iA I

'el

' '2

g-

I N,1

IMEWN

-1- n~maz

3Pv A2 n M -1

"W

.*'~ QA

vli fpe~ ~-, ~ E

-z

Ie g: F Y'-

* --

',- VIeTY C I. ASSIICATb~ IO 001TISO PA*Z f*%001 Dille tPo,,,,j 1A

REPORT DOCUMENTATION PAGE Dh9'FOij. COMPIA'TINCi FOR'MIfNORTg NUM9UIU ,~ OQ%' AC(C961O'. NOC., IPI 9001tIY' C4h * .' v~eft

N00014-75-C-1015 A. D41~7" 3oL-.4 T I 9 (hV Sub(Ifle) I~. , 1YPg of REtPORT b PCIVIOD COV90119

'rojernnca or the flood and Nock to\ Tuchnicnt Report No. 11-(;" Inrtial Loding of the lHeadp ,P~~MN 0 PN Iu~

1 'uo1.,5 CONTRACT OR GRANT, Nwuc.'.,1

Voight R./Ilodg~on) 4-7j 1//,01? ,

I, OLqOOM161iORGAoNIZATION. 00AMI AND ADDRSS 1, OOAW 9 g~g%

Bloengincering Center, Wayne State University418 Health Science Building NR 064-524/12-10-75Detroit, Michigan 48202 _____________

CONTROL6INGO PPICt 14AMI AND ADON96S 12, *O04 DATE

Department of the Navy, Office of Naval Research March 9. 1981Structural Mechanics Program (Code 474) 115 01a.1109 OF P {1"%42 tor- VA 22 217 ____5 _______v___

ffO,~Oi P AOILNC9 NAI4 £ ADORg51kl E110eni from, Controling Office) It, *tCUPITY 4L6AISS. 4f'* Fo';a'f'

same (J~j~ -Unclassified

Approved~~fI71A~oa fo0pblc elas; itibuio uliitd

' OSTIUIION SAT911094 tot the e11e011'I 611P IR~es &is#* to, if dolle,.'g, Item efessff)

It SUPPL961900AAV NOT&$

I* Oc o WORDS rconfius ny. ,.uefs* side It asoceepr and idenify by block 0pvobot)

biodynamic, response, -Gx acceleration, injury tolerance levels,mathematical neck model

P0 A*STPAC? (CenAuwe0 on, roer". side of noeeow .,O Idenify bor sch Rm"b.)The purpose of this

investigation has been three folds 1) to review the literature for experi-mental results which either contribute quantative tolerancht data or date sup-porting mechanisms or criteria of injury; 2) develop new wi.thods of inves-tigating neck response 'to Indirect loading; 3) further refine a mathematicalneck models

It has been found that retinal hem~orrhage or mild concussion ware thethreshold injuries produced In forward facing harnessed individuals subjected,

DD ~ 1473 EDIION OF I NOV O6 1110169T9PS N 0 102- LP. Old.A 6601 59CURSTY C&.ASSIPICATION OF TNII PAD Woff re.eDAI.N AIev,

1gCUmIY CL.ASSIFICATION OF THIS PA9 ("On DO cee Enle,.

to 39-45 g sled acceleration impulses lasting on the order of 0.270 ms depen-ding on head-neck orientation, On the other hand, field collision data indi-,caes insignificant head-neck injuries of belted passengers from purely iner-tial loading of the head due to collisions at highway automotive speeds, iiow-ever, in abrupt neck stretch experiments with cats it has been found that neckstretch and possible odontoid process - cord interaction are related to uncon-sciousness in this species, Tetanizing the cervical muscles reduced the inci-dence of "concussion" symptons produced in this animal, Collars on monkeyssubjected to flexion producing occipital impacts, were reported to provideconcussion protection...

. -Vollow#hgi-o?1with a freshly dead, hemisactioned monkey head model taggedto measure shear strain, it has been postulated that highest shear strainin a pure rotational setup was found in the brainstem. This was caused by thebrainstem pulling on the cervical cord restrained by dentate ligaments as thebrain attempted to rotate inside the skull. Another group using anesthetizedmonkeys accelerated on a Hyge translational sled, stopped the body lens abrup-tly than the head, producing a range of symptons in the monkey from short con-cussion to death. Pathological examinations showed that they produced manyneck injuries and large amounts of brainstem damage. Recent high speed workwith hemisectioned cadaver necks shows that abrupt arrest of the body at only3.9 m/s (11 ft/sec) causes inertial head loading to flex and stretch the car-vical spine up to 2.54 cm (1 in).

- -?,>While no clear picture of tolerable levels or even criteria of Injury conbe pulled out of this array of evidence, it is clear that until the problemcan be better defined, relative motion between head ind neck and a ponitionwhich will minimize stretch in the retinal attachments should be part of pro-tective systems, where feasible, when abrupt -C) can be anticipated.

4 N 010P , .0 ,6

1gCUiRI Y CLASSIFICATION OF TNI PAGEMM De InlfeeE)

TOLERANCE OF THE HEAD AND NECK TO -G INERTIAL LOADING OF THE HEADx

V. R. HodgsonWayne State UniversityBioengineering CenterDetroit, MI 48202

U.S.A.

Summary

The purpose of this investigation has been three fold: 1) toreview the literature for experimental results which either contri-bute quantative tolerance data or data supporting mechanisms orcriteria of injury; 2) develop new methods of investigating neckresponse to indirect loading; 3) further refine a mathematicalneck model.

It has been found that retinal hemmorrhage or mild concussionwere the threshold injuries produced in forward facing harnessedindividuals subjected to 39-45 g sled acceleration impulses Lastingon the order of 0.270 ms depending on head-neck orientation. Onthe other hand, field collision data indicates insignificant head--neck injuries of belted passengers from purely inertial loading ofthe head due to collisions at highway automotive speeds. However,in abrupt neck stretch experiments with cats it has been found thatneck stretch and possible odontoid process - cord interaction arerelated to unconsciousness in this species. Tetanizing the cervicalmuscles reduced the incidence of "concussion" symptoms produced inthis animal. Collars on monkeys subjected to flexion producingoccipital impacts, were reported to provide concussion protection.

Following work with a freshly dead, hemisectioned monkey headmodel tagged to measure shear strain, it has been postulated thathighest shear strain in a pure rotational setup was found in thebrainstem. This was caused by the brainstem pulling on the cer-vical cord restrained by dentate ligaments as the brain attemptedto rotate inside the skull. Another group using anesthetizedmonkeys accelerated on a Hyge translational sled, stopped the bodyless abruptly than the head, producing a range of symptoms in themonkey from short concussion to death. Pathologicol examinationsshowed that they produced many neck injuries and large amounts ofbrainstem damage. Recent high speed work wiLh hemisectioned cadavernecks shows that abrupt arrest of the body at only 3.9 m/s (11 ft/sec)causes inertial head loading to flex and stretch the cervical spine !A .03 p.. _up to 2.54 cm (1 in). O

While no clear picture of tolerable levels or even criteria of , F) '!.injury can be pulled out of this array of evidence, it is clear that/ . o.,until the problem can be better defined, relative motion between j

head and neck and a position which will minimize stretch in the /--- t 1 c . d

retinal attachments should be part of protective systems, wherefeasible, when abrupt -G can be anticipated./

A /

bt 4 Iacob

A. INTRODUCTION

1. Human Volunteer Exposure

Col. John P. Stapp was one of the pioneers of voluntary

submission to forward facing linear deceleration (eyeballs

out) head loading. In his studies, twelve healthy male sub-

jects were exposed to acceleration at right angles to the

long axis of the body during high speed braking of a rocket

sled on which they were riding. Using an inverted V leg

strap added to the shoulder straps and lap belt assembly,

they sustained exposure to 45.5 g at 493 g/sec rate of onset

of deceleration, and up to 38.6 g at 1370 g/sec. Stapp

suffered mild retinal hemorrhage on a run in which the peak

mouth accelerometer registered about 42 g, total duration

around 270 ms. 1 He noted that much higher levels can be sur-

vived, although reversible injurious effects may intervene

(1). Stapp noted that in one test (Run 133) the "Subject

failed to follow instructions to keep his head down," (head

and neck flexed forward as nearly horizontal as possible to

minimize neck injury and chest impact) his helmet flew off

during deceleration and he lapsed into brief unconsciousness

on the sled. He revived and relapsed into unconsciousness

lasting about half a minute, responding to being slapped on

the back of the neck with head held down to knee level.

IVerbal communication with the New York State Boxing Commission Chairmanindicated that retinal detachments are a growing concern in that sport.Although gloves have been redesigned in recent years to prevent thumbs

from being used to gouge the eye of an opponent, it is conjectured bythe author that these injuries are due to fromtal blows causing relatively

high -G impulses. Preliminary work on dummies has indicated thatblows of 40 g, 8-10 ma duration are easily produced by an amateur wearingregulation 8 oz gloves.

4

In a repeat run to determine what caused the losA of un-

consciousness in Run 133, Stapp, with head held down to aviod

amplification of head loading, did not suffer uncon3ciousness

but did sustain comminuted fractures or radius and ulna of

the right arm. Gadd (2) has done an analysis of some of the

more severe runs by the Stapp group and estimated from the

unixial head acceleration oscillographs that considerably

higher biaxial accelerations were experienced with Severity

Indices to 1500.

The impact enviornment of Stapp and his co-workers was

evidently in excess of what is generally experienced in motor

vehicles. With regard to the applicability of head injury

(concussion) criteria (HIC) to seat belt system compliance

with U.S. Government motor vehicle safety standard tests, auto

manufacturers petitioned successfully for removal of the

criteria partly on grounds that field collision data does not

indicate that head movement (without striking an object)

by shoulder-belted vehicle occupants is a serious injury pro-

ducing factor (3). Part of the reason for rescinding the HIC

was also artifactual head waving response by existing dummies.

2. Anesthetized Animal Exposure

Hollister, et al (4) clamped the heads of anesthetized

cats in a stock with the body unsupported below and allowed

them to drop in guided free-fall. The stock was arrested

abruptly, causing the neck to be stretched by the inertial

loading of the body producing symptoms of experimental con-

concussion interpreted by loss of corneal reflex. They also

:- , • • • • • • • • • • • • • • • • • • • • • •5

performed the experiment with the body supported, and required

higher energy to produce "concussion." The symptoms were

also produced by a blow and by static neck stretch. They

found that the location and amount of histological damage

were not discernible between cats which were dropped and those

which received a blow. Brain neuronal damage was found

similar to those reported previously in experimental animal

head impact tests. However the neck stretch experiments

produced more pronounced damage around C1-C2 on the medio-

ventral surface of the cervical spinal cord. They attributed

the mechanism to a sharp flexion of the cord around the

odontoid process. It was conjectured that a subluxation of

the odontoid process during a forced position change might

contribute to aggravate the effect. Tentanizing the cervical

muscle reduced the incidence of "concussion."

These researchers confronted the same problem others

have experienced in head injury work, that of separating

the effects of variables. In addition to neck stretch,

when the stock is arrested, a blow is delivered to the bottom

of the skull due to the inertia of the head. Modification

of the apparatus failed to produce reproduceable, reliable

test results.

Ommaya and Rockoff (5) have produced concussion i i

experimental monkeys with and without a cervical collar,

the latter associated with the most severe concussive effect

and brain damage. It is not certain whether the increased

effect was caused by more neck stretch without the collar

6

or because of higher head acceleration without the mass of

the collar.

Interesting results were obtained by two Japanese teams

using a HygeR translational sled in anesthetized monkey

experiments (6, 7). They accelerated the whole body of the

primates and stopped the head first, followed by a more

gradual deceleration of the body, producing a range of neural

response from short duration concussion to death. No re-

lation was found between brain injur, and intracranial

pressure but many cervical cord and brainstem injuries were

produced.

3. Fresh Tissue Animal Brain Model

Hodgson and Thomas (8) devised a model in which shear

strain could be measured using a freshly dead monkey brain -

cervical cord hemisection. It was subjected to pure trans-

lation, pure rotation and a mixed motion mode. Rotation

produced the highest shear strains, which were 3-4 times

higher than had been predicted by mathematical models, and

were measured in the brainstem rather than as predicted in

the peripheral cortex. It was postulated that rotational

motion permits the brain to rotate within the cranial cavity

to the degree to which the tethering action of vessels and

spinal cord will allow. This action pulls on the cord

through the brainstem, stretching both, due to the reaction

of the dentate ligaments connected on either side of the

cervical cord pia mater to dura. Kahn (9) and later

Schneider (10) discussed the possible role of strong dentate

7

ligaments on the exertion of stress on the cord during

accidents.

4. Observation of Cervical Spine Ktion

4.1 Human Cadaver Neck Models

Recent work with hemisectioned cadaver necks by Wayne

State University researchers has helped to visualize the

motions of the cervical spine when subjected to experimental

-G impact. In this configuration the neck stretches due to in-x

ertial loading of the head as it attempts to continue moving for-

ward when the body stops. Excerpts taken from film exposed at

500 fps following arrest of the body at only 3.9 m/s (11 ft/sec)

are shown in Figure 1. The cervical spine is seen on film

to begin in the normal convex forward (lordotic) curvature;

straighten as the head moves linearly and with approximately

13 mm (0.5 in) elevation during the first 30 ms, and,

gradually curve into flexion. The spine, which began at

114 mm (4.5 in) length, stretches to a maximum of approxi-

mately 140 mm (5.5 in) when the chin contacts the chest at

90 ms, after a 60 degree rotation of the head. Figure 2

is a blow-up of the cervical spine near maximum flexion.

It is not known how much the cord stretches during this

maneuver.

4.2 Spine Displacement Transducers

Another approach to the measurement of cervical spine

motion during impact to the almost intact cadaver or

anesthetized animal spine, is by means of a vertebral

displacement transducer. It utilizes a Hall effect cell

8

which can measure magnetic field strength. The sensor

provides a linear single-ended output which is a

function of magnetic field intensity. In this applica-

tion it is desirable to vary the strength of a magnetic

field around the Hall sensor in a manner that is pro-

portional to the relative vertebral deflection so that

the output of the Hall effect sensor is proportional

to relative deflection.

The Hall effect sensor has the advantages of small

size, simple circuitry and being relatively impervious

to fluids. The difficulty is in obtaining enough linear

output for a limited range of displacement. It is

necessary therefore to condition the output with a

logarithmic amplifier to get a linear output. This

arrangement has been tried and appears to be linear within

4Z over a limited range of 3.0 m (0.12 in). It is now

being set up on a simulated cervical spine and tested for

cross-talk, as shown in Figure 3.

4.3 Cineradiography

A cineradiographic technique is also being examined

for the visualization of neck motion during impact. The

x-ray image is projected onto a television screen which

records the resultant motion of the cervical vertebrae due

to a quasi-static load. This method has the advantage

of observing spine movements in the intact neck to

witness such things as process fracture due to bone inter-

ference or ligament tension under extreme motion. It

9

has the current disadvantages of: relatively small field

(just encompasses the cervical spine); shoulder super-

imposition in the cadaver is difficult to overcome; and

slow rate of phosphor decay in the image intensifier

limits the upper framing rate to about 200 fps. Informa-

tion on neck stretch and motion of the dens from any or all

of the above techniques is for refinement of a mathematical

spinal model under development in this study.

5. Tolerance Criteria and the Effect of Head Protection on the Neck

Patrick and Hertz (11) have investigated the effects

of the added mass of helmets on neck reactions of volunteers

and cadavers subjected to an acceleration environment producing

hyperflexion of the head and neck. They found that both

magnitude and the location of the mass on the head contribute

to an increase in the neck reaction. The effective moment

at the occipital condyles was determined to be the critical

injury criterion, Maximum voluntary static moment at the

occipital condyles was 35 N.m (25.9 ft-lb), while under

dynamic conditions the same volunteer reached 88 N.m

(65 ft-lb). In general, it was found that the equivalent

moment at the occipital condyles was higher for the

cadavers than for the human voluuteer under the same con-

ditions. The restraint of the neck musculature of

the volunteer reduced the peak reaction at the occipital

condyles.

Ewing, et al, have done extensive work in the area

of head-neck hyperflexion movements from -Gx accelerations

10

(12, 13). He estimates that Stapp's -Gx sled acceleration

run (1) may have caused acceleration measured at his mouth

of 200 g. Ewing also has reported a complete disarticulation

of the atlanto-occipital junction on an 89 N (20 lb) rhesus

monkey subjected to a 160 -G sled acceleration.

6. SUMMARY

The work of many researchers with anesthetized animals,

brain models, human cadavers and volunteers indicates that:

1. The amount of relative movements at the cranio-

spinal junction may be vital to whether or not

consciousness is lost in high acceleration environ-

ments which produce hyperflexion of the head and

neck. Such motion should be minimized.

2. The odontoid process (dens) may be intimately involved

in the injury process to the cord as It bends over

the dens in this maneuver. Subluxation of the dens

may aggravate the injury to the cord.

3. Wearing a helmet will aggravate the problem by virtue

of added bending and axial and shear loads at the

atlanto-occipital junction due to higher mass and CG

of the head. A helmet presents an advantage, however,

in providing an attachment point on the head with which

to fasten a belt strapI inertia cable or collar lim4ting

head-neck motion to impact.

'Such as used by U.S Navy football players to prevent excessivebending of the neck.

11

nmmm m =nmm nmmm nmI.

4. A flexed head and neck with chin on sternum has been

found helpful to avoid losing consciousness and possible

retinal damage from -Gx impact but should be considered

with respect to possible increased hazard from -G .

REFERENCES

1. Stapp, J. P.: "Human Exposures to Linear Deceleration, Part 2.The Forward-Facing Position and the Development of a CrashHarness, AF Technical Report No. 5915, February 1952.

2. Gadd, C.W.: "Tolerance Severity Index in Whole-Head Non-mechanicalImpact." Proceedings of the Fifteenth Stapp Car Crash Conference,Coronado, California, November 1971, p. 809-816.

3. Department of Transportation National Highway Traffic SafetyAdministration (49 CFR Part 571), Docket No. 67-7, "OccupantCrash Protection Head Injury Criterion."

4. Hollister, N.R., Holley, W.R., Horne, R.G. and Friede, R.:"Biophysics and Concussion." WADC Technical Report 58-193and ASTIA Document No. AD 2033885, September 1958.

5. Omnmaya, A.K., Rockoff, S.D. and Baldwin, M.: "Experimental Con-cussion - A First Report." Journal of Neurosurgery, 21:249-265,1964.

6. Tsubokaga, T., Nakamura, S., Hayashi, N., Miyagami, M., Taguma,N., Yamada, J., Kurisaka, M., Sugawara, T., Shinozaki, H., Goto,T., Takeuchi, T., and Noriyasu, T.: "Experimental PrimaryFatal Head Injury Causes by Linear Acceleration-Biomechanicsand Pathogenesis." Tokyo, Japan.

7. Komaki, U., Kikuchi, A., Horii, M., Ono, K., Kitagawa, N., andMatsuno, M.: "The Research on the Fatal Level of the PrimatesHead Impact Tolerance." The Japan Automotive Research Institue,inc., (JARI) October 11, 1978.

8. Hodgson, V.R. and Thomas, L.M.: "Acceleration Induced Shear Strainin a Monkey Brain Hemisection" (719023) Twenty-Third Stapp CarCrash Conference, San Diego, California, p. 589-611, October 1979.

9. Schneider, R.C.: "A Syndrome in Acute Cervical Spine Injuriesfor Which Early Operation is Indicated." Journal of Neurosurgery,8:360-367, 1951.

10. Mertz H.J., and Patrick, L.M.: "The Effect of Added Weight onthe Dynamics of the Human Head," U.S. Army Natick Laboratories,Report on Contract No. DDAG-17-67-C-0202, Natick, Mass., 1971.

12

References (Continued)

11. Ewing, C.L.: "Injury Criteria and Human Tolerance for the Neck."Aircraft Crashworthiness, University Press of Virginia, p. 141-151,1975.

12. Ewing, C.L., Thomas, D.J., Belier, G.W.J., Patrick, L.M., andGillis, D.B., "Dynamic Responses of the Head and Neck of theLiving Human to -G Impact Acceleration, "Proceedings of theTwelfth Stapp Car trash Conference, Society of AutomotiveEngineers, p. 424-439, New York, 1968.

13

Asapolte Villina - 0al Ship slots"a ceemd-

Q~tll.rtutcve 4 LuIOIO1"o 1 19 1 iho Nalilot0*. ~aeplls. swrylad 21402 Code 39522HAWSlowniih Caest Atl Calls 2140 - t..Veal essarteest of th0 Navy

,hl -1.tl Vote tlol.'_f loft 12161 2SS 35 Mr p*N.J.' Wait0. -vaeie.s. 20360-on~s,1fte 'o"O At"! Diector of $&searh lt- mir. a.. lodetrsrer'

~~rll~l!00. viralvi~a 2:317 2414 - Dr. .VdrW~ iarfS4214.- %Iedeteee Stleliti Imiet..a CeiDept.t~~vtiS piCse?4

0, t . COl. 41. (1) USkia Noaar 15vel Acad..?

2Chief,0 mOCU112 gottlen F#.Ag jm*x . sevalrAd Status Coomd

#* :(.*es U.S. Arley Ristto CO~ll 2502 1.' Peehill vivo. Vast. of %he $levy'. ottllh clile. seto., Araal. Atlases009im Panadm, C619ltavea 91101 valeItlM. D.C.~ 40

0,t. 4sat1at 011 A26 Clos.: erri1 C.dNla:a w O f ster SKIiet dat le tolec

ee~'Fort Soevatheetl6 Si12sha2060 Cehlsd ladv. ga altrrt 93S5.. Cee17 1S@Sltelra~lvaCIeII.. 1Lbrtr M Alias Coda 4042 - SMr. Is. Vlterts 06 lock. Library4$30~ -- r. 1,80 sioclai 32m Ssroet.'e

va,.ltol Officer 8.4oltr Dietr-iitg.AtAe"l aval. Ship Alvorri 6 Devoloperst foeveri uS.. ltCivil Za~t, tab .""Il Air &*aealse Cesici

.ttn: C0 261 Alto: Code 042 (Tech. Its.- St.) Dart hamClOSe91041 Nemlnter, t.prnlvaeltA8l14

JP;"YokArea 6.5.oI? Navle Oak e.Ihtit eaSe;Cltrt 92132

4laot.N 1000) 511 O.ND a )loilnoo casc

19 tohaal !faoer -U.S. Newl At&""otreosor 1901 Mrh. tanes) Nvl Usoldetsn Cae .. sd 10

on o",h iOiilce 1945 gsetp.C1fru90

f-.44,.. Calilaoeia 01101 1942 S.oerleor of Silluiild" Dae. of the Navy15 * ae a-t. S 4 401Cre

U.S. Nall Neoint". D.C. 205MO0

14e 1:1a4lIl (14 ~'Technical Otloa. Er 1444 Yeh, Library

PA~l) U.S. N. -Ser* Vs.0 Sat. Wa. Vahlptee. D.C. .111601.It4 .. IWi. 1118246 alvel s..rch Alto$ IlAwf1iIp 01 Re.. & TothmiSy

li1.; r. i.eI. ?,lJy :440 Po hae Illi 021 CIA. Scientist lot 500

COD-A.A.Zt 4200 ouiesda. Pllia 42011 634 1 SyReehaftIse14. 0.. o. StAilc 4290 027 Ship sleit- . .

NqiIAs. %orth Carolina 27104 (2) 40 1.0.8 of Novel oportesa @31 6.05..'e "LnheeDept, of ike Navy Nvl~pttaeisCge

coaradaila4 oficert odwoa loploelec Research DIV. unass.gi C,.C.-SO)S0,Nea shi n, PaIl'W(.)IwNaallip $60 Center Alto Celsd po Poolevlle Cal as0e8

Itiol .1 . kilo8 kat Naval ShAP)ard rteil.fayn 308

1.0 Aid? 4;1a1411 a oSh. Asoui Pre seil. Tirtiele 22109 0Sategic Systrn Project Office Aliasi NANSIC 4100 Ship Sys. later. A Co. Sep.Vttrirn, Mlstcheto 01112 Attes Dr. 9. Palooero enot of ii. wavy 41021 CoePuiei.Aided ship Oe.

Cedle Igo . uehiagoe. D.C. 20)90 4100

4120 Nlot lsI.

6US Satt ship Sine.0129 Subarine stotc.

Air fort.Director1Nat,94 leeat haOfa. Standard*

.,4 hAlO lfiattoo D.C. 1011410 ~l, 0 Iir Fit. 110. Atn: Mt. S.I. Wilsn I 1 19Ot In. .7. %0.11Oit,- C..l vik?.wI Or.. Coos

at 101. 875)352 Nalve Ioiat.dui..Sitlir Sivelvo. fLiOoSiNGfa 01.101.047151 iIhl.) feshiestes. SD:.- 20120

.,W. vple 1so C lvi~nti Creep Scene* A Tech. Diel$'& s1 k.'s tyod. of c.h. Library at leevlrce.57..'ii.i ~ FoArc nt 1.0 vashiefivo. S.C. 0540

W s lega esriesi trench Defenea S,.cioor Agency,;.e.r 51we,1vsio Seehiaes . S.C. 02

is Fit.* 4vpo Laboraty as $SO.Itiiee A79. NOW MadCc Still

Co=rnder field Cossand.4 rgto w185c of Srevotifl Cecoarch Deeo" Xloee 4seP1

S~~~~ iaeAe) edla list

Al51olv rc1etc Sly.8ce411Dietr Detentes 1eeterch A insrs.

* II Tachmeiel Lottary

.5IIIr *~aitD ivision The Pentagons11n'. 1,1CCI 4 pace, Ad... watehieotla. D.C. 2001... P... re ole

.. .o.., Chief. Aiaria A Ille.posnl Sraerh

*(t ic# .8 Flight Sla&,ar'SodAweteete A Speco Adele. lateial AV1etie. Agency

.51.1. .'A,!vlfti$tler (fr A114604d baekloglaft. S.C. :0551)o.mcrh A Ittcrlav6

tn~.. .C. 0111 Chief. Research dad Developeeshull..m Adioslratioe

'..lltt1 A Toch, life . Pacility M~holer, D.C. 202ls.54 ho~ootaaatleo (S-A151.10 a )400 Ceopelp Chief. Sfficae o Ship Coert.

we'-Ja osiaa 0014 =fill"m Aeieieiellta-1§1134lv. S.C. 40215

.~lo r.t ~lActlle A11.1 Its. 11.1. Asseo

A0601 teeny CommoereDe. ..t o I saee0it flY. DIV. GI #"ette revel. A tech.

-11100Le.. D.C. 12 Ship 11.1 81414r.1, 0ettlsed

Nalional A ....... of.,tii

'tl0 -I it he. Auac. Cmod 2101 knotsllvlio Soecee-1tte. Virginia 2212 51AaAklae. D.C. 10-I1S

Alike Pr. A.A. lite

14

P402 C4TKACtILOAU t-lit St.~U I ral. VLIIIa* A. Yeah Or. N.C. SchaefferCOLL&Jot~i Cl-.aUtrcy Vuiraratr at CU-o Ieet.C Int .1 Aat..dDopt. at C1.91 LEst-riag Dept. .t Me.h...~ 6 Uso'a, t . A-,.Oe~r- Sat..t .Va61 . K'w 8.14. Aa et. ttaaaa,h...9.cOo Call.$. Sn. C~i~J.~

11-1.7i9 o t.4a atLcicPa . .cAM,:ak LibtitCJ:O1:).' S Nacat. S . Vittnc* ~a.l.tt . 1 ... a U11 i Fr. A.Mfanai5 a ~dD~. Cadent.1 V.Iant~la C Sp - ..t .an6a Lcir

M 1b . %.It t d S~ j . as $* vst~s C

A.it.. .,.. t91. he.aa' "1 Aa L.A . hSchool at Ingoer.. C Applies Stsc $.See lanes. Cos ..es-

DIea. bIll tentAS AaAPasor AScience@ tI."ICatibofataahC.11101.1 910qomutr$coaa ivson32 Ig treapto heck.&C 94 tA4# I eal 000 t.

Casalla9i0 eo. tak it, tO 44mto Jco 10 ClteSite.I- 1Vt Naa d ate

Ct'a Aple C iect a. f i. DnProf. 5,4 6. pathl Cr. 0.5. Scdga fles ista So ate Of.alt l L A.ct Ste ar iaC.aa t ele ft'4M Cilerstt Moay.. occ ttat. V vaat pocoo. Dar .ofAp0 j, Cat.atcfbaelaitoicarcDept. O.fvl.rhtett Aple "&elselt Sc414ol 30; Scoo fdicteeM 6A 1.4St

tiacant ids Cat i . PAS scga s 4000 0 2 ) tri ltet " C 4 a a tey v~i 14Los aales P h. Caeyifao 2024falay t al ebrta. 94120~ Aler aLo!Po. Ja . .mh ae a yb STa. B.. K eel.

01. f .f.6 ppid1CIaeaiaOstt Statelit tuA itaait 6020t. ?% ofK iiios, Ares" 1F8664.04 .. Sy..,aa 911aeroitr O~c ttaaat 4pijtr4nh La.rtnat02eha Mr~rFt-(. tal Anatl fat. V.At a. a teal tiar Catm . a pt t: 10,i. - V a l S 'f. Dr. Ioda s.1 . Man eaJ aia

No;aca0 .tta l w141ya .stae Uandr~t Sli 11 40e S~at. IS V~eaat ' AreediGC~ yOfPCySr~~neia,,ca.. pas. 30. Deptaa...ltbae411C . o.f rP .1eaaa &.st

01. iof ppir eeatr M#Ch~iC s~colr t %iirc ~ts sat.at Ceg. tear.ns ylvanad 1 . aCtt@&@ lark. ltlw 04~itt .. a try al t o Detroi Ca t. of hie Aao, 4aIa. tctato ) apoeamot~lo . C lif rna 9 7.0?ta . 9 4" J. kdrylCho. Ise ld . taraCaireka tivrelDOOltRap LA f lot*,~ t S.~ate. satet t treoty. Dellpt. oflIZ.or'

I Se ?tC4l tlaato Saaa"d No twe s er U io tag Seplt Noot Lare p :.4 A .r t etb. U- tila y at CiC IaMt1%0 11S 111.. Or.. tllaf 160 ") (01t.4e900ap" [.-I. 71.. iOOR.It. 11 1- Peah $0a1,11O 101Coiaat ki 00

St at. A.J. Sl t ? at t el at, Il r.o C aet. of C cl oColcak~~s OvlartaDort Capt Asfa tfeti lae6ero Pret.4 "..h, capr Poe.I ra lCapt.I atpt Cifi taaetoearlc Arnaea &l f 61601c Jet.et CSt reet aiegDtlta. eaala 15.11

tro. .. te.t. 1V0NT. D.. Saiaaganr trot.g J tt. .Ko t a DefpStt. O A teOrb a gAnlysiC.-4 O'l~yCalvarelty otf itaua 1LA Is . miege Stat. ~ t o.C P11k.1 I taleA tto f CaafntzCap f ii A6r.I4 s ta pied ct le UPS.rtt at Y~pr~ 4appfa Wel Cap~t. y of Ckas~taleaisar" .N1 " S ran 5. 1.,Clmlaa 6 001 Cap1 Jay Sareepta Cincinnl8 at i. 0da 110a tc 111

Li.a loc P.. rat. 0I.N. Neaierk Scokym N.C. 11101tr. W.V Hetitt tPa ftbte r arita y of I Iagtaaro ht. .. t pr oAo lc"tCreacant uflth to.ty a Cepta C oa Caviltgae ?on~ed e Afivea lat le Lehiatgh t Vtb1edCiltarta osaDart. IaO .C111 1 k 11040~LD Mtviea thi . Iao M 1 0 2110 Capt. Sof) cii thtn50 n lotahalas ept.la is IS.4Pet rNT.lac 00l 1tJ t Stat. 9.arce mr ColdctkP legSie. s tarla. 1004sfUniversity of California, Sea DiSeet. atst. c.Da palktel aettasS;";rofiWAddeltan

toot attalteelnt attvDeptl. of Appled Itachanie colvertit aOf Strepalde a d Dep Selta of 1. fec aia EcngyernProf. ~~I A..OLLet Atlc. California 9420 feapr.o t pacell 04ri1ta Sette of arlsht.t r C1a19 OCapt. ~~~~~ ~lstetnvlo at~ts Araa:2110.3tete Sat .. lieS.V..lSt

titata. trot.tt 11 0.1. at lof ant10I.tlataa Dee~t ofaRa l Arcite40 r Drawsioinrei9.ttrlt Dr. LCte ak. CFARot P.0447rC ... A eahraa' ' -Lacatre t et a 0010ao2loRsarhLbrtoy t e*-aiomsCmatpI at . at., Aortt. A ot d Stat. 5.5. hd S vla w Ca1 Dp. 5.6 . $Is.2if cstc et. 4I'lt.c Cntaelrtl t Feet.t faerner appnttb ~ tPia lctaet o cosat tat 14ate

VignaMttd IC colt Deft.k ofMciatvt l Iteahaatta Sctaan~a.NSt.Q Efitot. n KAheeC DAYltkeCa.:al oi .. O aner 0 " he 01044ar41tCn We&. lavaralty .0 Univ esiy1O Faatadaa Perfect Ca. aveC S i dnndD Dr C. A1190 he oTcnlg

krao d. Cifekt 401t ie y, Califataia 9140 NewporetN . vcaae tal to 0etfieofNaaltata. 4 4 0Stot. S.C. 1901011. 04,fsts Virginia Ce mtel ap.a Se1tcc oaclast, at Citveity la SIn, tttarlcptar otale 4.0~ Maeatt O set Dog0 6 110 catP eto. taf e se y Sc05si Dr tv ta~mt ttae $S. &*tI"e TAu 2F. lod ai46f ta e ' am*eateltl at a. 1e ama~a kh C aat,.t #610" lOfk Uf..0 o.107 . et trottc. 1.0.RI.4f14 C dI.110. Ase&o.tt

__t,_aser__ rth_ Apliatont____ ~ lc soCaetr. Reeac ISiaaePrat o. 1.A.8ts0 Univsa esint teeittcm10 cat Vic. Fctraa tmarteat. aebacica Liorarls Pocvitt.a $pir...

if. tl.., CaL ta4 l P104Lpr ati.Sf.1-4,.Ov. 46" JIM..AVm..n $Ils. linoLb ar la9ai 0 akoat4 r be lkat attee01AF

Seat..S.tt6Sad 6100 5. Case A chool$005~t t cayial Aonterey, l4Ieale 4 40440 Sas C. lar

Inanemtmf setkaai atniastitluteLstFt(A.D 1,41 r.Iaaqeoesal art. a tao Pelte 61111 'Dep. ofivi l :e.SoetdbsC D C. a aticpiaysuisaRsac ODae 91

02-CIA 33 vrd t School ofk~d Ac.ttccn A"ala~ Ast.T l. long1ta 8

Skiyoltke N.Y. irat 19104 1091 k.etAkr.I.Pl Lt. MeanarhLhrttStat. t3 . DtC m t a, f a e h c t , 0 1 0 I 3311 5 se rc A ssoc iat es

Lottta A A taI.,. itito t " 1 Cesactsi~ lo $pa ira .Ct ctiteSp~qaa, .1 t1bOtate Natoa Lboat ory ft. V.A. "ea a

fee.a Netan ?..ete00.. oCas tenue $"40 a Laboatrisnr. ra a .rc, t to P. Mo o1 AS.C . ga taf ,.ecca Aia l0t40 Ma5. il aoes t

74- SiY4to Civil Int% CeOh Sit.. Aluu re.tia.l "sIot M l$k irSlot. -..6 ?Mettc 8.1tti, . C Jager 201601tattaSaa21 S.. 31dactreet ttaiL4 Atagts topS.e f.T..Cat

thectatip h . .ISytats 110 1h. Houaept CA1brpS. okm"Ps e4SpcC.iliatila, Piccaoiaaiaat 021341 his3 Alto Resarh1117ao

C-ft OfCll~tl~ E.iftscig 4 ittll. DrL. P ac. Ci ec~ rae1lo.0009li 9 0

sym~s U-~s'.ty c astl Or elceC Irr15