advances in soil physical measurements at...

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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


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

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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

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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

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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)


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)


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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)


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)

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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

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Thermal and Electrical Thermal and Electrical Conductivity Probe Conductivity Probe

(TECP): 2007 Phoenix (TECP): 2007 Phoenix Mission to MarsMission to Mars

Phoenix


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

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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

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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

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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

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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

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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


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

30

Questions?Questions?Phoenix

advances in soil physical measurements at...

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