July 2024
Volume 82 • Number 7
JOURNAL STAFF
PUBLISHER: Neal J. Couture, CAE
DIRECTOR OF PUBLICATIONS/
EDITOR: Jill Ross
ASSOCIATE EDITOR:
Stefanie Laufersweiler
PRODUCTION MANAGER: Joy Grimm
DIGITAL PUBLISHING MANAGER:
Synthia Jester
ASNT MEDIA &EVENT SALES
Peter Roy, proy@asnt.org
1-614-384-2431
Sonny Hines, shines@asnt.org
1-614-384-2434
TECHNICAL EDITOR
John Z. Chen, KBR
ASSOCIATE TECHNICAL EDITORS
John C. Aldrin, Computational Tools
Sreenivas Alampalli, Stantec
Ali Abdul-Aziz, Kent State University
Narendra K. Batra, Naval
Research Laboratory (retired)
Yiming Deng, Michigan
State University
Dave Farson, Ohio State University
Jin-Yeon Kim, Georgia
Institute of Technology
Cara A.C. Leckey, NASA
Langley Research Center
Mani Mina, Iowa State University
Ehsan Dehghan-Niri,
Arizona State University
Yi-Cheng (Peter) Pan, Emerson Inc.
Anish Poudel, MxV Rail
Donald J. Roth, Roth
Technical Consulting LLC
Ram P. Samy, Consultant
Steven M. Shepard,
Thermal Wave Imaging
Ripi Singh, Inspiring Next
Surendra Singh, Honeywell
Roderic K. Stanley, NDE
Information Consultants
Lianxiang Yang, Oakland University
Reza Zoughi, Iowa State University
CONTRIBUTING EDITORS
Toni Bailey, TB3NDT Consulting
Bruce G. Crouse, Inspection Services
Huidong Gao, PEMEX Deer Park
Saptarshi Mukherjee, Lawrence
Livermore National Laboratory
Hossein Taheri, Georgia
Southern University
UPFRONT
|
SCANNER
DIRECT AND REMOTE
VISUAL TESTING
Welcome to Materials Evaluation’s Technical Focus Issue on the nonde-
structive evaluation (NDE) method of visual testing (VT). Enhancing
the attention given to the VT method, for both direct and indirect
techniques, has been a career-long goal of mine. It is an honor and
privilege to serve as the guest editor for this special issue in the ever-
evolving landscape of VT. This NDE method has come a long way from
using a flashlight, magnifying glass, six-inch scale, and a dental mirror
for direct visual testing (DVT) of various metallurgical products, to the
complex world of digital remote visual inspection (RVI) with a myriad of
applications.
Advanced VT technologies enable the modern inspector to address
the inspection needs of a number of major industries. Several indus-
tries have utilized VT/RVI techniques to examine piping systems with
crawlers, power plant heat exchanger tubing with push tube cameras,
aerospace engines with videoscopes, reactor containments with
telescopes, and assembly line components with image-enhanced
measurement techniques.
The VT method has evolved from line-of-sight direct access, aided
by magnifiers and mirrors, to indirect techniques such as telescopes,
rigid borescopes, flexible fiberscopes, electrical pulses imaged by
charge-coupled device (CCD), computer-processed images, and
AI-assisted evaluations. We can now extend far beyond what the
human eye can directly see, using images captured by advanced tech-
nology and interpreted by the brain.
This special issue brings together a diverse range of contributions
from experts in power generation, gas turbines, the automotive
industry, and the petrochemical industry, focusing on VT personnel
qualification and certification methodologies.
Electric power generation plants—whether nuclear, fossil, hydro,
or wind power—and gas turbines have all been inspected using VT/
RVI techniques for decades. Any system or component experiencing
loose parts falling into unwanted spaces has relied on the expertise of
remote visual inspectors. These inspectors possess the special skills of
a puppeteer and the ability to operate using indirect images to retrieve
loose parts, a service provided by the RVI industry.
I am grateful to the authors whose dedication and expertise have
enriched this special issue. The compilation of varied applications
and the insights gained from these challenges will serve as a valuable
resource for professionals, researchers, and practitioners involved in
the dynamic realm of VT and RVI across a wide range of applications.
Thank you for your interest and support.
MIKE ALLGAIER
CHAIR, VISUAL TESTING COMMITTEE (T&E COUNCIL)
MWALLGAIER@OUTLOOK.COM
It is an honor
and privilege
to serve as the
guest editor
for this special
issue in the
ever-evolving
landscape of
visual testing.
J U L Y 2 0 2 4 • M A T E R I A L S E V A L U A T I O N 7

LASER TECHNOLOGY
OFFERS
BREAKTHROUGH
IN DETECTING
ILLEGAL IVORY
A new way of quickly distinguishing between illegal
elephant ivory and legal mammoth tusk ivory could
prove critical to fighting the illegal ivory trade. A
laser-based approach developed by scientists at the
Universities of Bristol and Lancaster could be used
by customs worldwide to aid in the enforcement of
illegal ivory from being traded under the guise of
legal ivory.
Despite the Convention on the International
Trade in Endangered Species (CITES) ban on ivory,
poaching associated with its illegal trade has not
prevented the suffering of elephants and is esti-
mated to cause an 8% loss in the world’s elephant
population every year. The 2016 African Elephant
Database survey estimated a total of 410 000
elephants remaining in Africa, a decrease of approx-
imately 90 000 elephants from the previous 2013
report.
While trading/procuring elephant ivory is illegal,
it is not illegal to sell ivory from extinct species,
such as preserved mammoth tusk ivory. This legal
source of ivory is now part of an increasing and
lucrative “mammoth hunter” industry. It also poses a
time-consuming enforcement problem for customs
teams, as ivory from these two different types
of tusks are broadly similar, making it difficult to
distinguish from one another, especially once speci-
mens have become worked or carved.
In this new study, scientists from Bristol’s School
of Anatomy and Lancaster Medical School sought
to establish whether Raman spectroscopy, which is
already used in the study of bone and mineral chem-
istry, could be modified to accurately detect differ-
ences in the chemistry of mammoth and elephant
ivory. The nondestructive technology, which involves
shining a high-energy light at an ivory specimen,
can detect small biochemical differences in the tusks
from elephants and mammoths.
Researchers scanned samples of mammoth
and elephant tusks from London’s Natural History
Museum using the laser-based method Raman
spectroscopy. Results from the experiment found the
technology provided accurate, quick, and nonde-
structive species identification.
“The gold standard method of identification
recommended by the United Nations Office on
Drugs and Crime for assessing the legality of ivory
predominantly are expensive, destructive, and
time-consuming techniques,” said Dr. Rebecca
Shepherd, formerly of Lancaster Medical School and
now at the University of Bristol’s School of Anatomy.
“Raman spectroscopy can provide results quickly (a
single scan takes only a few minutes) and is easier
to use than current methods, making it easier to
determine between illegal elephant ivory and legal
mammoth tusk ivory. Increased surveillance and
monitoring of samples passing through customs
worldwide using Raman spectroscopy could act as
a deterrent to those poaching endangered and criti-
cally endangered species of elephant.”
SCANNER
A selection of
elephant and
mammoth tusk
samples.
An ivory object, assumed to be of Asian elephant origin,
under the microscope inside a research-grade Raman
spectrometer.
8
M A T E R I A L S E V A L U A T I O N • J U L Y 2 0 2 4
CREDIT:
BEN
BOOTH
CREDIT:
DR.
REBECCA
SHEPHERD