NDT is primarily used in industry (automotive, aerospace, power industry, infrastructure, transportation, military equipment, and many others), but from time to time it is also used in more unusual circumstances.

Over the years, many historical items have been tested using NDT methods. Though antique paintings and the Liberty Bell were famously examined using film radiography, more recently computed digital radiography (CR) and computed tomography (CT) have taken center stage. These two techniques are used to examine many features of historical objects such as structure, damage, missing parts, and more.

Stuart Kleven will detail many unique objects examined over the years when he presents “NDT in Historical Applications” during ASNT’s Digital Imaging for NDT 2021 on Thursday, 29 July.

Some of the many items he has helped examine include artifacts from René-Robert Cavelier, Sieur de la Salle’s ship, La Belle; the Confederate submarine, H.L. Hunley; a Korean War era F86 Sabre Jet; paintings by Monet; and both the Magdalenian woman and African elephants at the Field Museum of Natural History in Chicago.

“Usage of digital technology has several advantages for historic objects such as minimizing radiation and ALARA concerns when radiography is performed in open spaces of museums,” said Kleven.

Of all the historical pieces he’s examined, Kleven says performing CT on ancient clay token balls from Babylon is his favorite. The balls, covered in symbols, had small items inside. CT examination helped researchers to see inside and determine the balls were ancient receipts—precursors to clay tablets.

Kleven’s Digital Imaging presentation will focus on the La Belle, the H.L. Hunley, and both the Magdalenian woman and Fighting African Elephants at the Field Museum.

Recovery and Conservation of La Salle’s ship, La Belle

La Belle was a French vessel that sank off the coast of Texas in Matagorda Bay in the 1680s. The French explorer La Salle was the leader of an expedition with four ships sent to colonize the mouth of the Mississippi, provide maps and charts of the area, and establish a fort. Trade goods were onboard for trading with the local indigenous people.

The expedition was a disaster—the supply ship sank in a storm, another was taken by pirates, and the crew of the third ship mutinied and returned to France. La Belle eventually was lost in a storm while La Salle was on land. 

The Texas Historical Commission, along with the Conservation Research Laboratory and the Nautical Archaeology Program at Texas A&M University, began the recovery and restoration project in 1996–1997. The artifacts have been undergoing preservation techniques and extensive study. Kleven will discuss how recent developments in CR have made it a valuable tool in identifying and conserving these items.

Recovery and Restoration of the Confederate Submarine, H.L. Hunley

The first successful use of a submarine in combat was by the Confederacy during the Civil War. The Hunley was pressed into action to break the Union blockade of Charleston Harbor and sank the USS Housatonic. During the battle the submarine sank and was recovered over 130 years later. NDT was used to evaluate the structure prior to and during restoration. Kleven will highlight some of the methods used and the progress of the work being performed on the submarine. (To read more about the Hunley, check out “The Confederate Submarine H.L. Hunley and Nondestructive Testing” in Volume 60, Issue 3 of Materials Evaluation. Available on the ASNT Digital Library.)

The Magdalenian Woman—A 12 000-Year-Old Makeover

The Field Museum used NDT in conservation work on some of the ancient skeletons that had been acquired in the 1920s. Using digital images from CT scans of the skull of the Magdalenian woman taken by Kleven, anthropologists digitally reconstructed her skull in 2012, and in 2013 a sculptor completed a facial reconstruction. Kleven will address the work performed to allow the museum to accurately conserve the skull and create the facial reconstruction. 

Fighting African Elephants—Uncovering Museum History

The Fighting African Elephants are located on the main floor in the lobby of the Field Museum and is one of the first displays to greet museum visitors. The elephants were donated to the museum by Chief Taxidermist Carl Akeley, a museum employee. 

On a trip to Africa in 1905, Akeley and his wife shot the elephants in Kenya and brought the skin, tusks, and hair back to the United States. The base for the pachyderms was fashioned using wood, steel, and chicken wire, upon which the skin was attached. (No bones were used.) 

Over time, the elephants have been exposed to natural light as well as humidity and dry air, which has caused cracks in the skin. These minor fissures have been mended over time, but with more than 100 years of exposure, it was time for a major renovation. 

To perform proper repairs and restoration, the scientists had to know what was immediately below the skin and the condition of the base that held the elephants together.  Because the elephants were preserved so long ago, no records exist regarding the process used. 

Kleven will discuss how CR was used to record their structures and look for damage or weakening of the internal structure. (More information about the inspection of the Fighting African Elephants can be found in this December 1 blog post. https://blog.asnt.org/radiography-has-a-night-at-the-museum/)

For more information on Kleven’s presentation, or to register for Digital Imaging in NDT, go to the ASNT website https://asnt.eventsair.com/digital-imaging-for-ndt-2021.

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Stuart Kleven, Alloyweld Inspection Company, Inc., has a lifelong love of history. He holds ASNT SNT-TC-1A/ACCP Level III in RT, UT, MT, and PT; is an ASNT Fellow; and is a Certified Welding Inspector with the American Welding Society. He is a member of the ASTM E07 subcommittee on radiographic testing, liquid penetrant testing, and magnetic particle inspection, and has authored and/or presented numerous papers on NDT over the past 47 years.

Cindi Leeman is the ASNT Educational Materials Supervisor and editor of ASNT Pulse; cleeman@asnt.org.

Unless otherwise indicated, photos courtesy of Stuart Kleven.