1
Advances in Soil Physical Advances in Soil Physical Measurements at Measurements at
DecagonDecagon
Colin Campbell, Ph.D.Colin Campbell, Ph.D.
IntroductionIntroduction
Areas of focus Areas of focus Water ContentWater Content
Making more robust water content measurementMaking more robust water content measurementInclude electrical conductivity (EC) and temperature measurementInclude electrical conductivity (EC) and temperature measurement in in a single probea single probeImproved Improved dataloggingdatalogging capabilitiescapabilities
Thermal PropertiesThermal PropertiesDevelop Thermal and Electrical Conductivity Probe (TECP) for Develop Thermal and Electrical Conductivity Probe (TECP) for NASA Phoenix 2007 mission to MarsNASA Phoenix 2007 mission to MarsKDKD--2 Pro 2 Pro –– Thermal conductivity, diffusivity, heat capacityThermal conductivity, diffusivity, heat capacity
InfiltrationInfiltrationInexpensive hydraulic conductivity measurementInexpensive hydraulic conductivity measurement
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Water Content MeasurementWater Content Measurement
ECHECH22O dielectric sensorO dielectric sensorProblemProblem
Temperature sensitivity Temperature sensitivity FineFine--textured soilstextured soilsModerate to high salinitiesModerate to high salinities
Salt sensitivitySalt sensitivityCalibration shift due to increasing electrical conductivity (EC)Calibration shift due to increasing electrical conductivity (EC)
Reduced sensitivity at high water contentsReduced sensitivity at high water contents
Cause?Cause?ECHECH22O circuitry currently runs at ~10 MHzO circuitry currently runs at ~10 MHzLow measurement frequency may lead to the problems aboveLow measurement frequency may lead to the problems above
BackgroundBackground
Conventional wisdomConventional wisdomIncreasing measurement frequency decreases:Increasing measurement frequency decreases:
Sensitivity to soil salinitySensitivity to soil salinitySensitivity to temperature fluctuationsSensitivity to temperature fluctuationsRequirement for individual soil calibrationRequirement for individual soil calibration
Literature suggested different oscillator frequenciesLiterature suggested different oscillator frequencies50 MHz (Campbell et al., 1988)50 MHz (Campbell et al., 1988)300 MHz? (Or, 2003)300 MHz? (Or, 2003)
Based on network analyzer analysis for temperature and salinity Based on network analyzer analysis for temperature and salinity (dielectric (dielectric loss)loss)
>500 MHz (>500 MHz (KellenersKelleners et al., 2004)et al., 2004)Based on network analyzer Based on network analyzer Looked at dielectric loss in extreme soil (Looked at dielectric loss in extreme soil (bentonitebentonite))Did not include temperatureDid not include temperature
3
BackgroundBackground
Development constraintsDevelopment constraintsFrequency cannot be increased indefinitely without Frequency cannot be increased indefinitely without problemsproblems
Scientific: Increases in dielectric dispersion >500 MHzScientific: Increases in dielectric dispersion >500 MHzPractical: Higher measurement frequency often increase Practical: Higher measurement frequency often increase probe costprobe cost
ObjectiveObjective
ObjectiveObjectiveRefine ECHRefine ECH22O technology to:O technology to:
Reduce temperature and electrical conductivity (EC) Reduce temperature and electrical conductivity (EC) sensitivity sensitivity Maintain or improve accuracy, affordability, and Maintain or improve accuracy, affordability, and robustnessrobustness
4
Methods Methods –– HardwareHardware
ECHECH22O CircuitryO CircuitryChanged circuitry to measure in a Changed circuitry to measure in a range from 5 to 150 MHzrange from 5 to 150 MHz
Probe designProbe designMain focus on new, small probesMain focus on new, small probes
Two typesTwo typesECHECH22O TEO TE
HH22O, electrical O, electrical conductivity, temperatureconductivity, temperature
ECHECH22O 5O 55 cm long ECH5 cm long ECH22O probeO probe
Sensor dimensions are the same Sensor dimensions are the same for both probesfor both probesUse the same circuitry to measure Use the same circuitry to measure water contentwater content
Methods Methods –– Hardware (Continued)Hardware (Continued)
Existing probesExisting probesECHECH22O 20 cm probeO 20 cm probe
Problems with increasing the Problems with increasing the frequencyfrequency
ECHECH22O 10 cm probeO 10 cm probeNo problems increasing frequencyNo problems increasing frequencyFunctioned similarly to the shorter Functioned similarly to the shorter probesprobes
5
Methods Methods –– MeasurementsMeasurements
Testing water content sensitivity to ECTesting water content sensitivity to ECSolutionSolution
0.002 to 8 0.002 to 8 dSdS mm--11
Solutions were made using granular fertilizerSolutions were made using granular fertilizerReadings were normalized on 1 Readings were normalized on 1 dS/mdS/m to interpret datato interpret data
Substrate Substrate RockwoolRockwool
Used to grow crops in hydroponics (greenhouses) Used to grow crops in hydroponics (greenhouses) 0.5 to 8 0.5 to 8 dSdS mm--11
SoilSoilSand, sandy loam, silt loam, claySand, sandy loam, silt loam, clay
0.1 to 8 0.1 to 8 dSdS mm--11
Based on saturation extractBased on saturation extract
Methods Methods –– MeasurementsMeasurements
TemperatureTemperatureTemperature chamberTemperature chamber
Sinusoidal temperature cycles: 5 to 45 CSinusoidal temperature cycles: 5 to 45 CResponse in air (circuitry temperature Response in air (circuitry temperature dependence)dependence)Response in four different media (3 Response in four different media (3 salinities)salinities)
Soil: dune sand, sandy loam, silt loam, claySoil: dune sand, sandy loam, silt loam, clay
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ECEC--5 Response to EC using Several 5 Response to EC using Several Measurement Frequencies Measurement Frequencies
0.8
0.9
1
1.1
1.2
1.3
1.4
0 1 2 3 4 5 6Probe Measured EC (Probe Output)
Mea
sure
d S
olut
ion
Wat
er C
onte
nt
(m3 m
-3)
10 MHz 50 MHz 80 MHz 77 MHzECHO TE (66 MHz)
ECHECH22O 10 cm Probe Response to O 10 cm Probe Response to EC at Several Frequencies EC at Several Frequencies
0.9
0.95
1
1.05
1.1
0 1 2 3 4 5 6Solution Electrical Conductivity (dS/m)
Nor
mal
ize
Prob
e ou
tput
(mV/
mV)
55 MHz
65 MHz
75 MHz
Standard EC-10
7
Evaluation of ECEvaluation of EC--5/ECH5/ECH22O TE in O TE in RockwoolRockwool
Higher frequencies reduced sensitivity to high Higher frequencies reduced sensitivity to high ECECIncreasing frequency beyond ~65 MHz does not Increasing frequency beyond ~65 MHz does not appear to decrease sensitivity furtherappear to decrease sensitivity further
Measurement in Measurement in RockwoolRockwool (EC(EC--5)5)Standard Measurement FrequencyStandard Measurement Frequency
Water Content vs. Probe Output for 6 MHz (Standard Frequency) Probe
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
300 400 500 600 700 800 900 1000 1100
Probe Output (mV)
Wat
er C
onte
nt (m
3/m
3)
5.02 dS/m2.52 dS/m1.07 dS/m0.497 dS/m0.025 dS/m0.002 dS/m
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RockwoolRockwool (EC(EC--5): 72 MHz5): 72 MHz
Water Content vs. Probe Output for 72 MHz Probe
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
500 550 600 650 700 750 800 850 900 950 1000
Probe Output (mV)
Wat
er C
onte
nt (m
3/m
3)
5.02 dS/m
2.52 dS/m
1.07 dS/m0.497 dS/m
0.025 dS/m
RockwoolRockwool (EC(EC--5): 93 MHz5): 93 MHz
Water Content vs. Probe Output for 93 MHz Probe
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
300 400 500 600 700 800 900 1000
Probe Output (mV)
Wat
er C
onte
nt (m
3/m
3) 5.02 dS/m2.52 dS/m1.07 dS/m0.497 dS/m0.025 dS/m0.002 dS/m
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RockwoolRockwool with ECHwith ECH22O TE: 33 MHzO TE: 33 MHz(New Circuit Gives Three Frequencies Simultaneously)(New Circuit Gives Three Frequencies Simultaneously)
33 MHz Frequency Curve
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
200 250 300 350 400 450 500 550 600 650 700
Probe Output (mV)
Vol
. Wat
er C
onte
nt (m
3/m
3)
1.0 dS/m1.37 dS/m2.74 dS/m4.09 dS/m5.9 dS/m8.0 dS/m
RockwoolRockwool with ECHwith ECH22O TE: O TE: 66 MHz66 MHz
66.5 MHz Frequency Curve
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
200 250 300 350 400 450 500 550 600
Probe Output (mV)
Vol.
Wat
er C
onte
nt (m
3/m
3)
1.0 dS/m1.37 dS/m2.74 dS/m4.09 dS/m5.9 dS/m8.0 dS/m
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RockwoolRockwool with ECHwith ECH22O TE: O TE: 133 MHz133 MHz
133 MHz Frequency Curve
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
150 200 250 300 350 400 450 500
Probe Output (mV)
Vol
. Wat
er C
onte
nt (m
3/m
3)
1.0 dS/m1.37 dS/m2.74 dS/m4.09 dS/m5.9 dS/m8.0 dS/m
Evaluation in Mineral SoilsEvaluation in Mineral Soils
We found similar result in mineral soils We found similar result in mineral soils compared to compared to rockwoolrockwool
Increasing frequency decreased EC sensitivity Increasing frequency decreased EC sensitivity considerably in coarse textured soilsconsiderably in coarse textured soils
Differences were not as apparent in fine textured soilsDifferences were not as apparent in fine textured soils
Also appeared to reduce need for individual Also appeared to reduce need for individual calibrationcalibration
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6 MHz ECH6 MHz ECH22O 10 cm in Dune SandO 10 cm in Dune Sand
0
0.05
0.1
0.15
0.2
0.25
300 400 500 600 700 800 900 1000
Probe Output (mV)
Wat
er C
onte
nt (m
3/m
3)Sand 0.16 dS/m Sand 0.65 dS/mSand 0.47 dS/mSand 2.2 dS/mSand 3.57 dS_mSand 7.6 dS/m
65 MHz ECH65 MHz ECH22O 10 cm in Dune SandO 10 cm in Dune Sand
0
0.05
0.1
0.15
0.2
0.25
450 500 550 600 650 700
Probe Output (mV)
Wat
er C
onte
nt (m
3/m
3)
Sand 0.16 dS/m Sand 0.65 dS/mSand 0.47 dS/mSand 2.2 dS/mSand 3.57 dS_mSand 7.6 dS/m
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ECHECH22O 10 cm Frequency O 10 cm Frequency Comparison for Silt LoamComparison for Silt Loam
6 MHz 65 MHz
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
300 400 500 600 700 800 900 1000Probe Output (mV)
Wat
er C
onte
nt (m
3/m
3)
Palouse Silt Loam 0.2 dS/mPalouse Silt Loam 0.35 dS/mPalouse Silt Loam 0.7 dS/mPalouse Silt Loam 1.5 dS/mPalouse Silt Loam 5.13 dS/m
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
450 500 550 600 650 700Probe Output (mV)
Wat
er C
onte
nt (m
3/m
3)
Palouse Silt Loam 0.2 dS/mPalouse Silt Loam 0.7 dS/mPalouse Silt Loam 1.5 dS/mPalouse Silt Loam 5.13 dS/m
Temperature SensitivityTemperature Sensitivity
Temperature sensitivity changed with increasing Temperature sensitivity changed with increasing measurement frequencymeasurement frequency
SandSandLow frequency: minimal correlation to temperatureLow frequency: minimal correlation to temperatureHigher frequency: negative correlation (as expected)Higher frequency: negative correlation (as expected)
The higher the frequency, more negative slopeThe higher the frequency, more negative slope
Silt Loam/ClaySilt Loam/ClayAs the texture becomes finer, correlation becomes more As the texture becomes finer, correlation becomes more positivepositiveLow frequencies are affected much more than high Low frequencies are affected much more than high frequencyfrequency
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ECEC--5 Output 5 Output vsvs Temperature in Sand Temperature in Sand (0.08 m(0.08 m33 mm--33 VWC)VWC)
84 MHz
560
600
640
680
720
0 10 20 30 40 50
Temperature (C)
Pro
be O
utpu
t (m
V)
6 MHz
0
40
80
120
160
200
0 10 20 30 40 50Temperature (C)
Pro
be O
utpu
t (m
V)
5.02 dS m-11.05 dS m-10.2 dS m-1
65 MHz
460
480
500
520
540
560
580
0 10 20 30 40 50
Temperature (C)
Pro
be O
utpu
t (m
V)
72 MHz
500
540
580
620
660
0 10 20 30 40 50
Temperature (C)
Pro
be O
utpu
t (m
V)
ECEC--5 Output 5 Output vsvs Temperature in Silt Temperature in Silt Loam (0.20 mLoam (0.20 m33 mm--33 VWC)VWC)
6 MHz
0
50
100
150
200
250
300
0 10 20 30 40Temperature (C)
Pro
be O
utpu
t (m
V)
5.53 dS m-11.5 dS m-10.2 dS m-1
65 MHz
550
560
570
580
590
600
610
0 10 20 30 40
Temperature (C)
Prob
e O
utpu
t (m
V)
72 MHz
600
610620
630
640
650660
670
0 10 20 30 40
Temperature (C)
Pro
be O
utpu
t (m
V)
80 MHz
600
620
640
660
680
700
0 10 20 30 40
Temperature (C)
Prob
e O
utpu
t (m
V)
14
ECEC--5 Output 5 Output vsvs Temperature in Temperature in Houston Black Clay (0.25 mHouston Black Clay (0.25 m33 mm--33 VWC)VWC)
6 MHz
0
100
200
300
400
0 10 20 30 40
Temperature (C)
Prob
e O
utpu
t (m
V)
1.5 dS m-10.7 dS m-10.2 dS m-1
65 MHz
550
590
630
670
710
0 10 20 30 40
Temperature (C)
Pro
be O
utpu
t (m
V)
72 MHz
600
620
640
660
680
700
720
0 10 20 30 40
Temperature (C)
Pro
be O
utpu
t (m
V)
80 MHz
600
620
640
660
680
700
720
0 10 20 30 40
Temperature (C)
Pro
be O
utpu
t (m
V)
ECHECH22O TE EC Measurement AnalysisO TE EC Measurement Analysis
Electrical Conductivity Evaluation of ECHO TE
0
2
4
6
8
10
0 2 4 6 8 10 12
ECHO TE Output
Actu
al E
C (d
S/m
)
15
ConclusionConclusion
Increasing measurement frequency appeared to Increasing measurement frequency appeared to improve or maintain measurement quality under all improve or maintain measurement quality under all conditionsconditions70 MHz appears to be a good choice measurement 70 MHz appears to be a good choice measurement frequencyfrequency
Low sensitivity to solution ECLow sensitivity to solution ECLow sensitivity to salinity in Low sensitivity to salinity in rockwoolrockwool and soiland soilLower sensitivity to temperature Lower sensitivity to temperature
Higher frequencies are somewhat attractive but did not Higher frequencies are somewhat attractive but did not show any superiority so far in our testsshow any superiority so far in our testsEC measurement appears to be very good EC measurement appears to be very good
New Em50 New Em50 DataloggerDatalogger
Decagon developed a new Decagon developed a new dataloggerdatalogger
Reads all current and future Reads all current and future probes as well as digital probes as well as digital sensorssensors
ECHO TEECHO TETemperature/Temperature/RelRel. Humidity. Humidity
Longer battery life, 1 MB Longer battery life, 1 MB storage, better sealed casestorage, better sealed case5 analog/digital ports, 5 analog/digital ports, dedicated comm. portdedicated comm. port
16
Thermal and Electrical Thermal and Electrical Conductivity Probe Conductivity Probe
(TECP): 2007 Phoenix (TECP): 2007 Phoenix Mission to MarsMission to Mars
Phoenix
BackgroundBackground
Working with JPL and NASA to develop Working with JPL and NASA to develop instrument for 2007 Phoenix Mission to Marsinstrument for 2007 Phoenix Mission to MarsPhoenix Mission: To look for possible indicators Phoenix Mission: To look for possible indicators of life, past or present, and scan the landing site of life, past or present, and scan the landing site for water ice, and potential habitatsfor water ice, and potential habitatsLocation: Northern polar regionsLocation: Northern polar regionsType: Lander (remains in one place)Type: Lander (remains in one place)
Phoenix
17
BackgroundBackground
TECP is a part of a instrument suite called MECA TECP is a part of a instrument suite called MECA (Microscopy, Electrochemistry and Conductivity (Microscopy, Electrochemistry and Conductivity Analyzer) Analyzer) MECA includes:MECA includes:
TECPTECPOptical microscopeOptical microscopeAtomic force microscopeAtomic force microscopeWet chemistry cellWet chemistry cell
Goal: Assess physical and chemical properties of Goal: Assess physical and chemical properties of Martian regolithMartian regolith
Phoenix
Phoenix LanderPhoenix LanderPhoenix
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Phoenix
TECP Constraints TECP Constraints
TECP must tolerate compressive load of 150N, and side TECP must tolerate compressive load of 150N, and side load of 50Nload of 50N
Robot arm must operate in preRobot arm must operate in pre--programmed routines, but wonprogrammed routines, but won’’t t apply more force than thisapply more force than thisTECP needles must be short and fat to withstand abuse TECP needles must be short and fat to withstand abuse
TECP needles must taper TECP needles must taper ≥≥ 0.08 radians 0.08 radians Robot arm can only guarantee this accuracy of linear insertionRobot arm can only guarantee this accuracy of linear insertionA cylindrical probe would result in voids around needle A cylindrical probe would result in voids around needle Result is a short (15 mm), thick, conical needleResult is a short (15 mm), thick, conical needle
Thermal: Must operate under any conditions when RA Thermal: Must operate under any conditions when RA expected to operate (165 expected to operate (165 –– 313K)313K)
Well beyond ratings of electronic componentsWell beyond ratings of electronic componentsIssues with thermal expansion of materialsIssues with thermal expansion of materials
Phoenix
Robot arm with scoopRobot arm with scoopRight: Polar Lander ArmRight: Polar Lander ArmLeft: Purposed Phoenix Left: Purposed Phoenix arm with TECP attachedarm with TECP attached
TECP
Cable
19
Phoenix
Phoenix
20
TECP CapabilitiesTECP Capabilities
Primary measurementsPrimary measurementsSoil temperatureSoil temperatureThermal propertiesThermal properties
Thermal conductivity (single needle technique)Thermal conductivity (single needle technique)Volumetric heat capacity (dual needle technique)Volumetric heat capacity (dual needle technique)
Dielectric permittivityDielectric permittivitySimilar to ECHSimilar to ECH22O circuitryO circuitry
Electrical Conductivity Electrical Conductivity Two probe, resistance methodTwo probe, resistance method
Secondary measurementsSecondary measurementsVapor PressureVapor PressureWind speedWind speed
Phoenix
TECP Physical DesignTECP Physical Design
Four conical metal sensing Four conical metal sensing needles mounted in plastic headneedles mounted in plastic head3 needles contain heater and 3 needles contain heater and thermocouplethermocouplePlastic head mounted to Al Plastic head mounted to Al electronics housing electronics housing –– also also interface with RA scoop wrist.interface with RA scoop wrist.Humidity sensor mounted on Humidity sensor mounted on electronics board electronics board –– open to open to atmosphereatmosphere
Phoenix
21
Design ExplanationDesign Explanation
Conical needlesConical needlesEnsure good regolith contact with +/Ensure good regolith contact with +/-- 5 5 0 0
insertion angleinsertion angleRequires modification of the infinite line heat Requires modification of the infinite line heat source model (ILHS)source model (ILHS)
Plastic (PEEK) headPlastic (PEEK) headComparatively low thermal (0.25 W mComparatively low thermal (0.25 W m--11 KK--11) ) and electrical conductivity, high strengthand electrical conductivity, high strengthThermal conductivity of head is still large Thermal conductivity of head is still large compared with minimum regolith conductivity compared with minimum regolith conductivity (0.03 W m(0.03 W m--11 KK--1)1)
Phoenix
Calibration and TestingCalibration and Testing
CalibrationCalibrationImpossible to calibrate sensors in all possible thermal Impossible to calibrate sensors in all possible thermal propertiespropertiesUse finite Element Analysis (FEA) modeling to derive Use finite Element Analysis (FEA) modeling to derive calibrationcalibration
CosmosWorksCosmosWorks 3D CAD thermal modeling program3D CAD thermal modeling programSimulate heat transfer through needles, regolith, and PEEK plastSimulate heat transfer through needles, regolith, and PEEK plasticicSave time and temperature data from any node in systemSave time and temperature data from any node in systemUse data to adjust models for deviations from infinite line heatUse data to adjust models for deviations from infinite line heatsource model (ILHS)source model (ILHS)
Use standards to validate calibrationUse standards to validate calibration
Phoenix
22
FEA ModelingFEA Modeling
Phoenix
Infinite Line Heat Source (ILHS) ModelInfinite Line Heat Source (ILHS) Model
Analytical solution for constant heat applied to infinitely Analytical solution for constant heat applied to infinitely long, zero mass heater over time:long, zero mass heater over time:
For heating:For heating:
For cooling: For cooling:
Using conical needles deviates from the analytical solutionUsing conical needles deviates from the analytical solution
Phoenix
1
2
044
tttkCrEi
kqT ≤<⎟⎟
⎠
⎞⎜⎜⎝
⎛ −−=∆
π
11
22
)(444tt
ttkCrEi
tkCrEi
kqT >⎥
⎦
⎤⎢⎣
⎡⎟⎟⎠
⎞⎜⎜⎝
⎛−
−+⎟⎟
⎠
⎞⎜⎜⎝
⎛ −−−=∆
π
23
Adjusting ILHS for Conical NeedlesAdjusting ILHS for Conical Needles
Still, adaptation by Still, adaptation by KluitenbergKluitenberg et al. for short, fat et al. for short, fat needles give an idea of the departure from the needles give an idea of the departure from the ideal (see ideal (see CobosCobos et al.)et al.)Thus, it is should be possible to develop Thus, it is should be possible to develop calibrations for the needle using ILHS approachcalibrations for the needle using ILHS approach
Phoenix
Developing TECP CalibrationDeveloping TECP Calibration
Fit curves using ILHS modelFit curves using ILHS modelUse MultiUse Multi--Stage Monte Carlo (MSMCO) method to Stage Monte Carlo (MSMCO) method to provide global search for best fitprovide global search for best fitEmploy Marquardt nonEmploy Marquardt non--linear least squares analysis to linear least squares analysis to find true local minimumfind true local minimum
Phoenix
24
Measurement and Curve fit in WaterMeasurement and Curve fit in Water
Phoenix
00.5
11.5
22.5
33.5
44.5
0 30 60 90 120
Time (s)
Tem
pera
ture
Ris
e (C
)
-0.1
-0.05
0
0.05
0.1
0.15
0.2
0.25
0 60 120 180
Time (s)
Tem
pera
ture
Ris
e (C
)
Temperature rise on single needle Temperature rise on needle 7 mm away
Results of Curve FitResults of Curve Fit
Curve fit using this technique is near perfect when Curve fit using this technique is near perfect when using both heating and cooling curvesusing both heating and cooling curves
But, as expected, values for thermal conductivity (k) But, as expected, values for thermal conductivity (k) and heat capacity (C) were not equal to correct valuesand heat capacity (C) were not equal to correct values
Requires application of fitting parameter model Requires application of fitting parameter model where actual k and C are assumed to be linear where actual k and C are assumed to be linear functions of the k and C fitting parameters from functions of the k and C fitting parameters from the single and dual needle fitsthe single and dual needle fits
Phoenix
25
Further Manipulation of Curve FitFurther Manipulation of Curve Fit
Fitting model to solve for Fitting model to solve for actualactual k and Ck and C
Where kfit(1) and Cfit(1) are from the curve fit of the Where kfit(1) and Cfit(1) are from the curve fit of the single needle data and kfit(2) and Cfit(2) are from the single needle data and kfit(2) and Cfit(2) are from the dual needle data dual needle data
Phoenix
)2(723.0)2(18.1)1(046.0)1(33.2708.0)2(016.0)2(048.0)1(056.0)1(820.0129.0
CfitkfitCfitkfitCCfitkfitCfitkfitk
+−−+−=−+++−=
Comparison of Measured vs. Actual Comparison of Measured vs. Actual k and Ck and C
Phoenix
3.191.904.3294.0050.0152.3623.21.92Sat. sand
4.180.585.5871.0220.4300.8894.180.60Water
4.180.585.6951.0840.4340.8884.180.60Water
2.680.284.5150.5721.8190.4342.810.282Glycerol
2.770.284.3680.5091.7330.4472.810.282Glycerol
0.110.0531.0990.2011.4680.1320.090.053AETB-8
0.100.0311.1550.1481.8490.0820.0630.033EPS
0.110.0341.1690.1501.8850.0830.0630.033EPS
pred. Cpred. kCfit(2)kfit(2)Cfit(1)kfit(1)Actual
CActual
K
26
Actual vs. Predicted k and CActual vs. Predicted k and CPhoenix
0.01
0.1
1
10
0.01 0.1 1 10
Actual Conductivity (W m-1 C-1)
Pred
icte
d C
ondu
ctiv
ity (W
m-1 C
-1)
0
1
2
3
4
5
0 1 2 3 4 5
Actual Heat Capacity (MJ m-3 C-1)Pr
edic
ted
Hea
t Cap
acity
(MJ
m-3 C
-1)
Thermal Conductivity Volumetric Heat Capacity
ConclusionsConclusions
Using MSMCO and Marquardt analysis produced Using MSMCO and Marquardt analysis produced near perfect fit of datanear perfect fit of datak and C values, although initially incorrect, can be k and C values, although initially incorrect, can be used to find actual values using a combination of used to find actual values using a combination of fitting parameters from the single and dual needle fitting parameters from the single and dual needle curvescurvesAccurate k and C values can be found from Accurate k and C values can be found from conical needles despite deviation from ILHS conical needles despite deviation from ILHS modelmodel
Phoenix
27
Implications to Commercial Thermal Implications to Commercial Thermal Properties ProbeProperties Probe
Integrated heating and cooling analysis into Integrated heating and cooling analysis into current KDcurrent KD--2 Thermal Properties Analyzer2 Thermal Properties AnalyzerDeveloping KDDeveloping KD--2 Pro 2 Pro
Three needle optionsThree needle optionsStandard needleStandard needleLarger needle (10 cm long and 2.5 mm diameter)Larger needle (10 cm long and 2.5 mm diameter)Dual needleDual needle
Utilize MSMCO and Marquardt in data analysisUtilize MSMCO and Marquardt in data analysis
Phoenix
Other Other Developments: Developments:
Inexpensive Inexpensive InfiltrometerInfiltrometer
28
BackgroundBackground
Decagon has build an inexpensive Decagon has build an inexpensive infiltrometerinfiltrometerfor several yearsfor several yearsLimited in several respectsLimited in several respects
One suction available per instrumentOne suction available per instrumentOnly three total suctions availableOnly three total suctions availableCanCan’’t replace porous plastic member on baset replace porous plastic member on baseDifficult to manufactureDifficult to manufacture
InfiltrometerInfiltrometer RedesignRedesign
Redesigned Redesigned infiltrometerinfiltrometer to fix to fix these problemsthese problems
Adjustable suction from 0.5 to 6 Adjustable suction from 0.5 to 6 cm of head on a single cm of head on a single instrumentinstrumentStainless steel porous membraneStainless steel porous membrane
Easy to replace, cleanEasy to replace, clean
Base comes off for easy fill of Base comes off for easy fill of instrumentinstrumentLarger infiltration area for more Larger infiltration area for more accurate resultsaccurate results
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Making a MeasurementMaking a Measurement•Fill upper chamber with water
•This only needs to be filled occasionally
•Set the suction
Making a MeasurementMaking a Measurement
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Questions?Questions?Phoenix