Introduction

The P-wave velocity gantry measures the speed at which ultrasonic sound waves pass through materials that are placed between its transducers; this includes section halfs, discrete samples, and mini-cores.
The three orthogonal sets of piezoelectric transducers allow the velocity to be determined in the X-, Y-, and Z-directions on working-half split-core sections. The P-wave bayonets (PWBs) measure the velocity along the core (Z-direction) and across the split-core face (Y-direction), and a P-wave caliper (PWC) measures the velocity perpendicular to the split-core face (X-direction) (Figure 1). 
For discrete sample cubes, the velocity is measured along each of the three axes separately using the PWC; whereas, mini-cores are measured along the axis of the cylinder (X-direction). For discrete samples cubes and mini-cores, all sample information, including offset, is entered by the user???.

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Figure 8.- ABS Zoom display with threshold slide bar and uncorrected auto-pick location.

B) Manual pick

1. Pause the program.
2. Select MANUAL PICK tab (Figure 9).
3. Click on the crosshair tool on the far left side of the toolbox bar. Hover over the dotted yellow-green vertical pick line. When the icon changes, click and drag the pick line to the desired location and release.
You will now see that the "
4. The Velocity –Manual
"
5. box
has
6. will be updated with the manually picked velocity. Both the 'auto-pick' and 'manual pick velocities' are saved simultaneously to the database
when you
7. upload.

Figure 9.- Manual Pick display with yellow-green manual pick location.

C) Running a Standard as a QAQC Check

You can run a standards to verify if the instrument is giving the expected velocities for the material. There are three materials available as a standard: Aluminum and acrylic are used on the caliper, and a core liner with D.I. water on the bayonets.

Expected velocities for each standard: 
Aluminum 6295 m/s (+/- 63 m/s)
Acrylic 2730 m/s (+/- 27 m/s)
Water 1480 m/s (+/- 7 m/s)

Typical allowable deviation is 1% for the caliper and 0.5% for the bayonets. There will also be differences based on temperature, especially for water and aluminum. If the standard values are out of this range, ask a technician to help calibrate the instrument.

Uploading Data to LIMS

1. Click the MUT Icon. Log in using database credentials.
2. Once activated, the list of files from the C:\DATA\IN directory is displayed. Files are marked ready for upload by a green check mark (Figure 7).

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This document originated from Word document Gantry Velocity: Quick Start Guide Version 1.0; Version 372 written by A. de Loach (2017-12-16). Credits for subsequent changes to this document are given in the page history.

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P-Wave Quick Start Guide v2020
PWV_QSG_372.docx: A Word document of the Gantry Velocity: Quick Start Guide
C) Running a Standard as a QAQC Check
If you are not confident that the gantry system is running normally, you can run one of our standards to verify the instrument is giving the expected velocities for the material. We have three materials available as a standard. Aluminum and acrylic are for the caliper, and a core liner with D.I. water for the bayonets. The expected velocities for each are below:
Aluminum 6295 meters/sec (+/- 63 m/s)
Acrylic 2730 meters/sec (+/- 27 m/s)
Water 1480 meters/sec (+/- 7 m/s)
The typical allowable deviation is 1% for the caliper and 0.5% for the bayonets. There will also be differences based on temperature, especially for water and aluminum. If the standard values are out of this range, ask a technician to help calibrate the instrument.
Viewing Your Data
To view your data, or most data around the lab, you can use the LIMS Online Report Portal (LORE) or the LIMS data viewer (LIVE) through a Firefox web browser. It is good practice to check once per core or after each upload to check that your data has made it into the database.
With Firefox open, click on the toolbar link "LIMS Online Reports" or go to the "Download LIMS core data" link on the ship's homepage (Figure 15). Once in LORE, click through the search options and sample filters to find your data (Figure 16). You can leave the window open in the background and simply refresh next time you want to check your data.LORE gives you a fast way to download core data from most lab systems aboard the JR. You can export directly to an Excel or .csv file. Image Removed
Figure 15. Ship's Home page with links to LORE and core data.
Image Removed
Figure 16. LORE, with P-Wave caliper data downloaded by hierarchy search.
Calibrating the PWV CALIPER
Image Removed To begin calibration for the PWV select the "Caliper Piece X-Axis"Click on the "Stations" tab to access the drop down menu, then click on "Calibrate Calipers".Enter the Aluminum width- 30 mm, place Aluminum Standard (30mm) on the transducer.Close transducers slowlyClick "Laser Offset" tab (blue) Aluminum Standard field should be 6295.00Click "Determine System Delay" tab (purple)Adjust "threshold" till the redline on the graph is at first arrival pointThe Velocity should be very close to 6295.00. If so, then "Accept Changes".
Credits
This document originated from Word document Gantry Velocity: Quick Start Guide Version 1.0; Version 372 written by A. de Loach (2017-12-16). Credits for subsequent changes to this document are given in the page history.
Archived Versions
P-Wave Quick Start Guide (*.pdf)
PWV_QSG_372.docx: A Word document of the Gantry Velocity: Quick Start Guide