NATIONAL BUREAU OF STANDARDS REPORT

6995

QUARTERLY REPORT

ON

EVALUATION OF REFRACTORY QUALITIES OF

CONCRETES FOR JET AIRCRAFT WARM-UP, POWER CHECK,

MAINTENANCE APRONS, AND RUNWAYS

by

W. L. Pendergast, E. C. Tuma, Bruce Foster

U. S. DEPARTMENT OF COMMERCE
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 by Congress in Public Law 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; in- vention and development of devices to serve special 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. Research projects are also performed for other government

agencies when the work relates to and supplements the basic program of the Bureau or when the

Bureau’s unique competence is required. The scope of activities is suggested by the listing of

divisions and sections on the inside of the back cover.

Publications

The results of the Bureau’s work take the form of either actual equipment and devices or published papers. These papers appear either in the Bureau’s ow n series of publications or in the journals

of professional and scientific societies. The Bureau itself publishes three periodicals available from

the Government Printing Office: The Journal of Research, published in four separate sections,

presents complete scientific and technical papers; the Technical News Bulletin presents summary

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

data for determining the best frequencies to use for radio communications throughout the world.

There are also five series of nonperiodical publications: Monographs, Applied Mathematics Series,

Handbooks, Miscellaneous Publications, and Technical Notes. Information on the Bureau’s publications can be found in NBS Circular 460, Publications of the

National Bureau of Standards ($1.25) and its Supplement ($1.50), available from the Superintendent

of Documents, Government Printing Office, Washington 25, D.C.
NATIONAL BUREAU OF STANDARDS REPORT

NBS PROJECT NBS REPORT

1007-20-10472 October 10, 1960 6995

QUARTERLY REPORT

ON

EVALUATION OF REFRACTORY QUALITIES OF

CONCRETES FOR JET AIRCRAFT WARM-UP, POWER CHECK

MAINTENANCE APRONS, AND RUNWAYS

by

W. L. PendergaSC, E. C. Tuma, Bruce .Foster

IriorgAnic! BUildlng Materials Sdctioii

Building Research DivisioA

Sponsored by

Department of the Navy

Bureau of Yards and Docks

References Task Y-F015-15-102

NBS File No. 10.7/10472

Approved?

Raymond L« Blaine, Chief

Inorganic Building Materials Section

IMPORTANT. NOTICE

NATIONAL BUREAU OF STAND'

Intended for use within the Gove

to additional evaluation and revlm

listing of this Report, either in wt

the Office of the Director, Nations however, by the Government ager

to reproduce additional copies foi

Approved for public release by the

Director of the National Institute of

Standards and Technology (NIST) on October 9, 201 5.

ss accounting documents

published it Is subjected

luctlon, or open-literature obtained In writing from

permission Is not needed, ed If that agency wishes

y. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

QUARTERLY REPORT

ON

EVALUATION OF REFRACTORY QUALITIES OF

CONCRETES FOR JET AIRCRAFT WARM-UP, POWER CHECK,

MAINTENANCE APRONS, AND RUNWAYS

1. INTRODUCTION

The purpose of this project is the development of criteria for

the fabrication of jet exhaust resistant concretes. Concretes under

development are evaluated by exposure to hot gases from a combustion

chamber. The combustion chamber delivers these gases at velocities

and temperatures approaching field conditions.

2. ACTIVITIES

2.1 Fabrication of Test Specimens

Twelve brick shape concrete specimens were fabricated for the

purpose! of studying the effect of the vacuum method of placing concrete

oa the resultant permeability. The mix used for one set of six specimens was portland-diabase concrete, referred to in many previous

reports as P-D^-. The mix used in the second set of six specimens

was a portland cement-blast furnace slag concrete, referred to in

previous reports as P-BF-. In each set of six specimens four were

evacuated immediately after placing. Two of the four were evacuated

from the top surface, as positioned in the mold, two were evacuated

from the bottom surface, and the remaining two were conventionally

placed.

In that phase of the project dealing with pressure developed

within concrete during exposure to rapid heating, such as occurs during jet exhaust impingement, three specimens were fabricated using

the aforementioned mix P-D.-. These specimens were instrumented with

axially slotted probe tubes with the open end positioned at one- sixteenth of an inch from the surface which is to be exposed to jet

exhaust.

Four molds were so constructed that hypodermic needles as probe

tubes could be positioned in the concrete specimen when cast. These

needles were soldered to a plate which became integral with the back

of each specimen when removed from the mold. Four specimens were cast

using the P-D^ mix. The needle sizes were B & S 13, 19, 20, and 21.

2.2 Testing of Specimens

The permeability, change in water content, and modulus 6f

elasticity were determined on the 12 brick shape specimens mentioned

in 2.1. These properties were determined at varying moist curing

and drying periods, indicated in Tables I and II, and additional

measurements of modulus of elasticity were made at seven day intervals

during moist curing.

2.3 Results

The data obtained on the specimens fabricated using mix P-D^-

appears in Table I and that for specimens fabricated using mix

P-BF- appears in Table II.

The changes in water content during curing and drying are illustrated in Figures 1 and 2 for the evacuation and conventional placing

methods. The effect of duration of the test on permeability values

is shown in Figure 3. Figures 4 and 5 show the effect of moist

curing and drying on permeability.

2.3.1 Weight Change

As shown in Figures 1 and 2 the specimens fabricated by the vacuum method gained more water in the fog room than those conven- tionally placed. However, the conventionally placed specimens lost

much more weight, assumed to be water, in the early stages of drying

than the specimens fabricated by the vacuum method.

The water/cement ratio of the conventionally placed specimens

was considerably higher than that remaining after fabrication by the vacuum process as given in Tables I and II. It may be speculated

that somewhat more water enters into chemical combination with the

cement in the vacuum process. This is also indicated by the modulus

of elasticity data.

2.3.2 The Effect of the Duration

of the Permeability Test on Permeability Values

The duration of the flow of permeating gases through a specimen

has been shown to affect the value of permeability for some materials.*

The extent of this effect on two concrete specimens as shown in Figure

3. The variation in permeability values with the time of flow in the

permeability test depends on the history of the specimen. The con- ventionally placed specimen when tested during moist curing had less

stability in permeability than it had after drying treatments. The

specimen of similar composition which was placed by the vacuum method

was comparatively stable in permeability during moist curing and drying.

The instabilities were probably due to water transportation and/or

evaporation of water.

*"Permeability and Some Other Properties of a Variety of Refractory

Materials I and II." J. American Ceramic Society, Vol. 36 [7] and [8]

(1953), G. B. Massengale et al.

o

N

O

<0

O

in

o

<3-

O

fO

O

CM

1H9I3M Am NO O3SV0 S1N31NOO H31VM Nf 39NVH0 !N30d3d

Moist

Curing

—

-

—

—

—

—

—

-»j^

—

—

—

—

—

Drying

TIME,

DAYS

.90

.80

.70

.60

.50

.40

,30

.20

.!0

0

.10

.20

.30

.40

.50

.60

.70

.80 jBL

SO

Moitf curing

20 30 40

Drying]

50

TIME, DAYS

3

0) nO| a

003

-3

U

to •H 3 rH O "r*J

-d

-4 & 3 CO rH 4 |3 X

00 4 3 PM,

-t-» 3 u 3 3 CO <0 O m\ a) 3 H M3

4-1 > 4 w u

-rH -H 4J ! o a •rH ' n E ”H t-H p U •’rH <0 o

00

w 3 1 3 3 cd 4 O

"fH T~1 4 <3 3 w B CO

X 3 3 rQ O <4H <0 O PM °rH 3 CO 3 « W

0)

w 3 3 3 r-H 3 4 3 4 T3 O a t3 a rH O •3 o o

•3 S p3 3 CO

(0 PM 3 CO 4 1 (1) 3 3 3 3 3 3 4 »3 a CO •3 3 CO a 4 3 H 4 3 00 XJ

00 o 3 00 00 ^5 3 c_> 4 •rH 3 4 rC 4 •3

-3 a)u 3 o w4

T3 M3 3 4 ‘N

cd 3Q (0 3

®s 00 r3

to T3 3 3 oo 3 0) 4 •3 ’3 S'? -3 a £. 4 4 4 a 12 "3 rH 3 CM

004 to CM 1 t-3 t3 w i—1 00 4 3 co 13 3 3 o O tn 4

•3 3 O

M 3 a P 3

p3 4 3 £> 3 00 ”3 C co 3 CO 0 O •3 "rH to E CJ O 3 4 E 3 Q

to ”3

U

rs 3 U 4

*iH 3 7

r,~H TO 4

•iH <u e

M3 3 H

cd 4 o o 3 3 M3 4 a3 a4 2 o £ 0) >

CM

W

0) 3

-3O

H UM 3O

•3 9 3 w 43

0) 00

r—1

•3 £> CO

cd 4 • H <3

40 o m

m o 00 o 40 rH 40 3

On o O nd o o m o O' o in ^-S II 4 9 9 • « 9 9 9 9 • * 9 NO 3

CM CM r^. o ON ro o r-H t-H t-H

H 4

40 r—1

co LO co rH 00

M o 3. CM Y-”l ON On 3 3 a

CM 4 4 3 3 3 i-/ 34 a

00 <M O' r-~ CN i3 tJ o

CM CO nO 00 <r

m 4 o

oo o o 00m 3 9 • 3 9 ft 9 9 o « 4 00 TO O' 00 00 O' 40 vO P 3 4 3 3 •iH 4 4 2 u 4 4 rH 3

TO i-3a *3 40 On LO CTn 3 m ON 40 CM DO CN 3 PM 4

r~- CM 00

O 00 NO 00 1*3 O' CO in

O >N r> ON CN CM o m 00 CO NO 4 3 r-H 9 • a 9 9 9 9 1 9 9 l « « 4 4 t-H 3

3- 00 00 00 00 O' in 40

r

vD CO 3

13

cdC

TO

no

nO

PQHI CMQI P-i

QO

1-3 CMNO

lO

o-O9 nO

O'oo

u~i

m

ON

oo

PQCM

CM

1—I I •|H Q

PM

H

COI CMQl PM

H•4"l •3a

PM 0m1 CMQl CM

to

IX) m

cn oo CO CM 00

O CM CO co co 1-3 CM

v*H CD ,-3

O 1-3O r3 o 1-3O o o « o 9 9 e * ft 0 9 9 9 9 9 O O9 9 ! O O1 1 l o oi 1 o o1 1 1 o o1 1 1 o o1 1

ndm

O O' cm

m Mr O' O' NO NO 1-3 CO rH m 1-3 m o m o <r cm CO CM o * 9 9 « » ft o 9 9 9 9 +0 +0 , ?? ’ ?<? • ?? , ? o 1 ? ? 1 I CO i l o 1 1 00 1 1 CO • • o i i -d"

i*3 co 1—1 CO CO r3 o so m O ON in o cm in O i-3 in o o m o 0- m

r3 cn CM CO CM CO co co co co .-3 co

vt -d vO NO CO CO

NO NO r^* O' ON On

CM CM CN CM <r <]-

cjnOt CMQl PM

CO4

•U -3

•a4 o 00 M

Pm

<1) 33X

0) rH

Pmw3

rH3

TdOEa

COCQ

cm |

co | j m|

X|

00X

d

X

-1-1X

PoX

X

Q

X 7—1 3 X

X 3 c S 3 w3

00 PQ c

•r-l 4J

X

X - ^ tf> 3 3 m| V X o H. X

Pn 3 X

03 •HX

4-» H \ o X . a •rl O 05 •X i—l b X « X 3 r—

3 03 X X

00

a 3 3 o a x H 3 X

X

X CJ

X E 3 X 3 X X 3 (X X 3 *r-4 O CO o PQ COPQ X 3 03 G x P 3 3 rX Pn X X P 3 X d o X a X 0 c o O u o X i—l u x3 00 — X 3 <T| 1 3

£2 Cn

C 3 X

”r-(

Q 03

a 3 3 X 3 3 4-1 H 3 00 X 3 e C 00 OO OO X 3 ®r*4 C d 3 X 3 •H 3 IX o s XU X

03 •ft

X 3 cn| C X 3 pq 3 4-) 00 X X c d oc X 3 3 ®H s-s X o X 3 O 3 o s •X i—4 X PL, cn3 ^ CN 1 i—i i—

W x OC 3 c 03 X c •H PX 0 0 3 X X PQ

03

X

a P c x 3 p > oo X C 4-) c 03 1 0 0 W X kO X U *i-4 X 3 0 p n i X S o pr-> d X 3 X c x X 3 X 3 E x x X 3 3 o cj 3 P -ft.

m 3 I 3 5 o a X 3 cn 3 >

CU

X 3 X XI X O H X Co • •X H X H 3C 3 00 X -X X 03 3 3 H a

O I"- o

CN cn O' m x x o o i o o o i i i o cn m

<f <r o

??m cn o co oo oo X CN CM O

m

co

PQ

r—

Ii IQ

PQI O-i

•<1- in 9 © © co o m o cn o o o o o o o

co oo o

co

r-'

O'. o <t

oo

m o oo CN cn CN X i—4 i—4 CO n- r-|

X

*v

P3u

X CN i—

co

m o i—

o >>

a 3

F—

r—4 i—4 3 3 M <U

X

X PQ nj

X

O 3 cn 3 a 4-4 X 3 il o 3 O O' 00 X r—4 in *<f co r-4 o o X t—4 O n- t—4 O' X c X O o o X O r-4 r- o X e'- r-H cn cn X o CN H CT-5 O' o i—

i—4 O' CN *tN o co o en o X CO O' O'

X

X o S © 11 o • o • 4 • • e © • • « • • • • c X 3 O X m UO in in m vD m 'J X <r •o o 3 cn x o X g S_4 X 3 X O ^—

C/3 3 00 o X co i—4 cn -O CO t—4 00 'd* CN CN vO o O' o x X o CO • CN T—

cn

X r^

O vD CO i—4 00 CO o CN 00 cn CN CN • - -- r^ o\ o i—4 C^ t—4 i—4 CN 7—1 o 00 <r X 00 O' O' CO X 00 xO 1 r-l • 9 « * it • o • « © e 9 • 9 9 * * 9 E d

sax | in in uo in «n m m in in >d“ Nt X

cn CN cn v© V© O' 3 X m m CO CN m 00 X 3 o o O m r-' X o » Q 9 « X X . cn •O <r cn CN 3 3 X

i—I -j" r—

r-l

OO

obo

O' i-. in

in i—

> o+ ??

in vO odd

NO V© O' vf vO i—

1 i i i

\D <t

r-l

O

O o o o I I I

CN n- cn o o O O O i I l

in co in

i-l CN

O o o o I I I O 1-1 00 00

CN CN CN

O'

in

CO i i <r

'O 00 00

1-1 CN CN

co

PQCNI r~- X

PQI PQ

H

CO

IQ

PQi PQ

X r© o #x O' Q O O' n- m in 1—4 00 o Jx

r\

m if o co Nj- cn i—4 iX 00 00 E U • • 9 • • v • • • c O II . 1 ?$ C5 ? ? o1 1 ? ot o X

00

X 3x X oX

T53C/3 3

cn 3 3 PQ X X 3 3 X O P 3 <f| 3 CJ hJ d 3 X > • 

s i <f 00 1 i 1 Nf i i i© O' 3 3 00 i—4 i—l r—4 IQ d d X X 3 CJ w E 3 3 X i—

X o a • PQ 3 fa

PQ

X o O X 00 00 o m 00 00 O Q© oo 00 II cn 3 CO

CN CN CNr-4 CN CN CN CN CN

X

IQ II

X

PQ 3 >>

PQ 4J • Pn •H X X 1—4

X

X

C 3 3 •r^ r- cn on 3 X X P

co iO V© E X 3 e • • 3 3 X rC O XI X3 a) X . <- a > C d a i-i 3 3 X 4-> i—4 E cd X X a t—4 X o o <D H u CJ o 3 X M m vO (Q co- i i 1 cn E 5^

r- II o i i i X X

O

u. lx fa PQ o X

m

PQ PQ PQ CU PQ fa

x | ^1 X TO 3 3

JO 4J a 3 3 3 c o3

OT > 4J a) oc c

Cl) 0)

c/3

O 3 CO

4-4 r-H o CQ 3 £o CJ §

i—i cO 3 i-l

d 4J

a

cO

4-4

X

1/3

X

X

X 3

IQ

CO00

<0

>1

4-4

X)

CO3EX0) PQ3XOX3XXX

00

•i-l 3S 3X3X

a) T—

X

CO3

t—i3XOXo

®f-4 E

cOC

Pn QX

00

i-l3301 Po

CO Xl3COcoX3

053

PQ I

PERMEABILITY

PERMEATING TIMES HOURS

2.3.4 Change in Permeability

with Curing and Drying

For concrete P-BF the permeability after 28 days moist curing was

less than that at shorter curing periods, Figure 5. This data and that

given in NBS Reports 6653 and 6909 show that permeability usually increased for most concretes during the early stages of drying, or capillary water is lost.

Concrete’s fabricated by the evacuation method developed greater

permeabilities than those of the conventionally placed, irrespective

of the type of aggregate or method of evacuation. Data indicates that some of the connected pores formed during evacuation are retained after

curing and drying. The difference in permeability for the evacuated

and conventionally placed concretes was more pronounced for the con- cretes having the blast furnace slag as aggregate. The range of permeabilities was about the same for the concretes made from the porous

blast furnace slag aggppgate as it was for concretes made using the

dense diabase aggregate. This data together with that previously

reported indicates that the pores in the blast furnace slag aggregate,

do not greatly effect the permeability of the resulting concrete.

2.3.5 Moduli of Elasticity

The modulus of elasticity of the portland-diabase concretes, when

placed by the vacuum method, gave values higher than when placed by

the conventional method, especially during the early moist curing

periods and remained higher for ages up to 40 days drying. The con- cretes made with blast furnace slag aggregate and fabricated by the vacuum method also had higher moduli at the early curing ages than

the conventionally placed, but the moduli of specimens fabricated

by both methods were practically equal after three weeks drying.

2.4 Pressure Developed within Concrete

During Rapid Heating

Three jet impingement tests were made on concrete specimens for

the purpose of determining the pressure developed within concrete during

rapid heating. The pressure transducer method was used to detect rise

in pressure with accompanying rise in temperature. The results were

unsatisfactory, indicating less than 10 psi pressure.

Some additional apparatus was obtained with the intent to improve

the instrumentation in the study of pressure developed within concrete

during exposure to the jet impingement test. The schematic arrangement

of this apparatus was similar to a Direct Venous Pressure instrument.

The three-way valve, the filling syringe, and the hypodermic needle

will be used. The manometer, however, will be replaced by a closed end,

gas filled, capillary pressure tube suitable for higher pressures. The

hypodermic needles will serve as miniature probe tubes and will be cast

in place in the concrete test specimens. Paragraph 3 of Part 2.1 describes

molds used and specimens cast for this phase of the project.

- 3-

2.5 Cooperative Jet Impingement Tests

Two panels of a series of seven, that were fabricated at the

National Bureau of' Standards laboratory to be used in cooperative jet

impingement tests with NAVCERELAB, have been subjected to our laboratory

jet test. Both evidenced slight failure, the first after 51 days and

the second after 105 days drying at 50% relative humidity and 73°F.

The second panel, due to the 54 days additional drying, had ten percent

less loss caused by jet impingement.

2.6 A Study of Concreting Materials

and Concretes for Naval Facilities

Four ooncrete test panels (18 x 18 x 6 inches) were received from

the Fifth Naval District. These panels were fabricated with the con- crete used in placing, "Turn-up Pads," at the Naval Air Station, Norfolk,

Virginia. The panels were shipped in wet saw dust, well packed, and

received in good condition. After being moist cured for 28 days, they

will be dried at 73°F and 50% relative humidity for different periods

of time before subjecting them to the jet impingement test.

- 4 -

USCOMM-NBS-DC

PERMEABILITY

IOOOO.OX IO“®

First Indication Of Permeablllty-o-g

Fig. 4. Psrmeablltfy During Moist Curing And Drying For Conoretes Fabricated With Diabase Aggregate By

Evacuation or Conventional Method

O.l 10 20 — Moist curing

SO 40

TIME

* DAYS

SO 60

Drying

PERMEABILITY

SOOOO.OX 10”®

A—A Specimen 0 A A Specimen 2 Both Evacuated From Top

0—0 " 3 O O " 4 Bottom

O-—O “ 8 O O

M @ Conventionally Placed

Fig. 8. Permeability During fVtolsV Curing

And Drying For Concretes Fabricated With

Blast Furnace Slag Aggregate By Evacuation

Or Conventional Method

1.0

I “MFIret Indication 0? Permeability

II

I

I

.

i

I

0.1 o

10 20

Moist Curing — 40 50

Drying —

60

TIME 0 DAYS
.
U.S. DEPARTMENT OF COMMERCE

Frederick H. Mueller, Secretary

NATIONAL BUREAU OF STANDARDS

A. V. Astin, Director

THE NATIONAL BUREAU OF STANDARDS

The scope of activities of the National Bureau of Standards at its major laboratories in Washington, D.C., and

Boulder., Colo., is suggested in the following listing of the divisions and sections engaged in technical work. In

general, each section carries out specialized research, development, and engineering in the field indicated by its

title. A brief description of the activities, and of the resultant publications, appears on the inside of the front cover. WASHINGTON, D.C. ELECTRICITY. Resistance and Reactance. Electrochemistry. Electrical Instruments. Magnetic Measurements.

Dielectrics. METROLOGY. Photometry and Colorimetry. Refractometry. Photographic Research. Length. Engineering

Metrology. Mass and Scale. Volumetry and Densimetry.

HEAT. Temperature Physics. Heat Measurements. Cryogenic Physics. Rheology. Molecular Kinetics. Free

Radicals Resear,ch. Equation of State. Statistical Physics. Molecular Spectroscopy.

RADIATION PHYSICS. X-Ray. Radioactivity. Radiation Theory. High Energy Radiation. Radiological

Equipment. Nucleonic Instrumentation. Neutron Physics.

CHEMISTRY. Surface Chemistry. Organic Chemistry. Analytical Chemistry. Inorganic Chemistry. Electrodeposition. Molecular Structure and Properties of Gases. Physical Chemistry. Thermochemistry. Spectrochemistry. Pure Substances. MECHANICS. Sound. Pressure and Vacuum. Fluid Mechanics. Engineering Mechanics. Combustion Controls. ORGANIC AND FIBROUS MATERIALS. Rubber. Textiles. Paper'. Leather. Testing and Specifications.

Polymer Structure. Plastics. Dental Research.

METALLURGY. Thermal Metallurgy. Chemical Metallurgy. Mechanical Metallurgy. Corrosion. Metal Physics.

MINERAL PRODUCTS. Engineering Ceramics. Glass. Refractories. Enameled Metals. Constitution and

Microstructure.

BUILDING RESEARCH. Structural Engineering. Fire Research. Mechanical Systems. Organic Building Materials. Codes and Safety Standards. Heat Transfer. Inorganic Building Materials. APPLIED MATHEMATICS. Numerical Analysis. Computation. Statistical Engineering. Mathematical

Physics.

DATA PROCESSING SYSTEMS. Components and Techniques. Digital Circuitry. Digital Systems. Analog

Systems. Applications Engineering.

ATOMIC PHYSICS. Spectroscopy. Radiometry. Mass Spectrometry. Solid State Physics. Electron Physics.

Atomic Physics.

INSTRUMENTATION. Engineering Electronics. Electron Devices. Electronic Instrumentation. Mechanical

Instruments. Basic Instrumentation.

Office of Weights and Measures. BOULDER, COLO.

CRYOGENIC ENGINEERING. Cryogenic Equipment. Cryogenic Processes. Properties of Materials. Gas

Liquefaction.

IONOSPHERE RESEARCH AND PROPAGATION. Low Frequency and Very Low Frequency Research. Ion- osphere Research. Prediction Services. Sun-Earth Relationships. Field Engineering. Radio Warning Services. RADIO PROPAGATION ENGINEERING. Data Reduction Instrumentation. Radio Noise. Tropospheric Measurements. Tropospheric Analysis. Propagation-Terrain Effects. Radio-Meteorology. Lower Atmosphere Physics.

RADIO STANDARDS. High frequency Electrical Standards. Radio Broadcast Service. Radio and Microwave

Materials. Atomic Frequency and Time Standards. Electronic Calibration Center. Millimeter-Wave Research. Microwave Circuit Standards.

RAuIO SYSTEMS. High Frequency and Very High Frequency Research. Modulation Research. Antenna Research. Navigation Systems. Space Telecommunications.

UPPER ATMOSPHERE AND SPACE PHYSICS. Upper Atmosphere and Plasma Physics. Ionosphere and

Exosphere Scatter. Airglow and Aurora. Ionospheric Radio Astronomy.