
developed transparent phosphors
which, in combination with flat
picture tube developments now in
progress, may permit radar images
on windshields instead of on spe-
cial screens.
      FISHING FOR SCIENCE
  Scientists at the Hanford Atomic
Products Operation spendI a lot of
time fishing the nearby Columbia
River. Not for fun, h o w e v e r.
They're sarmpling all marine life in
the river to determine how mulch
radioactivity seeps into the water,
THE WISCONSIN ENGINEER
46;


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