I/EC
REPORTS
the content of atoms lighter than the main constituent. Reason: Protons h a v i n g the m o m e n t u m in question come from t w o sources— the surface atoms of the lighter e l e m e n t plus the d e e p e r atoms of the main constituent. Y o u have to take the difference b e t w e e n two large numbers—statistically an a p proach w h i c h leads to unreliable results.
. . . a machine with "A G O O D RECORD as a REVENUE PRODUCER"
Sister Approaches A typical case of using a Niagara Aero Heat Exchanger to provide cooling for p r o d u c t i o n e q u i p m e n t shows amortization of this machine in 16 m o n t h s and $90 per day r e v e n u e thereafter. Industrial engineers with careful cost, upkeep and revenue records on all machines, credit Niagara Aero Heat Exchangers with important gains over other methods. They use these machines to provide cooling for production equipment, welders, extruders, drawing dies, fur
naces, quench baths, plating, chemical and electronic process...all millwater system uses. They get positive control of critical process temperatures with improved product quality, rejection losses pre vented. Heat is removed at the rate of in-put. A closed system, dirt free prevents all troubles from bad water; transfer ring heat to the atmosphere by the evaporation of a very small amount of water solves all problems of water sup ply or disposal.
Write for Bulletins 120,135
N I A G A R A BLOWER COMPANY Dept. E C - 8, 4 0 5 Lexington A v e . , N e w York 1 7 , N . Y . Niagara District Engineers in Principal Cities of U. S. and Canada
BBL dsa β
Piccoflex Piccoflex Resins arc a new line of tough and flexible hydrocarbon resins. Because of its unusual grease and oil resistance, Piccoflex shows utility in the manufacturing and converting industries.
PENNSYLVANIA I N D U S T R I A L C H E M I C A L CORPORATION Clairton, Penna.
40 A
INDUSTRIAL AND ENGINEERING CHEMISTRY
You can get better results for heavier elements by using douterons or a l p h a particles. T h e heavier incident particles give a wider mo m e n t u m spread when reflected off heavy surface a t o m s ; the spectrom eter can then give better resolution, a n d you get a clearer idea of the specific heavy element in the sur face. T h e break point—where deuterons become preferable to protons —is a b o u t at iron. W h e n p r i m a r y interest lies in one of the lighter elements on a base of a heavier one (such as c a r b o n on iron), nuclear reactions give good results. For example, when opal glass is b o m b a r d e d with protons, the fluorine absorbs a proton a n d kicks out a n a l p h a particle and g a m m a radiation as it transforms to oxygen. By measuring the a m o u n t of g a m m a you find the orig inal fluorine content. T h e r e are a host of these nuclear reactions which could be used, R u b i n points out. I n fact, as he puts it, " t h e surface has h a r d l y been scratched." Even so, the m e t h o d has already yielded valuable data and insight into m a n y surface phe nomena. S R I , for example, has checked the effects of glass cleaning methods on the glass surface, finds that the surface composition is significantly different after a nitric acid wash, say, as c o m p a r e d to a d i c h r o m a t e wash. It finds, as well, that sur face composition of alloys is a great deal different from bulk composition, that it can measure thicknesses of electrodepositcd films on iron or a l u m i n u m , a n d that it can measure aerosol composition by depositing its content on a clean surface (by j e t impaction or electrostatic pre cipitation) a n d then analyzing the deposit by proton scattering. D.E.G.
