JLA Vol:1 Iss:3 (Laser Welding of Plastics in Low and High Gravity Environments)

Authors:
R. E. Mueller
W. W. Duley
CRESS and Laser Processing Laboratory, York University, Toronto, Ontario, Canada M3J 1P3

S. MacLean
M. Garneau
B. Tryggvason
Canadian Astronaut Office, National Research Council, Ottawa, Ontario, Canada K1A 0R6

W. F. J. Evans
Atmospheric Environment Service, 4905 Dufferin Street, Downsview, Ontario M3H 5T4

Initial results of a series of laser processing experiments performed under the micro‐gravity conditions supplied by NASA's KC‐135 aircraft are presented. Weld morphologies of polypropylene and polyethylene were obtained under both hyper‐ and hy...

JLA Vol:1 Iss:3 (Performance of a Broadband Free‐Electron Laser and Preliminary Studies on Its Application to Biology and Medicine)

Authors:
Stephen Benson
John Madey
Dept. of Physics, Duke University, Durham NC 27706

Richard Straight
Brett Hooper
Utah Laser Institute, Department of Veterans Affairs and the University of Utah Medical Centers, Salt Lake City, Utah 84148

Recent performance improvements in the free‐electron laser (FEL) have allowed it to operate at a level suitable for most applications in laser medicine. A brief description of the operation of a free‐electron laser will be presented. The performance desired in a medical FEL will be described and the performance to date of the Mark III mid‐infrared to visible FEL at Stanford Univer...

JLA Vol:1 Iss:3 (Simultaneous Laser Velocimeter and Concentration Measurement)

Authors:
David T. Walker
William G. Tiederman
School of Mechanical Engineering, Purdue University, West Lafayette, Indiana 47907, U.S.A.

Inability to predict the high Schmidt number mixling of a concentrated polymer solution injected into a channel flow of water motivated the development of a method for measuring the product of the velocity fluctuation normal to the wall and the fluctuation in the polymer concentration. Time‐resolved concentration measurements were obtained using a laser‐induced fluorescence technique. The injected fluid was marked with a fluorescent dye and the spatial distribution of the intensity of fluorescent light emitted from an argo...

JLA Vol:1 Iss:4 (FDA Medical Incident Report Is Sobering Reminder of Laser Safety Education Needs)

Authors:

JLA Vol:1 Iss:4 (Installation of a Commercial Excimer Laser in the Operating Room)

Authors:
H. Benoit
J. Clark
W. J. Keon
University of Ottawa Heart Institute, Ottawa Civic Hospital, Ottawa, Ontario, K1Y 4E9

A multi‐use commercial excimer laser was modified for use in the cardiovascular operating room. The laser was originally designed for research and laboratory applications and required on‐site development to become acceptable for the clinical environment. Particular care was taken to control the associated hazards of toxic gas storage, handling and disposal. Resolution of problems relating to line isolation and leakage currents, design of administrative and engineering controls for laser and associated hazards, safety and ...

JLA Vol:1 Iss:4 (Laser Accidents: Are They All Reported and What Can Be Learned from Them?)

Authors:
R. James Rockwell
Rockwell Laser Industries, Cincinnati, Ohio

JLA Vol:1 Iss:4 (Laser System for Dulling Work Roll by Q‐Switched Nd:YAG Laser)

Authors:
K. Minamida
J. Suehiro
T. Toshimitu
T. Kawamoto
R & D Laboratories‐I, Central R & D Bureau, Nippon Steel Corporation, 1618 Ida, Nakahara‐ku, Kawasaki 211, Japan

A new dulling system for the work rolls used to roughen the surface of cold‐rolled steel sheet has been developed. Such sheets are used in various products, such as outer panels of automobiles, and decorative outer plates of electric appliances. In this process, several pulsed laser beams generated by Q‐switched Nd:YAG lasers produce small craters with rims around them. This process includes a longitudinal scanning system...

JLA Vol:1 Iss:4 (Optical Engineering — A New Form of Industrial Energy)

Authors:
W. M. Steen

A brief review OF the development of civilization on this planet leads to a fairly strong correlation between our ability to apply new forms of energy and the growth of our quality of life. With the comparatively recent invention of the laser, optical energy has become available in a form and at intensities which can be applied. This article examines some of the differences between optical energy and other forms of industrial energy with a view to suggesting where future growth may occur and why our grand‐children may bask in a higher quality of life due to our efforts to apply this new form of energy. Some of the principle differences noted are: the current laser ...

JLA Vol:1 Iss:4 (Optical Methods in Flow Visualization)

Authors:
Wen‐Jei Yang
Yi Chen
Department of Mechanical Engineering and Applied Mechanics, The University of Michigan, Ann Arbor, Michigan 48109

Optical techniques for flow visualization are presented, including light‐sheet flow visualization, shadowgraphy, schlieren method, interferometry, holography, speckle photography, laser‐induced fluorescence and thermography. The principles of these methods are briefly described and the examples of their applications to flow visualization are given.

JLA Vol:1 Iss:4 (Recent Developments in Laser Melt/Particle Injection Processing)

Authors:
K. P. Cooper
Geo‐Centers, Inc., 10903 Indian Head Highway, Fort Washington, Maryland 20744

P. Slebodnick
Naval Research Laboratory, Washington, D.C. 20375.

Investigations into crack formation in particle injected surfaces and into microstructural evolution during cladding were some of the recent developments in laser melt/particle injection processing. Both surface modification techniques involved blowing powder particles into a melt pool formed by a laser beam. When the particulate materials were metal carbides composite surface layers were formed and the thermal stresses that developed during cooling of the carbide injected layer resulted in th...