Blackbeard’s infamous pirate ship, The Queen Anne’s Revenge (QAR), lay lost on the ocean floor off the North Carolina coast for almost 300 years. It was discovered in 1996, but most of the relics of colonial culture aboard its decks, such as specks of gold, glass beads, firearms and brass pins, remain hidden inside a thick crust of muddy sand and shells.
With the help of the Davidson Research Initiative, Ryan Kozlowski ’16 and Professor of Physics Dan Boye hope to shed some light on those items by using their Digitome non-destructive x-ray imaging system. Their examination of a half-dozen items from the pirate ship this summer at the N.C. Department of Cultural Resources lab located at Eastern Carolina University could add to the evidence that this was indeed Blackbeard’s ship.
“Digitome imaging can be done on a laptop,” explained Kozlowski. The configuration at Davidson consists of three main parts. A source shoots x-rays into the cabinet. The object of the examination rests inside the cabinet on a circular plastic plate attached to the image plate. The object and image plate can be tilted and the plastic plate can be rotated to record as many as 32 different perspectives of the object, though just eight views are commonly captured. The system’s proprietary software immediately assembles the different views such that any mathematically-defined contour can be viewed.
The original Pythagoras cup was designed around 500 BC to teach its users to drink in moderation. If liquid is filled into the cup above a specific height, it all completely funnels out of a hole in the bottom of the cup and onto the drinker’s lap. A three-dimensional radiographic exam of a modern Chinese Pythagoras cup was taken to reveal the simple structure of the cup that allows the siphoning mechanism to occur. Though design or object material changes across cultures and time, the functionality of the Pythagoras cup remains the same.
The cup has a neck at its center with an opening at its base. Inside of the neck, which is sealed off at the top, is an inner tube that is open at the top (within the neck) and the bottom (visibly seen on cup surface). As a user pours fluid into the cup, the fluid fills in the neck to the same height as the fluid in the open, visible area of the cup. When a portion of the fluid in the neck overflows and begins to pour down the inner tube by gravity, the remainder of the fluid in the entire cup follows the flow up through the neck and down the inner tube because of reduced pressure and an overall decrease in the gravitational potential energy of the system. The Pythagoras cup is really just a self-priming siphon.
The three-dimensional exam reveals that the inner tube is at a height of approximately 1.20 inches from the bottom layer of the cup. It affirms that the dragon’s head is sealed off from the neck and demonstrates the effectiveness of the Digitome software in accurately measuring object parts and picking up on fine details like the horns of the dragon or the opening in the back of its neck. This video shows a scan upward through the object—Digitome can produce a “stack” of images for an object, and the user can export the stack to commercial software that can then produce a 3-dimensional surface view, as displayed at the end of the video.
View a video of a Digitome scan.
Davidson physics students plowed new scientific ground in 1896 when they took the first X-ray images on American soil. Contemporary Davidson physicists now have a similarly momentous opportunity. The department has recently become the first non-governmental entity in the country to acquire a revolutionary Digitome VXI-500Fx non-destructive imaging system. The system combines a series of conventional two-dimensional x-ray images taken from various angles around an object into a three-dimensional “volumetric” screen image that can be turned, rotated and probed from any angle or plane.
Images of a Digitome scan are recorded on an 8-inch by 10-inch CCD plate rather than a piece of film. The image is therefore recorded instantly as a computer file rather than being projected onto film that must be developed.
The Digitome’s unique ability to create a three-dimensional image of an object led Professor of Physics Dan Boye to hail the system as a “cross-disciplinary game changer” for Davidson. He said, “We believe we can apply the Digitome to help understand topics of interest in the humanities and social sciences.”
In his proposal to purchase the system, Boye wrote, “It would foster trans-disciplinary learning and research throughout the college by partnering physics faculty and students with teaching and research efforts in other departments and programs.”
For instance, Boye envisions its use by the art department to examine layers of paintings which may have been covered with other layers. Archeologists could examine mummies inside sarcophagi. Book conservators could view intricate binding techniques of rare works without having to open them.
The Digitome company has already documented several uses in the arts. A Digitome examination of a music stand owned by Mozart revealed that pieces were screwed together with reverse threading. The emperor of Japan requested a Digitome examination of an urn to see if the handle had been modified. A Digitome exam found that the general absence of cracks in the intricate enamel of a Ming vase at the Los Angeles County Museum of Art resulted from expansion joints on the inside surface. An examination of a jet engine turbine blade revealed cracks that could have been dangerous.
How It Works
The Digitome machine consists of three main parts. A generator shoots x-rays downward into a four-foot tall lead-lined cabinet. The object of the examination rests inside the cabinet on a circular plastic plate attached to the CCD plate. The CCD plate can be tilted and the plastic plate can be rotated to record as many as 32 different views of the object. The system’s proprietary software immediately assembles the different views such that any 2D mathematically-defined contour can be viewed.
The system’s portability, scalability, rapid results and ability to measure any aspect of tested subjects make it comparable if not superior to other techniques such as computed tomography (CT), positron electron tomography (PET), ultrasound and magnetic resonance imaging (MRI).
Though the Digitome exams are most easily accomplished in the cabinet, the mounting fixture and image plate are removable and easily portable to remote locations such as a museum for off-site examination of fragile or valuable pieces.
Physics and math major Phillip Wall ’14 is spending the summer in the lab learning the Digitome system and writing user protocols. He said, “More and more I’m realizing this is a pretty big deal for Davidson, and it’s fun to blaze a trail as the first student operator.”
In one of his tests, Wall examined his iPod, revealing its components stacked on top of each other inside the case. His examination of a baboon’s skull obtained from the biology department revealed non-emergent teeth concealed in the jawbone. He conducted an exam of a Chinese “cadogan” style wine pot with no lid which revealed the interior hollow stem that allows it to pour without spilling. He examined a closed prayer locket from the college archives to determine whether it concealed a scroll.
Wall operates sliders on the screen to control image contrast and resolution, and movement around and through the sample through image rotation, tilt and zoom.
His examination of a common gaming die vividly displayed the system’s capabilities. The captured three-dimensional image began on the one-dot side of the cube. Wall then moved straight through the die to reveal the six dots on the opposite side. Through rotation and controlled movement, he revealed all the other sides of the die. “It’s a graphic way to demonstrate its volumetric capability,” Wall said.
Boye plans to enlist future students to learn the system as well so that they can handle requests from other departments and external agents. The techniques and skills they learn in operating the machine will prepare them to operate almost any radiographic system.
Since he has no professional training in radiography, Boye is also learning the system along with Wall. To make the most of the department’s new resource, Boye has joined the American Society of Nondestructive Testing, and will attend its digital imaging meeting later this month.
Digitome’s Local Connection
Boye is also enjoying the new collaboration with an outside business. Digitome is a tightly held 30-year-old corporation that has supplied imaging devices almost exclusively to the defense and aerospace industries. NASA has used its imaging products to detect cracks inside a space shuttle surface forewing, and the armed forces have examined exploded IED pieces to gain clues about their origins.
One stage in the development of the Digitome company took place in Davidson where it was housed in the Industrial Dynamics building off Griffith Street. The company is led by CEO Donald Twyman, who currently lives in the Davidson area. Twyman approached Davidson’s physics department earlier this year as a means for exploring new applications for the Digitome. Impressed with the physics program and its personnel, Twyman helped arrange purchase of the machine by the college, and created a proprietary license for its software.
Twyman has been a regular visitor to the physics lab, helping Boye and Wall learn to operate the system and explore new functionalities. Boye explained, “They want to see uses that may emerge when they put the Digitome system in the hands of liberal arts students rather than engineers. This is a great opportunity for us in applied physics. Who knows? We might even discover new uses for it that could yield patents and generate revenue for the college. It’s an exciting step for us not only in partnering with other departments inside the college, but with an outside, private business.”
Original article written by Bill Giduz