Journal of the National Academy of Forensic Engineers <p>The JOURNAL OF THE NATIONAL ACADEMY OF FORENSIC ENGINEERS is intended to provide a means for the Associate Members, Members, Senior Members, Fellows and Affiliates of NAFE to present case studies and principled discussion of the application of their specific technologies in the practice of forensic engineering.</p> <p>A concise abstract of 100 to 150 words maximum shall be sent to the Manuscript Editor for initial consideration. Upon approval of the abstract, authors will be scheduled to present their work at one of the semi-yearly NAFE Technical Conferences. A 90% complete draft copy of the manuscript shall be submitted to the assigned Associate Editor for review and approval no later than 60 days before the conference.&nbsp; Presentation slides are due 45 days before the conference.</p> <p>For details about requirements for manuscripts, visit:<br><a title="NAFE Journal Contents" href="">NAFE Journal Contents</a></p> <p>For details on the NAFE Journal peer review process, visit:<br><a title="NAFE Peer Review Process" href="">NAFE Peer Review Process</a></p> <p>For the NAFE Bylaws content “Responsibilities of, Obligations of and Guidelines for Authors, the Journal Editor, Technical Review Committee Chair, and Technical Reviewers,” visit:<br><a title="NAFE Author Guidelines" href="">NAFE Author Guidelines</a></p> <p>The Journal of the National Academy of Forensic Engineers® contains papers that have been accepted by NAFE. In most cases, papers have been presented at NAFE seminars. Members and Affiliates receive a PDF download of the Journal as part of their annual dues. All Journal papers may be individually downloaded from the NAFE website at There is no charge to NAFE Members &amp; Affiliates. A limited supply of Volume 33 and earlier hardcopy Journals (black &amp; white) are available. The costs are as follows: $15.00 for NAFE Members and Affiliates; $30.00 for members of the NSPE not included in NAFE membership; $45.00 for all others. Requests should be sent to Arthur Schwartz, Executive Director, NAFE, 1420 King St., Alexandria, VA 22314-2794.</p> <p>Comments by Readers<br>Comments by readers are invited, and, if deemed appropriate, will be published. Send to: Arthur Schwartz, Esq., Executive Director, 1420 King St., Alexandria, VA 22314-2794. Comments can also be sent via email to</p> <p>Material published in this Journal, including all interpretations and conclusions contained in papers, articles, and presentations, are those of the specific author or authors and do not necessarily represent the view of the National Academy of Forensic Engineers® (NAFE) or its members.</p> <p>© 2019 National Academy of Forensic Engineers® (NAFE). ISSN: 2379-3252</p> National Academy of Forensic Engineers en-US Journal of the National Academy of Forensic Engineers 2379-3244 <p>In connection with my efforts as a presenter at any NAFE educational program and/or as an author of a NAFE Journal article, I may have occasion to perform tasks and activities which could be determined to constitute authorship under applicable copyright laws. It is my express intent never to exercise any intellectual property right in any NAFE document or publication, whether in final or draft form. With regard to any intellectual property I provide to NAFE, I hereby warrant that (1) I am the author of such work or that I have secured written consent for use of any portions of the work copyrighted by others and (2) to the best of my knowledge, the work does not violate or infringe the copyright or other personal property rights of others.</p> <p>I hereby acknowledge that my participation in NAFE activities provides me with substantial and valuable benefits, including access to current and revised forensic engineering content, discussion of existing and emerging legal and forensic principles, concepts and trends, and the opportunity to review forensic engineering information prior to its dissemination to the broader engineering community.</p> <p>Accordingly, for and in consideration of the foregoing, I hereby bargain, sell and irrevocably assign to the National Academy of Forensic Engineering (NAFE), all of my right, title and interest, property claim, and demand of every kind and nature whatever in any and all copyrights (including full and exclusive worldwide ownership of the copyright, and all of the rights comprised therein, in print and in all other media), under and by virtue of any acts of Congress, with the rights to any and all profits, benefits and advantage that may arise from printing, publishing or sale of printed copies, electronic versions or other media assigned to the NAFE.</p> Forensic Engineering Application of the Matchmoving Process <p>This paper presents a methodology that uses the photogrammetric process of matchmoving for analyzing objects (vehicles, pedestrians, etc.) visible in video captured by moving cameras. Matchmoving is an established scientific process that is used to calibrate a virtual camera to “match” the movement and optic properties of the real-world camera that captured the video. High-definition 3D laser scanning technology makes it possible to accurately perform the matchmoving process and evaluate the results. Once a virtual camera is accurately calibrated, moving objects visible in the video can be tracked or matched to determine their position, orientation, path, speed, and acceleration. Specific applications of the matchmoving methodology are presented and discussed in this paper and include analysis performed on video footage from a metro bus on-board camera, police officer body-worn camera footage, and race track video footage captured by a drone. In all cases, the matchmoving process yielded highly accurate camera calibrations and allowed forensic investigators to accurately determine and evaluate the dynamics of moving objects depicted in the video.</p> Richard M. Ziernicki Angelos G. Leiloglo Taylor Spiegelberg Kurt Twigg Copyright (c) 2018-01-01 2018-01-01 35 2 Forensic Engineering Investigation of a Fatal Farm Tractor Incident A farm owner was found unresponsive with crushing head injuries on his property in rural Ontario. His small farm tractor was found 60 meters away down a small incline with the engine running and transmission in neutral. The owner’s son alleged that when the parking brake was engaged (with the engine running and transmission in neutral), this tractor’s parking brake would “pop out,” allowing the tractor to move. Field tests were conducted on the tractor to attempt to duplicate the scenario and to determine if the alleged sequence of events was plausible. Components of the parking brake and one exemplar were assessed with specialized metrology to determine whether they were within the manufacturing specifications on the blueprint. A 3-D CAD model of fit was created, and several variances were identified between the parts and the factory drawing. The results of the analysis concurred with the scenario that these variances led to the disengagement of the parking brake and operator fatality. Daniel P. Couture Copyright (c) 2018-01-01 2018-01-01 35 2 Engineering Analysis of Cost to Protect Workers from Diacetyl Exposure and the Economic Benefit of Noncompliance Large commercial bakeries use artificial butter flavor (containing diacetyl) in its recipes, and have for more than 40 years. In 2012, a health-based exposure threshold was published for diacetyl by the American Conference of Governmental Industrial Hygienists (ACGIH). Bakery managers typically knew what was necessary to protect workers from exposure. However, for a variety of reasons, most did little to control exposure: The Food and Drug Administration said diacetyl was generally recognized as safe; substitute products had not been demonstrated as less harmful; and no regulatory standard had been established. This study develops the costs that would have been necessary to protect workers, using the U.S. EPA model (known as BEN) to calculate the economic benefit of noncompliance, and offers a characterization of the profit incentive to place workers at risk. Drew Peake Greg Hait Copyright (c) 2018-01-01 2018-01-01 35 2 Forensic Engineering Analysis of Fire Caused by Control Failure Due to Deviation from Patented Design A fire in a multi-unit condominium complex occurred, causing the building to be a complete loss. The point of the fire’s origin was traced to a recently drained hot tub’s electric heater. Examination of an exemplar heater revealed that a key safety-related control feature was manufactured in a configuration inconsistent with its original patent drawings in a way that would have lessened its performance for what may have been cost of manufacturing considerations. This change also brought into question whether the control that was reportedly tested at Underwriters Laboratory was one designed to the patent specifications. The manufacturer has since discontinued use of the control for subsequent installations. John Certuse Copyright (c) 2018-01-01 2018-01-01 35 2 Forensic Engineering Analysis of Commercial Vehicle Air Brake Systems Performance Braking systems for heavy commercial vehicles differ greatly from the design for light-duty motor vehicles. For example, 49 CFR 571.121 and 49 CFR 393.52 require loaded buses, single unit commercial vehicles, and vehicle-trailer combinations equipped with air brake systems to generate sufficient braking force to meet specific stopping distance, stopping acceleration rate, and brake force-to-weight percentage performance criteria. The combination of unique design, mechanical complexity, and maintenance issues characteristic to air brake systems also pose difficulty in the analysis of air brake system performance. Air brake system performance presents a difficult problem for the forensic engineer with limited familiarity regarding air brake system functions and the elements affecting brake performance. This paper provides insight into the evolution of air brake system standards and the applicable performance criteria for heavy commercial vehicles. The methods presented allow the forensic engineer to mathematically analyze and determine the effects of brake size, mismatched components, brake adjustment, and system air pressure on the overall braking force and stopping capabilities of air brake equipped commercial vehicles. Jerry S. Ogden Mathew Martonovich Copyright (c) 2018-01-01 2018-01-01 35 2