TK04 Thermal Conductivity System on the JR
I. Introduction
Thermal conductivity is the coefficient of proportionality relating conductive heat flow to a thermal gradient. The Teka Berlin TK04 system determines thermal conductivity based on a transient heat flow method. A line source is heated with constant power while recording source temperature. Thermal conductivity is calculated from the resulting heating curve.
The TK04 uses two types of probes: the full-space (VLQ) needle probe for soft sediments and the half-space (HLQ) probe for hard rock samples. Measuring a single point in a section takes ~54 min per sample, allowing for 3 replicates to be taken. A self-test including a drift study is conducted at the beginning of each cycle. To measure thermal conductivity the heater circuit is closed and the temperature rise in the probe is recorded. Thermal conductivity is calculated from the rate of temperature rise while the heater current is flowing. The thermal conductivity of each sample is the average of three repeated measurements for the full-space method and three to six repeated measurements for the half-space method.
Precision of the method is better than 2%, based on extended evaluation of the method; accuracy is about 5% because of random variations of thermal conductivity in natural materials.
Theory of method
Thermal conductivity is measured by transient heating of an isotropic material with a known heating power generated from a source of known geometry and measuring the temperature change with time. The needle probe contains a heater wire and calibrated thermistor. It is assumed to be a perfect conductor because it is much more conductive than unconsolidated sediments. With this assumption, the temperature of the probe has a linear relationship with the natural logarithm of the time after initiation of heating:
T(t) = (q/4πk) ln(t) + C,
where:
T = temperature,
q = heat input per unit length per unit time (W),
k = thermal conductivity (W/[m·K]),
t = time after initiation of the heat, and
C = a constant.
A simple way of calculating the thermal conductivity coefficient k is picking temperatures T1 and T2 at times t1 and t2, respectively, from the temperature vs. times measurement curve:
ka(t) = q/4π[ln(t2) – ln(t1)]/(T2 – T1).
ka(t) is the apparent thermal conductivity because the true conductivity (k) is approached only by a sufficiently large heating duration. The method assumes that the measurement curve is linear and ignores the imperfections of the experiment expressed in the constant C.
Thermal conductivity is an intrinsic material property for which the values depend on chemical composition, porosity, density, structure, and fabric of the material. Thermal conductivity profiles are used along with in situ temperature measurements to determine heat flow, which is an indicator of age of ocean crust and fluid circulation processes.
Available Probe Types
All probes consist of a source (i.e., a metal needle with an embedded heating wire and a temperature sensor), a handle or body (depending on the probe type), and a connection cable.
Full-space probes (VLQ) are needle probes equipped with a handle at one end of the source. They are completely inserted into the sample.
Half-space probes (HLQ), or "Pucks", are placed on top of the sample. The source is embedded into the bottom side of a puck-like probe body and has on-site contact with the material/sample.
Name | Standard VLQ | Standard HLQ | Mini HLQ |
---|---|---|---|
Probe type: | Full-space | Half-space | Half-space |
Dimension (source, mm): | L: 70 × diameter (D): 2 | L: 70 × D: 2 | L: 45 × D: 1.5 |
Dimension (handle/body, mm): | L: 90 × D: 16 | L: 30 × D: 88 | L: 30 × D: 50 |
Evaluation parameter set: | Standard VLQ (VLQ Source 70x2) | Standard HLQ (HLQ D88 Source 70x2) | Mini HLQ (HLQ D50 Source 45x1.5) |
Measuring range (W/m·K): | 0.1–10 | 0.3–10 | 0.3–3 |
Accuracy (%): | ±2 | ±2 | ±5 |
Duration of 1 measurement (s): | 80 | 80 | 60 |
Min. sample size (mm): | L: 75 × D: 30 | L: 15 × D: 80 | L: ~15 × D: 50 |
Picture: |
Analytical process
The approximate amount of time needed per sample is as follows:
Process | Time (min) | Comments |
---|---|---|
1. Obtain a whole-round core section from the core rack | 0.3 | See Preparing Sections & Samples |
2. Locate the appropriate probe for the sample type | 0.5 | |
3. Verify sample identification in software | 0.5 | See Set Measurement Parameters |
4. Configure measurement program | 0.3 | |
5. Perform drift control | 5 | See Making a Measurement |
6. Heat and measure sample | 2 | |
7. 10 minute pause between measurements | 10 | |
8. Repeat steps 5-7 for 2 additional measurements (3 total) | 34 | |
9. Upload results to LIMS | 0.2 | See Uploading Data to LIMS |
10. Check results in LIMS | 1 | |
11. Remove the section and deliver to splitting room | 0.2 | |
Total Time per sample: | 54 (max) |
Double-click the ThermCON icon on the desktop (Figure 1) and login using ship credentials. ThermCON window will pop-up. Sample data will be added in this window.
Double-click the TK04 icon (Figure 1). TK04 window will open. Measurement parameters will be added in this window.
Figure 1. ThermCON Icon (left). TK04 Icon (right).
The TK04 doesn't need to be calibrated. In order to verify that taken measurements are in the correct range of values, MACOR standards are measured at the start of each expedition.
Measuring the Standard
The Macor Standard for the Standard VLQ consists of its black holding shell, while the Macor Standard for both the Standard HLQ and Mini HLQ is a white disc. Calibration tests for any of the available probe types should provide results of TC=1.626-1.637±2%. The Macor standard drift calculations are based on a Macor standard (1.637 ± 0.033 W/mK) because its properties are closest to basalt cores (See Appendix: TK04 Recommended Heating Power for information).
Standard VLQ- MACOR Standard | Standard MACOR Disc |
Probe Test TC Value Expected Results: | Probe Test TC Value Expected Results: |
To conduct a probe test, scan the STND MACOR disc TCON (H) label kept above the testing apparatus and ensure that the appropriate heating time and drift control (DCL) settings are input under the Configuration settings (See Configuring the Measurement Program).
Example 1: A Standard HLQ properly positioned on the Standard MACOR Disc. |
The user should note that in many cases, the samples are not amenable to thermal conductivity analysis, whether because of fractures that lead to circulation, poor surface conditions, or other factors. If the Macor standard gives good results and a core section or piece does not, the sample may simply not work.
To configure Drift Control and Pause in Minutes in Expert Options:
Figure 2. Thermal conductivity measurement on a soft-sediment section using full-space probe.
5. Upload data to LIMS and review if they appear on the data base (See next section).
Note: The "expanded" report shows all of the database parameters and may be confusing to a general user; use the "standard" report.
6. Once uploaded data are confirmed, clean the needle probe and place it in its styrofoam storage container.
7. Repeat sample measurement process with a new sample.
Data Available in LIVE
The data measured on each instrument can be viewed in real time on the LIMS information viewer (LIVE).
Choose the appropriate template (Ex: PHYS_PROPS_Summary), Expedition, Site, Hole or the needed restrictions and click View Data. The requested data will be displayed. You can travel in them by clicking on each of each core or section, which will enlarge the image.
Data Available in LORE
Each data set from the Thermoconductivity Station is written to a file by section. These reports are found under the Physical Properties heading. The expanded reports include the linked original data files and more detailed information regarding the measurement.
Analysis | Component | Unit | Definition |
TCON | Bottom_depth | m | Location of bottom of measurement, measured from the top of the hole |
Comment | None | Comment about the run | |
Contact_value | None | Measure of contact quality between probe and sample | |
End_time | s | Elapsed time for end of analysis window | |
Heating_power | W/m | Power applied to needle during heating | |
Length_of_time | s | Elapsed time, start to finish, of analysis | |
Log_extreme_time | s | LET, used in calculation algorithm | |
Method | None | Data reduction method: SAM or TCON | |
Needle_name | None | Full-space or half-space | |
Number_of_solutions | None | Number of solutions found by the software | |
Offset | cm | Location of measurement from top of section | |
Start_time | s | Elapsed time into experiment for start of analysis window | |
Therm_con_average | W/(m·K) | Mean thermal conductivity result | |
Therm_con_number | None | Number of measurements in the population | |
Therm_con_result | W/(m·K) | Individual thermal conductivity result | |
Therm_con_stdev | W/(m·K) | Standard deviation (n-1) of measurement population | |
Top_depth | m | Location of top of measurement from top of hole |
Expedition data can be downloaded from the database using the instrument Expanded Report on Download LIMS core data (LORE).
Safety
This analytical system does not require personal protective equipment.
Pollution Prevention
This procedure does not generate heat or gases and requires no containment equipment.
Troubleshooting
Drift phase takes too long:
Variation of measurement series is too high:
Evaluation returns few or no solutions:
LET values too low:
Evaluation intervals start later than ~35 s:
Descending trend in thermal conductivity values:
Note: for loose sediments, use a lower heating power to avoid convective heat transport of pore fluids.
Material | Thermal Conductivity (W/m·K) | Recommended Heating Power (W/m) | ||
---|---|---|---|---|
Mean | Range | VLQ | HLQ | |
Wood | 0.21 | 0.1–0.35 | 0.15–1.3 | — |
Coal | 0.29 | 0.1–1.5 | 0.15–5.4 | — |
Concrete | 1.00 | 0.75–1.4 | 1.0–5.0 | 0.5–2.2 |
Fused silica | 1.40 | 1.33–1.46 | 1.8–5.2 | 0.8–2.3 |
Clay | 1.40 | 1.2–1.7 | 1.6–6.1 | 0.7–2.6 |
Silt | 1.60 | 1.4–2.1 | 1.9–7.5 | 0.8–3.2 |
Basalt | 1.95 | 1.4–5.4 | 1.9–19.0 | 0.8–7.6 |
Siltstone | 2.04 | 0.6–4.0 | 0.8–14.0 | 0.4–5.7 |
Limestone | 2.29 | 0.5–4.4 | 0.7–16.0 | 0.4–6.3 |
Syenite | 2.31 | 1.3–5.3 | 1.7–19.0 | 0.8–7.5 |
Amphibolite | 2.46 | 1.4–3.9 | 1.9–14.0 | 0.8–5.6 |
Claystone | 2.46 | 1.6–3.4 | 2.1–12.0 | 0.5–9.3 |
Lava | 2.47 | 0.2–4.5 | 0.3–16.0 | 0.2–6.4 |
Gabbro | 2.50 | 1.6–4.1 | 2.1–15.0 | 0.9–5.9 |
Dolerite (Diabase) | 2.64 | 1.6–4.4 | 2.1–16.0 | 0.5–6.3 |
Granodiorite | 2.65 | 1.3–3.5 | 1.7–13.0 | 0.8–5.0 |
Quartz sand (wet) | 2.70 | 2.4–3.1 | 3.2–11.0 | 1.3–4.5 |
Marble | 2.80 | 2.1–3.5 | 1.8–13.0 | 1.2–5.0 |
Porphyrite | 2.82 | 3.8–10.0 | 1.5–4.2 | |
Boulder clay | 2.90 | 2.5–3.3 | 3.4–12.0 | 1.4–4.8 |
Diorite | 2.91 | 1.7–4.2 | 2.3–15.0 | 1.0–6.0 |
Slate (perpendicular) | 2.91 | 1.5–3.9 | 2.0–14.0 | 0.9–5.6 |
Gneiss | 2.95 | 1.2–4.7 | 1.6–17.0 | 0.7–6.7 |
Granite | 3.05 | 1.2–4.5 | 1.6–16.0 | 0.7–6.4 |
Eclogite | 3.10 | 2.4–3.4 | 3.2–12.0 | 1.3–4.9 |
Andesite | 3.20 | 1.6–4.7 | 2.1–17.0 | 1.0–6.7 |
Dolomite | 3.62 | 1.6–6.6 | 2.1–20.0 | 1.0–9.3 |
Slate (parallel) | 3.80 | 2.2–5.2 | 3.0–19.0 | 1.2–7.4 |
Peridotite | 3.81 | 5.0–14.0 | 2.0–5.5 | |
Anhydrite | 4.05 | 1.0–6.0 | 1.3–20.0 | 0.6–8.5 |
Pyroxenite | 4.27 | 3.2–5.1 | 4.3–18.0 | 1.7–7.2 |
Dunite | 4.41 | 3.5–5.2 | 4.7–19.0 | 1.9–7.4 |
Quartzite | 4.55 | 3.1–>8 | 4.2–20.0 | 1.7–11.0 |
Quartz | 9.50 | 6.5–12.5 | 8.7–20.0 | 3.5–17.0 |
After finishing a measuring series, change to Evaluation Mode, select the data folder of the current measuring series and open a Results window for editing (button Results, marked with a red circle in the figure).
Select the single measurement to be removed in the Details table and delete it (number 1 in the figure), replace the Export List with the modified content of the Measuring Data & Results table (2 in the figure), Save Export List to file (3 in the figure) to overwrite Tc-List.dat, if required (or just use Export.dat instead of Tc-List.dat).
This document originated from 2009, TK04 UG v.,V378P | 372 (Revised: 372|V371T|no change 03/18 ), that had contributions from the authors Hastedt, Y.-G. Kim, M.A. Kominz, and the reviewers David Houpt, T. Gorgas, M. Vasilyev, R. Wilkens, K. Milliken, H. Barnes, S. Hermann; T. Cobb. Credits for subsequent changes to this document are given in the page history.
All improvements to the Quick Start Guides and User Guides are a communal effort, with honorable mention to the group of LOs, ALOs, and technicians who have helped.
ANALYSIS | TABLE | NAME (expanded report) | NAME (standard report) | ABOUT TEXT |
TCON | SAMPLE | Exp | Exp | Exp: expedition number |
TCON | SAMPLE | Site | Site | Site: site number |
TCON | SAMPLE | Hole | Hole | Hole: hole number |
TCON | SAMPLE | Core | Core | Core: core number |
TCON | SAMPLE | Type | Type | Type: type indicates the coring tool used to recover the core (typical types are F, H, R, X). |
TCON | SAMPLE | Sect | Sect | Sect: section number |
TCON | SAMPLE | A/W | A/W | A/W: archive (A) or working (W) section half. |
TCON | SAMPLE | text_id | Text ID | Text_ID: automatically generated database identifier for a sample, also carried on the printed labels. This identifier is guaranteed to be unique across all samples. |
TCON | SAMPLE | sample_number | N/A | Sample Number: automatically generated database identifier for a sample. This is the primary key of the SAMPLE table. |
TCON | SAMPLE | label_id | N/A | Label identifier: automatically generated, human readable name for a sample that is printed on labels. This name is not guaranteed unique across all samples. |
TCON | SAMPLE | sample_name | N/A | Sample name: short name that may be specified for a sample. You can use an advanced filter to narrow your search by this parameter. |
TCON | SAMPLE | x_sample_state | N/A | Sample state: Single-character identifier always set to "W" for samples; standards can vary. |
TCON | SAMPLE | x_project | N/A | Project: similar in scope to the expedition number, the difference being that the project is the current cruise, whereas expedition could refer to material/results obtained on previous cruises |
TCON | SAMPLE | x_capt_loc | N/A | Captured location: "captured location," this field is usually null and is unnecessary because any sample captured on the JR has a sample_number ending in 1, and GCR ending in 2 |
TCON | SAMPLE | location | N/A | Location: location that sample was taken; this field is usually null and is unnecessary because any sample captured on the JR has a sample_number ending in 1, and GCR ending in 2 |
TCON | SAMPLE | x_sampling_tool | N/A | Sampling tool: sampling tool used to take the sample (e.g., syringe, spatula) |
TCON | SAMPLE | changed_by | N/A | Changed by: username of account used to make a change to a sample record |
TCON | SAMPLE | changed_on | N/A | Changed on: date/time stamp for change made to a sample record |
TCON | SAMPLE | sample_type | N/A | Sample type: type of sample from a predefined list (e.g., HOLE, CORE, LIQ) |
TCON | SAMPLE | x_offset | N/A | Offset (m): top offset of sample from top of parent sample, expressed in meters. |
TCON | SAMPLE | x_offset_cm | N/A | Offset (cm): top offset of sample from top of parent sample, expressed in centimeters. This is a calculated field (offset, converted to cm) |
TCON | SAMPLE | x_bottom_offset_cm | N/A | Bottom offset (cm): bottom offset of sample from top of parent sample, expressed in centimeters. This is a calculated field (offset + length, converted to cm) |
TCON | SAMPLE | x_diameter | N/A | Diameter (cm): diameter of sample, usually applied only to CORE, SECT, SHLF, and WRND samples; however this field is null on both Exp. 390 and 393, so it is no longer populated by Sample Master |
TCON | SAMPLE | x_orig_len | N/A | Original length (m): field for the original length of a sample; not always (or reliably) populated |
TCON | SAMPLE | x_length | N/A | Length (m): field for the length of a sample [as entered upon creation] |
TCON | SAMPLE | x_length_cm | N/A | Length (cm): field for the length of a sample. This is a calculated field (length, converted to cm). |
TCON | SAMPLE | status | N/A | Status: single-character code for the current status of a sample (e.g., active, canceled) |
TCON | SAMPLE | old_status | N/A | Old status: single-character code for the previous status of a sample; used by the LIME program to restore a canceled sample |
TCON | SAMPLE | original_sample | N/A | Original sample: field tying a sample below the CORE level to its parent HOLE sample |
TCON | SAMPLE | parent_sample | N/A | Parent sample: the sample from which this sample was taken (e.g., for PWDR samples, this might be a SHLF or possibly another PWDR) |
TCON | SAMPLE | standard | N/A | Standard: T/F field to differentiate between samples (standard=F) and QAQC standards (standard=T) |
TCON | SAMPLE | login_by | N/A | Login by: username of account used to create the sample (can be the LIMS itself [e.g., SHLFs created when a SECT is created]) |
TCON | SAMPLE | login_date | N/A | Login date: creation date of the sample |
TCON | SAMPLE | legacy | N/A | Legacy flag: T/F indicator for when a sample is from a previous expedition and is locked/uneditable on this expedition |
TCON | TEST | test changed_on | N/A | TEST changed on: date/time stamp for a change to a test record. |
TCON | TEST | test status | N/A | TEST status: single-character code for the current status of a test (e.g., active, in process, canceled) |
TCON | TEST | test old_status | N/A | TEST old status: single-character code for the previous status of a test; used by the LIME program to restore a canceled test |
TCON | TEST | test test_number | Test No. | TEST test number: automatically generated database identifier for a test record. This is the primary key of the TEST table. |
TCON | TEST | test observation_time | Timestamp (UTC) | Timestamp (UTC): point in time at which the observation was made THIS SHOULD BE A NEW COLUMN ADDED TO THE EXPANDED REPORT. CURRENTLY ONLY REPORTED IN STANDARD REPORT |
TCON | TEST | test date_received | N/A | TEST date received: date/time stamp for the creation of the test record. |
TCON | TEST | test instrument | N/A | TEST instrument [instrument group]: field that describes the instrument group (most often this applies to loggers with multiple sensors); often obscure (e.g., user_input) |
TCON | TEST | test analysis | N/A | TEST analysis: analysis code associated with this test (foreign key to the ANALYSIS table) |
TCON | TEST | test x_project | N/A | TEST project: similar in scope to the expedition number, the difference being that the project is the current cruise, whereas expedition could refer to material/results obtained on previous cruises |
TCON | TEST | test sample_number | N/A | TEST sample number: the sample_number of the sample to which this test record is attached; a foreign key to the SAMPLE table |
TCON | CALCULATED | Depth CSF-A (m) | Depth CSF-A (m) | Depth CSF-A (m): position of observation expressed relative to the top of the hole. |
TCON | CALCULATED | Depth CSF-B (m) | Depth CSF-B (m) | Depth [other] (m): position of observation expressed relative to the top of the hole. The location is presented in a scale selected by the science party or the report user. |
TCON | RESULT | contact_value | N/A | RESULT contact value (unitless): unitless measure of contact quality between probe and sample |
TCON | RESULT | dat_asman_id | N/A | RESULT DAT file ASMAN_ID: serial number of the ASMAN link for the .DAT file |
TCON | RESULT | dat_filename | N/A | RESULT DAT filename: file name of the .DAT file |
TCON | RESULT | dwl_asman_id | N/A | RESULT DWL file ASMAN_ID: serial number of the ASMAN link for the .DWL file |
TCON | RESULT | dwl_filename | N/A | RESULT DWL filename: file name of the .DWL file |
TCON | RESULT | end_time (s) | N/A | RESULT end time (s): the ending time of the experiment in seconds from initialization |
TCON | RESULT | erg_asman_id | N/A | RESULT ERG file ASMAN_ID: serial number of the ASMAN link for the .ERG file |
TCON | RESULT | erg_filename | N/A | RESULT ERG filename: file name of the .ERG file |
TCON | RESULT | heating_power (W/m) | N/A | RESULT heating power (W/m): heating power applied to the sample (it can be useful to reduce this if it is challenging to get a good result) |
TCON | RESULT | length_of_time (s) | N/A | RESULT length of time (s): duration of the linear portion of the heating experiment, determined by subtracting start time from end time |
TCON | RESULT | mdb_asman_id | N/A | RESULT MDB file ASMAN_ID: serial number of the ASMAN link for the .MDB file |
TCON | RESULT | mdb_filename | N/A | RESULT MDB filename: file name of the .MDB file |
TCON | RESULT | method | N/A | RESULT method: indicates whether the TeKa Berlin SAM method or the linear-calculation TCON method was used |
TCON | RESULT | instrument | Instrument | RESULT instrument: name of the instrument used |
TCON | RESULT | needle_name | Needle name | RESULT needle name: serial number of the needle used (H#### for half-space; V#### for full-space) |
TCON | RESULT | number_of_solutions | N/A | RESULT number of solutions: number of independent valid solutions the SAM method found; the higher this number, the better (and <100 should be carefully checked) |
TCON | RESULT | offset (cm) | Offset (cm) | RESULT offset (cm): position of the measurement relative to the top of a sample (generally a section) |
TCON | RESULT | ssup_asman_id | N/A | RESULT spreadsheet uploader ASMAN_ID: serial number of the ASMAN link for the spreadsheet uploader file |
TCON | RESULT | ssup_filename | N/A | RESULT spreadsheet uploader filename: file name of the spreadsheet uploader file |
TCON | RESULT | start_time (s) | N/A | RESULT start time (s): the starting time of the experiment in seconds from initialization |
TCON | RESULT | therm_con_average (W/(m*K)) | Thermal conductivity mean (W/(m*K)) | RESULT average thermal conductivity (W/(m*K), SAM): mean result of successive thermal conductivity observations using the SAM method |
TCON | RESULT | therm_con_number | Measurements (no) | RESULT number of measurements (SAM): the number of measurements performed to produce the mean result for the SAM method |
TCON | RESULT | therm_con_result (W/(m*K)) | Thermal conductivity observations (W/(m*K)) | RESULT individual thermal conductivity (W/(m*K), SAM): individual thermal conductivity measurement using the SAM method |
TCON | RESULT | therm_con_stdev (W/(m*K)) | Conductivity std. dev (W/(m*K)) | RESULT standard deviation (W/(m*K), SAM): standard deviation of the averaged results from the SAM method |
TCON | RESULT | therm_con_average_calc | N/A | RESULT average thermal conductivity (W/(m*K), TCON): mean result of successive thermal conductivity observations using the TCON method NOT CURRENTLY REPORTED IN EXPANDED REPORT BUT SHOULD BE |
TCON | RESULT | therm_con_number_calc | N/A | RESULT number of measurements (TCON): the number of measurements performed to produce the mean result for the TCON method NOT CURRENTLY REPORTED IN EXPANDED REPORT BUT SHOULD BE |
TCON | RESULT | therm_con_result_calc | Calculated TCON value (W/(m*K)) | RESULT individual thermal conductivity (W/(m*K), TCON): individual thermal conductivity measurement using the TCON method NOT CURRENTLY REPORTED IN EXPANDED REPORT BUT IT IS IN THE STANDARD REPORT |
TCON | RESULT | therm_con_stdev_calc | N/A | RESULT standard deviation (W/(m*K), TCON): standard deviation of the averaged results from the TCON method NOT CURRENTLY REPORTED IN EXPANDED REPORT BUT SHOULD BE |
TCON | SAMPLE | sample description | Sample comments | SAMPLE comment: contents of the SAMPLE.description field, usually shown on reports as "Sample comments" |
TCON | TEST | test test_comment | Test comments | TEST comment: contents of the TEST.comment field, usually shown on reports as "Test comments" |
TCON | RESULT | result comments | Result comments | RESULT comment: contents of a result parameter with name = "comment," usually shown on reports as "Result comments" |