NATIONAL BUREAU OF STANDARDS REPORT

QUiiRTERLY REPORT

ON

evaluation of REFRACTORY QUALITIES OF

CONCRETES FOR JET AIRCRAFT '^iRM-UP, POUER CHECK,

maintenance aprons, and RUN^iAYS

W. L. Pendergast, E. C. Tuma , L.E. Mong

5601

by

and E. Trattner

<NBS>

U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS
THE NATIONAL BUREAU OF STANDARDS

Functions and Activities

The functions of the National Bureau of Standards are set forth in the Act of Congress, March

3, 1901, as amended h\ Congress in Public l.aw 619, 1950. These include the development and

maintenance of the national standards of measurement and the provision of means and methods

for making measurements consistent with these standards; the determination of physical constants and properties of materials; the development of methods and instruments for testing materials,

devices, and structures; advisory services to Government Agencies on scientific and technical

problems; invention and development of devices to serve s[>ecial needs of the Government; and the

development of standard practices, codes, and specifications. The work includes basic and applied

research, development, engineering, instrumentation, testing, evaluation, calibration services, and

various consultation and information services. A major jK>rtion of the Bureau’s work is performed

for other Government Agencies, particularly the Department of Defense and the Atomic Energy

Otmmission. The scope 'of activities is suggested by the listing of divisions and sections on the

inside of the back cover. , . .

Reports and Publieations

The residts of the Bureau’s work take the form of either actual equipment and devices or published papers and reports. Reports are issued to the sponsoring agency of a particular project or program. Published papers appear either in the Bureau’s own series of publications or in the

journals of professional and scientific societies. The Bureau itself publishes three monthly periodicals, available from the Go\ eminent Printing Office: The Journal of Research, which presents

complete papers reporting technical investigations; the Tcihnical News Bulletin, which presents

summary and preliminary reports on work in progress; and Basic Radio Propagation Predictions,

which provides data (or determining the best frequencies to use for radio communications throughout

the world. There are also five .series of nonperiodical publications: The .\pplied Mathematics

Series, Cinulars, Handbooks, Building Materials and Structures Reports, and Mis<ellaneous

Puhlii-ations. Information on the Bureau’s publications can he found in N BS Circular f60. Publications of

the National Bureau of Standards (.'SI. 25) and its Supplement ($0.75), available from the Superintendent of Documents, Government Printing Office, Washington 25, D. C.

Inquiries regarding the Bureau’s reports should he addressed to the Office of Technical Information, National Bureau of Standards. Washington 25, D. C.
NATIONAL BUREAU OF STANDARDS REPORT

NBS PROJECT NBS REPORT

0903-20-4428 October 1, 1957 5601

QUARTERLY REPORT

ON

EVALUATION OF REFTLiCTORY QUALITIES OF

CONCRETES FOR JET AIRCRAFT WARM-UP, POWER CHECK,

maintenance aprons, and RUlWAYS

by

L. Pendergast, E. C. Tuma , L. E. Mong

and E. Trattner

Refractories Section

Mineral Products Division

Sponsored by

Department of the Navy

Bureau of Yards and Docks

Reference: NT4-59/NY 420 008-1

NBS File No. 9.3 / 1134-C

Approved:

Dr. Samuel Zerfoss

Chief, Refractories Section

IMPORTANT NOTICE

NATIONAL BUREAU OF S' intended for use within the

to additional evaluation and

listing of this Report, either the Office of the Director, N

however, by the Governmen

to reproduce additional cop

Approved for public release by the

Director of the National Institute of

Standards and Technology (NIST)

on October 9, 2015.

progress accounting documents

rmally published it is subjected

, reproduction, or open-literature

sion is obtained in writing from Such permission is not needed,

prepared if that agency wishes

<NBS>

U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS
•K

I

t Jf V.-

f

\

\

‘ ‘

L
QUARTERLY REPORT

ON

EVALUATION OF REFRACTORY QUALITIES OF

CONCRETES FOR JET AIRCRAFT ^aRM-UP , POWER CHECK,

MAINTENANCE APRONS, AND RUMAYS

1. INTRODUCTION

This phase of the project includes the determination of

the cause or causes of failure that occur in concrete aprons

and runways exposed to jet exhaust gases. A combustion

chamber that delivers hot gases at velocities and temperatures

approximating those of field conditions is being used. The

approach includes instrumentation of the concrete test panels

to determine the heat gradients and stresses set up during

flame impingement at several locations on the test area and

at varying depths below the surface.

2. ACTIVITIES

2.1 Pressure Developed in Concrete

During Heating

2.1.1 Bomb Tests

Pressure-temperature curves were drawn from data taken

in eight tests in which the stainless steel bomb and mercury

filling was used. The materials, treatments, and data showing

the characteristics of the curves are given in Table I.

The evacuation drying (to constant weight) removed nearly

all of the capillary water and left "chemically combined"

water. Materials tested x^rithout this treatment contained

appreciable amounts of capillary water, and the concretes had

comparatively large amounts. The bonding of the water to the
%
- 2 -

material, whether chemical or capillary, would be expected to

cause deviations of the pressure-temperature curves from the

steam curve. The capillary bonding would be expected to vary

according to the fineness of the capillaries, and it has been

shown, N.B.S. Report No. 5353, p. 3, that brick aggregate with

interstitial water does not appreciably alter the pressuretemperature curve from the steam curve.

The extent of these bonding effects are indicated in

Table I. The temperature for initial pressure (lOO^C for the

steam curve) is elevated for all samples having capillary

water to values ranging from 105° to 17C°. Where aggregate

was present the values were nearly the same. It appeared

that Portland cement developed the finest capillary texture

and Alcoa cement the coarsest, possibly because the Alcoa was

aged only 7 days and had not had adequate time to develop its

fine crystal structure. The offsets from the Steam Curve at

the higher pressures showed the persistence of the capillary

effects

.

Samples, containing chemical combined water only, gave

rather high temperatures for initial pressure and large offsets

from the Steam Curve. For Portland cement this chemical

bonding was similar to the capillary bonding. For the high

alumina cements, however, the temperature required to separate

chemical combined water or "threshold temperature" rose to

212 and 222°C. Also, for the high aluminas, there was a
V 'f ' f

‘

I •, *j.

j > ^i'‘ ,'.j \

' «)(W

t I' ’1 f

.

* V

* * V ^

'

V • ;

’ - I. ••I

I.

t

.. . > ) v

1*-

'

i i • i

'.

»

T ..- ' 0 ?

\

'

7'.*’1 ifi

'

,

'

' '. vT.

'

"••’i • l^r

u V

^ s

.•4 V

. f) i

r s

' ' f.

‘

I

' '•'
Table

I.

Data

from P

res

sure

-Tempe

ra t

ure

Curves

for

Neat

Cements

and

Concretes - 3 -

too>3O03

COCO(1)

Oh1o3

-o

(0oas

CD H

C

-p—

fCMl 0 -H rHrHiO C^lO OeOC-H

tp 0 0 u -<-• >-• -P 0 >3 P 0 3+1 II 11 + 00 0

cp 0 O

M-cO oo o Of

Eh

CO O4 CO iO

io

COf

toI

l>-I

to CO 10

r-dI I +

CO0 g to

to fCj o

to 0 > O +J o o CO 3 O O

to to 0 to 0 0 0 -p -p

to 00 to to CO CO 00 3 0 1—1

iH rH rH r*l (M rH rH 0 •H c

-M

fcj oK

T3 0p P--

(TO

toC 3 (N) 3 1

•H 3 0 0 0 0 0 0 0 H-J

m P3 00 0

-H

CO0 30 0

+J 30 30 0

-P 30 0

-M 30 u

rH 30 V0 0 ca 3 CV) 3 3 0 3 CVl 3 g +j p S'- rH CV] 0 3 p (Nl (Nl CnI -P 0 0 o• CO 0, CO O -Hi to co*o

CO p,|o

ltC<3 i t|-- -P o w

(0 to tt^ 0 C -Hi tp !h O Colo

to to

H- +

r-+

to

HO

O

®

VhOcooo

-p

tn©

tn

O’

(d

g >H © rQ

a,|o 0

(N)

C-H LO

rH

CO <N3 rH

ii

p3 + + + + + + + ' PCl 0 g 0 0 P

£h P 0 -h| 0 00

cv PjO

GV1

<N1 +

COCC+CO+ 0

rH+ 1

yg+ 1 +7 +

35 0+ 0g00 0

JJ PP P 0 0 3 0 rH P 0 p

tp :t)

H -p 0 0 TH 0 0 0 CO IN- 0 C<i to CN3 0 •iH 3 }> Ph -P 0 0 0 CD in rH 0 <NJ 3 0 S'! g -rH 0 rH rH rH rH 0<! rH CO iH g 0 3 0 H P 3 0

EhM fi. 0

O’C

•rHpQ3O

-H

-P33O3>

CO

t3’ O

©g

-H

EH

tJ’

to

(Nl f • I 6S1

CO 1 • 1 r-| « 0 0 0 0 0 -P P 0 3 iH 3 3 3 CO 3 3 rJQ P 0 (D 0 0 to 0 rH 0 0

ffi 3 3 3 1—1 3 CO 3 g 1 0

Fp Oi,

p3O

CO3Q

a oq.ujvi

q.ueoa e j

CO1—1

80 !13 1

16 cr> rH

o- C'- 21

to 10 (Nl urj to to to CO

IN- IO C-- tN- IN- to

C3 CO rH CO CO (Nl CO rH

D/M

LO

C^ toC" LO

LO to

IN- LOCN- to

IN- to 3 P 0

tp

CO (Nl CD CO (Nl (N (NI to II II tp

Ph Dh

PQ

Pu

IX) 30 3 3 OO

II rH

Pi

-P Pi 3

-P 3 3 O’ 0 0 3

b‘3O

uO -P3

T! 0 3 g 3 0

rH

O

-PP Tf O 3

Ph 3t—I

-p -p 3 P 0 O

Ph

m

Ph

T53

•HW00030

-PCOgop

tp0p3

-P3P0Pg0

-P

•Ho

r-l| (m|
I

1
-4

succeeding temperature range where the pressure rose very

rapidly indicating the decomposition of hydrates. The corresponding range in rapid pressure rise was foTind to be much

higher for the Portland cement indicating a second decompostion

These changes for chemical x-zater vre re masked in the tests

where capillary water was present.

Since water was liberated from the material, the cooling

curves were not greatly different from the steam curves, a convergence of the curves in the range from 150 to 185°C may

possibly indicate some recombination of water with the material

to form hydrates having water contents much lower than in the

original cured cement.

As pointed out previously, sufficiently high pressures

to fracture concretes are developed at temperatures x-^ell within

the operating temperatures of pavements exposed to jet aircraft

VJhile thorough drying by evacuation raises the tem.perature of

this evolution of water, the rise is not sufficient to avoid

explosive spalling, especially for open-throttle operation.

The data given in Table I is useful in comparing the

pressure development of different cementing materials, but does

not consider other factors, such as the permeability of the

concrete, in its performance in heat-resisting applications.

2.1.2- X-ray Examinations

X-ray examinations of neat Portland cement, after three

heating cycles ( 280*^C) in the bomb test, were made. The
' i >'v >

(' X K'

-I I
-5-

patterns were similar for each treatment, and showed peaks

corresponding to those reported for Tobermorite, 4-5 CaO^SSiO^*

SHgO, (Reference given in literature reviewed) dicalcium

silicate, 2Ca0«Si02, and calcite, Ca CO^ • The absence of

other peaks made pocitive identification of these minerals

uncertain 3 Additional samples of Portland, Alcoa, and Luranite

cement s, afte r heating to approximate constant weight at

progressively hig'her temperatures, are being collected for

X-ray examination.

2.2 IJarer in Concrete During Curing and Drying

The dependency of humidity on the concentration of water

in cured concrete has been utilized to estimate the transfer

of v;ater during drying. In this study, specimens described

in Figure 2 of N.E.S. Report 4869, October 1956, have been

prepared. The ceramic hygrometers originally ordered for

this study were unstable, and the manufacturer decided to

replace them vrith miniature hygrometers of the Dunmore type

which had recently become available. Three quarters of the

order has been filled.

Although these hygrometers x^ere carefully calibrated by

the manufacturer, some tests were made in this laboratory to

detect the calibration drift. Known relative humidities were

obtained by means of saturated salt solutions—^ and these

Letter Circular LC1026, U. S, Department of Commerce,

National Bureau of Standards, April, 1957.

- 6 -

humiditles were used in checking the hygrometers. A comparison

of the results with the manufacturer's data indicated differences

ranging as high as two percent, with the exception of one

hygrometer which was obviously defective. Inasmuch as different

secondary standards were employed in the measurement of

relative humidities in the two laboratories, the uncertainties

involved by the use of these methods could account for such

differences. The correlation of secondary standards with the

primary standard lacks precision, and humidity measurements

by means of secondary standards may be considered as art rather

1 / than a science.— In spite of the possible inaccuracies, the

Dunmore type hygrometers have advantages of rapid response

and reliable electric indicators, both valuable in measuring

relative humidities which are progressively changing.

Hygrometers have been inserted in one set of tiles, as

sho’.'m in Figure 2 of N.B.S. Report 4869 , October 1956 . These

tiles have one three-by-three inch face exposed to drying at

40 percent relative hum idity and 77°F. The humidities within

the tiles and the change in weight of the tiles are being

recorded

.

2.3 Relation of Properties of Neat Cements, Aggregates,

and Resulting Concretes

2.3.1 Weight Changes During Curing and Drying

Neat cement cubes (1x1x1 inches) were prepared from

each of three cements, Portland, Lumnite, and Alcoa using the
« c '^4 *: o •s

'{. c 91 'i-'-f .

.

. ' *>

. •Nh*'' •-"?'? ^:t>'

Oi: C.:^- .

hrV ^ r- j o

'i. ,

.-.LrKtt ..:t

' : •/::•> < wr{ s

:

, Sri '

v.l I •V’-X -:^i

:

. O'

“• c r r:

• "*i;- -tr-f

'VI- -

{• ' - ' nv'i

'

tr\xhh. -

- - ' ^'' *i0fi

• . -r.-o '^>1?

'V

.

A
-7-.

same W/C ratio (0.275). These cubes were cured for 28 days

in the fog-room and stored at 50 percent relative humidity at

73°F. Their weights were determined at seven-day intervals

and the percent change in weight, based on one day weight, are

shov/n in Figure 1 These curves indicate larger, but comparative,

changes than those for concrete shown in Figure 1, M.B.S.

Report 4767, July 1956. The larger ratio of exposed area to

volume accounts for the more rapid rate changes. It should

be noted that after 28 days drying the water content of the

cubes ranges from 25 to 30.5 percent. These values are much

higher than the values for concretes designed using these

cements, vjhich range from 6.5 to 8.5 percent. and very much

higher than the aggregate used, which range from 0.3 to 1.7

percent. The Alcoa cement absorbed appreciably more water

during curing than was absorbed by either the Lumnite or

Portland, but its loss during drying was quite similar to that

for Lumnite.

2.3.2 Resistence of Neat Cement Cubes to Jet Impingement

The cubes were retained, in contact with each other, in

a holder, and arranged as shown in Figure 2 during the test.

whi c h was a five-mi nute ex posure to ga se s a t 1 200°F a1t

vel oci t ie s of 1200 ft /sec. —2/ ^D umray cubes we re used to f rame

the n ine test cubes . This arrange men

t

of t he cube s was mad

to obt a in an equal ave rage temper at ure for the cube s of eac

11

Temper atures and i n s t r ume n t a t i o n of pane Is dur in g i:e st a shown in Figures 2 and 3 , N.B.S

.

Re port 476 7, Ju ly 1956 .
- ’ f Ci'y
PERCENT

CHANGE

IN

WEIGHT

(

Based

on

Weight

after

I

Day

in

Mold )

t

>

FIG. 2 EFFECT OF JET IMPINGMENT TEST ON

NEAT CEMENT.

A* ALCOA XCA-25, L=LUMNITE, P= PORTLAND PAL

- 10 -

composition. The temperature determined adjacent to the cubes

and at their exposed surface ranged from 1320*^F near the

center to 1150°F at the outer edge.

All cement cubes failed in this first test (Figure 2).

Although the Lumnite appears to be slightly superior to the

others. One Portland cube shattered completely. In general,

the resistence of these cubes to j et - impingement was much less

than that shown by the aggregate material alone, N.B.S. Report

4869, p. 3, October 1955. The concretes, of comparable age,

designed using these cements and aggregates, differed in their

resistence to the jet impingement ranging from severe failure

to no appreciable failure.

2.4 Tests of Conventional Sand and Gravel Concrete Panels

with a Protective Topping

Two (18 X 18 X 6 inch) panels were subjected to the jetimpingement test during the period covered by this report.

These panels were fabricated in two layers. The backing layer

was four and one-half inches thick and fabricated with the

conventional sand-gravel-portland cement concrete and cured.

The exposed layer or topping was one and one-half inches thick.

The topping for one panel was designed with Lumnite cement

and diabase aggregate. In the second panel Alcoa cement was

substituted for Lumnite. The topping was cured for 14 days

in the fog-room and stored for 14 days at 50 percent relative

humidity and 73°F.
f \< '

«!fc. u) ^,V

' • ’ -.ip* ruff •>»../!• V *>UM'

fit* -litir*

, < ^.r r.X-: •:r.t •? ?-|‘? .ni iv^HT * 'X FA •' ’

•

!J^

e -

< Ht ^ Jl.-> i; IVl

. -r '

• • '2 if^ '' ' «' tfTrTTJ/J

; - fl!

’ #5^ ‘‘

' ''*' -'*' '«* M/f?. **ji*;v^ ;• Tvf f Tb<-

t Mlu.V> vv u q. *»©« «>«

i. *

. . V ,J

'•- '••'

<: ^ *J - £••'» V'vf 7. ‘*‘ V/'. •' -

* ' -•»

'•-»• ^ 'vrr* »if?,:‘- • I ocf >'*0 "* t i

- -J ''• , rfi- •’ 7 6 f ‘•i!'^>',4ft;>' yi.-J rr 'f 4 rijf'ijlf'tr • S'^h^NwilF

i''^ *• • t ir{_ N,<7 Cif

- t-.fx.' f ’: r •

s.< * ,;^Xi

.

• V.'

1 '-S f.-' V br:s;. t A*:..': f.

'u' i

•', ' ?'.

^

. t

'

i )!.'' *• •r .'?:• .:

•

. i ,>r : 1

' U :. f; " 'yj"“ >\ ' .; ! ^ .!> i. . 4?^.j

~ 'a. r n ( * ., i- rj t '

; L. .' (? 7’0 i

' / * <'

'“i 'V u;^.': :: o.v: •;• N ' .

•’5

;

^•f :uL%f fc:-' '. r-‘

•Tr;:J'' K

a'' 'M 5?^: V

' .; ".i'V i tC,'\r.r ©if.

•**

' - * : 1 > ;

k

''

t S.

•’5 - i *»T .V » p-k’ix-i ' -t i

.?5

’. r-*' 4f7''">.'t >C '’a

I*'.') i/W.iXJ l O^'

-r.-lSS

.r-' i:-.>.J' •'

I,.

•

. J •«..

•1/- ; ^.ii.j
- 11 -

The impingement test caused no observable loss to the

panel containing Lumnite cement. In contrast, the panel

containing Alcoa cement shov/ed considerable loss. The loss

was greater than that shown by any other panel containing

diabase aggregate.

The difference in the performance of the two panels cannot

be explained on the basis of the water content at the time of

test or by fabrication differences. A factor to which the

difference might be attributed is permeability since the

other properties were quite similar.

2.5 Thermal Conductivity

In the previous report, it was pointed out that high

thermal conductivity of concretes designed with the high-alumina

cement, Alcoa, might account for the better results obtained

in the jet-impingement test compared with those containing

Portland cement. The thermal conductivity of a concrete

3 / designed with Alcoa cement has been determined— and found to

be 6.55 Btu/hr.ft"^ ( 116°F / inch ) . This value is slightly less

than that for other concretes of similar density as shown in

Figure 3, N.B.S. Report No. 1817, June 1952.

3

/ “ —' Thermal conductivity was determined by the Building

Technology Division, Heat Section of the National Bureau

of Standards.
3
- 12 -

2.6 A Study of the Mechanism by which ’^ater Vapor Travels

Through Concrete

A constant temperature chamber has been outfitted to hold

the water-vapor-transfer apparatus. Improvement of the

apparatus has continued. The plastic containers, used at first

to hold a reservoir of an appropriate water-salt solution

proved inadequate; the containers could not be properly sealed.

The plastic containers were replaced by 125 ml ground stopper

gas washing flasks. Air, under slight pressure, from the

diaphragm pumps was bubbled through the water-salt solution

at the bottom of the flask, and then circulated through the

cylindrical chambers. This arrangement, however, did not

prove quite satisfactory. The sodium chloride, used in one of

the flasks, had a tendency to crystallize at the end of the

bubbling tube and cause it to he stopped up. Hereafter, the

air over the water-salt solution will be circulated without

bubbling it through.

2.7 Miscellaneous

Three hundred pounds of emery v;as submitted by the IJalter

Maguire Company, Inc. for use as an aggregate in this project.

A sieve analysis of the material indicated that the sizing of

the emery, all passing a 3/8 inch sieve, would m.ake it impracticable to design concrete for other than surfacing or

topping. This material will be used as an aggregate in topping

concrete test panels.
: -••• *

f,

•

r: T»

V*

». V

{ 4

t / 1- <:>i'a.

t'.

' Hr ' ’

iL '.v

. ^ v; / f .ft

, fiidi

.i

. -y
-13-

A review of the following articles vxas made during the

quarter.

Crystal Chemistry'- of Hydrous Calcium Silicates; II

Characterization of Interlayer Water, George L. Kalousek

and Rustom Roy. J. Amer. Ceram. Soc., Vol. 40, No. 7, July

1957 . Examination of Tobermorite, 4 - 5 CaO. 5 SiO

2

. 5H

2 O, and

Xonotlite, 5CaO • 5S i02 *H20 , by infra-red absorption revealed

striking structural similarities and differences in the two

phases. In the 8 to 15// region the absorption was the same

for both: the difference arose from the manner in which wate

and hydroxyl ions were bonded. Tobermorite exhibited strong

absorption at 6 . 2/V a band which is generally associated with

interlayer water, and at 2 ,^/1 , a band generally attribiited

to bonded (OH). The mineral Xonotlite did not shovr these two

bands but contained the band at 2 . 7 5 gene ral ly associated

^^rith free (OH). Synthetic Xonotlite prepared at 300°C vras essentially the same as the mineral, but samples prepared at

progressively lower temperatures exhibited the 2.9^// in

increasing intensity. The fibrous form of Tobermorite showed

a band at 6.5 to 7.0/-^ which increased in intensity with

/ increasing amounts of CaO in the solid. This band was also

found in the 14 a.u. 1.0 CaOrSiO^ hydrate, but not in the

Xonotlite. The great volume stability of Xonotlite during

drying and wetting is readily explained on the basis of the
1J
-14-

present results. Shrinkage of Tobermorite during drying at

temperatures up to 650*^C may be due to the removal of both

interlayer water and bonded (OH). The changes in absorption

during drying at room temperature were too small to permit

drawing any conclusion. Similarities and differences between

Tobermorite and certain clays are discussed.

The System CaO-Al gO^ -H ^0 , A. J. Majumdar and Rustum Roy,

J. Amer. Ceram. Soc., Vol. No. 12, December 1956 . Phase equilibria have been determined in the system

CaO-AlgOg -H

2 O in the temperature range 100° to 1000°C under

water pressures up to 3000 atmospheres. Only three hydrated

phases are formed stably in the system: Ca( 0K)

2

/ SCaO^Al^O^*

SHgO, and 4CaO • SAl^O^ • SHgO. Pressure-temperature curves

delineating the equilibrium decomposition of each of the phases

have been determined and some thermochemical data have been

deduced therefrom. It has been established that both the

compounds CaO-AlgO^ and SCaO-Al^O^ have a minimum temperature

of stability which is above 1000°C. The relevance of the new

data to some aspects of cement chemistry is discussed.

The Chemistry-?' of Cement and Concrete. F. M. Lea, C. H.

Desch, Second Edition revised 1956. Edward Arnold Publishers,

London

.

Chapters IV, IX, X, XI and XVI pertaining to the composition of cements and hydrated products were reviex.red.
' 1*
U. S. DEPARTMENT OF COMIMERCE

Sinriair Vk'feks, Secretary

NATIONAL BUREAU OF STANDARDS

A. V. Astin, Director THE NATIONAL BLREAU OF STANDARDS

The scope of activities of the National Bureau of Standards at its headquarters in Washington,

D. C-, and its major field laboratories in Boulder, Colorado, is suggested in the following listing of

the divisions and sections engaged in technical work. In general, each section carries out spe- cialized research, development, and engineering in the field indicated by its title. A brief

description of the activities, and of the resultant reports and publications, appears on the

inside front cover of this report.

WASHINGTON, D. C.

Electricity and Electronics. Resistance and Reactance. Electron Tubes. Electrical Instruments. Magnetic Measurements. Dielectrics. Engineering Electronics. Electronic Instrumentation.

Electrochemistry.

Optics an<l Metrology. Photometry and Colorimetry. Optical Instruments. Photographic

Technology. Length. Engineering Metrology.

Heat and Power. Temperature Physics. Thermodynamics. Cryogenic Physics. Rheology

and Lubrication. Engine Fuels.

Atomic and Radiation Physics. Spectroscopy. Radiometry. Mass Spectrometry. Solid State Physics. Electron Physics. Atomic Physics. Nuclear Physics. Radioactivity. X-rays. Betatron. Nucleonic Instrumentation. Radiological Equipment. AEC Radiation Instruments. Chemistry. Organic Coatings. Surface Chemistry. Organic Chemistry. Analytical Chemistry.

Inorganic Chemistry. Electrodeposition. Gas Chemistry. Physical Chemistry. Thermochemistry. Spectrochemistry. Pure Substances.

Mechanics. Sound. Mechanical Instruments. Fluid Mechanics. Engineering Mechanics.

Mass and Scale. Capacity, Density, and Fluid Meters. Combustion Controls.

Organic and Fibrous Materials. Rubber. Textiles. Paper. Leather. Testing and Specifications. Polymer Structure. Organic Plastics. Dental Research.

Metallurgy. Thermal Metallurgy. Chemical Metallurgy. Mechanical Metallurgy. Corrosion.

Metal Physics.

Mineral Products. Engineering Ceramics. Glass. Refractories. Enameled Metals. Concreting

Materials. (Mnstilution and Microstructure.

Building Technology. Structural Engineering. Fire Protection. Heating and Air Conditioning. Floor, Roof, and Wall Coverings. Codes and Specifications.

Applied Mathematics. Numerical Analysis. Computation. Statistical Engineering. Mathematical Physics.

Data Processing Systems. SEAC Engineering Group. Components and Techniques. Digital

Circuitry. Digital Systems. Analogue Systems. Application Engineering.

• Office of Basic Instrumentation • Office of Weights and Measures

BOULDER, COLI^RADO

(Cryogenic Engineering. Cryogenic Equipment. Cryogenic Processes. Properties of Materials.

Gas Liquefaction.

Radio Pro[>agalion Physics. Upper Atmosphere Research. Ionospheric Research. Regular

Propagation Services. .Sun-Earth Relationships.

Radio Propagation Engineering. Data Reduction Instrumentation. Modulation Systems.

Navigation Systems. Ra«lio Noise. Tropospheric Measurements. Tropospheric Analysis. Radio

Systems Application Engineering.

Radio Standards. Radio I’requencies. Microwave Frequencies. High Frequency k.lectrical Standards. Radio Broadcast Service. High Frequency Impedance Standards. (.alibration Center. Microwave Physics. Microwave Circuit Standards.