Bench test model of the human skull for testing the Variable Frequency Pulse Phase-Locked Loop Instrument

170 Pages·1.8 MB·en_US

by  Burin, Amy Diana.

NAVAL POSTGRADUATE SCHOOL
Monterey, California
THESIS
BENCHTESTMODELOFTHEHUMAN SKULL
FORTESTINGTHEVARIABLEFREQUENCY
PULSEPHASE-LOCKED LOOPINSTRUMENT
by
AmyDianaBurin
December, 1996
ThesisAdvisor: SandraL. Scrivener
Approvedforpublic release; distributionis unlimited.

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1. AGENCYUSEONLY(Leaveblank) REPORTDATE REPORTTYPEANDDATESCOVERED
December1996 Master'sThesis
TITLEANDSUBTITLE FUNDINGNUMBERS
BENCHTESTMODELOFTHEHUMANSKULL
FORTESTINGTHEVARIABLEFREQUENCY
PULSEPHASE-LOCKEDLOOPINSTRUMENT
6. AUTHOR(S)
Burin,AmyDiana
7. PERFORMINGORGANIZATIONNAME(S)ANDADDRESS(ES) PERFORMING
NavalPostgraduateSchool ORGANIZATION
MontereyCA93943-5000 REPORTNUMBER
SPONSORING/MONITORINGAGENCYNAME(S)ANDADDRESS(ES) 10. SPONSORING/MONITORING
AGENCYREPORTNUMBER
11. SUPPLEMENTARYNOTES Theviewsexpressedinthisthesisarethoseoftheauthoranddonotreflectthe
officialpolicyorpositionoftheDepartmentofDefenseortheU.S.Government.
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Approvedforpublicrelease;distributionisunlimited.
13. abstract(maximum200words)JheVariableFrequencyPulsePhase-LockedLoop(VFPPLL)
instrumentiscurrentlybeingusedtonon-invasivelyevaluatethehumanskullforincreasesin
intracranialdistancesbroughtaboutbyincreasesinintracranialpressure. Itisdesignedto
determinedistancechanges,inthesub-micronrange,calculatedfromchangesinfrequencyofan
ultrasonictoneburstproducedbyatransducer,traversedthroughtheskullandreceivedbackbythe
transducer. AbenchtestmodelofthehumanskullwillcalibratetheVFPPLLbycomparingknown
distancechangestotheVFPPLLderiveddistancechanges,andtherebyverifytheaccuracyofthe
instrument. Additionally,thebenchtestmodelwilldetermineabroadrangeofoperatinglimitson
temperature,pressureandelongationoverwhichtheVFPPLLcanoperateaccurately. Eachofthe
threemodelsmadedemonstratesadifferenteffectonthefrequencychangebasedonthedifferent
parameters,i.e. temperature,pressureorelongation. TheOpenChannelModelcomparesclosely
approximatedelongationswithVFPPLLderivedelongations, showingfavorableresultsfor
calibrationoftheVFPPLLinstrument. Specificationsforcreatingabenchtestmodelofthehuman
skullfortestingtheVFPPLLinstrumentareestablishedinthisthesis.
SUBJECTTERMS 15. NUMBEROF
Humanskullmodel,pulsephase-lockedloop,intracranialpressure,intracranial PAGES 137
distance 16. PRICECODE
17. SECURITYCLASSIFICA- 18. SECURITYCLASSIFI- 19. SECURITYCLASSIFICA- 20. LIMITATIONOF
TIONOFREPORT CATIONOFTHISPAGE TIONOFABSTRACT ABSTRACT
Unclassified Unclassified Unclassified UL
NSN7540-01-280-5500 StandardForm298(Rev.2-89)
PrescribedbyANSIStd.239-18298-102

Approvedforpublic release; distributionis unlimited.
BENCHTESTMODEL OFTHEHUMAN SKULL
FORTESTINGTHEVARIABLEFREQUENCY
PULSEPHASE-LOCKEDLOOPINSTRUMENT
AmyDianaBurin
Lieutenant, UnitedStatesNavy
B.S., UniversityofMichigan, 1987
Submittedinpartialfulfillment
oftherequirementsforthedegreeof
MASTEROFSCIENCEINASTRONAUTICALENGINEERING
fromthe
NAVALPOSTGRADUATE SCHOOL
December 1996
//
C-jb
CA
ABSTRACT 93943°-0511U011
The Variable FrequencyPulse Phase-LockedLoop (VFPPLL) instrumentis
currently being used to non-invasively evaluate the human skull for increases in
intracranial distances brought about by increases in intracranial pressure. It is
designed to determine distance changes, inthe sub-micronrange, calculated from
changesinfrequencyofanultrasonictoneburstproducedbyatransducer, traversed
through the skull andreceivedbackbythe transducer. A benchtestmodel ofthe
humanskullwillcalibratetheVFPPLLbycomparingknowndistancechangestothe
VFPPLLderiveddistancechanges,andtherebyverifytheaccuracyoftheinstrument.
Additionally, thebenchtestmodelwill determine abroadrange ofoperatinglimits
on temperature, pressure and elongation over which the VFPPLL can operate
accurately. Each ofthe three modelsmade demonstrates a different effectonthe
frequency change based on the different parameters, i.e. temperature, pressure or
elongation. The OpenChannel Modelcomparesclosely approximatedelongations
with VFPPLLderivedelongations, showingfavorableresultsforcalibration ofthe
VFPPLL instrument. Specificationsfor creatingabenchtestmodel ofthe human
skullfortestingtheVFPPLLinstrumentareestablishedinthisthesis.
VI
..
TABLEOFCONTENTS
INTRODUCTION
I. 1
A BACKGROUNDAND SIGNIFICANCE
1
B. INTRACRANIALPRESSURE(ICP)MEASUREMENTTECHNIQUES
2
II. THEPULSEPHASE-LOCKEDLOOPINSTRUMENT 5
BACKGROUND
A. 5
B. OPERATION 8
C. FREQUENCYEQUATIONS 11
III. PURPOSEOFTESTS 13
A. MOTIVATION 13
B. MODELS 13
1 AluminumModel 13
a. Description 14
b. Set-up 17
c. Procedure 19
2. PVCModel 20
a. Description 20
b. Set-up 21
c. Procedure 23
3. OpenChannelModel 23
a. Description 24
b. Set-up 26
c. Procedure 26
IV. RESULTSANDDISCUSSION 27
A. OPERATINGLIMITS ONTEMPERATUREANDPRESSUREOFTHE
VFPPLL(ALUMINUMMODEL) 27
1 Frequencyvs. Pressure 27
a. Results 27
b. Discussion 31
2. Elongation vs. Pressure 32
a. Results 32
b. Discussion 36
3. Frequencyvs. Elongation 36
a. Results 36
b. Discussion 40
B CALIBRATION 41
1. PVCModel 41
a. Results 41
b. Discussion 43
2. OpenChannelModel 43
a. Results 43
b. Discussion 46
V. CORRELATIONTOTHEHUMANSKULL 47
A. CADAVERSTUDIES 47
1. Background 47
2. Discussion 47
VI. FURTHERDISCUSSIONANDCONCLUSIONS 53
A. THEORY 53
B. FUTURESTUDIES 62
APPENDIXA. ALUMINUMMODEL 65
A. NUMERICALDATA 65
B. GRAPHS 65
APPENDIXB. PVCMODEL 83
A. NUMERICALDATA 83
B. GRAPHS 83
APPENDDCC. OPENCHANNELMODEL 93
A. NUMERICALDATA 93
B. GRAPHS 93
APPENDIXD. CADAVERS Ill
A. NUMERICALDATA Ill
B. GRAPHS Ill