JLA Vol:3 Iss:3 (ANSI Z136.2 Update: Ocular Effects of Laser Infrared Radiation)

Authors:
William T. Ham
Harold A. Mueller
Division of Biome´dical Engineering, Department of Biostatistics, Virginia Commonwealth University, Richmond, Virginia

Laser radiation employed in fiber optic communications systems is a possible hazard to the eyes of personnel working with or maintaining such equipment. To investigate the potential hazard of infrared laser wavelengths centered around 1550 nm we exposed the corneas of 12 Dutch belted rabbits to a laser diode furnished by Bell Laboratories. Maximum power output through a 4‐meter fiber optic cable was 5.6 mW. Anesthetized and fully dilated rabbits were exposed for time durations of 1, 10 and 100 s to po...

JLA Vol:3 Iss:3 (Determining Weld Quality in Pulsed Nd:YAG Laser Spot Welds)

Authors:
H. N. Bransch
Z. Y. Wang
J. T. Liu
D. C. Weckman
H. W. Kerr
Department of Mechanical Engineering, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1

For pulsed Nd:YAG laser spot welding applications, the development of optimum welding procedures ought to include various measures of weld size and quality, such as weld diameter, depth, surface contour and porosity. A split‐specimen technique has been developed that, despite the small size of the welds, allows such measurements to be made faster and more accurately than the traditional metallurgical technique involving sectioning, polishing and etching. In the sp...

JLA Vol:3 Iss:3 (Fusion Zone Structures in Laser Welded Al‐SiC Composites)

Authors:
Mary H. McCay
T. Dwayne McCay
Narendra B. Dahotre
C. Michael Sharp
Center for Laser Applications, University of Tennessee Space Institute, Tullahoma, Tennessee 37388

Metal matrix composites continue to be desirable structural materials but difficulties in joining limit their usefulness. This paper describes the results of a study on the laser welding of A356‐AI/SiC particulate composites. Three separate processing regimes are identified based upon analytical model predictions and metallographic analysis of the solidification structures.

JLA Vol:3 Iss:3 (The Role of Oxidation in Laser Cutting Stainless and Mild Steel)

Authors:
A. Ivarson
J. Powell
C. Magnusson

This paper gives the results of a detailed examination of the particles ejected from the cut zone during CO₂ laser cutting of mild and stainless steels. Cuts were carried out over a range of material thickness at the optimum speed for each at a laser power of 900 Watts. Particles ejected from the cut zone were collected and analyzed to establish their chemical and physical characteristics. Analysis techniques included Scanning Electron Microscopy, wet chemical analysis, optical microscopy, metallography and particle sizing. The results from this extensive analysis have enabled the authors to estimate the...

JLA Vol:3 Iss:3 (Comparison between Abrasive Water Jet Cutting and Laser Cutting)

Authors:
L. Ohlsson
J. Powell
A. Ivarson
C. Magnusson

This paper is intended to demonstrate the advantages and disadvantages of laser profiling techniques as compared with the Abrasive Water Jet (AWJ). The growth of AWJ as a cutting tool has provided engineers with a new profiling technique which often offers great technical and commercial advantages over more traditional methods. However, AWJ cutting is not the best solution to all profiling problems. There are a number of techniques which compete with or complement the process and the optimum profiling method can be difficult to identify[1]. The following paper serves as a general guide&hyphe...

JLA Vol:3 Iss:3 (The American Society for Laser Medicine & Surgery Presents the William B. Mark Award to Myron L. Wolbarsht)

Authors:
Caroline S. Mark

JLA Vol:3 Iss:3 (Treating Birthmarks With Diabetes)

Authors:
Myron L. Wolbarsht
Psychology Department, Duke University

JLA Vol:3 Iss:3 (Safety of Medical Excimer Lasers with an Emphasis on Compressed Gases)

Authors:
David H. Sliney
Laser Microwave Division, US Army Environmental Hygiene Agency, Aberdeen Proving Ground, MD 21010‐5422

Terrance N. Clapham
VISX, Inc., 919 Kifer Road, Santa Clara, CA 94086

Excimer lasers which emit short ultraviolet radiation (UVR) are currently being used in experimental and developmental surgical applications. Although UVR exposure is possible, it is not normal in laser angioplasty (cardiovascular surgery) and is insignificant in photokera‐toplasty (ophthalmic surgery). However, significant potential hazards exist with the use of excimer laser gases such as fluorine and HCI. Stringent safeguards for handling and use are ...

JLA Vol:3 Iss:3 (Cooperative R&D Project: Laser Biomedical Subsurface Imaging)

Authors:
Leon Goldman
J. H. Kerr
Department of Dermatology, Naval Hospital, San Diego, California 92134‐5000

With the experience of the U.S. Navy in photon transmission through turbid media, a cooperative research and development project has been initiated for laser subsurface imaging. This concerns laser expertise, laser institutes, and consultants. The initial technologies considered at present are laser transmission with chromophores, including photodynamic therapy, spectroscopy, biomedical optical phase conjugation, pulsed thermal radiometry of Nelson, digital ultrasound with hopeful laser additive imagery, and MRI with holography and radiowaves. Laser transil...

JLA Vol:3 Iss:3 (Comparison of the CDRH and IEC Standards for Laser Products. Part I)

Authors:
Jerome E. Dennis
Center for Devices and Radiological Health, Food and Drug Administration, Rockville, Maryland

David H. Edmunds
Xerox Corporation, Webster, New York