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Introduction

The TeKa Thermal Conductivity Meter (TK04) system determines thermal conductivity based on a transient heat flow method. A line source is heated with constant power, while source temperature is recorded simultaneously. Thermal conductivity is calculated from the resulting heating curve.

Both, whole-round sections and section halves could be measured. 

Procedures

  • Preparing Samples

A) Soft-Sediment Samples

  1. Equilibrate core sections to room temperature for at least 4 hr in the core rack before bringing a target section to the thermal conductivity workstation.
  2. Select measuring points in the core and record offset in cm (measured from the top - blue endcap).
    – Intact core: middle of section.
    – Cracked core: just above/below the middle.
  3. If measuring a whole-round section, use the cordless drill to drill a ~2 mm hole into the core liner on the line between the working and archive halves. If the sediment is semi-consolidated, drill a small hole in the sediment for the needle probe as well.
  4. Optional - Apply thermal joint compound to the probe unless the sample is very soft and/or moist.
  5. Carefully insert a clean full-space needle into the sediment. Avoid twisting the needle into the core (Figure 1a).
  6. If measuring a section-half, place the puck or mini-puck on a smooth place, avoiding cracks (Figure 1b). 
  7. Secure the puck to the sample with velcro or a rubber band.


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Figure 1.- Correct sensor position: (a) Needle on whole-round section, (b) Puck on section-half.

B) Hard-Rock Samples

  1. Place hard rock samples in an ambient temperature seawater bath to equilibrate and saturate (4–12 hr). Keep sample saturated until measurement. A bell jar/vacuum pump can aid in saturation.

    Note: Seawater bath is not necessary when using the mini-puck.

  2. If the surface of the split core is excessively rough, use a lap plate and grit from the Thin Section Lab to prepare a smooth surface on a split-core piece. Pieces must be at least 10 cm long.
  3. Equilibrate the sample and sensor together in an insulated seawater bath for at least 15 min prior to measurement. Note: Do not submerge the puck – let the water level rise to half the depth of the puck or less.
  4. Secure the puck to the sample with velcro or a rubber band (Figure 2).
  5. Optional - Apply thermal joint compound to the side of the probe where the line source is located.


Add Picture

Figure 2.- Correct sensor position for measuring hard rock samples.


  • Making a Measurement

  1. Double-click the ThermCon icon (Figure 3a) on the desktop and login using ship credentials. ThermCon window will open (Figura 3b). Ensure that the Text_ID field is blank.





Measuring Sampl

Configuring the Measurement Program

1.

Load ThermCon software in offline mode. Ensure that the Text_ID field is blank.

2.

Scan the core label using a scanner, then click Verify Sample.

3.

If login is requested, enter UserName and Password and then click OK.
Note: The folder path is shown on the screen. Do not close this window during measurement.

4.

Run TK04 program and choose Measuring > Configuration.

5.

Set configuration parameters as follows:

–Probe Number: serial number of probe to be used in the measurement (Note: results may be wrong by several percent if the wrong serial number is entered or by a factor of ~2 if the wrong type of probe is entered).
–Root Name: 6 characters or less; suggest Core-Type-Section (no special characters).
–Serial Number: number of repeat measurements at each point (1–99 single measurements).
–Folder: path for saving data results.
–Heating Power: for the VLQ (needle probe), set to twice the estimated thermal conductivity value of measured sediment. For example, 2–3 is good for sediment.

For the HLQ (large and mini puck), set equal to the estimated thermal conductivity value of the measured sediment. The mini puck often gets better results without the thermal compound when measuring the standard.
–Measuring Time: set to at least 80 s (needle probe); set to 60 s for Puck.

Click Expert Options to configure Drift Control and Pause in Minutes (see Step 6).

Enter comments.

6.

To configure Drift Control and Pause in Minutes in Expert Options:
–Drift Control (DCL): limit for the range of temperature drift allowed prior to heating and measuring. A larger number allows quicker but less accurate measurement. Default (unchecked) DCL = 10; Recommended DCL =. 10-20

–Pause in Minutes: insert a pause between single measurements; recommended = 10 min. This parameter does not apply when conducting a single measurement on each core or each core section.

Measuring Samples

1.

Confirm configuration settings shown in the lower part of the TK04 screen, insert the probe into the hole drilled into the sample, and click Start Measuring.

2.

Drift control (DCL) repeats until the criterion for drift (set in the Expert Options window) is met. Each drift control measurement takes 0.5 min.
For DCL = 40, drift control is <10 series (~5 min). For DCL = 10, drift control is <30 (~15 min).

3.

After satisfying drift control, sample heating and measuring begins, and temperature values are corrected automatically for the drift effect predicted from the last drift series. Elapsed measurement time is controlled by the value entered in Configuring Measurement Program > Step 5.

4.

Best solutions calculated by the TeKa SAM algorithm are shown on the screen. Note the sample result on the hand-written log.

Uploading and Verifying Data in LIMS

1.

To upload results to LIMS, click Upload to LIMS.

2.

If upload is successful, a message like "Logged results for sample …" is shown.

3.

Close the ThermCon program.

Verifying Data in LIVE (LIMS Viewer)

Run LIVE from the ship application page to check thermal conductivity data:

  1. Select the PHYS_PROPS_Summary template.
  2. Select the Site/Hole/Interval to be queried.
  3. Click View Data.

Retrieving Data from LIMS Reports

1.

Go to LIMS Reports at http://webserv.ship.iodp.tamu.edu:8080/UWQ/.

2.

Under Select Report, choose Physical Properties > Thermal Conductivity (TCON).
a. Note: The "expanded" report shows all of the database parameters and may be confusing to a general user; use the "standard" report.

3.

Under Select Sample Range, specify Expedition, Site, Hole, and Section image(s) to retrieve.

4.

Click View data or Download data file to view results or download a CSV file.

After Verifying Data Upload

1.

Once uploaded data are confirmed, clean the needle probe and place it in its storage container.

2.

Repeat sample measurement process with a new sample.

Credits

V368X (T. Cobb, B. Novak) ;V371T – 7/11/17 (T. Cobb); V1.1; M. Hastedt 8/15/2011 reviewed |S. Frazier March 2018

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