new tools for measuring the reactivity of energetic...
TRANSCRIPT
![Page 1: New Tools for Measuring the Reactivity of Energetic Materialscoesdytse/NanoE-Workshop2008/Zachariah.pdf · Temperature (K) Al, AlO, Al2O O WO, WO2, WO3 Zn Total Gas Temperature (K)](https://reader035.vdocument.in/reader035/viewer/2022070711/5ecb4053737b35191326d3b4/html5/thumbnails/1.jpg)
New Tools for Measuring the Reactivity of Energetic Materials
L. Zhou, K. Sullivan, N. Piekiel, S. Chowdhury, M. R. Zachariah
www.enme.umd.edu/~mrz
Department of Mechanical EngineeringDepartment of Chemistry and Biochemistry
Support
![Page 2: New Tools for Measuring the Reactivity of Energetic Materialscoesdytse/NanoE-Workshop2008/Zachariah.pdf · Temperature (K) Al, AlO, Al2O O WO, WO2, WO3 Zn Total Gas Temperature (K)](https://reader035.vdocument.in/reader035/viewer/2022070711/5ecb4053737b35191326d3b4/html5/thumbnails/2.jpg)
6.80*10-24Reddy & Cooper, 1977
7.4*10-9 (for 10 nm rad. Particle) (not at 1200 C)
Campbell et, 1999 (MD)
5.45*10-21Oishi & Kingrey, 19608.41*10-27Reed & Wuensch, 1980
1.09*10-19Lessing & Gordon, 1977
Value at 1200 C, m2/sExpression of D, m2/sSource
)/543400(09.2 RTExpD −=
)/785840(104.6 1 RTExpD −×=
)/240768(109.1 12 RTExpD −×= −
)/608580(1066.2 2 RTExpD −×= −
Diffusion Coefficient of Oxygen in Alumina
Diffusion Coefficient of Al in Alumina
1.5*10-19 at 773 KGarcia-Mendez et al, 19801.2*10-8 (for 10 nm rad. particle) (not at 1000 K)
Campbell et, 1999 (MD)
4.1*10-35Gall & Lesage, 1994 Value at 1000 K, m2/sExpression of D, m2/sSource
)/849282(103.1 10 RTExpD −×=
Huge discrepancy in the transport properties in literature
![Page 3: New Tools for Measuring the Reactivity of Energetic Materialscoesdytse/NanoE-Workshop2008/Zachariah.pdf · Temperature (K) Al, AlO, Al2O O WO, WO2, WO3 Zn Total Gas Temperature (K)](https://reader035.vdocument.in/reader035/viewer/2022070711/5ecb4053737b35191326d3b4/html5/thumbnails/3.jpg)
1. New Ion-Mobility MethodsA. Ni OxidationB. Surface Energy of Zn
1. New “T-Jump Mass-Spectrometry” ApproachA. NitrocelluloseB. RDXC.High Nitrogen Organics
OUTLINE
We have new materials and materials classes, it thus stands to reason that we need new (EXPERIMENTAL) tools to study them.
Primary Question: What is the nature of nanoscale materials combustion.i.e. Architectures, Mechanisms and Scaling laws
![Page 4: New Tools for Measuring the Reactivity of Energetic Materialscoesdytse/NanoE-Workshop2008/Zachariah.pdf · Temperature (K) Al, AlO, Al2O O WO, WO2, WO3 Zn Total Gas Temperature (K)](https://reader035.vdocument.in/reader035/viewer/2022070711/5ecb4053737b35191326d3b4/html5/thumbnails/4.jpg)
How can we come to terms with the size dependence Issue ?
Characterizing Nanoparticles Using Ion-Mobility
• Prepare particles of known size,• Measure their size and mass, • Determine how it changes with time in a reacting system.
![Page 5: New Tools for Measuring the Reactivity of Energetic Materialscoesdytse/NanoE-Workshop2008/Zachariah.pdf · Temperature (K) Al, AlO, Al2O O WO, WO2, WO3 Zn Total Gas Temperature (K)](https://reader035.vdocument.in/reader035/viewer/2022070711/5ecb4053737b35191326d3b4/html5/thumbnails/5.jpg)
HVcarriergas Polydisperse
nanoparticles
Mono-Surface areaParticles
• A Differential Mobility Analyzer ( DMA) selects particles based on electrical mobility.
2
1
pp
drage
dEvelocitymobilityelectricalZ
FF
∝=≡
=
CHARGED
→← drage FF
70 nm Ag particles Deposited on Charged Substrate
Differential Ion-Mobility: Gas-phase Electrophoresis
![Page 6: New Tools for Measuring the Reactivity of Energetic Materialscoesdytse/NanoE-Workshop2008/Zachariah.pdf · Temperature (K) Al, AlO, Al2O O WO, WO2, WO3 Zn Total Gas Temperature (K)](https://reader035.vdocument.in/reader035/viewer/2022070711/5ecb4053737b35191326d3b4/html5/thumbnails/6.jpg)
Mass classified aerosol exit
Aerosol Particle Mass analyzer (APM)
Outer electrode
Z
Aerosol entrance
w
Inner electrode
r2r1High voltage
(Ehara et al., 1997)
Aerosol entrance
mr d r neEvetrue APMω π ρ ω2
32
6= =
Fundamental measurement of particle mass
High Voltage
qE
2ωmr
Another Approach: Measure Total Mass or Change in Total Mass
![Page 7: New Tools for Measuring the Reactivity of Energetic Materialscoesdytse/NanoE-Workshop2008/Zachariah.pdf · Temperature (K) Al, AlO, Al2O O WO, WO2, WO3 Zn Total Gas Temperature (K)](https://reader035.vdocument.in/reader035/viewer/2022070711/5ecb4053737b35191326d3b4/html5/thumbnails/7.jpg)
Nickel Nanoparticle Synthesis and Size-resolved Oxidation Kinetics Study
ωAPM
CPC
Computer
Neutralizer
Sintering Furnace~1100 oC
~ 25 - 1100 oC
Tube FurnaceIsothermal Reactor
Air 0.5 lpm
Electrostatic Particle Sampler
DM
A2
CO
Carry gas A
r
Dilution flow
Tube FurnaceIsothermal Reactor
~400oC~50oC
Ni(CO)4Nickel packed bed
DM
A1Ni particles 0.5 lpm
Neutralizer
![Page 8: New Tools for Measuring the Reactivity of Energetic Materialscoesdytse/NanoE-Workshop2008/Zachariah.pdf · Temperature (K) Al, AlO, Al2O O WO, WO2, WO3 Zn Total Gas Temperature (K)](https://reader035.vdocument.in/reader035/viewer/2022070711/5ecb4053737b35191326d3b4/html5/thumbnails/8.jpg)
-0.2
0
0.2
0.4
0.6
0.8
1
1.2
35 40 45 50 55 60
25oC 700oC1100oC500oC
Nor
mal
ized
Num
ber C
once
ntra
tion
Dp (nm)
Initial Size:40nm
-0.2
0
0.2
0.4
0.6
0.8
1
1.2
50 60 70 80 90
25oC 700oC1100oC500oC
Nor
mal
ized
Num
ber C
once
ntra
tion
Dp (nm)
Initial Size:62nm
-0.2
0
0.2
0.4
0.6
0.8
1
1.2
70 80 90 100 110 120
Nor
mal
ized
Num
ber C
once
ntra
tion
Dp (nm)
25oC 700oC1100oC500oC
Initial Size:81nm
-0.2
0
0.2
0.4
0.6
0.8
1
1.2
1 10-19 2 10-19 3 10-19 4 10-19 5 10-19
25oC
700oC
Mass (kg)
Nor
mal
ized
Num
ber C
once
ntra
tion
Initial Size:40nm
-0.2
0
0.2
0.4
0.6
0.8
1
1.2
4 10-19 8 10-19 1.2 10-18 1.6 10-18 2 10-18
25oC
700oC
Nor
mal
ized
Num
ber C
once
ntra
tion
Initial Size:62nm
Mass (kg)
-0.2
0
0.2
0.4
0.6
0.8
1
1.2
0 1 10-18 2 10-18 3 10-18 4 10
25oC
700oC
Nor
mal
ized
Num
ber C
once
ntra
tion
Mass (kg)
Initial Size:81nm
Tandem-DMA and DMA-APM ResultsD
MA
-APM
Tand
em-D
MA
![Page 9: New Tools for Measuring the Reactivity of Energetic Materialscoesdytse/NanoE-Workshop2008/Zachariah.pdf · Temperature (K) Al, AlO, Al2O O WO, WO2, WO3 Zn Total Gas Temperature (K)](https://reader035.vdocument.in/reader035/viewer/2022070711/5ecb4053737b35191326d3b4/html5/thumbnails/9.jpg)
0 200 400 600 800 1000 1200
40 nm62 nm81 nm96 nm
Ave
rage
Den
sity
(g/c
m3 )
Density of Ni
Density of NiO
Density of Ni2O
3
9
8
7
6
5
4
Temperature (oC)
from combination of both size ( TDMA) and mass change (DMA-APM)
The average density profile show a transition of Ni2O3 →NiO
Density
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1
10
100
30 40 50 60 70 80 90 100
400 oC
500 oC
600 oC
700 oC
y = 0.0079 * x^(1.6) R= 0.96
y = 0.011 * x^(1.3) R= 0.89
y = 0.058 * x^(0.71) R= 0.82
y = 0.0013 * x^(1.4) R= 1
Bur
n Ti
me
(s)
Dp (nm)
1
10
100
30 40 50 60 70 80 90100
400 oC
500 oC
600 oC
700 oC
y = 0.0013 * x^(1.5) R= 0.88
y = 0.00095 * x^(1.8) R= 0.87
y = 0.00018 * x^(2.4) R= 0.96
y = 0.0022 * x^(2) R= 1
ΔM
/Δt x
10-1
6 (g/s
)
Dp (nm)
Mass rate Burn time
Burning Rate and Times
Ni Particle oxidation does not follow D2 => more like D1.4
Consistent with Al nanoparticle ~ D1.6 Combustion Theory and Modeling (2006)
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Nickel Nanoparticle Oxidation Kinetics
Two different slopes show reaction regime and phase transition regime.
Smaller particles have smaller activation energy
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Effe
ctiv
e D
iffus
ion
Coe
ffici
ent c
m2 /s
ec
Nickel Nanoparticle Oxidation Kinetics
Kinetically Ni is more reactive than AlAlthough releases less energy
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Surface Energy Measurement of Nanocrystals
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Al + MO => Some Experimental Results
0.09330270.011116412.6Fe2O3
0.07037080.01483111.8WO3
0.38626492.126.152.6SnO2
0.35830404.218.472.9CuO
GasMol Frac
T Ad
(K)
Pressurizationrate
(psi/usec)
Rise Time
(usec)
PressureRise (psi)
Pressurization Rate = Func ( Gas, T , dP? )
-The experimental pressure rise seems to correlate with the equilibrium gas prediction.Note: Rise Time is Drastically Different between CuO andFe2O3.
![Page 15: New Tools for Measuring the Reactivity of Energetic Materialscoesdytse/NanoE-Workshop2008/Zachariah.pdf · Temperature (K) Al, AlO, Al2O O WO, WO2, WO3 Zn Total Gas Temperature (K)](https://reader035.vdocument.in/reader035/viewer/2022070711/5ecb4053737b35191326d3b4/html5/thumbnails/15.jpg)
0
1
2
3
4
5
0% 20% 40% 60% 80% 100%
% WO3 by mole
Nor
mal
ized
Pre
ssur
izat
ion
Rat
e
0.00
0.05
0.10
0.15
0.20
0.25
0% 20% 40% 60% 80% 100%
% WO3 by mole
Mol
e Fr
actio
n
3000
3200
3400
3600
3800
Tem
pera
ture
(K) Al, AlO, Al2O
OWO, WO2, WO3ZnTotal GasTemperature (K)
Al + WO3 + ZnO ZnO is a very poor oxidizer.
But when added as a minor component can enhance combustion.
High Zn vapor concentration.
In general however we employ bulk thermodynamic properties.
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Surface Energy and Nanocrystals
Surface energy and Nanocrystals:Surface energy plays an essential role in:- Melting- Coalescence- Evaporation and condensation.
Definition of surface energy:Surface energy is the energy required to create a unit area of new surface.
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So What ?
While there are many theoretical studies on surface energy, there are only a few studies that reported the measured surface energy of nanocrystals.
Most experimental surface energy data stems from surface tensionmeasurement in the liquid phase and then extrapolate to solid.
=> At best this would give a result for a amorphous solid, not a crystal. [Vitos, et al., Surf. Sci., 186, 1998]
Why us:Our capability to manipulate small particles on the fly offers the opportunity to extract the surface energy from solid nanocrystals.
![Page 18: New Tools for Measuring the Reactivity of Energetic Materialscoesdytse/NanoE-Workshop2008/Zachariah.pdf · Temperature (K) Al, AlO, Al2O O WO, WO2, WO3 Zn Total Gas Temperature (K)](https://reader035.vdocument.in/reader035/viewer/2022070711/5ecb4053737b35191326d3b4/html5/thumbnails/18.jpg)
Experiment to Measure Surface Energy of Zn Nanocrystal
ωAPM
HEPA
DM
A
Exhaust flow
Zn aerosol 0.5 lpm
Zn NC Generation FurnaceIsothermal Reactor
~ 250 - 400 oC
Evaporation FurnaceIsothermal Reactor
~550oC
CPC
Neutralizer
Computer
TSI Particle Sampler
Excess flow
Carrier gas Ar~ 1 lpm
Experimental system for Zn, generation, size selection by DMA,evaporation and subsequent mass analysis with the APM.
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TEM Images of Zn Nanocrystals
A. B.
C.
100nm mobility size Zn nanocrystals generated by condensation-evaporation method after DMA size selection
100nm
100nm
200nm
Basal planedepositionof Zn crystal
![Page 20: New Tools for Measuring the Reactivity of Energetic Materialscoesdytse/NanoE-Workshop2008/Zachariah.pdf · Temperature (K) Al, AlO, Al2O O WO, WO2, WO3 Zn Total Gas Temperature (K)](https://reader035.vdocument.in/reader035/viewer/2022070711/5ecb4053737b35191326d3b4/html5/thumbnails/20.jpg)
DMA-APM Measurement of Zn Nano-Crystal Evaporation
0
0.2
0.4
0.6
0.8
1
1.2
0.25 0.3 0.35 0.4 0.45
Room T250C275C300C325C350C375C400C
Nor
mal
ized
Num
ber C
once
ntra
tion
Particle Mass (fg)
Zn particle mass distributions for Zn evaporate at different temperatures
50 nm
For Zn, can detect a mass change < 0.01fg.
Uncertainty in precision for mass measurement ~ 2%
![Page 21: New Tools for Measuring the Reactivity of Energetic Materialscoesdytse/NanoE-Workshop2008/Zachariah.pdf · Temperature (K) Al, AlO, Al2O O WO, WO2, WO3 Zn Total Gas Temperature (K)](https://reader035.vdocument.in/reader035/viewer/2022070711/5ecb4053737b35191326d3b4/html5/thumbnails/21.jpg)
Onset Temperature of Evaporation
The onset temperature of evaporation is plotted against the inverse of theparticle size. The solid line is the least-squares fit to the experimental data
8
8.5
9
9.5
10
0 100 200 300 400 500
Part
icle
Mas
s (0
.1 fg
)
Temperature (C)590
600
610
620
630
640
650
0.006 0.008 0.01 0.012 0.014 0.016 0.018 0.02 0.022
y = 666.06 - 3537.1x R= 0.99
Ons
et te
mpe
ratu
re o
f eva
pora
tion
(K)
1/Dp (nm-1)
![Page 22: New Tools for Measuring the Reactivity of Energetic Materialscoesdytse/NanoE-Workshop2008/Zachariah.pdf · Temperature (K) Al, AlO, Al2O O WO, WO2, WO3 Zn Total Gas Temperature (K)](https://reader035.vdocument.in/reader035/viewer/2022070711/5ecb4053737b35191326d3b4/html5/thumbnails/22.jpg)
Kinetic Model
• Evaporation rate to the temperature dependent surface energy.
• Zn NC surface energies are calculated to be 11.2 and 16.1 J/m2
at 3750C and 350 0C, respectively.
2/11
)2()(
TkmppSv
dtdm
Bm
dm
πρα −
=
Where pd = vapor pressure of the condensing species given by Kelvin equation:
)4exp(RTd
Mpp sd ργ
=
The mass change rate of the Zn NC is given by:
Comparison of Kelvin effect calculatedfrom our data of surface energy for
Zn NC and reference data for bulk Zn
1
10
100
0 50 100 150 200
Particle Mobility Diameter
Pd/P
s
Surface energy=12J/m2
Surface energy=1J/m2
Particle Size (nm)
s
d
pp
1
10-
100-
Experimental surface energy
Bulk
0 50 100 150 200
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Developing a new type of Mass Spectrometry/Optical Emission to
study Ultra Fast Solid-State Reactions
Developing a new type of Mass Spectrometry/Optical Emission to
study Ultra Fast Solid-State Reactions
“T-Jump Mass Spectrometry”“T-Jump Mass Spectrometry”
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Develop new diagnostic tool to measure how new molecules fall apart and the chemical reaction times of energetic systems
A New Approach: T-Jump Mass Spectrometry/Optical Emission
I or RI or RI or R
Mass-Spec Optical Emission
Fine wire coated and rapidly heated
Basic Approach:
Coat wire with:• Organics, • Organics+ binder• Thermites,• Thermites + organics• Sputtered thin films• Etc.
Similar to Ed Dreizen
Photonsions
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T-Jump Wire Ignition
Example of heating rate of 105 C/s
Wire temperature determined by resistance.
Ignition temperature ~ 800 C
![Page 26: New Tools for Measuring the Reactivity of Energetic Materialscoesdytse/NanoE-Workshop2008/Zachariah.pdf · Temperature (K) Al, AlO, Al2O O WO, WO2, WO3 Zn Total Gas Temperature (K)](https://reader035.vdocument.in/reader035/viewer/2022070711/5ecb4053737b35191326d3b4/html5/thumbnails/26.jpg)
Positively charged ions accelerated by electric field move up in time of flight tube to the detector
Detector Oscilloscope Computer
Electron Gun
• Temperature Jump T1 ~15 ms (5 ms ~ 100 ms adjustable)
• Cycle Time T2 ~1 ms (up to 5 us)
• EI Ionization Time T3 ~5 us (50 ns to 12 us adjustable)
•Rise and Fall time ~10 ns
Temporal Mass-SpectrometryCan generate Multiple Mass Spectrum from a single heating event
![Page 27: New Tools for Measuring the Reactivity of Energetic Materialscoesdytse/NanoE-Workshop2008/Zachariah.pdf · Temperature (K) Al, AlO, Al2O O WO, WO2, WO3 Zn Total Gas Temperature (K)](https://reader035.vdocument.in/reader035/viewer/2022070711/5ecb4053737b35191326d3b4/html5/thumbnails/27.jpg)
Linear Motion Feedthrough
Electron gun
Flight-tube
Gate valve
Coated Platinum Filament
T-Jump Mass-Spectrometer
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0 10 20 30 40 50 60 70 80
T = 1.1 ms
T = 1.5 ms
T = 2.0 ms
T = 7.0 msT = 6.0 msT = 5.0 ms
T = 4.0 ms
T = 2.5 ms45
30
29
26
NO
T-Jump MS of Nitrocellulose
First:Mass 28 COMass 29 CHOMass 31 HNO Mass 45 HCO2
ThenMass 30 NOMass 46 NO2
NO2HNONO
HCO2
RO(NO)2 => RO + NO2RO + NO2 => ROO. + NOROO. => HCOO + R’
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0
2
4
6
8
-2 0 2 4 6 8 10
Experiment 1Peak 27Peak 28Peak 29Peak 30Peak 31Peak 32Peak 45Peak 46
Time (ms)
-0.5
0
0.5
1
1.5
2
2.5
3
-2 0 2 4 6 8 10
Experiment 3 Peak 27Peak 28Peak 29Peak 30Peak 31Peak 32Peak 45Peak 46
Peak
27
Time (ms)
Nitrocellulose: Effect of Heating Rate
Low Heating Rate
High Heating Rate
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400
600
800
1000
1200
1400
1600
0 10 20 30 40 50 60 70 8
Inte
nsity
(a.u
.)
m/z
0
200
400
600
800
1000
0 0.5 1 1.5 2 2.5 3
RDX Heating Temp
Tem
pera
ture
(deg
. C)
Time (ms)
1.0 ms
1.5 ms
2.0 ms
2.5 ms
RDX
Heating rate = 1.5 X105 C/s
Sample courtesy of R. Doherty, NSWC-IH
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N=N
CH2
42
Products Mass
NO2 46
NO,or CH2O 30
N2 or CH2N 28
H2CN
N OO
H75 or 74
RDX
or N=C=O
No evidence for:CH3NHONON2O
CHO from CH2O 29
HCN 27
120 ( also seen by Y.T. Lee)
56
(NO2)-NCH2-NO2 + = RDX – NO2
Large signal
Large signal
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+ 2 NO2
+
N2 + CH2
42CH2
CH2
CH2
74
CH2
O
Revised NO2 Dissociation PathwayRevised NO2 Dissociation Pathway
Goddard
R. Behren, Sandia will provide iosotopecally labeled RDX
![Page 34: New Tools for Measuring the Reactivity of Energetic Materialscoesdytse/NanoE-Workshop2008/Zachariah.pdf · Temperature (K) Al, AlO, Al2O O WO, WO2, WO3 Zn Total Gas Temperature (K)](https://reader035.vdocument.in/reader035/viewer/2022070711/5ecb4053737b35191326d3b4/html5/thumbnails/34.jpg)
N
N
N
N C
C
NO2
NO2
NO2
NH 2
CH
H 2H
1000
1200
1400
1600
1800
2000
0 10 20 30 40 50 60 70 80
1 ms
1.5 ms
2 ms
MIG-1
N
42
43
Sample provided byProf: Thomas KlapoetkeUniversity of Munich
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N
N
N
N
NNO2
H
H
800
1000
1200
1400
1600
1800
2000
0 10 20 30 40 50 60 70 80
0.7 ms
1 ms
1.5 ms
2 ms Sample provided byProf: Thomas KlapoetkeUniversity of Munich
4356
HN=NH + N2
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800
900
1000
1100
1200
1300
0 10 20 30 40 50 60 70 80
1.6 m s
2.0 m s
2.5 m s
btnm m oxam ide
46
42
45
28
29
30
31
32
18
Sample provided byProf: Thomas KlapoetkeUniversity of Munich
42
30
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SUMMARY• New material types ( nanoscale materials, new molecules) may under some circumstances require specialized tools to characterize their fundamental properties and reactive behavior.
• Ion-Mobility: Here we demonstrate its applicability to the reactivity and surface properties of nanoparticles.
• T-JUMP Mass-Spectrometry: Opportunity to probe the reaction dynamics at fast time scales.
SURGEON GENERALS WARNINGIn the absence of experimental validation a modeling result if repeated often enough becomes a fact.
SURGEON GENERALS WARNINGIn the absence of experimental validation a modeling result if repeated often enough becomes a fact.
Particularly as it relates to new materials the ability to use computation exceeds the capability to implement experiments to elucidate microscopic properties and details.