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History in 3-D.

Mechanical and aerospace engineering students at Cornell University see Franz Reuleaux's kinematic mechanisms every day. But until recently, they didn't get to touch them. The university's Sibley School of Mechanical and Aerospace Engineering owns the largest set of cast iron and brass models of machines designed by Reuleaux more than 130 years ago.

The models are on display throughout the department, but now they're also available to anyone with a connection to the Internet, thanks to reverse-engineering software and 3-D printing hardware.

The use of reverse engineering and 3-D printing at Cornell is one of several recent applications of the technology to illuminate history. The technologies are duplicating artifacts under the ground and have been used to identify the remains of a soldier who died almost a century ago.

Reuleaux, a mechanical engineer and professor in the latter part of the 19th century, is often considered the father of kinematics--the geometry of motion. The mechanisms he created teach students about kinematics and the history and theory of machines. Having developed his theory, he directed the design and manufacture of more than 800 models of simple mechanisms, such as a crank, said Hod Lipson, Cornell associate professor of mechanical and aerospace engineering.

More than 300 of those models were manufactured; Cornell University in Ithaca, N.Y., owns 220 of them, having acquired them in 1882.

Recently, Cornell librarians helped develop the Kinematic Models for Design Digital Library, or K-MODDL to allow Internet users to view the models close up.

The Cornell Reuleaux Collection contains numerous kinematic mechanisms for rotary and reciprocating engines using both steam and internal combustion. It also includes a dozen working clock escapement mechanisms, from the early verge and foliot escapement to the gravity escapement employed in London's famous Big Ben, according to the K-MODDL website, kmoddl.library.cornell.edu.

K-MODDL will make the collection available to educators, researchers, and students well beyond the Cornell campus, according to the site.

Those with access to a 3-D printer will be able to build a reproduction of the real thing, to see up close how the mechanism works, Lipson said.

The K-MODDL team uses laser scanning to create CAD files, which are converted to be used by a Dimension printer from Stratasys of Eden Prairie, Minn., to reproduce physical models. Stereolithography files for several models are available for download at the K-MODDL website allowing users with access to a 3-D printer to download, print, and study their own functional physical replicas.

The physical replicas of the originals are expected to be particularly useful for students. Rather than just seeing virtual models or watching movies online, students anywhere with access to the Internet and a 3-D printer will be able touch and experience these models directly and get a true sense of how they function, Lipson said.

Lipson was featured in the January 2012 issue of Mechanical Engineering magazine about his work with bioprinting, another application of 3-D printing technology.

SOLDIER IDENTIFIED

Reverse engineering also served as a critical toot in solving a mystery from World War I. A soldier killed in action was finally identified and laid to rest in March 2011 at La Chaudiere Military Cemetery in Vimy, France, thanks to help from the technology.

The remains of the soldier, now identified as Private Thomas Lawless of Calgary, Alberta, were discovered in 2003 at a construction site near Avion, France. He was killed in action on June 8, 1917, a few months after the Battle of Vimy Ridge. He was 28.

Two sets of remains were found at the site. The first soldier was identified using DNA analysis in 2007 as Private Herbert Peterson.

A combination of historical research, forensic anthropology, 3-D facial reconstruction, and isotopic analysis yielded Lawless's identification, said Andrew Nelson, an associate dean of research for faculty of social science at the University of Western Ontario in London. He led research on the identification project.

"Although it's sad to contemplate the loss of young lives in war, it's rewarding to account for the missing, both for the sake of the deceased and for long-grieving family members," Nelson said.

In order to narrow the list of possible matches for the remains, Nelson and his team created 3-D CAD models of Lawless's skull, derived from computer tomography scan data of several large skull fragments. Physical models of the skull were then made from scan data with a 3-D printer from Z Corp. of Burlington, Mass.

Next, artist Christian Corbet, guided by muscle markings on the skull model and tissue-depth tables, used modeling clay to reconstruct a face.

The team then photographed that face, and superimposed images of it on photographs of soldiers who were potential matches, Nelson said.

By seeing how the images lined up--by face height and width and by features such as jaw shape--the team was able to narrow the list of potential matches to two. An isotopic analysis of teeth and the jawbone indicated that the recovered soldier grew up in Dublin, which matches with Lawless's history, Nelson said.

Lawless, born April 11, 1889, was a member of the 49th Battalion, Canadian Expeditionary Force.

"Anthropological analysis and mitochondrial DNA testing are standard approaches for identification," Nelson said. "However, mitochondrial DNA requires material from living family members on the maternal side to make a connection. In this case, we had none of that at our disposal.

"To the best of my knowledge, this is the first instance in which facial reconstruction and isotopic analysis were added to the mix," he said. "It may result in a new protocol, or certainly new tools, for the identification of the missing."

Reverse engineering and 3-D printing tools have a variety of applications in anthropology beyond the identification of soldiers' remains, Nelson added. For example, his team used 3-D printing in the 2003 facial reconstruction of an Egyptian mummy housed at the Chatham-Kent Museum in Chatham, Ontario.

"Societies who wish to move forward must know their past to better understand who they are now and where they might be going," he said. "The high variability of cultures of the past--before the internetworking of the world--tells us a lot about the interplay of traits like gender, status, health, and wealth in different settings.

"It's the bones that help us associate those cultural traits with a particular set of human remains," he added. "And though CT scans enable us to look inside a mummy, for example, without disturbing the bones, wrappings, and so on, 3-D printing lets us extract these pieces, figuratively speaking, by creating a physical model from CT scan data. We can thus examine the bones more closely and learn more from them."

SEEING SCULPTURES

Archaeologists at the University of South Florida in Tampa have used technologies that include laser scanners and geophysical imaging to document the past without the need to dig at a site or to remove artifacts.

Travis Doering and Lori Collins codirect the university's Alliance for Integrated Spatial Technologies, which specializes in 3-D and spatial documentation and analysis. They're also assistant professor and visiting instructor, respectively, in the school's anthropology department.

The pair recently carried out heritage preservation work at the archaeological site known as La Venta in Tabasco, Mexico. It has been identified as a pre-Columbian civic-ceremonial center of the Southern Gulf Coast Olmec civilization. It dates from around 900 to 400 B.C., Doering said.

The site was first excavated in the early 1940s by expeditions led by archaeologist Matthew Stirling, who uncovered monumental carved stone heads and other monolithic stone objects that would come to define Olmec art.

In 2007, Doering and Collins, along with Mary Pohl, an associate anthropology professor at Florida State University in Tallahassee, visited the archaeological site and the Mexican museums where the sculptures reside, and with permission from the Mexican government, they used close-range 3-D laser scanning techniques to capture the La Venta sculptures.

They then performed post-processing of the sculpture data in University of South Florida's AIST visualization laboratories. The team used post-processing software from Geomagic software of Morrisville, N.C., to create 3-D models and surface elevation models that show carved elements in new and better ways, Doering said.

Students can then view the sculptures in high resolution as well as manipulate the pieces to examine dimension and surface metrology and virtually rake light across the pieces to bring out details.

The trio shares its 3-D data and images with archaeologists and researchers who want to interpret and understand ancient Olmec communication systems. The data is also used to teach classes in heritage and museum studies, allowing students to learn about the ancient past in new ways, including 3-D renderings and models, 3-D printing of objects, and virtual site visitation, Doering said.

The team has visited other Olmec sites in Mesoamerica, where they have added advanced photographic imaging techniques such as reflectance transformation imaging and other forms of photographic analysis to provide details about surface treatment, stone weathering, and ancient and modern modifications to the stone, he added.

It is expected that engineering technology will find an increasing a role to play in reconstructing the past for modern study. As Nelson from the University of Western Ontario said, academics and historians are just getting started with these reconstructive techniques.

Jean Thilmany is an associate editor of Mechanical Engineering magazine.
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Author:Thilmany, Jean
Publication:Mechanical Engineering-CIME
Geographic Code:1U2NY
Date:Apr 1, 2012
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