a generalized theory of elastodynamic homogenization for periodic media 2016 international journal...

Upload: abdullah

Post on 01-Mar-2018

221 views

Category:

Documents


0 download

TRANSCRIPT

  • 7/26/2019 A Generalized Theory of Elastodynamic Homogenization for Periodic Media 2016 International Journal of Solids and

    1/8

    InternationalJournalofSolidsandStructures84(2016)139146

    ContentslistsavailableatScienceDirect

    International

    Journal

    of

    Solids

    and

    Structures

    journalhomepage:www.elsevier.com/locate/ijsolstr

    A generalized theory of elastodynamic homogenizationfor

    periodic

    media

    H.Nassar,Q.-C.He,N.Auffray

    ModlisationetSimulationMulti-Echelle,Universit Paris-Est,MSMEUMR8208CNRS,5bdDescartes,77454Marne-la-Valle,France

    a

    r

    t

    i

    c

    l

    e

    i

    n

    f

    o

    Articlehistory:

    Received13August2015

    Revised

    18

    December

    2015

    Availableonline4February2016

    Keywords:

    Homogenization

    Willistheory

    Generalizedcontinua

    Optical

    branches

    Bandgaps

    a

    b

    s

    t

    r

    a

    c

    t

    For

    periodically

    inhomogeneous

    media,

    a

    generalized

    theory

    of

    elastodynamic

    homogenization

    is

    pro-

    posed

    so

    that

    even

    the

    long-wavelength

    and

    low-frequency

    asymptotic

    expansions

    of

    the

    resulting

    ef-

    fective

    (or

    macroscopic)

    motion

    equation

    can,

    approximately

    but

    simultaneously,

    capture

    all

    the

    acoustic

    and

    some

    of

    the

    optical

    branches

    of

    the

    microscopic

    dispersion

    curve.

    The

    key

    to

    constructing

    the

    gen-

    eralized

    theory

    resides

    in

    incorporating

    new

    kinematical

    degrees

    of

    freedom

    in

    conjunction

    with

    rapidly

    oscillating

    body

    forces

    as

    microscopic

    and

    macroscopic

    loadings

    while

    satisfying

    an

    energetical

    consis-

    tency

    constraint

    reminiscent

    of

    Hill

    Mandel

    lemma.

    By

    this

    constraint,

    an

    effective

    displacement

    field

    is

    naturally

    defined

    as

    the

    projection

    of

    a

    microscopic

    one

    onto

    the

    dual

    to

    the

    space

    of

    body

    forces.

    To

    illustrate

    these

    results,

    a

    two-phase

    string

    is

    studied

    in

    detail.

    2016

    Elsevier

    Ltd.

    All

    rights

    reserved.

    1.Introduction

    Theelastodynamichomogenizationapproachesreportedupto

    nowintheliteratureareobservedtorunintodifficultieswhenbe-ingusedtomodeldynamicaleffectsoverawidefrequencyrange.

    1.The classical lowest-order Long-Wavelength (LW) Low-

    Frequency(LF)homogenizationapproaches(Bensoussanetal.,

    1978;Sanchez-Palencia,1980)yieldahomogeneoussubstitu-

    tionCauchymediumwhichmissesalldispersiveeffectsandall

    internalresonances,i.e.,allopticaloscillationmodes.

    2.Thehigher-orderLW-LFasymptotichomogenizationapproaches

    (Andrianovetal.,2008;BoutinandAuriault,1993)leadtoef-

    fectivestrain-gradientmediawhichcanmodelwelldispersive

    behaviorsandsizeeffectsbutarevalidonlyneartheacoustic

    branchesindependentlyoftheorderoftheasymptoticapprox-

    imationsused.

    3.

    The

    high-frequency

    asymptotic

    approaches

    (

    Antonakakis

    et

    al.,

    2014;Boutinetal.,2014;Colquittetal.,2014;Crasteretal.,

    2010;Dayaetal.,2002;Noldeetal.,2011)aresuccessful in

    capturinghigh-frequencyopticalmodesbutstillvalidonlyin

    thevicinityofsomefinitefrequency.

    4.The high-contrast asymptotic approaches (Auriault and Bon-

    net,1985;AuriaultandBoutin,2012;Smyshlyaev,2009)havea

    widefrequencyvaliditydomainenglobinganinfinitenumberof

    Correspondingauthor.Tel.:+33160967794.

    E-mailaddress:[email protected](H.Nassar).

    opticalbranches.However,thecorrespondingeffectivebehavior

    iscomplexandnonlocalintime.

    5.Thenon-asymptotictheoryofWillis(1997,2011)yieldsexactly

    thewholedispersioncurve.Nonetheless,thedescribedeffectivefieldsareonlyrelevantforlowfrequencies(Nassaretal.,2015b;

    SrivastavaandNemat-Nasser,2014).

    Themainpurposeofthepresentpaperistoconstructagener-

    alizedtheoryofelastodynamichomogenizationforperiodicmedia

    whichimprovesthequalityoftheWilliseffectivebehaviorasan

    approximationtothemicroscopicbehaviorinawaythatLW-LF

    asymptoticexpansionsbecomeabletocapture,approximatelybut

    simultaneously,alltheacousticandsomeoftheopticalbranches

    ofthemicroscopicdispersioncurve.Toachievethispurpose,new

    kinematicalDegreesOfFreedom(DOFs)aretakenintoaccountso

    astodescribesomeshort-wavelengthcomponentsofthemicro-

    scopicdisplacementfieldwhichbecomedominantathighfrequen-

    cies.

    The

    new

    DOFs

    are

    excited

    by

    incorporating

    various

    rapidly

    oscillatingbodyforcesonthemicroscaleandonthemacroscale

    underanenergetical consistency constrainthereaftercalledEn-

    ergyEquivalencyPrinciple(EEP).TheEEPisabalancebetweenthe

    microscopicandmacroscopicvirtualworksandislaterprovento

    yieldageneralizedversionofthewell-knownHillMandellemma.

    WithrespecttoWillistheory,weunderlinetwomajordifferences.

    First,theincorporatedloadingsaremuchricherthanthoseem-

    ployedbyWillis(1997,2011).Thishastheconsequenceofreduc-

    ingtheerrorcommittedduringtheupscalingprocessandprovid-

    inganextendedfrequencyvaliditydomain.Second,theEEPcon-

    cernsvirtualworksandnottheirexpectancies.Fromthephysical

    http://dx.doi.org/10.1016/j.ijsolstr.2016.01.022

    0020-7683/ 2016 Elsevier Ltd. All rights reserved.

    http://dx.doi.org/10.1016/j.ijsolstr.2016.01.022http://dx.doi.org/10.1016/j.ijsolstr.2016.01.022http://dx.doi.org/10.1016/j.ijsolstr.2016.01.022http://dx.doi.org/10.1016/j.ijsolstr.2016.01.022http://dx.doi.org/10.1016/j.ijsolstr.2016.01.022http://dx.doi.org/10.1016/j.ijsolstr.2016.01.022http://dx.doi.org/10.1016/j.ijsolstr.2016.01.022http://dx.doi.org/10.1016/j.ijsolstr.2016.01.022http://dx.doi.org/10.1016/j.ijsolstr.2016.01.022http://dx.doi.org/10.1016/j.ijsolstr.2016.01.022http://dx.doi.org/10.1016/j.ijsolstr.2016.01.022http://dx.doi.org/10.1016/j.ijsolstr.2016.01.022http://dx.doi.org/10.1016/j.ijsolstr.2016.01.022http://dx.doi.org/10.1016/j.ijsolstr.2016.01.022http://dx.doi.org/10.1016/j.ijsolstr.2016.01.022http://dx.doi.org/10.1016/j.ijsolstr.2016.01.022http://dx.doi.org/10.1016/j.ijsolstr.2016.01.022http://www.sciencedirect.com/http://www.sciencedirect.com/http://www.elsevier.com/locate/ijsolstrhttp://www.elsevier.com/locate/ijsolstrmailto:[email protected]:[email protected]://dx.doi.org/10.1016/j.ijsolstr.2016.01.022http://dx.doi.org/10.1016/j.ijsolstr.2016.01.022mailto:[email protected]://crossmark.crossref.org/dialog/?doi=10.1016/j.ijsolstr.2016.01.022&domain=pdfhttp://www.elsevier.com/locate/ijsolstrhttp://www.sciencedirect.com/http://dx.doi.org/10.1016/j.ijsolstr.2016.01.022
  • 7/26/2019 A Generalized Theory of Elastodynamic Homogenization for Periodic Media 2016 International Journal of Solids and

    2/8

    140 H.Nassaretal./InternationalJournalofSolidsandStructures84(2016)139146

    standpoint,thisleadstoacleardistinctionbetweenthemacroscale

    andthemicroscaleintermsofwavelengths.Nevertheless,itshould

    bepointedoutthatthegeneralizedtheorypresentedhereisby

    construction limited toperiodically inhomogeneousmediawhile

    Willistheoryisformallyvalidbothforperiodicallyandrandomly

    inhomogeneousmedia.

    Thepaperisorganizedasfollows.InSection2,werecallsome

    geometricalelementsusefulfordescribingperiodicmedia,summa-

    rize

    the

    equations

    governing

    the

    kinematics

    and

    dynamics

    of

    them,

    andsimplifytheseequationsbyusingBloch-waveexpansions.The

    mainbodyofthegeneralizedtheoryispresentedinSection3.The

    EEPisfirstpostulated;thespaceofadmissiblebodyforcesisthen

    definedasthesetofmacroscopicallyappliedloadings;theeffec-

    tivedisplacementfieldassociatedtoamicroscopicdisplacementis

    obtainedbytheEEPandproventobeanimprovementoverthe

    onedefinedbyWillis;theeffectivemotionequationisfinallyde-

    rivedinaformalwayandaHilMandelrelationisdemonstrated.

    InSection4,ananalyticalLW-LFasymptoticapproximationtothe

    effectivemotionequationisgivenforaparticular1Dtwo-phase

    string.Exactandapproximatedispersioncurvesareplottedand

    compared. Itappears thenhow the resultingasymptoticmodel,

    thoughbasedonLFexpansions,cansimultaneouslycaptureacous-

    ticandopticalbrancheswhileconservingalow-orderlocalmotion

    equation.

    2.Preliminaries

    Inthissection,somegeometricalelementsusefulforthestudy

    ofperiodicmediaarerecalled.Thegoverningequationsoflinear

    elasticityare recapitulated.Bloch-waveexpansionsoffieldsand

    workarealsointroduced.

    2.1.Geometryandperiodicity

    Let bead-dimensionalinfinitebody.DefineE asthevector

    spaceoftranslationsactingonthepointsof.Givendindepen-

    dent

    translations

    (b

    j

    )

    j=1

    ...

    d

    ,

    denote

    byR

    the

    subset

    ofE

    obtained

    byintegercombinationsofthesevectors.ThesubsetR iscalled

    alattice.Then,ascalar,vectorortensorfieldhdefinedover is

    saidtobeR-periodicifandonlyifitsatisfiesh(x+r)=h(x)forallpointsx andalltranslationsrR.Accordingly,hneedsbeingdefinedonlyoveraunitcell

    T=

    xo+r

    r= dj=1

    rjbj,1/2rj

  • 7/26/2019 A Generalized Theory of Elastodynamic Homogenization for Periodic Media 2016 International Journal of Solids and

    3/8

    H.Nassaretal./InternationalJournalofSolidsandStructures84(2016)139146 141

    WenowassumethatCand areR-periodicsothatthesolutionuk

    (x)canbewrittenas

    uk

    (x)=uk

    (x)eikx

    withanR-periodicamplitude uk

    (x

    )(Gazaletetal.,2013).Inother

    words,totheexpansion(2.2),therecorrespondsasimilarBloch-

    waveexpansionofthesolutionto(2.1):

    u(x)=

    Tuk(x)dd

    k=

    Tuk(x)ei

    kxdd

    k, (2.3)

    withuk

    (x)beingthedisplacementfieldover subjectedtofk

    (x).

    Incontrast,exceptforahomogeneousbody,therearenosimilar

    resultsforplanewaves.

    Given theBloch-wave formofuk

    ,andsimplifying thephase

    factoreik x,themotionequationbecomes,intermsof uk(x)andfk

    (x),

    (+ik) {

    C(x):[

    (+ik)suk

    (x)]

    }

    +fk

    (x)=2(x) uk

    (x).

    (2.4)

    Last, thex-dependenciesofBloch amplitudes fordisplacements

    and body forces were explicitly annotated. In what follows, all

    fieldsareunderstoodtobex-dependentunlessotherwisestated.

    2.4.Externalwork

    Define the virtualworkofexternal body forcesf associated

    withavirtualdisplacementfielduby

    f

    u

    whereasuperscripted denotescomplexconjugation.Also,intro-ducetheaveragingoperatorby

    h

    = 1|

    T|

    T

    h(x)ddx

    for all R-periodic functions h. Note that is independent ofthe choiceofT and is ill-defined fornon-R-periodic functions.

    PlancherelsidentityforFouriertransformandParsevalsidentity

    forFourierseriesdeliverthenasimilaridentityforBloch-waveex-

    pansions:

    f u=(2 )d

    T

    fk

    uk

    d

    dk

    =(2 )d

    |

    T|

    T

    T

    fk

    (x) uk

    (x)ddxddk. (2.5)

    Consequently,indefiningtheenergeticallyequivalenteffectivebe-

    havior,wecanworkwithfieldsofasingleBlochwavenumberkT andthenapplythesuperpositionprincipleeventhoughworkis

    quadratic

    and

    not

    linear.

    3.

    A

    general

    theory

    Inthissection,theenergyequivalencyprinciple(EEP),thecor-

    nerstoneofthepresentapproach,isfirstpostulated,givenasim-

    pleformandexploitedtodefinetheeffectivedisplacementfield.

    Aformalderivationoftheeffectivemotionequationisthenpre-

    sented.Theeffectiveconstitutivebehaviorisnonlocalinbothspace

    andtimewhichraisesquestionsaboutitsuniqueness(Fietzand

    Shvets,2010;Willis,2011). Inorder toavoid thisdifficulty,we

    willbeinterestedonlyintheeffectivemotionequationwhichis

    unique.Nonetheless,wewillderiveexpressions forthegeneral-

    izedstress,momentum,velocityandstrainmeasureswhichare,in

    particular,neededfordetermininganeffectiveconstitutivelaw.

    Fig.

    1.

    The

    effective

    displacement

    field

    D

    associated

    to

    a

    given

    microscopic

    one

    u

    is

    geometrically

    interpreted

    as

    the

    projection

    of

    the

    latter

    onto

    the

    space

    of

    admissible

    displacements.SpacesF andF areisomorphicand,here,aretakentobeequaluptoachangeinunits.

    3.1.Energyequivalency

    In classical static or quasi-static homogenization, an energy

    equivalencyrelation,knownasHillMandellemma,isprovenfora

    familyofboundaryconditionsprescribedonarepresentativevol-

    umeelementasmacroscopic loadings.Once theboundarycon-

    ditionshavebeenspecified,HillMandel lemmacanbeusedto

    define, by duality, the macroscopic stress in a strain-based ap-

    proachorthemacroscopicstraininastress-basedapproach.Inthe

    presentformulation,admissiblebodyforcesappliedgloballytoinsteadofboundaryconditionsaretakentobemacroscopicload-

    ing.Then,anEEPispostulatedsoastodualizebodyforcesand

    displacements.Thisdualitywillallowustodefinethemacroscopic

    displacementfield,calledD, in termsofthemicroscopiconeu,

    onceadmissiblebodyforceshavebeenimposed.

    LetF bethespaceofBlochamplitudes fk,involvedin(2.2),

    ofadmissiblebodyforces.TheelementsofFareseenasexternal

    loadingslikelytobeappliedto.Notethattheywillremainthe

    sameafterthescaletransition.ThespaceFactsasaparameterof

    theapproachtobeelaboratedandneedstobechosenadequately.

    Next,letF,thespacedualtoF,bethespaceofBlochampli-tudes Dk

    ofadmissibleeffectivedisplacementfields.Foragiven

    microscopicdisplacementfieldu,thecorrespondingeffective(or

    macroscopic)displacementfieldisdefinedastheuniqueadmissi-bledisplacementsuchthat

    fD=

    f u (3.1)

    foralladmissiblevirtualbodyforcesf(i.e., fkF,forallkT).Physically,theEEP(3.1)canbeinterpretedasrequiringthattheef-

    fectivedisplacementfieldDassociatedtoagivenmicroscopicfield

    ubesuchthattheworkdonebyeveryadmissiblevirtualbody

    forcefinthecourseofD isequaltotheonedonebyfinthe

    courseofu.Geometrically,theEEP(3.1)simplymeansthatDisthe

    projectionofuontothespaceofadmissibledisplacements(Fig.1).

    OnthebasisoftheEEP(3.1),ageneralizedHillMandellemmawill

    beproveninSection3.4.

    UsingtheBlochdecomposition(2.5),theEEP(3.1)canbeequiv-

    alentlywrittenintermsofBlochamplitudesas

    kT, fk

    F,fk

    Dk

    =fk

    uk

    . (3.2)

    3.2.Effectivedisplacementfield

    BearinginmindtheEEP(3.1),choosingthespaceFofadmis-

    siblebodyforcesbecomesakeysteptowardelaboratingageneral-

    izedtheory.ThechoiceofFdependsultimatelyonthedegreeof

    accuracywithwhichDisrequiredtoapproximateu.ThebiggerF

    is,thecloserDistou.Whenallbodyforcesareconsideredasad-

    missible,therelation(3.1)impliesD=uandtheeffectivemediumistriviallytheoriginalone.Inwhatfollows,westudytherather

    generalcaseofpracticalimportancewhereFisfinite-dimensional

    andshowhowDderivesfrom(3.1)correspondingly.

  • 7/26/2019 A Generalized Theory of Elastodynamic Homogenization for Periodic Media 2016 International Journal of Solids and

    4/8

  • 7/26/2019 A Generalized Theory of Elastodynamic Homogenization for Periodic Media 2016 International Journal of Solids and

    5/8

    H.Nassaretal./InternationalJournalofSolidsandStructures84(2016)139146 143

    Fig.2.Plotsoftherealpartsofthemicroscopic(u),Willis(U),andgeneralized(D)Blochdisplacementamplitudesoveroneperiodfor3eigenmodes:(k=0,=1

    (0))

    (top),(k=/2a,=2

    (/2a))(middle),(k=0,=2

    (0))(bottom).Twoshapefunctionshavebeenused:aconstantandasinewave.DetailsaregiveninSection4.

    3.2.4.Effectivedisplacementfieldunderinfinitescaleseparation

    ItisofinteresttoexaminewhatDbecomesunderthehypoth-

    esisofinfinitescaleseparation,namely,whenk

    0and

    0.

    Itisknownthatinthiscase,tothelowestorder,thedisplacementfielddependsonlyontheslowvariable (refertoBoutinandAu-

    riault,1993,forinstance).IntermsofBlochamplitudes,thismeans

    that ukisconstant.Consequently,

    Uk

    =

    uk

    =uk

    ,

    u

    k

    =

    uk= uk=0.Therefore,thetranslationalDOFUistheonlynon-nullcomponent

    ofD,tothelowestorder.Theuseofageneralizedkinematicsis

    hencejustifiedonlyunderweakscaleseparationorforhighfre-

    quencieswhenmicroscopicdeformationmodesbecomesignificant.

    Otherwise,itisenoughtokeeptrackofUexclusivelyasintheun-

    weightedWillistheory.Asamatteroffact,ithasbeenobserved

    that

    a

    periodic

    medium

    was

    homogenizable in

    the

    Willis

    sense

    overtheacousticandthefirstopticalbranchesonly(Nassaretal.,

    2015b;SrivastavaandNemat-Nasser,2014).Forhigherfrequencies,

    oneneedstousenon-uniformshapefunctions.

    3.3.Effectivemotionequation

    Havingspecifiedbodyforces,themotionEq.(2.4)becomes

    (

    +

    i

    k)

    {

    C(x

    )

    :[

    (

    +

    i

    k)suk

    (x

    )]

    }

    +

    Fk

    +

    f

    k

    (x

    )(x)

    =2(x) uk

    (x

    ),

    whichneeds tobe solvedover.Since uk

    isR-periodic, it is

    enoughtosolvetheaboveequationoveraunitcellTunderpe-

    riodicboundaryconditions.Letgkbethecorrespondingperiodic

    secondorderGreenoperator.Then,

    uk

    (y)

    =

    1

    T

    T

    gk

    (y,x)

    fk

    (x)ddx

    =

    1

    T

    Tgk

    (y,x)ddx

    Fk

    +

    1

    T

    Tgk

    (y,x) ddx

    f

    k

    (3.7)

    which,combinedwith(3.5),deliversthefollowingexpressionsfor

    thecomponentsofthemacroscopicdisplacementfield:

    Uk

    =gk

    (y,x) Fk

    +gk

    (y,x) (x) fk

    ,

    u

    k

    =(y)gk

    (y,x)

    Fk

    +(y)gk

    (y,x) (x)

    f

    k

    ,(3.8)

    wheremeansaveragingwithrespecttobothxandy.TheGreenoperatoroftheeffectivemediumGkisgivenbythe

    lasttwoequalitieswhichcanbewrittenconciselyas

    u

    j

    k

    =G

    ji

    k

    f

    i

    k

    ,

    wherenodistinctionismadebetweentheclassicalandgeneralized

    DOFs(recallthat Uk

    =

    dj=1

    ujk

    j).Invertingtheprecedingequa-tiondeliverstheeffectivemotionequationinFourierdomain:

    Z

    i jk

    u

    jk

    = fik

    , (3.9)

    whereZk,theinverseofGk,iscalledtheeffectiveimpedance.It

    dependsimplicitlyonthefrequency.BysummingoverkTandover,weobtaintheeffectivemotionequationinxandtas

    Z

    i j(x,t) uj(x,t)=fi(x,t),

    whereZ(x,t)isanintegro-differentialoperatorand denotescon-volutionproductwithrespecttospaceandtime.Theeffectivemo-

    tionequationishencenonlocal inbothspaceandtimeand in-

  • 7/26/2019 A Generalized Theory of Elastodynamic Homogenization for Periodic Media 2016 International Journal of Solids and

    6/8

    144 H.Nassaretal./InternationalJournalofSolidsandStructures84(2016)139146

    volveslongwavelengths(kT)only.Thisgeneralizesequation(3.28)derivedbyWillis(1997)forperiodicmedia.

    3.4.Internalwork

    Asmentionedearlier,itisnotessentialforachievingthemain

    purposeofthepresentworktoderiveanexplicitexpressionfor

    theunderlyingeffectiveconstitutive lawwhichisnotuniqueas

    in thetheoryofWillis.However, it isof interesttospecifythemacroscopicstress,momentum,strainandvelocitymeasuresthat

    aneffectiveconstitutivelawinvolves.Inaddition,thesegeneralized

    macroscopicmeasureswillbeshowntoberelatedtotheirmicro-

    scopiccounterpartsthroughanextendedHillMandelrelation.

    3.4.1.Generalizedstressandmomentummeasures

    Saidmeasuresaretakentobetheonesinvolvedintheeffective

    motionequationwrittenasaconservationlawequivalentto(3.9).

    Startingwiththemicroscopicmotionequation

    (+ik) k

    +Fk

    +fk

    =i pk

    , (3.10)

    where kand pkaretheBlochamplitudesofstressandmomen-tum,wetakeitsvolumeaverageoveraunitcelltoobtain,with

    thehelpofthedivergencetheorem,

    ik k

    +Fk

    =i Pk

    . (3.11)

    Thisisthefirsteffectivemotionequationinvolvingtheclassical

    macroscopicstressandmomentummeasures:

    k

    k

    , Pk

    pk

    .

    Further,projectingEq.(3.10)ontothespacespannedbytheother

    shapefunctions givesriseto

    ik k

    s

    :k

    +f

    k

    =i pk

    ,

    where,forsimplicity,wehaveassumedthecontinuityof sothattheboundarytermvanishes.Thegeneralizedstressandmo-

    mentummeasurescanbeidentifiedas

    k

    k

    , s

    k

    s

    :

    k

    , p

    k

    pk

    .

    Theadditionalmotionequationbecomesthensimply

    s

    k

    +

    i

    k

    k

    +

    f

    k

    =

    i

    p

    k

    . (3.12)

    NotethatEqs.(3.11)and(3.12)ononehand,and(3.9)ontheother,

    arerelatedtooneanotherthroughanon-uniqueeffectiveconsti-

    tutive lawwhosecharacterization isbeyond thepurposeof the

    presentwork(seethediscussionbyWillis,2011,2012).

    In summary, the motion equations in the spacedomain are

    givenby

    +F

    =

    iP,

    s

    +

    +f =ip . (3.13)

    Theseequationsareamicromechanicalversionoftheequations

    ofequilibrium phenomenologicallyderivedbyGermain(1973).

    3.4.2.Generalizedstrainandvelocitymeasures

    Saidmeasuresareobtainedbyduality.Thevirtualworktheo-

    remcombinedwiththeEEPyieldsk

    :

    k

    pk

    vk

    =

    fk

    u

    k

    =

    Fk

    U

    k

    +

    f

    k

    u

    k

    ,

    where kandvkaretheBlochamplitudesofthestrainandveloc-ityfields,respectively,givenby

    k

    =(

    +

    ik)

    s

    uk

    , vk

    =

    i uk

    .

    Fig.3.Unitcell.

    Substitutingbodyforcesbythecorrespondingstressandmo-

    mentummeasuresaccordingto(3.12)delivers

    k:

    k

    p

    k

    vk

    = k:(iksUk) Pk (i Uk)+

    k

    (i

    k

    u

    k

    )

    p

    k

    (i

    u

    k

    )

    s

    k

    u

    k

    .

    Summingoverk,andusingPlacherelsidentity,weobtainagener-

    alizedversionoftheHillMandellemma:

    {

    :p v}

    =

    {

    :(sU)P (iU)

    + (u)p(iu) su}

    .(3.14)

    Thisresult isvalid forallvirtualcouples (,p)equilibratedbyanadmissiblebodyforcefieldandforallcouples(,v)derivedfromanarbitrarydisplacementfieldu.Fromtheaboverelation,

    weidentifytheclassicalmacroscopicmeasuresofstrainandve-

    locityassUandiUwhilethegeneralizedonesareu ,uandiu .

    Finally,theconstructedmacroscopicfieldsmeetthemostfun-damentalrequirementsforthemtobeinterpretedasstresses,mo-

    menta,strainsandvelocitiessincetheyrigorouslysatisfylocalbal-

    anceandcompatibilityequations.Nonetheless,howtophysically

    interpretandmeasurethesequantitiesinaprecisewayultimately

    dependsonthechosensetofshape functions.Moredetailsare

    giveninSection4.4regardingthisaspect.

    4.

    An

    application:

    high-frequency

    behavior

    through

    low-frequencyasymptotics

    At this point, we have generalized Willis theory by using

    enrichedkinematics to improve thequalityofapproximationof

    amicroscopicdisplacementubyamacroscopiconeD.Thecost

    is

    however

    the

    increasing

    complexity

    of

    the

    resulting

    effective

    motionequation.Anumericalprocedurededicatedtotheimple-

    mentationofWillis theoryorourpreviousone isquiteheavy,

    theeffectivebehaviorbeingnonlocalinbothspaceandtimewith

    infiniteradiiofinfluenceingeneral.

    Taylorasymptoticexpansionsprovideanefficientwaytoap-

    proximate thenonlocalbehaviorwitha localoneunderappro-

    priateassumptionsonkand.LW-LFexpansionshavethemainadvantageofonly requiring the solutionof staticproblemsbut

    presentthedisadvantageofbeinglimitedtotheLFbehavior.The

    purpose of this section is to show explicitly how generalizing

    Willistheorymakesitpossibletoextendthevaliditydomainof

    LW-LFexpansionstohigh-frequencybehavioroverasimple1Dex-

    ample.

    4.1.Setting

    Considertheperiodicallyinhomogeneousstringwhoseunitcell

    isdepictedinFig.3,anddefinetheshapefunction

    (x

    )=

    2

    sin(

    x/a)

    whichdescribestherapidlyoscillatingbodyforce

    f

    =

    F

    +

    q

    andwillcarrythenewDOF .ThemacroscopicdisplacementDthenreads

    D=U+with

    U=u, =u.

  • 7/26/2019 A Generalized Theory of Elastodynamic Homogenization for Periodic Media 2016 International Journal of Solids and

    7/8

  • 7/26/2019 A Generalized Theory of Elastodynamic Homogenization for Periodic Media 2016 International Journal of Solids and

    8/8

    146 H.Nassaretal./InternationalJournalofSolidsandStructures84(2016)139146

    homogenization theorywiththehigh-frequencyhomogeniza-

    tiontheorysuggestedbyDayaetal.(2002)andCrasteretal.

    (2010)andco-workers.

    5.Concludingremarks

    ThroughincorporatingnewkinematicalDOFs,thepresentwork

    hasproposedanelastodynamichomogenizationtheorygeneraliz-

    ing

    the

    one

    of

    Willis

    in

    the

    case

    of

    periodic

    media

    and

    reduc-

    ingtheerrorcommittedduringtheupscalingprocess,especially

    athighfrequencies.Inordertoillustratethepotentialofthepre-

    sentedtheory,ithasbeenshownthattheLW-LFasymptoticex-

    pansionoftheeffectivemotionequationiscapableofsimultane-

    ouslycapturing theacousticand thefirstopticalbranchof the

    microscopicdispersioncurveforasimple1Dmedium.

    Two problems remain open. The first concerns the effective

    elastodynamicconstitutivelawproducedbythegeneralizedtheory

    proposed.Inthispaper,toavoidthedifficultyrelatedtoitsnon-

    uniqueness,theeffectivemotionequationhasbeendirectlytreated

    andexploited.However, innumeroussituations,itisusefuland

    importanttoexplicitlyknowtheeffectiveelastodynamicconstitu-

    tivelaw.Thesecondproblemregardstheoptimalchoiceofshape

    functionsforwhichguidingcriteriaexistbutremainincomplete.

    References

    Andrianov,I.V.,Bolshakov,V.I.,Danishevskyy,V.V.,Weichert,D.,2008.Higherorderasymptotichomogenizationandwavepropagationinperiodiccompositemate-rials.ProceedingsoftheRoyalSocietyA:Mathematical,PhysicalandEngineer-ingSciences464,11811201.

    Antonakakis,T.,Craster,R.V.,Guenneau,S.,2014.Homogenisationforelasticpho-toniccrystalsanddynamicanisotropy.J.MechanicsPhys.Solids71,8496.

    Auriault,

    J.-L.

    ,

    Bonnet,

    G.

    ,

    1985.

    Dynamics

    of

    periodic

    elastic

    composites

    (Dynamique

    descompositeselastiquesperiodiques).ArchiwumMechanikiStosowanej37(4),269284.

    Auriault,J.-L.,Boutin,C.,2012.Longwavelengthinner-resonancecut-off frequenciesinelasticcompositematerials.Int.J.SolidsStruct.49(23-24),32693281.

    Bensoussan,A.,Lions,J.L.,Papanicolaou,G.,1978.Asymptoticanalysisforperiodicstructures.North-HollandPublishingCompany.

    Boutin,C.,Auriault,J.-L.,1993.Rayleighscatteringinelasticcompositematerials.Int.J.Eng.Sci.31(12),16691689.

    Boutin,C.,Rallu,A.,Hans,S.,2014.Largescalemodulationofhighfrequencywavesinperiodicelasticcomposites.J.Mech.Phys.Solids70,362381.

    Colquitt,D.J.,Craster,R.V.,Antonakakis,T.,Guenneau,S.,2014.Rayleigh-Blochwavesalongelasticdiffractiongratings.Proc.RoyalSoc.A:Math.Phys.Eng.Sci.471,20140465.

    Craster,R.V.,Kaplunov,J.,Pichugin,A.V., 2010.High-frequencyhomogenizationforperiodic

    media.

    Proc.

    Royal

    Soc.

    A:

    Math.

    Phys.

    Eng.

    Sci.

    466,

    23412362

    .

    Daya,E.,Braikat,B.,Damil,N.,Potier-Ferry,M.,2002.Continuummodelingforthemodulatedvibrationmodesoflargerepetitivestructures.ComptesRendusM-canique330,333338.

    Fietz,C.,Shvets,G.,2010.Current-drivenmetamaterialhomogenization.PhysicaB:

    Condensed

    Matt.

    405

    (14),

    29302934

    .

    Forest,S.,2006.Milieuxcontinusgnralissetmatriauxhtrognes.CollectionSciencesdeLaMatire.PressesdelEcoledesMines.

    Forest,S.,Sab,K.,1998.Cosseratoverallmodelingofheterogeneousmaterials.Me-chanicsRes.Commun.25(4),449454.

    Gazalet,J.,Dupont,S.,Kastelik,J.C.,Rolland,Q.,Djafari-Rouhani,B.,2013.Atuto-rialsurveyonwavespropagatinginperiodicmedia:electronic,photonicandphononiccrystals.PerceptionoftheBlochtheoreminbothrealandFourierdo-mains.

    Wave

    Motion

    50

    (3),

    619654

    .

    Germain,P.,1973.Themethodofvirtualpowerincontinuummechanics.Part2:Microstructure.SIAMJ.Appl.Math.25(3),556575.

    Nassar,H.,He,Q.-C.,Auffray,N.,2015a.Onasymptoticelastodynamichomogeniza-tionapproachesforperiodicmedia.J.Mech.Phys.Solids(Submitted).

    Nassar,

    H.

    ,

    He,

    Q.-C.

    ,

    Auffray,

    N.

    ,

    2015b.

    Willis

    elastodynamic

    homogenization

    theory

    revisitedforperiodicmedia.J.Mech.Phys.Solids77,158178.Nolde,E.,Craster,R.V.,Kaplunov,J.,2011.Highfrequencyhomogenizationforstruc-

    turalmechanics.J.Mech.Phys.Solids59(3),651671.Qur,Y.,1988.Physiquedesmatriaux:coursetproblmes.XEcolePolytechnique.

    EditionMarketing.Sanchez-Palencia,

    E.

    ,

    1980.

    Non-homogeneous

    media

    and

    vibration

    theory.

    Springer-

    Verlag.Smyshlyaev,V.P.,2009.Propagationand localizationofelasticwaves inhighly

    anisotropicperiodiccompositesviatwo-scalehomogenization.Mech.Mater.41(4),434447.

    Smyshlyaev,V.P.,Cherednichenko,K.D.,2000.Onrigorousderivationofstraingra-dienteffectsintheoverallbehaviourofperiodicheterogeneousmedia.J.Me-chanicsPhys.Solids48,13251357.

    Srivastava,A.,Nemat-Nasser,S., 2014.Onthelimitandapplicabilityofdynamicho-mogenization.WaveMotion51(7),10451054.

    Willis,J.R.,1997.Dynamicsofcomposites.In:Suquet,P.(Ed.),ContinuumMicrome-chanics.Springer-VerlagNewYork,Inc.,pp.265290.

    Willis,

    J.R.

    ,

    2011.

    Effective

    constitutive

    relations

    for

    waves

    in

    composites

    and

    meta-

    materials.Proc.RoyalSoc.A:Math.Phys.Eng.Sci.467(2131),18651879.Willis,J.R.,2012.Theconstructionofeffectiverelationsforwavesinacomposite.

    ComptesRendusMcanique340(4-5),181192.

    http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0001http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0002http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0002http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0002http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0002http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0002http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0002http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0002http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0002http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0002http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0002http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0002http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0002http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0002http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0002http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0002http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0002http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0002http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0002http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0002http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0002http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0002http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0002http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0002http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0002http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0002http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0002http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0002http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0002http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0002http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0002http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0002http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0002http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0002http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0002http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0002http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0002http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0002http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0002http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0003http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0004http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0004http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0004http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0004http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0004http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0004http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0004http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0004http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0004http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0004http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0004http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0004http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0004http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0004http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0004http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0004http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0004http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0004http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0004http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0004http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0004http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0004http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0004http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0004http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0004http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0004http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0005http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0006http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0007http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0007http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0007http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0007http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0007http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0007http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0007http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0007http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0007http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0007http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0007http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0007http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0007http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0007http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0007http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0007http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0007http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0007http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0007http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0007http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0007http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0007http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0007http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0007http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0007http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0007http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0007http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0007http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0007http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0007http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0007http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0007http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0007http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0007http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0008http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0009http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0009http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0009http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0009http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0009http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0009http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0009http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0009http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0009http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0009http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0009http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0009http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0009http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0009http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0009http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0009http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0009http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0009http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0009http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0009http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0009http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0009http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0009http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0009http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0009http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0009http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0009http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0009http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0010http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0011http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0011http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0011http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0011http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0011http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0011http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0011http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0011http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0011http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0011http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0011http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0011http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0011http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0011http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0011http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0011http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0011http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0011http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0011http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0011http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0011http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0011http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0011http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0011http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0011http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0011http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0011http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0011http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0011http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0011http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0011http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0011http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0012http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0012http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0012http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0012http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0012http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0012http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0012http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0012http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0012http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0012http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0012http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0012http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0012http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0012http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0012http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0012http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0012http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0012http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0012http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0012http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0012http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0012http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0012http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0012http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0012http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0012http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0012http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0012http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0012http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0012http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0012http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0012http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0012http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0012http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0013http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0014http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0015http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0015http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0015http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0015http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0015http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0015http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0015http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0015http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0015http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0015http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0015http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0015http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0015http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0015http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0015http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0015http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0015http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0015http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0015http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0015http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0015http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0015http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0015http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0015http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0015http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0015http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0015http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0015http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0015http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0015http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0015http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0015http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0015http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0015http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0015http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0015http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0015http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0015http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0015http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0015http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0015http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0015http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0016http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0017http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0018http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0019http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0020http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0020http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0020http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0020http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0020http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0020http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0020http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0020http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0020http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0020http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0020http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0020http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0020http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0020http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0020http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0020http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0020http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0020http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0020http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0020http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0020http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0020http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0020http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0020http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0020http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0020http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0021http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0021http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0021http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0021http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0021http://refhub.elsevier.com/S0020-7683(16)00044-5/sbref0021http://refhub.elsevier.com/S0020-7683(16)000