JLA Vol:6 Iss:2 (Laser cladding of Ti–6Al–4V with various carbide powders)

Authors:
J. A. Folkes
K. Shibata
Nissan Motor Co., Ltd, Material Research Laboratory, Central Engineering Laboratories, 1, Natsushima‐cho, Yokosuka 237, Japan

Laser cladding Ti–6Al–4V can be achieved with various weight percentages of different carbide powders. The microstructure and morphology of the clad layer is determined by the cladding powder composition, for a given set of laser parameters, such that 10 and 20 wt %Cr₃C₂ results in a β + TiC clad microstructure; 10 and 20 wt %WC results in an α + TiC clad microstructure (plus some original WC); and Mo₂C gives an α + &be...

JLA Vol:6 Iss:2 (Laser safety notes)

Authors:
Robert Weiner
Weiner Associates, Manhattan Beach, California, U.S.A.

JLA Vol:6 Iss:2 (Laser safety programs in general surgery)

Authors:
Raymond J. Lanzafame
University of Rochester and Laser Center, Rochester General Hospital, Rochester, NY, U.S.A.

General surgery represents a speciality where, while any procedure can be performed with lasers, there are no procedures for which the laser is the sine quo non. The general surgeon may perform a variety of procedures with a multitude of laser wavelengths and technologies. Laser safety in general surgery requires a multidisciplinary approach. Effective laser safety requires the oversight of the hospital's “laser usage committee” and “laser safety officer” while providing a workable framework for daily laser use in a variety of clini...

JLA Vol:6 Iss:2 (Laser safety standards in Europe)

Authors:
B. A. Tozer
Lasermet Ltd and City University, London, U.K.

This paper reviews the present state of the standards‐making process in Europe, explaining such arcane terms as ‘CEN’, ‘CENELEC’, ‘Euronorm’ and ‘directive’. Standards‐making bodies in Europe work to strict guidelines with regard to their relationship to member countries of the EEC and EFTA, and work closely with the international standards bodies, IEC and ISO, to minimize duplication of effort and to ensure minimum conflict with international standards. The current situation with regard to laser safety standards in Europe is reviewed, and the author specul...

JLA Vol:6 Iss:2 (National Science Foundation undergraduate faculty enhancement workshop on advanced laboratory experiments using lasers)

Authors:
James E. Parks
Charles S. Feigerle
Robert Deserio
Joseph Wiest

A National Science Foundation undergraduate faculty enhancement workshop on advanced laboratory experiments using lasers was developed at the University of Tennessee, Knoxville, with the authors as the instructors. The workshop emphasized the development and implementation of laser‐based experiments primarily suitable for advanced undergraduate physics and chemistry laboratories. Participants gained practical, hands‐on experience in approximately 16 unique laser‐based experiments in atomic and molecular physics, physical chemistry, and biophysics. The wo...

JLA Vol:6 Iss:2 (Probability and risk in laser safety)

Authors:
Peter A. Smith
Special Senses Division, Royal Air Force Institute of Aviation Medicine, Farnborough, Hampshire GU14 6SZ, U.K.

International standards for the protection of the eyes from the hazards of laser radiation define a nominal ocular hazard distance (NOHD) beyond which an individual would not be expected to suffer any adverse effects from laser radiation. The NOHD assumes deliberate viewing of the laser source over an indefinite period of time and takes no account of the probability of the observer's eye being irradiated. This approach may lead to unrealistically large hazard areas for some laser devices. An alternative method of hazard assessment without compromising ...

JLA Vol:6 Iss:2 (Proposal for a standard for laser plume filter technology)

Authors:
Douglas E. Ott
School of Engineering, Mercer University, Macon, Georgia, and Georgia BioMedical, Inc., Macon, Georgia, U.S.A.

A methodology to critically appraise and assess the efficiency and efficacy of filters used in smoke evacuation systems is proposed. Currently the methods for evaluation of laser smoke evacuation systems and filtering are fraught with inconsistency, and laced with innuendo and extraopolation. A variety of tissues including beef, chicken, pork, mouse and human have been described. Both carbon dioxide and ND:YAG lasers have been used. A wide range of power densities have been applied. Environmental conditions during the studies either have not been descr...

JLA Vol:6 Iss:3 (Acoustic emission response of soda lime glass after a single Nd‐YAG laser pulse)

Authors:
R. Harrysson
P. Vomacka
Department of Engineering Materials, Luleå University of Technology, S‐951 87 Luleå, Sweden

When machining brittle solids with a laser, crack formation can occur in the material around the irradiated area causing a strength reduction of the machined material. The purpose of this work was to study a well known brittle material (soda lime glass) by means of acoustic emission (AE) in order to investigate the correlation between visually observed crack formation and detected AE energy released by the crack formation in the material. During and after irradiation of soda lime glass with an Nd‐YAG laser pulse, the number...

JLA Vol:6 Iss:3 (Attenuation of laser radiation by particles during laser materials processing)

Authors:
F. Hansen
W. W. Duley
Guelph‐Waterloo Centre for Graduate Work in Physics, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1

The extinction, absorption and scattering of laser radiation by small aerosol particles of Fe, Fe₃O₄, Al, and Al₂O₃ have been calculated using Mie theory at wavelengths of 1.06 and 10.6 μm. It is shown that the attenuation of incident laser radiation by particles with radii r in the range 10 nm ⩽ r ⩽ 10 μm can be significant over pathlengths as small as 10⁻² m when the ratio of aerosol mass density to solid density, M/ρ &...

JLA Vol:6 Iss:3 (Characterization of metal surfaces irradiated by a long‐pulse KrF excimer laser)

Authors:
Th. Sarnet
J. E. Montagne
G. Inglesakis
M. Autric
L. Barrallier
G. Barreau

Metallic samples were irradiated by a long&hyphen;pulse (τ > 300 ns) KrF laser. The experiments were performed with an energy density of 0.3–120 J cm⁻² and a power density of 1–400 MW cm⁻². The samples investigated were pure aluminum, aluminum alloy, low&hyphen;alloy constructional steel and titanium alloy. They were polished to obtain a roughness of 10 < Ra < 0.08 μm and stress&hyphen;relief heat&hyphen;treated for some residual stress measurements. The characterization of th...