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EngineeringTechnology Reports

FY03 UCRL-TR-203952

Laboratory DirectedResearch and DevelopmentLaboratory DirectedResearch and Development

April2004April2004

Lawrence Livermore National LaboratoryUniversity of California

P.O. Box 808, L-151Livermore, California 94551

http://www_eng.llnl.gov/

Complex Distributed Systems

Microtechnology and Nanotechnology

Nondestructive Characterization Precision Engineering

Computational Engineering

Manuscript Date April 2004Distribution Category UC-42

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ENG-03-0095-AD

Acknowledgments

Scientific EditingCamille Minichino

Graphic DesignIrene J. Chan

Art Production/LayoutJeffrey BonivertDebbie A. MarshKathy J. McCullough

ENGINEERING

Pushing engineering science to the Xtreme

Cover:Graphics representing LDRD projects fromEngineering’s Technology Centers.


FY03 UCRL-TR-203952


April2004April2004





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IntroductionSteven R. Patterson . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .iii

Center for Computational EngineeringAdaptive Mesh Refinement Algorithms for Parallel Unstructured Finite-Element CodesD. Parsons, J. M. Solberg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

Analysis and Optimization of Novel Filtration, Sample-Collection and Sample-Preparation SystemsD. S. Clague, T. H. Weisgraber . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

Generalized Methods for Finite-Element InterfacesM. A. Puso, J. M. Solberg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

Higher-Order, Mixed Finite-Element Methods for Time-Domain ElectromagneticsN. K. Madsen, D. A. White, N. J. Champagne . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

Hypersonic Flow about Maneuvering Vehicles with Changing Shapes F. F. Felker, V. M. Castillo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Modeling and Characterization of Recompressed Damaged MaterialsR. C. Becker . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

Propagation Models for Predicting Communication System Performance in Adverse EnvironmentsH.-Y. Pao . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

Center for Microtechnology and NanotechnologyDeterministic, Nanoscale Fabrication of Mesoscale ObjectsR. P. Mariella, Jr., M. D. Shirk, G. H. Gilmer, A. M. Rubenchik, K. Carlisle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13

Disposable Polymerase Chain Reaction DeviceE. K. Wheeler, W. J. Benett, K. D. Ness, P. L. Stratton, A. A. Chen, A. T. Christian, J. B. Richards, T. H. Weisgraber . . . . . . . . .14

Integrated Microfluidic Fuel Processor for Miniature Power SourcesR. S. Upadhye, J. D. Morse, M. A. Havstad, D. A. Sopchak . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15

Microfluidic System for Solution-Array-Based BioassaysG. M. Dougherty, F. Y. S. Chuang, S. S. Pannu, K. A. Rose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16

Modeling Tools Development for the Analysis and Design of Photonic Integrated CircuitsT. C. Bond, J. S. Kallman, G. H. Khanaka . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17

Reconfigurable Optical Code-Division Multiple Access for Fiber-Optic NetworksR. J. Welty, C. E. Reinhardt, N. P. Kobayashi, V. R. Sperry, I. Y. Han, E. M. Behymer, C. V. Bennett, S. W. Bond; Y. Du, S. J. Yoo(University of California at Davis) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18

Center for Nondestructive CharacterizationConcealed Threat Detection at Multiple Frames/sJ. T. Chang, S. G. Azevedo, D. H. Chambers, P. C. Haugen, R. R. Leach, C. E. Romero, J. M. Zumstein; V. R. Algazi (Universityof California at Davis) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21

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High-Accuracy X-Ray Imaging of Mesoscale TargetsW. W. Nederbragt, T. W. Barbee, J. L. Klingmann, C. Vargas, H. E. Martz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22

Radial Reflection Diffraction TomographyS. K. Lehman, D. H. Chambers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23

Tabletop Mesoscale Nondestructive CharacterizationH. E. Martz, M. B. Aufderheide, T. W. Barbee, A. Barty, H. N. Chapman, J. A. Koch, B. J. Kozioziemski, W. W. Nederbragt, D. J. Schneberk, G. F. Stone; M. Pivovaroff (University of California at Berkeley) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24

Ultrasonic NDE of Multilayered StructuresM. J. Quarry, K. A. Fisher; J. Rose (Pennsylvania State University) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25

Center for Precision EngineeringHigh-Bandwidth Fast Tool Servo for Single-Point Turning High-Energy-Density Physics TargetsR. C. Montesanti, J. L. Klingmann; D. L. Trumper (Massachusetts Institute of Technology) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29

Center for Complex Distributed SystemsCargo Container Security Sensor SystemS. G. Azevedo, K. E. Sale, B. D. Henderer, C. L. Hartmann-Siantar, J. Lehmann, L. S. Dauffy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33

Developing Smart Seismic ArraysP. E. Harben, D. B. Harris, S. C. Myers, S. C. Larsen, J. L. Wagoner, J. E. Trebes, K. E. Nelson . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34

Evaluating a Regional Simulation Model for Seismic Wave Propagation H. Tkalcic, A. J. Rodgers, D. B. McCallen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35

Ultrawideband CommunicationsF. U. Dowla, A. Spiridon, D. M. Benzel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36

Author Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39

iii

FY2003 Center HighlightsThe Center for Computational Engineering orches-

trates the research, development, and deployment of soft-ware technologies to aid in many facets of the Laboratory’sengineering mission. Computational engineering hasbecome a ubiquitous component throughout the engineer-ing discipline. Current activities range from tools to designthe next generation of mixed-signal chips (systems on achip) to full-scale analysis of key DOE and DoD systems.

Highlights of the Center’s LDRD projects for this yearinclude advances in finite-element methods, and modelingand simulation tools; hypersonic flow; modeling and charac-terization of recompressed damaged materials; and propa-gation models for communication system performance.The Center has offered a real-world computing capabilitythat opens the door to solving a wide variety of fluid/solidinteraction problems in transportation, aerospace, andinfrastructure settings.

The mission of the Center for Microtechnology andNanotechnology is to invent, develop, and applymicroscale and nanoscale technologies to support theLaboratory missions in Stockpile Stewardship, HomelandSecurity, Nonproliferation, and other programs. Theresearch topics for this Center cover materials, devices,instruments, and systems that require microfabricatedcomponents, including microelectromechanical systems(MEMS), electronics, photonics, micro- and nanostruc-tures, and micro- and nanoactuators.

This year’s projects include analysis and optimization ofsample systems; integrated microfluidic fuel processor;microfluidic system for bioassay; modeling tools for photonicICs; nanoscale fabrication of mesoscale objects; disposablePCR device; and optical code-division multiple access forfiber-optic networks.

The Center for Nondestructive Characterization(NDC) researches and develops nondestructive characteri-zation measurement technology to significantly impact themanner in which the Laboratory inspects, and through this,designs, fabricates, and refurbishes systems and compo-nents. The Center plays a strategic and vital role in theresearch and development of scientific and engineeringNDC technologies, such as acoustic, infrared, microwave,visible and x-ray imaging, to enable Engineering in the far- tomid-term to incorporate the successful technologies intoLaboratory and DOE programs.

This year’s LDRD projects include concealed threatdetection at multiple frames/s; high-accuracy x-ray imagingof mesoscale targets; radial reflection diffraction tomogra-phy; tabletop mesoscale NDC; and ultrasonic NDE of multi-layered structures.

The Center for Precision Engineering advances theLaboratory’s high-precision capabilities in manufacturing,dimensional metrology and assembly, to meet the futureneeds of the Laboratory and DOE programs. Precision engi-neering is a multi-disciplinary systems approach to achieve

IntroductionSteven R. Patterson, Associate Director for Engineering

This report summarizes the science and technologyresearch and development efforts in Lawrence LivermoreNational Laboratory’s Engineering Directorate for FY2003,and exemplifies Engineering’s 50-year history of researchingand developing the engineering technologies needed to sup-port the Laboratory’s missions. Engineering has been a part-ner in every major program and project at the Laboratorythroughout its existence, and has prepared for this role witha skilled workforce and the technical resources developedthrough venues like the Laboratory Directed Research andDevelopment Program (LDRD). This accomplishment is wellsummarized by Engineering’s mission: “Enable program suc-cess today and ensure the Laboratory’s vitality tomorrow.”

Engineering’s investment in technologies is carried outthrough two programs, the LDRD program and the “TechBase” program.

LDRD is the vehicle for creating those technologies andcompetencies that are cutting edge, or that require a signif-icant level of research, or contain some unknown that needsto be fully understood. Tech Base is used to apply those tech-nologies, or adapt them to a Laboratory need. The term com-monly used for Tech Base projects is “reduction to practice.”

Therefore, the LDRD report covered here has a strongresearch emphasis. Areas that are presented all fall intothose needed to accomplish our mission.

For FY2003, Engineering’s LDRD projects were focusedon mesoscale target fabrication and characterization, devel-opment of engineering computational capability, materialstudies and modeling, remote sensing and communications,and microtechnology and nanotechnology for national secu-rity applications.

Engineering’s five Centers, in partnership with the DivisionLeaders and Department Heads, are responsible for guidingthe science and technology investments for the Directorate.The Centers represent technology areas that have beenidentified as critical for the present and future work of theLaboratory, and are chartered to develop their respectiveareas. Their LDRD projects are the key resources to attainthis competency, and, as such, nearly all of Engineering’sportfolio falls under one of the five Centers. The Centers andtheir Directors are:

Center for Computational Engineering:Robert M. Sharpe

Center for Microtechnology and Nanotechnology:Raymond P. Mariella, Jr.

Center for Nondestructive Characterization:Harry E. Martz, Jr.

Center for Precision Engineering:Keith Carlisle

Center for Complex Distributed Systems:Donald Meeker (Acting Director)

iv

an order of magnitude greater accuracy than currentlyachievable. Essential to the Center’s success are its coretechnologies, which are the building blocks for themachines, systems, and processes that will be required forfuture programs. Our LDRD portfolio is driven to supportthis goal.

Highlights for this year include a high-bandwidth fasttool servo for single-point turning of high-energy-densityphysics targets, and our work with the other Centers onhigh-accuracy x-ray imaging of mesoscale targets andnanoscale fabrication of mesoscale objects.

The Center for Complex Distributed Systems (CDS)was formed to promote technologies essential to theanalysis, design, monitoring and control of large-scale,complex systems. Given the ubiquitous nature of large sys-tems, CDS obviously covers a very broad technical area. Thisincludes development of integrated sensing, communicationand signal processing systems for efficient gathering of thedata essential for real-time system monitoring. The Center

also promotes the development of new methodologies forcombining measured data with computer simulations inorder to achieve enhanced characterization and control ofcomplex systems.

This year, the Center has LDRD projects in security sen-sor systems, seismic arrays and wave propagation, andcommunications. Particular emphasis is on technologiesapplicable to national security missions.

Science-Based EngineeringOur five Centers develop the key engineering technologies

that make Laboratory programs successful. They providethe mechanism by which Engineering can help programsattract funding, while pioneering the technologies that willsustain long-term investment.

Our Centers, with staff who are full partners in Laboratoryprograms, integrate the best of mechanical and electronicsengineering, creating a synergy that aids Engineering’s mis-sion, and helps turn the impossible into the doable.

Center forComputationalEngineering

Center forComputationalEngineering

Center for Computational EngineeringFY03 • ETR • LDRD

3

procedures is the AMR block, which can beviewed as a single hexahedral element onthe initial coarse mesh presented for adap-tive refinement. Isotropic or anisotropicrefinement is implemented as refinement ofthe individual AMR blocks, which in turn pro-duces new elements and nodes in the AMRdatabase that are eventually transferred tothe global mesh database. During the refine-ment procedures, the elements and nodesin an AMR block are referenced using twosets of octrees. Manipulation of selected elements and nodes is then readily achievedusing suitable recursive procedures.

Error estimators. Both patch-basedrecovery and residual-based error estima-tors are being developed. Patch-basedrecovery procedures smooth computedsolution gradients to produce an improvedestimate of the true solution; the estimatederror is then the difference between theoriginal and smoothed solutions. Residual-based procedures reflect the degree towhich the computed solution satisfiesthe governingequations. Futurework will explore

improvements to thesebasic methodologies thatare pertinent to solidmechanics problems.

Test problems. Varioustest problems can beused to verify the AMRprocedures describedabove. Figure 1 showssequences of meshesgenerated using isotropicand anisotropic h-refine-ment of a single AMRblock. The refinements

were performed using a random selec-tion of elements and random refinementdirections. Both sequences of mesheswere used in a patch test to verify thecomputations. Figure 2 shows computedstress and temperature gradient fields ina symmetric portion of a square platewith a square hole subjected to bothmechanical and thermal loads. Localizedmesh refinement near stress singularitiesand thermal point fluxes is evident, demon-strating the viability of the AMR schemefor a coupled mechanics problem.

In FY04 the AMR functionality will be par-allelized for efficient performance on MPPsystems by introducing mesh-partitioningcapabilities for allocating load-balanced subassemblies of a refined unstructuredmesh to the available processors. The effectiveness of published algorithms for estimating discretization errors and forinterpolating state variables to refinedmeshes will be investigated and improved.

At LLNL, the state-of-the-art solversused for solid

mechanics simulationshave sufficient architec-tural and functional matu-rity to benefit from theintroduction of appropri-ate adaptive mesh refine-ment (AMR) strategies.These new tools willenable analysts to con-duct more reliable simula-tions at reduced cost, interms of both analyst and computer time.

Previous academic research in the fieldof AMR has produced voluminous litera-ture focused on error estimators anddemonstration problems. Relatively littleprogress has been made on producingefficient implementations suitable forlarge-scale problem solving on state-of-the-art computer systems. Researchissues that we will consider include: effec-tive error estimators for nonlinear struc-tural mechanics problems, local meshingat irregular geometric boundaries, andconstructing efficient software for paral-lel computing environments.

To date, progress has been made inthree areas: construction of the serialsoftware infrastructure, development oferror estimators, and development oftest problems.

Serial software infrastructure. Bothisotropic and anisotropic h-refinements arepermitted. Isotropic refinement is direction-ally invariant, causing a single hexahedronto be refined into eight new hexahedrons.Anisotropic refinement requires that theerror estimator identify local element direc-tions for refinement.This may cause ahexahedral elementto be split into two orfour new elements.Anisotropic refine-ment is useful forproblems that con-tain strong directionaldependencies, or formeshes that possesspoor aspect ratios.

The basic dataobject used in themesh refinement

Adaptive Mesh RefinementAlgorithms for Parallel

Unstructured Finite-Element CodesD. Parsons, J. M. Solberg

The objective of this research is to develop adaptive mesh refinementalgorithms in unstructured finite-element codes used for solving nonlin-ear solid mechanics problems on ASCI-class, multi-processor parallel(MPP) computers.

Figure 1. Meshes generated usingisotropic and anisotropic h-refinement.

Anisotropic

Isotropic

Figure 2. Stress and temperature gradient fields in a plate subjectedto mechanical and thermal loads.

2.00e+02

1.00e+02

0.00e+00

–1.00e+02

–2.00e+02–3.00e+02–3.50e+02

Stress [sx]

2.00e-01

1.50e-01

1.00e-01

5.00e-02

0.00e+00

2.50e-01

Flux [X flux]

FY03 • ETR • LDRDCenter for Computational Engineering

4

This project was a late mid-yearstart in FY02. In FY03, we achievedfour major milestones: 1) developmentof the media module, which includesvarious arrangements of cylindricalobstacles and porous membranes witha controllable distribution of pore sizes(Fig. 1); 2) development of the capability

to characterize hinderedtransport coefficients incomplex media (Fig. 2);3) inclusion of particle-particle and particle-medium colloidal interac-tions, e.g., van der Waalsand electrostatics; and4) incorporation of anenergy equation to han-dle thermal effects.

The proposed newdevelopments for FY 04include the completion offluid species transportstudies in membranesand the validation of pre-dictions with data from

the dialysis project. We are also workingon including more complex geometries,e.g., cylinders, in support of the nano-barcode project. Finally, we will develop theability to handle gas phase transportand gas phase with particles in porousmedia with surface forces.

To accomplish ourgoals, we are devel-oping new lattice-

Boltzmann simulationtools that include detailedmicrostructure descrip-tions, relevant surfaceinteractions, tempera-ture effects, and the abili-ty to handle both liquidand gas phase systems.The new capability isbeing validated withexperimental data andwill be applied to real-world issues of concernto LLNL programs.

This work directlyimpacts continuing and future LLNLefforts that involve filtration, collectionand sample preparation. This capabilitywill be directly applicable to detectionsystems relevant to LLNL’s medicaltechnology program, chemical and bio-logical counter-proliferation mission, andhomeland security mission.

Analysis and Optimization ofNovel Filtration, Sample-Collection and Sample-Preparation Systems

D. S. Clague, T. H. Weisgraber

With the heightened attention on chemical and biological early-detectionsystems, there is an increased need for high-efficiency filtration, sample-collection and sample-preparation systems. The goal of this researchproject is to provide new computational analysis tools designed to opti-mize these critical operations and to characterize system efficienciesbased on the details of the microstructure with environmental effects.

Figure 1. (a) Media generated on demand. Three arrangements of cylinders, including the pillar chip, and a porous membrane withspecified porosity and pore size distribution. (b) 3-D perspective of porous membrane with mobile species.

Figure 2. Results from characterization of hindered convection and species capture in a regular array of cylinders. The hindered transportcoefficient as a function of volume fraction and position within the gap between cylinders is shown.

(a) (b)3D Disordered Array Hexagonal Array (Pillar Chip)

50

40

30

20

1010 20 30 40 50 60 70 80

Porous Membrane

20

40

140

60

80

120

100

16050 100 150

Square Array

10

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5010 20 30 40 50

Phillips, Deen, and Brady (1990)

25

20

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10

5

0 0

10

20

30

40

50

0 252015105

Y(µ

m)

x(µm)

Convective Transportφc =

<µp>

<µf>

Velocity(mm/s)

25

20

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10

5

0 0

20

40

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0 252015105

Y(µ

m)

x(µm)

Capture Efficiency

ηe = ccaptured

c ∞Velocity(mm/s)

1.4

1.2

1

0.8

0.6

0.40 0.10.080.060.040.02

u/<v

>

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1.2

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/v x

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λ = 5.0λ = 2.0

λ = 0.5

λ = 0.0

λ = 1.0


5

(a) (b)

connect arbitrary 3-D, curved meshesso that optimal convergence is achieved.In this way, refinement of the dissimilarmesh will have the same asymptotic con-vergence rate as the conforming mesh,thus dissimilar meshing will not compro-mise accuracy. This method requiressolving surface integrals involvingLagrange multiplier fields for tractionand displacement. Such surface inte-grals are straightforward for 2-D, flatinterfaces but complicated for 3-D,curved surfaces.

In FY01, we developed a closest-point projection type algorithm for 3-Dsurface integrals and used simpleLagrange multiplier fields to demon-strate optimal convergence on 3-Dmodels with curved, tied interfaces.

In FY02, we furtherdeveloped our theory forstability conditions; imple-mented a dual formula-tion for the Lagrangemultiplier fields, whichsped calculation times bya factor of seven overour previous results; andbegan work on the mor-

tar method for contact. In FY03, we worked on a mortar

implementation that can connect mesh-es with different element types (i.e.,tetrahedrals and quadratic elements).Now, automatically generated tetrahe-dral meshes can be accurately inter-faced with hexahedral meshes (Fig. 1.)

Friction was also added to the mortarcontact. The new mortar contact pro-vides vastly superior non-linear conver-gence behavior since it effectivelysmoothes the behavior near the interfaceand eliminates the “locking” associatedwith the standard contact methods.Consequently, contact analyses that failed(crashed) in the past can be successfullyanalyzed using implicit finite elements withour new mortar approach (Fig. 2).

Mesh genera-tion is now themain bottle-

neck in computer-aidedanalysis. Much of theeffort in the production ofa complex finite-elementmodel is the interfacing ofindividual parts at partboundaries. When individ-ually meshed parts are to be connected toform a single monolithic part, analystswork very hard to ensure that the meshesconform at the part interfaces, i.e., that thenodes match at the common boundary.

The process of producing conformingmeshes is one of the main difficulties inmesh generation and is intractable andsometimes impossible when connectingmeshes composed of different elementtypes (see Fig. 1). Although standardmesh tying methods are an alternativeto producing conforming meshes, it iswell known that they cause large errorsand are avoided. Consequently, amethod that can connect (tie) dissimilarmeshes accurately would be an effectivetool in mesh production and significantlysimplify analyst efforts. Furthermore, dis-similar (non-conforming) meshes areunavoidable when parts are interfacedvia contact surfaces (see Fig. 2). Despitetheir common use, contact surfaces stillcause serious analysis problems, suchas inaccuracies and code crashing.

The goal of this project is to researchand develop robust and accurate meth-ods for interfacing (i.e., tying and contact-ing) dissimilar meshes. This new technol-ogy could save a significant amount oftime and money invested in mesh pro-duction. For example, a large weaponsmodel takes a month to build and willundergo many revisions over a matter ofyears. Analysts estimate that an accu-rate method for tying dissimilar meshescould save 10 to 25% of their time inmeshing over the course of a project.

Furthermore, analysts spend a signif-icant amount of time dealing with prob-lems related to contact surfaces, partic-ularly for implicit finite-element analysis.The new, more robust approach shouldmake analysis with contact surfacesmore accurate and more reliable.

The “mortar method” for connecting2-D, flat interfaces has been extended to

Generalized Methods forFinite-Element Interfaces

M. A. Puso, J. M. Solberg

The goal of this project is to research and develop robust and accuratemethods for interfacing dissimilar meshes. In FY03, we worked on a mor-tar implementation that can connect meshes with different element types.

Figure 2. Elastic sphere forced into thick elastic shell. Analysis performed with implicit finite-element method using mortar contact. Standard contact methods cannot nearly approachthis significant amount of deformation with implicit finite elements.

Figure 1. Tied hexahedral-tetrahedral mesh of internally pressurized sphere. (a) Mortar tyingproduces smooth stresses with stress error at boundary of 1.78%. (b) The standard tyingmethod yields non-smooth stresses with stress error of 220% at boundary.


6

In Fig. 2 we illustratetwo applications thatrequire high-fidelity EMsimulations. Figure 2 (a)shows an EM wave prop-agating in a randomrough-surface tunnel. Thegoal of this simulation isto characterize the dis-persion and attenuationof the wave for communi-cation system perform-ance. Figure 2 (b) showsthe electric field intensityin a high-frequency ana-log integrated circuit.

The goal of this simulation is to gaininsight in substrate coupling effects thatare becoming increasingly important incircuit design.

Possible future research activities inthis area include adaptive mesh refine-ment, improved absorbing boundaryconditions, and coupled electro-thermal-mechanics simulations.

To demonstrate the accuracy andefficiency of our approach we computethe resonant frequencies of a sphereusing higher-order “curved” basis func-tions for spatial discretization and a high-er-order symplectic integration for tem-poral discretization. The results areshown in Fig. 1. For the same accuracy,the higher-order code (3rd order inspace and time) required 896 timesfewer elements and ran 43 times faster.

Time-domain compu-tational electromag-netic (CEM) modeling

is the most cost-effectiveapproach for EM designand analysis for problemsthat are electromagneti-cally very large or arenonlinear and transient innature. However, no sta-ble, higher-order, conser-vative methods, such asthose that exist for com-putational fluid dynamicsand other disciplines,exist for time-domain CEM, largelybecause of the unique characteristicspossessed by Maxwell’s equations.

Typically Maxwell’s equations aresolved with low-order, Cartesian-gridmethods. These simple, stable methodswork well for rectangular geometries butrequire prohibitively large meshes forquantitative field predictions on electricallylarge problems, and produce inconsistentsolutions for non-orthogonal geometries.In addition, finite-volume schemes, whichare often considered as an alternative,suffer from numerical instabilities, lack ofconservation, and low accuracy.

To overcome these limitations, thisproject investigated higher-order, mixedfinite-element methods (MFEM), a newmethodology for solving partial differentialequations on 3-D unstructured grids. Ourgoal is to develop a stable, conservative,higher-order accurate simulation code forMaxwell’s equations and related EM equa-tions. Our MFEM methodology builds onLLNL’s competency in computational engi-neering and will 1) enable engineers toperform EM simulations on unstructuredgrids, and 2) provide a coupled electro-thermal-mechanical modeling capability,both in support of the Laboratory’snational security mission.

Accomplishments in FY03 include1) completing the core higher-ordernumerical components of our simulationcode, such as integration rules, basisfunctions, and the hexahedron, tetrahe-dron, and prism elements; 2) developinghigher-order non-dissipative time-integration methods; and 3) complet-ing a prototype massively parallelMFEM code for Maxwell’s equations.

Higher-Order Mixed Finite-Element Methods For Time-Domain Electromagnetics

N. K. Madsen, D. A. White, N. J. Champagne

This project is investigating higher-order, mixed finite-element methods— a new methodology for solving partial differential equations on 3-Dunstructured grids. Our goal is to develop a stable, conservative, higher-order accurate simulation capability for Maxwell's equations and relatedequations of electromagnetism.

Figure 2. (a) Electromagnetic wave propagation in a rough-surface tunnel. (b) Electricfields in an integrated circuit substrate.

Figure 1. Computed resonant frequencies (red) compared to exact solution (blue). Thenew higher-order algorithm is 43 times more efficient for this problem than standard-order algorithms.

(a) (b)

0.8

FFT

spec

trum 0.6

0.4

0.2

0.4 0.6Frequency

0.8 1


7

mesh for the fluid domain must beattached to the vehicle as it undergoespotentially high accelerations, that meshmust be viewed in a non-inertial coordi-nate frame. The usual conservation-lawform of the fluid dynamic governingequations must be augmented. Thisapproach thus requires the derivation ofa significant new numerical formulation,especially to incorporate a modern flux-splitting methodology as needed fornumerical stability and accuracy.

In FY03 much of the numerical for-mulation was conceptualized, derived,and documented. This initial effort con-centrated on the deforming, non-inertialmesh considerations in the context ofinviscid flows.We are makingcontacts in theacademic com-munity, seekingan independentreview of thiswork, and antici-pate a futurepublication. Withthat baselineestablished, thenumerical for-mulation mustbe augmentedto considereffects of viscosi-ty and other “dif-fusive” mecha-nisms. Reactivechemistry isanother compo-nent that mustbe added toachieve our

eventual goals for hyper-sonic flow simulation.

The implementation ofthis new methodology isbeing supported throughLLNL programs. A “bornparallel” computer code,RVFlow, is being writtenwithin the Diablo frame-work. The code takesadvantage of some of thesophisticated features of

Fortran90 to pass data structures in anefficient manner. A steady inviscid capa-bility with explicit time integration hasbeen prototyped.

To demonstrate the accuracy of thecode, we use a series of verificationtests including simulations of a shocktube and simulations of various shapesin a hypersonic flow field (see figure).The shock tube simulation results showextremely sharp shock wave profiles.These demonstrate the advantage ofusing the flux-splitting method. Testcases simulating a wedge shape in var-ious flow fields up to Mach 20 showgood agreement with known results forthe shock angles.

Vehicles moving athypersonic speedshave great impor-

tance to LLNL’s nationalsecurity mission. Ballisticmissile re-entry vehicles(RVs) travel at hypersonicspeeds, as do missiledefense intercept vehi-cles. Despite the impor-tance of the problem, nocomputational analysismethod is available to predict the aerody-namic environment of maneuveringhypersonic vehicles, and no analysis isavailable to predict the transient effectsof their shape changes. The presentstate of the art for hypersonic flow calcu-lations typically still considers steady flowabout fixed shapes. Additionally, withpresent computational methods, it is notpossible to compute the entire transientstructural and thermal load for RVs.

The objective of this research is toprovide the required theoretical develop-ment and computational analysis tool.This key enabling technology will allow thedevelopment of a complete multi-mechanics simulation of the entire RVflight sequence, including important tran-sient effects such as complex flightdynamics. This will allow the computationof the as-delivered state of the payload inboth normal and unusual operationalenvironments. This new analysis capabili-ty could also provide the ability to predictthe nonlinear, transient behavior of endo-atmospheric missile interceptor vehiclesto the input of advanced control systems.

Due to the computational intensity offluid dynamics for hypersonics, the usualapproach for calculating the flow about avehicle that is changing shape is to com-plete a series of steady calculations,each with a fixed shape. However, thisquasi-steady approach is not adequateto resolve the frequencies characteristicof a vehicle’s structural dynamics.

Our approach is to include the effectsof the unsteady body shape changes inthe finite-volume method by allowing forarbitrary translation and deformation ofthe control volumes. Furthermore,because the Eulerian computational

Hypersonic Flow aboutManeuvering Vehicles with

Changing Shapes F. F. Felker, V. M. Castillo

The objective of this research is to provide the required theoretical devel-opment and a computational analysis tool for calculating the hypersonicflow about maneuvering, deforming re-entry vehicles.

Calculated pressure of a low-Mach-number flow, showing the predictedshock angle and relief wave.

Mach 2 flow15' nose angle

NACA report 1135(45' Shock Angle)

Relief wave


8

–10

–8

–6

–4

–2

0

Tria

xial

ity

Void fraction0.0001 0.001 0.01 0.1 1

(b)

Gursonn = 0.0001n = 0.01n = 0.1

(a)

laser focused on the prior spall blister toclose the spall.

A micrograph from the recom-pressed spall region is presented in thefigure (a). This shows a void partially col-lapsed by a jetting mechanism enteringfrom the right. There appears to be aparticle in the collapsed cavity. This maybe the particle responsible for initiatingthe void in the initial spall process. On alarger scale, it appears that the once-separated spall plane has been closed,but significant porosity remains.

Simulations of void growth andrecompression in a periodic array wereconducted to investigate how existingcontinuum level void models could be

adapted to reproducethe material responsepredicted by microme-chanical simulations.Since strain hardeningplays an important role invoid closure, unit cell sim-ulations were conductedusing a range of strainhardening. The materialresponse during recom-pression, represented interms of stress triaxiality(hydrostatic stress divid-ed by von Mises effectivestress), is plotted againstvoid fraction in the figure(b). Characterizing thebehavior in terms of the

triaxiality provides a scaling relation thatcollapses the widely disparate responseto a set of closely spaced curves.

Material point simulations using theGurson void growth model were rununder similar loading conditions. Modelparameters were adjusted to obtain areasonable fit to the triaxiality over arange of void fractions down to a frac-tion of a percent (see figure (b)). Basedon these results, a viable model forrecompression in large-scale continu-um simulations can be obtained byusing the Gurson model with differentparameters than those used for forma-tion of spall.

The severity of thedamage from spallranges from isolat-

ed voids to full fractureof the material by voidcoalescence. In many sit-uations the material issubjected to secondaryloading which acts toclose the spall-relatedvoids. While much workhas been done to char-acterize and model spalldamage, little has beendone to understand andmodel the recompres-sion process.

Prior experimentalwork under this projectinvolved creating spall-damaged sam-ples in a gas gun, performing recom-pression in a dynamic split-Hopkinsonbar apparatus, and evaluating thestrength of the resulting specimen. Theresults showed that the voids were notclosed under the conditions obtained inthe Hopkinson bar, even though thevoids occupied a significant fraction ofthe cross-section at the spall plane.

Further numerical analysis showedthat strain hardening of the copper nearthe voids was responsible for the nonclo-sure. The strength locally around thevoids was significantly higher than theoriginal strength of the material so, whencompressed, deformation occurred out-side of the voided region. These resultsindicated that stress states with highertriaxiality are required to close the poros-ity. This led to additional experiments andsimulations under conditions that wouldproduce higher pressures.

In the current phase, experimentswere run on lasers and gas guns toimpose the recompression. For thelaser experiments, spall damage wasinduced on thin samples by direct abla-tion of the copper target. This producedspall and, in most cases, a visible blisteron the backside of the specimen. Thesamples were recovered and coated onthe backside with an ablative layer.These were then reshocked with the

Modeling andCharacterization of

Recompressed DamagedMaterials

R. C. Becker

Materials subjected to dynamic loading from high-velocity impacts orexplosives frequently incur internal damage in the form of spall. Spall inmetals is characterized by nucleation and growth of voids under tensileloading conditions, created by the interaction of stress waves with sur-faces and interfaces. The purpose of this work is to examine the recom-pression of spall-damaged materials experimentally and to develop amodel capturing the recompression response.

(a) Micrograph showing jetting of material accompanying void closure. (b) Triaxialityresults for unit cell models with varying hardening and the Gurson model.


9

1. Sources should be polarized suchthat quasi-TE fields are preferentiallyexcited, to reduce field attenuation. For acircular tunnel, this indicates a circularelectric-current loop or a helix antenna.

2. Propagated field amplitudes canvary axially by 20 to 30 dB over short dis-tances. Our results in this regard areconsistent with theoretical and experi-mental results obtained in the past byother investigators.

3. Destructive interference amongthe modes or rays, in terms of which thefield is represented, plays a critical role indetermining the axial field attenuation.

Rough-walled waveguides. The prin-cipal results of the work on modal prop-agation in rough-walled waveguides arethe following:

1. The total modal field can be decom-posed into the sum of a deterministic or

coherent part and a zero-mean random or incoher-ent part. The coherentpart of a given modal fieldhas a structure similar tothat of the field in asmooth-walled wave-guide; the incoherentpart tends to be concen-trated near the wave-guide wall.

2. The modal cutofffrequencies are onlyslightly affected by thewall roughness; however,there is evidence that

certain of the waveguide modes canbecome slow (that is, the axial phasevelocity of the mode can become lessthan the speed of light) above certaincritical frequencies.

3. The auto- and cross-covariancefunctions that describe the incoherentpart of the field can be expressed interms of the power spectral density ofthe surface roughness.

The work has led to papers present-ed at the North American Radio ScienceMeeting and at the InternationalConference on Electromagnetics inAdvanced Applications.

In FY04 we will continue theoreticalwork, start analytic work on urbancanyons, and perform experimentalconfirmation.

In addressing propaga-tion models for com-munications in

adverse environments,our goals are to investi-gate the propagationphysics, develop themathematical models,derive the statisticaldescriptors, specialize toradio communication intunnels and caves, andselect the models/meth-ods best suited to theparameter space describ-ing enclosures of interest.

In addition to the ongoing develop-ment of a bibliography of the relevant lit-erature, analytical work during FY03 hasfocused on specific problems. These are1) propagation of waveguide modes in arough-walled quasi-circular perfect elec-trical conductor (PEC) waveguide; 2) cal-culation of the fields due to a horizontalelectric dipole in a rectangular tunnelwith two smooth PECs, and two smooth,lossy walls; 3) propagation of waveguidemodes in a rough-walled tunnel, using anequivalent surface impedance to modelthe wall roughness; and 4) calculation ofthe fields produced in a circular smooth-walled tunnel by circularly symmetricelectric and magnetic current loops.

Smooth-walled straight tunnels. Theprincipal results of the analytical work onsmooth-walled straight tunnels are thefollowing:

Propagation Models forPredicting CommunicationSystem Performance inAdverse Environments

H.-Y. Pao

This project addresses the problem of characterizing the propagation ofelectromagnetic fields in the adverse environments that are encounteredin enclosures such as caves, tunnels and urban canyons, where rough orcomplex bounding surfaces can compromise the quality of signals.

Electromagnetic wave propagation in a rough-surface tunnel.

Center forMicrotechnology andNanotechnology

Center forMicrotechnology andNanotechnology

Center for Microtechnology and NanotechnologyFY03 • ETR • LDRD

13

The equation of state quantities andrelated thermodynamics coefficientswere obtained from external tables. Forthe interaction with metals we used theThomas–Fermi model. Material electro-magnetic properties are described withan extended Drude model that includesboth intraband and interband transitions.

Laser ablation was modeled usinglarge-scale MD simulations (via the par-allel code MDCASK) (Fig. 2) of single-crystal copper. The computational cellscontained from four to thirty millionatoms. Interactions between the cop-per atoms were simulated using theembedded atom potential.

The description of thermal transportincludes temperature-dependent ther-mal conduction and heat capacities.Thermal conduction is determined bythe collision frequency in the Drudemodel. The cold value of transport con-stants are matched with experimental

data and interpolated tothe hot plasma expres-sion for an ideal plasma.

A rich diversity of phe-nomena was observed asa function of the pulseenergy density, includingthe ejection of a liquid film.Three distinct regimesare exhibited: 1) a low-energy regime with aminute ablation flux corre-sponding to evaporationof atoms from the hotcopper surface; 2) anintermediate regime

where void nucleation and growth, orspall, causes the ejection of a stable liquidlayer and particles; and 3) high-pulseenergies where liquid droplets areejected with a wide range of sizes.

Published observations of interfer-ence fringes during fs ablation are inexcellent agreement with our simulationsthat show the ejection of a liquid layer.

One important finding is that the abla-tion process inevitably generates subsur-face voids that ultimately can freeze outas undesirable residual surface rough-ness. Another important discovery is thatinitial surface scratches tend to nucleatethe instabilities that ensue during laserablation. Post-ablation surface process-ing may be able to reduce these residualsurface features to sub-20-nm sizes.

We have documented our progresswith conference presentations and publi-cations, as well as a record of invention(IL-11139).

We have chosento use sub-pslaser pulses for

our experiments becauseusing lasers with pulsesshorter than the elec-tron-phonon relaxationtime (under 1 ps) offersthe most precise controlof the energy that can bedeposited into a metalsurface. From the stand-point of scientific under-standing, pure, elementalmetal targets, includingsingle-crystal targets,were optimal.

The use of sub-ps laser pulses alsoallowed a decoupling of the energy-deposition process from the ensuingmovement/ablation of the atoms fromthe solid, which simplified the modeling.We have compared ablation of materialfrom copper and gold, which behavesimilarly (due to their high thermal con-ductivity) with nickel substrates (Fig. 1).

In FY03, we combined the powerof the 1-D hydrocode HYADES withstate-of-the-art, 3-D molecular-dynamics (MD) simulations. The stud-ies of material ablation by the shortlaser pulses consider the scales ofmaterials modification and ejectathat are much smaller than the laserspot; thus a 1-D treatment of theproblem is adequate. The code takesinto account the change of theabsorption during the pulse due tothe change of electron density, spa-tial profile, and temperature.

Deterministic, NanoscaleFabrication of Mesoscale Objects

R. P. Mariella, Jr., M. D. Shirk, G. H. Gilmer, A. M. Rubenchik, K. Carlisle

No organization has the capability to perform deterministic fabrication ofmm-sized objects with arbitrary, µm-sized, 3-D features with 20-nm-scale accuracy and smoothness. For deterministic fabrication of high-energy-density physics targets, it will be necessary both to fabricate fea-tures in a wide variety of materials and to understand and simulate thefabrication process. We continue to investigate, both in experiment andin modeling, the ablation/surface modification processes that occur withthe use of fs laser pulses that are near the ablation-threshold fluence.

Figure 1. Micrograph surfaces of (a) copper and (b) nickel,after ablation with 150-fs laser pulses, showing the relativelysmoother surface of the nickel.

Figure 2. Graphical output of molecular-dynamics simulations oflaser ablation, showing subsurface nucleation, growth, andcoalescence of nm-scale voids that lead to spall.

(a) (b)

Laser

10 ps70 nm

54 ps 100 ps 170 ps

FY03 • ETR • LDRDCenter for Microtechnology and Nanotechnology

14

During FY03 we focused on testingand optimizing our novel CPCR thermalcycler on a biological surrogate, startingwith genomic DNA. Erwinia herbicola (Eh)was chosen for its relevance to bothmedical and bio-warfare arenas. Both58- and 160-bp segments of Eh wereamplified in the CPCR thermal cycler.Agarose gel detection of an amplificationof the 160-bp amplicon is shown in Fig. 1.

The central energy consumptionrequirement is to heat an aqueous fluidfrom room temperature to 95 °C andthen to cycle the fluid between 55 °Cand 95 °C. The CPCR device minimizeslosses to the environment and maxi-mizes the energy transferred to the

fluid. The energy con-sumed by the thermalcycler for 30 min ofamplification for a 75-mlsample is 866 ± 50J.The basic heat require-ment for 50 cycles is 8.4J/µl/run. For a typical25-µl sample size thebasic energy require-ment is 210 J/run.Compared to existing fielddeployable technologies,the CPCR thermal cham-ber lowers energy con-sumption per unit volumean order of magnitude.

Based on the lowenergy requirements of the device, wehave fabricated a battery-operated ther-mal cycler, shown in Fig. 2. With ourincreased understanding, we have fur-ther optimized our selection of materialproperties and heater configurations.

We anticipate that this new andmore energy efficient PCR device willnot only see widespread use in the field,but could ultimately become pervasivein diagnostics such as food quality con-trol, medical diagnostics, and environ-mental monitoring, and could alsobecome a low-cost diagnostic for thirdworld countries.

To take appropriateaction, first respon-ders to a biological

attack (local emergencyresponse personnel, mili-tary, or intelligence per-sonnel) must identify the specific organismreleased. For this pur-pose, polymerase chainreaction (PCR) assays arebecoming increasinglyimportant because theycan amplify a target seg-ment of DNA (by thermalcycling of the necessaryreagents) and enable iden-tification of pathogens.

We have designed and demonstrat-ed a compact, disposable PCR thermalcycler. The convectively-driven PCR(CPCR) thermal cycler uses thermal con-vective forces created by fixed, nonfluctu-ating, hotter- and cooler-temperatureregions to thermally cycle the samplefluid to achieve amplification. Buoyancyforces cause the fluid to flow through thedifferent temperature zones.

The advantage of this approach islower power requirements, ensuringthat small batteries will suffice as thesystem's power source. The thermalcycler is also fabricated from inexpen-sive material, making it affordable tomore customers.

Disposable Polymerase ChainReaction Device

E. K. Wheeler, W. J. Benett, K. D. Ness, P. L. Stratton, A. A. Chen, A. T. Christian, J. B. Richards, T. H. Weisgraber

The September 11, 2001 attack on the United States and the subsequentanthrax scare have raised antiterrorist vigilance to new heights. Although9/11 was orchestrated with hijacked planes, the next threat could benuclear, chemical, or—as evidenced by the anthrax scare—biological.Planning and equipping for a biological attack requires detection devicesthat are robust in the field, easy to use, and relatively inexpensive. Thisproject has leveraged LLNL’s competencies in microtechnology and instru-mentation and provided new capabilities in support of LLNL’s homelandsecurity mission.

Figure 2. Battery-operated convectively-driven PCR thermal cycler.

Figure 1. Gel detection showing successful amplification of a160-base-pair (bp) segment of genomic Erwinia herbicola DNA,compared to amplification in a standard bench-top thermal cycler.Lanes 1 and 8 contain DNA markers (50-, 150-, 300-bp). Wells 2and 3 are positive and negative controls, respectively, performedon a bench-top thermal cycler. Wells 4 and 5 are two aliquots froma CPCR run; wells 6 and 7 are negative controls from a CPCR run.

AAAbatteries

Controllingelectronics Hot

zoneColdzone

CPCRthermalcycler

1 2 3 4 5 6 7 8

150 bp


15

gas fuel with minimal power input tosustain the microreaction. The hydro-gen and carbon dioxide byproducts(along with trace quantities of carbonmonoxide and steam) are then deliveredto the fuel cell manifold by microfluidicinterconnects. This system approachallows for an integrated solutionaddressing issues of fuel storage, pro-cessing, and delivery.

In the initial phase, we used two com-mercial catalysts containing CuO and ZnOon Al2O3. Our experiments (Fig. 2) on

these catalysts show conversions rangingfrom 80 to 96% at temperaturesbetween 250 and 300 °C, correspondingto 500 mW to 5 W electrical power.

We have done extensive comparisonsof both simple (tubular) reactors andadvanced reactors (serpentine reactorson a silicon wafer), and in all cases have

obtained reasonable orbetter agreement using atleast one of the sets ofkinetics constants avail-able in the literature.

In addition, we havesuccessfully synthesizedand deposited CuO/ZnOcatalyst on the walls ofthe microchannel reac-tor using a wash-coatprocess developed dur-ing the course of this proj-ect. We have also operat-ed a PEM fuel cell feddirectly by the reformateproduct gas to yield up to6 W electrical power; our

goal was to reach and exceed 500 mW. Building on ideas developed here and

under another project, we have devel-oped a thermal package that allows highthermal gradients under a geometrythat makes the device suitable for use inlaptop computers.

This project has already resulted infour conference presentations, withmore on the way. Two publications inpeer-reviewed journals are currentlybeing prepared. In addition, threerecords-of-invention have been filed.

The main customer for this productin the short run is the sensors communi-ty, where long-lasting power sources areneeded. Beyond that, the entire com-mercial sector of consumer electronicswhere long-lasting, light-weight powersources are desirable, constitutes thecustomer base.

Our key objectivewas the demon-stration of a pack-

aged microfluidic fuelprocessor with improvedcatalyst and integratedthermal management forwaste heat recovery. Todemonstrate the feasibilityof a microfluidic fuelprocessor, we addressedseveral technical issuesthrough iterative theoreti-cal and numerical analysis,design, and development.

Our approach was toform a catalytic micro-channel reactor (Fig. 1) for steam reforming of methanol. Thesteam reforming reaction occurs atabout 300 °C. The reaction produceshydrogen and carbon dioxide, accordingto the reaction:

CH3OH + H2O --> CO2 + 3 H2.

In addition to reforming, methanolalso undergoes a decomposition reac-tion to a minor (but significant) extent,producing hydrogen and carbon monox-ide according to the reaction:

CH3OH --> CO + 2 H2.

The carbon monoxide produced bythe above reaction tends to poisonthe catalyst used in the fuel cell, so itsconcentration needs to be reduced towell under 100 ppm with the use of apreferential oxidation catalyst, com-mercially available.

With adequate surface area of thecatalyst material and applied heat, themicrofluidic reformer produces hydrogen

Integrated Microfluidic FuelProcessor for Miniature

Power Sources R. S. Upadhye, J. D. Morse, M. A. Havstad, D. A. Sopchak

Portable power sources are important to all aspects of the military,weapons testing, and intelligence communities. New lighter-weight,longer-lasting power sources are required, with many of these havingspecific performance criteria for direct application. The current protonexchange membrane (PEM) fuel cells are limited to 3 to 15% methanolsolution, thereby limiting their power and energy density. Our approachis to reform the methanol in a separate microreactor, converting it tohydrogen, and feed the hydrogen to the fuel cell, thus exploiting the veryhigh energy densities of liquid fuels.

Figure 1. Photograph of the microreactorcontaining commercial CuO/ZnO catalyst.

Figure 2. Conversion vs. temperature data for different flow rates.

180

460 480 500 520T (K)

% C

onve

rsio

n of

met

hano

l

540 560

100

80

60

40

20

0

200 220 240 260 280

20 µL/min

10 µL/min

5 µL/min

Symbols: Experiment, ~65 mgSolid line: Theory, 65 mgDash line: Theory, 165 mg


16

ability to be identified using standard lightmicroscopy, avoiding the need for com-plicated spectroscopic or flow cytometrymethods. The surface functionalizationof metal particles is understood, and thenanobarcodes can be made with mag-netic materials, opening up new possibil-ities for manipulating, transporting, andtrapping the particles using magneticand electric fields.

In FY03, the first year of the project,we studied the transport behavior ofnanobarcodes in liquid, including theirbehavior in pressure-driven and electroki-netic flowfields, their sedimentation rates,orientation in suspension and on fixedsurfaces, and the changes in their behav-ior in solutions of varying ionic content.

With data from these experiments,computer models were advanced tobetter predict the behavior of metallicnanowires within microfluidic systems.We also advanced the methods of sur-face functionalizing the nanobarcodes

to optimize their trans-port behavior and theirperformance as sub-strates for biomoleculeimmobilization.

Antibody binding testsusing our most recentlydeveloped protocol showa 10x improvement overthe prior state of the art.Rapid progress hasallowed us to implementan assay panel of six dif-

ferent immunological tests within thenanobarcode format at the end of thefirst year.

In parallel with the transport andbioassay development efforts, we haveworked with an industrial collaborator, tofurther the state of the art in automatedreadout of nanobarcode arrays and totransition this technology to LLNL for thenext stages of our project.

In FY04, we will combine the knowl-edge gained in the first year of theproject with LLNL's expertise in poly-mer-based microfluidic devices to pro-totype components for mixing, moving,and incubating the particles, and dis-playing them for optical readout.

Parallel bioassay and optical imageprocessing efforts will converge withthese fluidic components to enablethe demonstration of a prototypeautomatic, low-cost system suitablefor benchtop or field use by the con-clusion of the project.

Multiplex bioas-says, capable ofperforming a

battery of screening testssimultaneously, are criti-cal for biodefense andmedical diagnostic appli-cations. Biomarkers com-posed of DNA sequences,RNA sequences, or spe-cific types of proteins canbe detected with assaysbased on nucleic acidhybridization or affinity-binding reactions.While tremendous advances in multi-plexed biomarker analysis have comeabout with the advent of DNA and pro-tein chips (microarrays), this technologyis limited in several important ways:microarrays are 2-D, limiting interactionwith target molecules; gene and proteinchips are aimed at only one type of mark-er (DNA, RNA, or protein); DNA and pro-tein chips are not reconfigurable by theuser; and microarray technologiesrequire the manufacture of specificchips, an approach that is expensive andtime-consuming.

Our approach uses solution arraytechnology within an integrated, recon-figurable microfluidic system for user-specified multiplexed biomarker assaysfor the early detection of disease.Solution arrays are similar to gene andprotein chips, but use surface functional-ized particles in solution, rather than thebinding of biomolecules to a fixed sur-face. Instead of correlating fluorescencewith location, as in a chip format, the par-ticles are encoded for identification.Results are read by examining particlesfor their encoded type and for the pres-ence or absence of the fluorescenceindicative of a positive binding event.

The flexibility of solution arrays meansthat different types of functionalized par-ticles can be added as desired by an enduser, and particles for DNA, RNA, andprotein detection can be used simultane-ously in a single low-cost format.

The particles used in this project arenanobarcodes (see figure), short metal-lic nanowires that bear patterns of lightand dark stripes, analogous to thestripes in a supermarket barcode. Theseparticles offer unique advantages in their

Microfluidic System forSolution-Array-Based

Bioassays G. M. Dougherty, F. Y. S. Chuang, S. S. Pannu, K. A. Rose

We are developing an integrated, reconfigurable microfluidic system forperforming user-specified multiplexed biomarker assays for the earlydetection of disease using solution-array technology.

Optical microscope image of nanobarcode particles. The light and darkstripes are due to alternating bands of gold and silver metal, havingdifferent reflectivities at the observation wavelength.

Ag AgAu Au 250 nm

6 µm

10 µm

AgAu


17

(quenched) enough to stop the devicefrom lasing.

Our lumped-parameter code,QUENCH_LLNL, uses a Runge-Kuttasolver to compute the time domainresponse of a two-segment laser logicdevice. We discoveredthat for a standard edge-emitting laser to bequenched it must be oper-ated near threshold, thecontrol region must belarge (on the order of 80 %of the length of the device),and the input light must bemuch more intense thanthe output light (on theorder of a factor of 30).

We used QUENCH_LLNLto explore the parameterspace for these devicesand determined that itwas possible to designdevices that could switchstates using less inputlight than they output, butit was impossible to actu-ally build them.

Our 1-D codes,QUENCHZ_TD andQUENCHZ_SS, wereused to determine theeffect that the control sec-tion position has on theswitching of gain-quenched laser logic.

Although there was aneffect, it was not found tobe large enough to makethe devices practical.

Our 2-D codes,QUENCH2D_TD andQUENCH2D_SS, wereused to determine theeffect of spatial hole burn-ing and carrier diffusionon these devices. Onceagain, there were signifi-cant effects, but notenough to make thedevices practical.

In a follow-on projectdescribed in the FY03t e c h n o l o g y - b a s e

reports, we began looking at nonlineareffects that could be responsible forthe observed switching in experimen-tal devices. Gain-quenching is inade-quate for describing the operation ofthese devices.

Design tools willbe of paramountimportance to

reduce the costs ofdeveloping PICs.Commercial photonicdesign tools are currentlynarrowly focused on thete lecommunicat ionsindustry and cannotcover the range of appli-cations necessary for PICdesign. The goal of thisproject was to createsophisticated PIC simula-tion tools that would ben-efit LLNL missions innational security, stock-pile stewardship, weapons miniaturiza-tion, high-bandwidth diagnostics, remotesensing, high-performance computing,and secure communications.

We focused on novel lasers and non-linear devices, such as logic gates, for all-optical digital circuits and signal process-ing, as well as highly sensitive sensorsfor analog and digital operations. Forinstance, the Boolean logic on whichcomputer technology is based can berealized in PICs by integrating laser gainelements with dielectric waveguides asboth optical inputs and optical outputs.

We have produced a suite of codes tosimulate these devices. The codes rangein sophistication from a simple lumped-parameter rate-equation-based time-domain code, through 1- and 2-D tran-sient and steady state simulations. All ofthese codes have been checked for con-sistency with one another and validatedagainst experimental data published inthe literature. All of these codes havebeen documented and have had manu-als written for them. We have usedthese codes to investigate the feasibilityof building PICs based on gain-quenchedlaser logic (see figure).

In gain-quenched laser logic, eachlaser is divided into a slave section andone or more control sections. Lightinjected into the side of the control sec-tions reduces the gain for the outputlight. The idea is that when the controlis turned on, the gain is reduced

Modeling Tools Developmentfor the Analysis and Design of

Photonic Integrated CircuitsT. C. Bond, J. S. Kallman, G. H. Khanaka

Photonic integrated circuits (PICs) are devices that use light (photons)rather than electrons to perform logic functions. These devices are poisedto become the next generation of high-speed information processing sys-tems. Recent advances in material processing and device engineeringlead to the integration of a number of functions on single chips. Such opti-cal chips may enable compact, low-latency, wide-bandwidth, ultrafast,secure information systems. The goal of this project was to create PICsimulation tools to benefit LLNL missions.

Screen capture of the lumped-parameter code simulat-ing a gain-quenched laser logic device. Although thissimulation shows a device with good gain and reason-able speed, the device itself is infeasible to fabricateand must be run at such high currents that the devicewould melt, even if it could be built.


18

InP/InGaAsP waveguide structures;3) developed state-of-the-art InP/InGaAsPchlorine hydrogen dry etching (Fig. 1);4) fabricated InP/InGaAsP AWGdevices (Fig. 2) and optical modulators;5) characterized the fabricated low-losswaveguides (loss = 1.2 dB/cm); and

6) characterized the fab-ricated 8-channel AWGwith channel spacing of3.4 nm and signal-to-noise ratio of 20 dB.

FY03 is the last yearfor this project. Our exitplan began in January2003, with the start ofour DARPA-sponsoredprogram on O-CDMAtechnologies, workingwith the University ofCalifornia at Davis (UCD).UCD leads the net-works simulation, cod-ing, and architecturesegment; LLNL leadsthe InP integrated tech-nology development.

The foundations ofthe DARPA project are the discretedevices that we have fabricated for thisLDRD project. The DARPA program isaimed at developing a complex semi-conductor chip integrating lasers,phase modulators, waveguides, AWGsand detectors.

This project entailsthe development ofadvanced technolo-

gies that have potentialapplications to nationalsecurity, such as secure,high-speed transmis-sions, and that willenhance LLNL’s compe-tencies in optoelectron-ics and high-speed com-munications.

By applying innovationsin WDM-component tech-nology, we are developinga compact optical CDMA(O-CDMA) encoding anddecoding device thatwould handle large codesizes, be remotely recon-figurable by a networkoperator, and be compatible with com-mercial fiber-optic infrastructures.

The device, which comprises two indi-um phosphide (InP) arrayed waveguidegratings (AWG) and an array of InPphase modulators, would allow eachuser of a network to spectrally phase-modulate (encode) a broadband, ultra-short, transmitted optical pulse. Only theintended recipient, in possession of thecorrect complementary phase code,would be able to decode the transmittedinformation.

In FY01 and the first half of FY02,the functionality of this system wasdemonstrated by evaluation of a table-top O-CDMA system. Subsequently, theeffort has been focused on the fabrica-tion of an integrated chip capable ofsupporting data streams within aCDMA platform. The building block ofthe system is the AWG, which requirescomplex semiconductor crystal growthand precision plasma etching.

Our design is based on InP semi-conductors using the quaternaryInGaAsP for the waveguide core. InFY03, we 1) designed waveguidesaimed at achieving large optical con-finement and low attenuation; 2) devel-oped epitaxial crystal growth of

Reconfigurable Optical Code-Division Multiple Access for

Fiber-Optic Networks R. J. Welty, C. E. Reinhardt, N. P. Kobayashi, V. R. Sperry,

I. Y. Han, E. M. Behymer, C. V. Bennett, S. W. Bond; Y. Du, S. J. Yoo (University of California at Davis)

High-speed, high-capacity fiber-optic communications networks, whichallow multiple users to access the same network simultaneously by shar-ing the same transmission medium, have proliferated for long-distance,metropolitan, and local-area communications systems. Recently, a rapidexpansion has begun into wavelength-division multiplexing (WDM) sys-tems, which use multiple wavelengths to increase capacity, In addition,code-division multiple-access (CDMA) techniques, which were originallydeveloped for wireless communications, can also be used to furtherincrease the number of channels on an optical fiber.

Figure 1. Scanning electron microscopephotograph of InP dry-etched waveguide(cross-section) defined by electroncyclotron resonance etching. Photographshows smooth etched surface (rmsroughness of 1.0 nm) and sidewall (rmsroughness of 3.7 nm).

Figure 2. Photograph of fabricated AWGdevice. Light with many wavelengths(channels) is multiplexed from one inputguide to n output guides by splitting,constructively interfering, and combining.

Sidewall

Surface

Arrayedwaveguides

Splitter

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Center forNondestructiveCharacterization

Center forNondestructiveCharacterization

Center for Nondestructive CharacterizationFY03 • ETR • LDRD

21

will further examine the cognitive inter-pretation process of real-time UWBelectromagnetic images.

While two front-end sensors can beused (acoustic and electromagnetic), wehave elected to develop a beam-formingand steerable UWB array. Among otherattributes, UWB has been shown to pen-etrate many materials (e. g., wood, someconcretes, non-metallic building materi-als, and some soils) with very high rangeresolution. Further, we are leveragingthe LLNL UWB technical knowledgebase and experiences gained throughfield deployments of monostatic sys-tems. Our approach, in collaborationwith cognitive sciences staff at theUniversity of California at Davis (UCD) willbe to formulate images in real time thatwill engage the user’s vision system in amore active way to enhance image inter-pretation capabilities.

We have developed anumerical imaging algo-rithm and implemented itto study UWB beam-forming and steering. Wehave developed a compu-tational simulator systemto evaluate and anticipatethe performance of theimaging system. It iscapable of generatingimpulse radar images ofmoving targets with arbi-trary trajectories, and offacilitating a parametric

study of the effects of transceiver ele-ment configuration.

Figure 1 shows an image frame of asphere target as determined from thesimulator. Figure 2 shows the measuredpsychometric functions of different typesof targets.

We have also been characterizingthe existing hardware to aid us indesigning the simulator to reflect themost realistic and desired perform-ance characteristics. The preliminaryresults have been very encouragingand indicate that the project continuesto be on track.

Figure 3 shows an image frame ofa circular plate target from the labo-ratory system. We continue to reachout to potential sponsors and cus-tomers within both LLNL programsand external agencies.

Existing approachesto threat detectionhave severe limita-

tions. In general, thereare trade-offs betweenrange of detection (espe-cially through obscurantsat a distance), specificity,data-processing time,and portability.

An example on oneextreme: metal detectorsare fast but they cannotdetect non-metallicweapons and cannot beused to monitor human threats at a dis-tance through walls. An example on theother extreme: backscatter x rays arelocation-specific but cannot provide thedata in real time, and are thus of no usein tactical situations. In both cases, thesetechniques are detecting and screeningfor objects, and do not have the capabilityto monitor in real time threateningactions of people through obstaclessuch as doors and walls.

In this project, we are researchingthe use of real-time FPGAs, integratedwith high-resolution (cm scale), ultra-wideband (UWB) electromagnetic sig-nals for imaging personnel throughsmoke and walls. Upon solving this larg-er-scale real-time imaging problem, wewill evaluate the real-time imagingissues of detecting smaller objects,such as concealed weapons that arecarried by the obscured personnel. We

Concealed Threat Detection atMultiple Frames/s

J. T. Chang, S. G. Azevedo, D. H. Chambers, P. C. Haugen, R. R Leach, C. E. Romero, J. M. Zumstein;

V. R. Algazi (University of California at Davis)

Our purpose is to investigate the science and technology necessary toenable real-time array imaging as a rapid way to detect hidden threatsthrough obscurants such as smoke, fog, walls, doors, and clothing. Thegoal of this research is to augment the capabilities of protective forces inconcealed threat detection.

Figure 1. Simulated radar image frame ofa spherical target taken by 7-transmitter,1-receiver circular array. The target is 30-cmouter diameter and 1-m down range, and islocated at the edge of the detection field ofview (1 m, 0 m).

Figure 2. Measured psychometric functionsof different types of targets. These aremeasurements of probability of detection asa function of target intensity.

Figure 3. Laboratory-acquired radar imageframe of circular metal plate target taken by7-transmitter, 1-receiver circular array. Thetarget is 30-cm outer diameter and 1-mdown range, and is located at the edge ofthe detection field of view (-0.5 m, -0.25 m).

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FY03 • ETR • LDRDCenter for Nondestructive Characterization

22

can be used in a variety of mesoscalecharacterization areas.

This project began in FY01. Duringthe past twelve months, we have replicat-ed several test optics using low-cost man-drels, and we replicated one developmen-tal optic using our super-polished high-accuracy mandrel (see figure). We havealso designed and partially constructedthe prototype microscope (see figure).

The microscope prototype consistsof four major parts: the optic and target-positioning hardware; the imaging sys-tem; the x-ray source hardware; and theprototype body. The prototype body isessentially a large aluminum tube that issupported by isolators. This design pro-vides high rigidity and good vibration iso-lation at a minimal cost. The x-ray sourceis a standard copper-anode tube source.

It is positioned via threetranslation stages andone rotation stage. Awater-cooled shield isplaced between thesource and the prototypebody to minimize heattransfer.

The imaging systemuses a scintillator to con-vert the x rays to visiblelight, which is imaged witha CCD camera. This hard-ware sits on an automatedpositioning system withthree degrees of freedom.

The optic and target-positioning systemis the most complicated part of the pro-totype. The target is positioned via acustom-built parallel mechanism thatuses flexures to provide rigidity with verylittle friction. The optic and target aremechanically aligned using tightly toler-anced parts. This approach will mini-mize alignment problems during thetesting of the prototype.

This project will continue as we man-ufacture more parts; assemble the pro-totype microscope; fabricate additionaloptics using super-polished mandrels;and test the microscope using phan-toms (test parts) and real target assem-blies. Ideally, this prototype will lead to theconstruction of a production microscopein the near future.

X-ray microscopy isone technique thatholds promise for

characterizing the inter-nal structure of targetassemblies. Sub-µm spa-tial resolution has beendemonstrated using asynchrotron x-ray source,but that approach doesnot accommodate ourrequirements for a high-throughput and low-costapproach for characteriz-ing production quantitiesof target assemblies.

This project is funding the researchand development of an x-ray microscopethat uses a replicated multilayer Wolteroptic. The fabrication of the optic is thekey to the success of this project. Thereplication technique coats a super-pol-ished mandrel with reflective multilayermaterials. The multilayers are coveredwith a 1- to 2-mm-thick layer of nickel toprovide structural rigidity. The Wolteroptic (multilayers with a nickel substrate)is then separated from the mandrel. Thisresults in an optic with nearly the samefigure and roughness as the mandrel. Ifsuccessful once assembled and tested,this prototype microscope will providehigh-throughput and high-resolution x-rayimaging of target assemblies in a labora-tory setting. Moreover, this prototypewould bring a new capability to LLNL that

High-Accuracy X-Ray Imagingof Mesoscale Targets

W. W. Nederbragt, T. W. Barbee, J. L. Klingmann, C. Vargas, H. E. Martz

High-energy-density (HED) experiments play an important role in cor-roborating the improved physics codes that underlie LLNL’s StockpileStewardship mission. Conducting these experiments will require not onlyimprovement in the diagnostics for measuring the experiment, but also inthe fabrication and characterization of the target assemblies. Specifically,a radical improvement is needed in characterizing the target assemblies(mm-sized components with µm-sized features).

X-ray microscope design and construction.

CAD representation of the prototype

Assembled prototype body

Mandrel

Replicatedoptic


23

HSIW algorithm, however, increasingthe number of frequencies and trans-ducers increases the complexity of thereconstruction, the size of the interme-diary data files, the reconstruction time,and the computer memory require-ment. Thus, the trade-off between com-puter resources and resolution mustalso be considered.

We studied these issues using LLNL’sE3D acoustic/elas-tic wave propaga-tion and scatteringcode. We simulateda medium with twoscattering objectswhose acousticproperties variedfrom 5% below thebackground to 15%above it. An exampleof the medium isshown in the figure(a). The dashed out-line indicates thelocation of the radialreflection probe.

We performedfive simulations withthe configurationshown in figure (a).The reconstructedimages are present-ed in (b) through (f).The dashed outlinessuperimposed onthe images indicatethe locations of thescatterers. Our con-clusion, based uponobservation of ther e c o n s t r u c t e dresults, is that a single transducer

offers insufficient spatialdiversity to localize theobject azimuthally. Ascan be seen in the multi-monostatic reconstruc-tion of (b), the concentricarcs indicate there is anazimuthal ambiguityresulting from the lack ofspatial receiver diversity.This is a result of off-radial axis scattering

that is not collected by the transducer.Improved azimuthal localization isachieved as more receivers are includ-ed; however there is a loss of rangeresolution as fewer frequencies areincluded in the reconstruction. In sum-mary, scatterer azimuthal resolutionimproves as more receivers are used;and range resolution improves asmore frequencies are used.

IVUS systems formimages of the mediumsurrounding the probe

based on ultrasonicscans, using a straight-ray model of sound prop-agation. Our achievedgoal was to develop awave-based imaging algo-rithm using diffractiontomography techniques.

Given the hardwareconfiguration and the imaging method,we refer to this system as “radial reflec-tion diffraction tomography.” We consid-ered two hardware configurations: amultimonostatic mode, using a singlerotating transducer, and a multistaticmode, consisting of a single transmitterand an aperture formed by multiplereceivers. In this latter case, the entiresource/receiver aperture rotates abouta fixed axis.

Practically, such a probe is mounted atthe end of a catheter or snaking tube thatcan be inserted into a blood vessel, part, ormedium, with the goal of forming imagesof the plane perpendicular to the axis ofrotation. We derived an analytic expres-sion for the multimonostatic inverse, butultimately used a Hilbert space inversewave (HSIW) algorithm to constructimages using both operating modes.

Applications include improved IVUSimaging, bore-hole tomography, andnondestructive evaluation of parts fromexisting access holes.

A trade-off must be made betweenthe number of transducers used andthe quality of the reconstructed image.Ideally, an aperture consisting of a 360°annular array would yield the bestimage. Practically, it is currently not pos-sible to construct such a fully wiredarray in a 0.25-mm IVUS probe, forexample. Thus, we have studied rotatingsub-apertures and compared recon-struction results to the single multi-monostatic configuration.

When operating in a reflectionmode, the imaging mathematics dic-tates that spectrally wideband pulsesmust be used. The resolution of thereconstructed image is directly propor-tional to the number of frequenciesused in the reconstruction. Under the

Radial Reflection Diffraction Tomography

S. K. Lehman, D. H. ChambersWe developed a wave-based tomographic imaging algorithm based ona single rotating radially-outward-oriented transducer. At successiveangular locations at a fixed radius, the transducer launches a primaryfield and collects the backscattered field in a “pitch/catch” operation. Thehardware configuration, operating mode, and data collection method isidentical to that of most medical intravascular ultrasound (IVUS) systems.

(a) Homogeneous medium with two scattering objects. (b) Multimonostatic reconstruction. (c) – (f) Multistatic recon-structions in which the number of elements in the apertureand number of frequencies used were varied as indicated.

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FY03 • ETR • LDRDCenter for Nondestructive Characterization

24

exercising laminographic and conjugategradient iterative object recovery tech-niques. This includes further developingour simulation capability. From sequencesof translated simulated images we areexploring algorithms that may identifyboundaries of images at various planes.

We have also investigated the use ofphase-contrast imaging techniques inboth the point-projection geometry andin the Wolter optical system. Numericalmodeling of a variety of objects indicatesthat phase contrast features have a sig-nificant effect on the collected image fora range of objects of interest. We mod-eled KCAT point projection imaging of aBe-shock tube (Fig. 1) and polyethylenesurrogates, including for the first timethe effects of phase contrast, andexplained the bright edges observed inpreviously collected data. Partially

coherent imaging simu-lations have been per-formed for the Woltermicroscope (without as-designed or as-fabricatedaberrations) and phasecontrast has beenobserved in the modeledimage data (Fig. 2). Weare investigating howsensitive this is to illumi-nation conditions in theWolter microscope witha view to optimizing the

x-ray illumination for phase contrast ofthis feature.

As one of our modeling accomplish-ments, we have built HADES input decksthat model recently fabricated cylindricaland spherical reference standards.These images were generated withHADES using LLNL’s Evaluated PhotonData Library, and are simply attenuationprojections. We are developing a newversion of HADES that will also computeoptical path difference (phase) projec-tions using form-factor tables from theCenter for X-Ray Optics at the Universityof California at Berkeley. These quanti-ties are the raw materials for use inpost-processing simulations of phase-contrast microscopy. We have workedout plans for including this new physicsin HADES, but the code has not yetbeen written.

In the area of ampli-tude contrast, we havefocused on two x-ray

microscopes, one 8 keV,the other 59 keV.

The mechanical designof the 8-keV prototypemicroscope is nearlycomplete. Several repli-cated optics have beenfabricated for testing. Thefirst developmentalWolter optic was fabri-cated. The optic qualitywill be determined in FY04. The proto-type is being assembled.

We have preliminary designs for a59-keV prototype instrument. Aftercarefully considering all system require-ments and performing coarse optimiza-tions, we have determined that thedetector will drive the final design. Unlikethe lower energy 8-keV microscope thatcan use several different types of detec-tors, there are few options for efficientlydetecting hard x rays at the requisitespatial scales needed to ultimatelyachieve sub-micrometer performance.After verifying that our proposed solution(coupling highly-collimated scintillatorscreens directly to a CCD) meets ourspecification, we will finalize the design ofthe 59-keV prototype microscope.

We have made progress also in algo-rithms for object recovery. We are fully

Tabletop MesoscaleNondestructive Characterization

H. E. Martz, M. B. Aufderheide, T. W. Barbee, A. Barty, H. N. Chapman, J. A. Koch, B. J. Kozioziemski,

W. W. Nederbragt, D. J. Schneberk, G. F. Stone; M. Pivovaroff (University of California at Berkeley)

We have made significant progress in the area of research and develop-ment of tabletop mesoscale nondestructive characterization. Our FY03accomplishments include completion of projects in amplitude contrast,algorithms for object recovery, phase contrast, and modeling.

Figure 2. Phase contrast images of a D/T ice boundary obtained bytransport-of-intensity defocus method using disk source and full Wolteraperture, where ∆z is the position of the object from the object planecenter. Phase enhanced images at ∆z of 0.5 to 20 µm reveal the D/Tice boundary not observed in amplitude contrast images, ∆z = 0 µm.

Figure 1. Top: KCAT point projection image at 50 kV of a hollowBe cylinder with a cap. Bottom: Calculated Fresnel-Kirchoffscalar diffraction theory results of the Be cylinder.

∆z = 0 µm ∆z = 0.5 µm ∆z = 1 µm

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ware to synthetically phase an array;combined a dispersion model with oursource model to calculate a simulatedRF waveform; and demonstrated thedetection of a notch in a multilayeredstructure. For bulk waves, a beam-forming reconstruction algorithm wasmodified for imaging. A void in anacrylic-epoxy-lexan structure was suc-cessfully imaged using the modifiedreconstruction algorithm.

Electronics capabilities were devel-oped to synthetically phase an arraywith an accuracy of 10 ns. A tone-burstpulser was added to the system to

enable pulse widths of upto 200 ms, which pro-duces a narrower bandof frequency excitation.The new pulser alsoenables weighted win-dowing of the pulse toreduce side lobes in thefrequency spectrum.The new electronics willresult in improved signal-to-noise.

The technique ofsweeping the dispersionspace to determine suit-able modes of inspectionfor a multilayered struc-

ture was demonstrated on an alumina-epoxy-aluminum structure. A notch wasplaced in the bottom aluminum layer anddetected, as shown in the figure. A paperdetailing our work was accepted for pub-lication in a peer-reviewed journal.

In FY04, we will perform experi-ments on multilayered structureswith surrogate materials for chal-lenging characterization applications.We will construct improved arrayswith feedback from modeling andexperimental results. Feasibility stud-ies will be conducted on program-matic-like structures.

Inspecting multilayeredstructures with a guid-ed wave relies on excit-

ing modes with sufficientenergy in the layer ofinterest and on the sur-face. Suitable modes forinspection must be deter-mined. We are developinga new method of phasingan array to search the dis-persion space for guidedwave modes suitable forinspecting inaccessibleareas of multilayeredstructures. This project isdeveloping a model andexperimental hardware to preferentiallyexcite guided acoustic waves to charac-terize multilayered structures.

We are also developing phased-arraymethods for beam-steering and focusingof bulk waves for the nondestructive eval-uation (NDE) of multilayered structuresfor accessible areas. We are extendingarray technology from a single layer intomultilayered media. This requires recon-struction algorithms to be modified toaccount for refractions at interfaces andchanging wave speeds in different layers.

During FY03, for guided waves wedesigned and built the electronics hard-

Ultrasonic NDE ofMultilayered Structures

M. J. Quarry, K. A. Fisher; J. Rose (Pennsylvania State University)

Several programmatic applications require the inspection of multilayeredstructures with barriers to placing sensors in the area of concern. This preventsthe use of many traditional nondestructive techniques. Inspection without dis-assembly is currently not possible. This project is developing two technologiesfor inspection: 1) ultrasonic guided waves, a potential method for sendingsound into inaccessible areas to characterize the integrity of embedded parts;2) bulk-wave-array technology, which can focus sound at an arbitrary pointwithout scanning or submersing the system in water. The inspection techniquesdeveloped in this work will enhance LLNL’s role of stockpile stewardship.

Sample RF waveform showing detection of a 1-mm-deep (30% through-wall) notch with a 1-mm-x-25-mm cross-section in an alumina-epoxy-aluminum multilayer structure with a guided wave mode.

Center forPrecisionEngineering

Center forPrecisionEngineering

Center for Precision EngineeringFY03 • ETR • LDRD

29

It should be noted that the environ-ment housing the diamond turningmachine used to produce this part isless than ideal for producing opticalquality surfaces because of the closeproximity of heavy rotating machinery(e.g., compressors) and poor thermalcontrol. Lower surface roughness val-ues should be achievable in a morecontrolled environment.

Closer examination ofthe “sinusoidal” profile inFig. 2 reveals a depar-ture from a pure sinewave. Note that thepeaks are slightly sharp-er than the valley. Theaddition of adaptive feed-forward cancellationcontrol techniques isexpected to reduce thefollowing error of the tooltip, thus allowing the pro-duction of higher accura-cy surface topographies.

Continuing work hasalready begun on thedesign of a new 10-kHzrotary FTS that will usea novel variable-reluc-tance actuator capable

of a ten-fold increase in actuator forcedensity, with a planned tool tip acceler-ation of 1000 g’s. The 10-kHz FTS willhave a maximum stroke of 50-µm PV.

FY04 activities will focus on devel-oping, building, and testing the new10-kHz system, and developingadvanced controller techniques forimproving trajectory following.

This project developeda 2-kHz rotary FTScapable of 50-µm PV

motion at low speeds,and 5-µm PV sinusoidalmotion at 2 kHz. Figure 1is a photograph of thesystem. We have demon-strated 2.5-µm PV at 2 kHz, producing 20 g’stool tip accelerations,while diamond turning anoptical quality surface ona workpiece (Fig. 2).

The aluminum work-piece in Fig. 2 has anouter diameter of 9 mmand 250 radial grooveson the face that weremachined at 480 RPM.Tracing a profile alongthe face, along any fixed radius, thegrooves describe a sinusoidal wave-form with 2.5-µm PV amplitude and aspatial wavelength ranging from 110µm at the outer diameter to 30 µm atthe inner diameter. Figure 2 also showsoptical measurements of the surface.The measured roughness along agroove (across the feed marks) is betterthan 12 nm rms.

High-Bandwidth Fast ToolServo for Single-Point Turning

High-Energy-Density Physics Targets

R. C. Montesanti, J. L. Klingmann; D. L. Trumper (Massachusetts Institute of Technology)

High-energy-density experiments play an important role in corroboratingthe improved physics codes that underlie LLNL’s stockpile stewardshipmission. Single-point diamond turning has been the best method for pro-ducing accurate, optically smooth surfaces on target components, butnew experiments require surfaces that exceed LLNL’s current capability. Afast tool servo (FTS) is a small, fast-moving machine axis which, whenadded to a single-point turning machine, will provide LLNL the capabilityto fabricate these more complicated target surfaces.

Figure 2. (Left) Diamond-turned workpiece with 250 radial grooves on theface. (Right) 3-D surface map of a section of two grooves (upper), andprofile across the grooves (lower). Profile along a groove (not shown)reveals 11.6 nm rms surface roughness.

Figure 1. 2-kHz rotary fast tool servo.

Actuator

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Sensors

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Center forComplex DistributedSystems

Center forComplex DistributedSystems

Center for Complex Distributed SystemsFY03 • ETR • LDRD

33

Measurements of radiation levelsfrom a known source in a shipping con-tainer compared well to simulated resultsfor various scenarios. These measure-ments have led to an initial design for thecoming year. The RF experiments pointedout the need for an ultrawideband (UWB)physical implementation of the communi-cations system, while the networkingresearch has produced a new energy-efficient protocol mechanism. We have

also initiated publica-tions describing ourwork and results.

Our project willstrengthen homelandsecurity by researchingand developing a sensorsystem concept to detectWMD components enter-ing the U. S. in shippingcontainers. Furthermore,both the sensor and net-working aspects of this

project have relevance to other nationalneeds in the military and intelligencefields. DOE/NNSA projects for long-termstorage of radioactive substances withsmall low-cost sensors will also benefitfrom this research. The exit plan calls fordeployments through DOE/NNSA, aswell as through other government agen-cies such as the Departments ofCommerce, Transportation, HomelandSecurity, and Border States.

Our goal is toinvestigate twocritical technolo-

gies for achieving securityin the containerized ship-ping industry: 1) a radia-tion sensor that must beextremely low power(<100 µA); and 2) a com-munications network thathas similar powerrequirements and formsan ad hoc network ofthousands of nodes (containers) in anextreme multipath environment.

These two areas are the key missingR&D components in support of a systemconcept (see Fig. 1) that would detectWMDs entering the country in shippingcontainers, before arriving at U. S. ports,and without impeding trade flow. Thesensors must be inexpensive and per-manently mounted (10-year lifespan).

The overall project will produce twokey results. The first is a new radiationsensor concept that can integrate theradiation over time (it takes seven daysto cross the ocean), has limited discrim-ination of energy bands, and is low inpower draw. The leading candidate is aset of dosimeters (either thermolumi-nescent (TLDs) or optically stimulable)that have varying amounts of shielding tocrudely measure spectral content, andare remotely read, then reset.

The second result will be a new com-munication technique for networkingtens of thousands of sensors (as is like-ly on a large ship) using energy-efficientsignaling and routing protocols. Thesensors must be queried and the dataextracted by multiple hops to the ship’sinfrastructure, using very low power lev-els (sub-milliwatt). Such scalable ultra-low-power networks have never beforebeen accomplished.

In this first year of the project, wehave studied possible radiation detectionsensors; performed several measure-ment studies of TLDs and advanced neu-tron detectors; measured backgroundradiation on two container ships; per-formed radio frequency propagationstudies on board two ships (see Fig. 2);and are developing low-power communi-cations and networking protocols.

Cargo Container SecuritySensor System

S. G. Azevedo, K. E. Sale, B. D. Henderer, C. L. Hartmann-Siantar, J. Lehmann, L. S. Dauffy

Security of the containerized shipping industry with respect to the traffick-ing of weapons of mass destruction (WMD) will be achieved with “smartcontainers” of the future. We have investigated smart containers withembedded, permanent sensors and communications subsystems.

Figure 2. LLNL team members on board a container ship (APL President Wilson) measuringbackground radiation and electromagnetic propagation at various ship locations aboveand below deck.

Figure 1. Conceptual drawing of a “container ship of the future” that has low-cost sensorpackages in every container. Each measures the distributed radiation environment andcommunicates results to authorities. Clustered anomalies will trigger inspection.

FY03 • ETR • LDRDCenter for Complex Distributed Systems

34

testbed was installed on site at LLNL forreal-time seismic tracking methods. Afield experiment was conducted over atunnel at NTS that quantified the tunnelreflection signal and, coupled with model-ing, identified key requirements in exper-imental layout of sensors.

A large field experiment was conduct-ed at the Lake Lynn Laboratory (Fig. (a)),a mine safety research facility inPennsylvania, over a tunnel complex inrealistic, difficult conditions. This experi-ment gathered the necessary data for afull 3-D attempt to apply the methodolo-gy, and to analyze the capabilities todetect and locate in-tunnel explosions.

In FY03 specifically, a large and com-plex simulation experiment was conduct-ed that tested the full modeling-basedapproach to geological characterizationusing E3D, the K-L statistical methodolo-gy, and matched-field processing appliedto tunnel detection with surface seismicsensors. The simulation validated the fullmethodology and the need for geological

heterogeneity to beaccounted for in the over-all approach. The LakeLynn site area was geo-logically modeled usingthe code Earthvision toproduce a 32-millionnode 3-D model grid forE3D (Fig. (b)).

Model linking issueswere resolved and a num-ber of full 3-D model runswere accomplished usingshot locations thatmatched the data. E3D-generated wavefield

movies showed that the reflection signalwould be too small to be observed in thedata due to trapped and attenuated ener-gy in the weathered layer. An analysis ofthe few sensors coupled to bedrock didnot improve the reflection signal strengthsufficiently because the shots, thoughburied, were within the surface layer, andhence attenuated. Ability to model a com-plex 3-D geological structure and calcu-late synthetic seismograms that are ingood agreement with actual data (espe-cially for surface waves and below thecomplex weathered layer) was demon-strated. We conclude that E3D is a pow-erful tool for assessing the conditionsunder which a tunnel could be detected ina specific geological setting.

Finally, the Lake Lynn tunnel explo-sion data was analyzed using standardarray-processing techniques, with theresult that single detonations could bedetected and located but simultaneousdetonations would require a strategicplacement of arrays.

The goal of this proj-ect is to build capa-bilities in acquisition

system design and appli-cation, and in full 3-Dfinite-difference modeling,as well as statistical char-acterization of geologicalheterogeneity. Suchcapabilities, coupled witha rapid field analysismethodology, based onmatched-field processing,are applied to problemsassociated with surveil-lance, battlefield manage-ment, detection of hard and deeplyburied targets, and portal monitoring.This project benefits the U.S. military andintelligence communities in support ofLLNL’s national security mission.

FY03 was the final year of this proj-ect. In the two and a half years this proj-ect has been active, numerous and var-ied developments and milestones havebeen accomplished. A wireless commu-nication module was developed to facili-tate rapid seismic data acquisition andanalysis. The E3D code was enhanced toinclude topographic effects. Codes weredeveloped to implement the Karhunen-Loeve (K-L) statistical methodology forgenerating geological heterogeneity thatcan be used in E3D modeling. Thematched-field processing methodologyapplied to vehicle tracking, and based ona field calibration, to characterize geolog-ical heterogeneity was tested and suc-cessfully demonstrated in a tank track-ing experiment at the Nevada Test Site(NTS). A 3-seismic- array vehicle tracking

Developing Smart Seismic Arrays

P. E. Harben, D. B. Harris, S. C. Myers, S. C. Larsen, J. L. Wagoner, J. E. Trebes, K. E. Nelson

Seismic imaging and tracking methods have intelligence and monitoringapplications. Current systems, however, do not adequately calibrate ormodel the unknown geological heterogeneity, nor are they designed forrapid data acquisition and analysis in the field. This project seeks to buildthe core technological capabilities, coupled with innovative deployment,processing, and analysis methodologies, to allow seismic methods to beused effectively in seismic imaging and vehicle tracking where rapid(minutes to hours) and real-time analysis is required.

(a) Surface seismic shot detonation at the Lake Lynn site during field experiment. (b) Map view of the surface wavefield potentialcalculated by E3D for (a). P-waves are magenta; S-waves are turquoise. Simulations verify that advanced signal processing methods arerequired to detect and image underground facilities.

(a) (b)

Center for Complex Distributed SystemsFY03 • ETR • LDRD

35

0

w/o basin

w/ basin

Tim

e (s

)

10

20

30

40

50

60

70

80

Dep

th (k

m}

0

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20

30

120 140 160 180Horizontal distance (km)

200 220

Velocity (relative units)

basin response and evaluate these mod-els. Delay times of teleseismic P-wavesshow variation of up to 0.5 s across rel-atively short distances (15 km or less),providing constraints on basin structure.Teleseismic P-waves have favorable sig-nal-to-noise for low frequencies (0.1 to1.0 Hz). These data provide complemen-tary site response measurements tothose obtained from earthquakes andNTS explosions. Our results indicate anamplification factor of 5 for the basinsites relative to “hard” rock sites.

To understand the sensitivity of groundmotion to basin structure we took a 2-D“slice” through a complex 3-D structuralmodel of Las Vegas Valley, including later-ally varying basin depth. We investigatedthe effects of various model features on

estimated ground motion,including sedimentaryvelocity profiles and shal-low (≤ 50 m) velocities.Figure 1 shows an illustra-tive model and demon-strates the influence ofthe basin structure on theseismic data.

We investigated thesensitivity of the amplifica-

tion observed at the basin sites by varyingthe shear and compressional velocitiesand density in a 50-m-thick surface layerof the basin. In Fig. 2, we illustrate the dif-ference between a basin and a rock site(red and black in Fig.1), for a series ofruns, for shear velocities of 500 m/s to1500 m/s, with a step of 250 m/s in theshallowest 50 m.

Although we cannot produce thesame amplitude as in the real data due tothe 2-D approximation, we can comparethe relative amplification between the twostations, for different values of elasticparameters. Decreasing the surfaceshear velocity clearly affects the ampli-tude, as well as the duration of the actualground motion. Our comparison of theo-retical and observed site response indi-cates that the properties of the thin sur-face soil layer significantly effect theobserved surface motions.

Sedimentary basinscan result in signifi-cant amplification of

ground motions and accu-rate simulations must becapable of representingbasin effects. We investi-gated the application ofthis model in a case studyapplication to a region inSouthern Nevada, encom-passing the Nevada Test Site (NTS) andthe Las Vegas Valley. We used historicalrecordings of NTS nuclear explosions andrecent earthquake recordings to con-strain ground motion response and basinstructure. We simulated low frequency(<1 Hz) ground motion in Las Vegas Valleywith the elastic finite-difference code. Wedemonstrated that the relative amplifica-tion, as well as some of the complexity inthe waveforms can be predicted.

A model of the basin depth wasderived from gravity data in an independ-ent published study, while a model ofcompressional velocity structure of thebasin was derived from seismic refrac-tion studies. We used historical accelero-meter data, as well as newly acquiredbroadband teleseismic data to measure

Evaluating a RegionalSimulation Model for Seismic

Wave PropagationH. Tkalcic, A. J. Rodgers, D. B. McCallen

A finite-difference-based, elastic wave propagation model has recentlybeen developed for simulating surface ground motions generated by prop-agating seismic waves.

Figure 1.Two-dimensional wave propagation simulations to investigate basin amplifica-tion. Top: theoretical seismograms for models with (red) and without (black) basin.Bottom: physical model showing seismic velocity structure.

Vel

ocit

y (r

elat

ive

unit

s)

0

10 20 30 40

1 Hz 2D synthetics (black-rock-site)

50 60 70Time (s)

Vs=1.50 km/s (top 50m)

0


0


0


0


Figure 2.The effect of low shear velocitysediments.

FY03 • ETR • LDRDCenter for Complex Distributed Systems

36

have completed and tested UWB radiosfor star networks and a mesh networkwith UWB repeater nodes. The featuresof the mesh network include flood rout-ing; unidirectional communication; andredundant transmission, with mediaaccess control by pseudo-slotted, fixed,re-transmission back-offs. These provide

a very wide set of networkprotocols for increasingthe range of our point-to-point UWB transceiversmany times.

FY03 is our final yearof this project. We havebeen working with vari-ous national agencies tocontinue our work forreal applications. Wehave also published sev-eral papers for peer-reviewed publicationsand conferences.

In summary, we have developedUWB radios meeting the radio speci-fications we had hoped to achieve.Our final design has resulted in small-size, low-power, low-cost hand-heldtransceivers that can be networkedfor various national intelligence anddefense applications.

Intelligence operationsrequire short-rangewireless communica-

tions systems capable ofcollecting data rapidly,and transmitting itcovertly and reliably.Such systems must berobust; have a low proba-bility of detection andintercept; employ low-power, small-size hard-ware; and interface easi-ly with other systems foranalysis or to establishlong-distance links. Commercial com-munication systems that operate infixed-frequency bands are easilydetectable and are prone to jamming,among other shortcomings.

We have been focusing on the threekey operational modes for DoD and theintelligence community: 1) secure sensorand voice communications over a 1-kmrange; 2) ground-to-ground and air-to-ground data channels for small,unmanned air vehicles; and 3) networkcommunication for large numbers of sen-sors in a local area, including multi-pathand extremely low-altitude operations.

The goals of this project are todevelop and demonstrate 1) UWBcommunication with a capacity of 5 Mbps and a range of 1 km; 2) multi-channel capability with sensors; 3) atestbed for application development;and 4) performance standards for biterror rate and low probabilities ofdetection and intercept.

In FY03, we have refined our UWBcommunication transceivers for voice,video, and digital-data communica-tions for intelligence applications (seefigure). We have performed modelingand propagation analyses and devel-oped 1) a UWB radio and bit error(BER) boxes with a capacity of 1 Mbps, a range of 100 m, and a powerrequirement of < 0.5 W; 2) a MATLABgraphical user interface for our models;3) an interface for real-time applica-tions; and 4) a network and architec-ture design and implementation.

Radio networking was one of themain objectives of our FY03 work. We

UltrawidebandCommunications

F. U. Dowla, A. Spiridon, D. M. Benzel

We have built an ultrawideband (UWB) radio for our compact sensornode. The sensor node is also equipped with an antenna, globalpositioning system (GPS), UWB radar, micropower impulse radar(MIR), processing unit, and batteries. Network protocols were devel-oped to interface with our UWB radio design. Sensor radio nodes ofthis type will play a critical role in modern wireless sensor networksfor intelligence and battlefield applications.

UWB communication transceiver.

AuthorIndexAuthorIndex





39

Algazi, V. R. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21Aufderheide, M. B. . . . . . . . . . . . . . . . . . . . . . . . . . . .24Azevedo, S. G. . . . . . . . . . . . . . . . . . . . . . . . . . . . .21, 33Barbee, T. W. . . . . . . . . . . . . . . . . . . . . . . . . . . . .22, 24Barty, A. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24Becker, R. C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8Behymer, E. M. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18Benett, W. J. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14Bennett, C. V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18Benzel, D. M. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36Bond, S. W. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18Bond, T. C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17Carlisle, K. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13Castillo, V. M. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7Chambers, D. H. . . . . . . . . . . . . . . . . . . . . . . . . .21, 23Champagne, N. J. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6Chang, J. T. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21Chapman, H. N. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24Chaung, F. Y. S. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16Chen, A. A. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14Christian, A. T. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14Clague, D. S. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4Dauffy, L. S. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33Dougherty, G. M. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16Dowla, F. U. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36Du, Y. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18Felker, F. F. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7Fisher, K. A. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25Gilmer, G. H. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13Haugen, P. C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21Han, I. Y. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18Harben, P. E. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34Harris, D. B. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34Hartmann-Siantar, C. L. . . . . . . . . . . . . . . . . . . . . . . .33Havstad, M. A. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16Henderer, B. D. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33Kallman, J. S. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17Khanaka, G. H. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17Klingmann, J. L. . . . . . . . . . . . . . . . . . . . . . . . . . .22, 29Kobayashi, N. P. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18Koch, J. A. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24Kozioziemski, B. J. . . . . . . . . . . . . . . . . . . . . . . . . . . . .24Larsen, S. C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34Leach, R. R. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21Lehman, S. K. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23

Lehmann, J. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33Madsen, N. K. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6Mariella, Jr., R. P. . . . . . . . . . . . . . . . . . . . . . . . . . . . .13Martz, H. E. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22, 24McCallen, D. B. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35Montesanti, R. C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29Morse, J. D. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15Myers, S. C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34Nederbragt, W. W. . . . . . . . . . . . . . . . . . . . . . . .22, 24Nelson, K. E. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34Ness, K. D. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14Pannu, S. S. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16Pao, H.-Y. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9Parsons, D. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3Pivovaroff, M. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24Puso, M. A. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5Quarry, M. J. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25Reinhardt, C. E. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18Richards, J. B. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14Rodgers, A. J. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35Romero, C. E. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21Rose, J. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25Rose, K. A. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16Rubenchik, A. M. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13Sale, K. E. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33Schneberk, D. J. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24Shirk, M. D. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13Solberg, J. M. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3, 5Sopchak, D. A. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15Sperry, V. R. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18Spiridon, A. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36Stone, G. F. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24Stratton, P. L. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14Tkalcic, H. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35Trebes, J. E. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34Trumper, D. L. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29Upadhye, R. S. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15Vargas, C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22Wagoner, J. L. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34Weisgraber, T. H. . . . . . . . . . . . . . . . . . . . . . . . . . .4, 14Welty, R. J. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18Wheeler, E. K. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14White, D. A. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6Yoo, S. J. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18Zumstein, J. M. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21

Author Index

Manuscript Date April 2004Distribution Category UC-42

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Acknowledgments

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