JLA Vol:18 Iss:2 (Investigation of the effects of nonconventional beam geometries in laser surface treatment of ceramics: Theoretical analysis)
Laser Processing Research Centre, School of Mechanical, Aerospace and Civil Engineering, The University of Manchester, Manchester M60 1QD, United Kingdom and Corrosion and Protection Centre, School of Materials, The University of Manchester, Manchester M60 IQD, United Kingdom
Laser Processing Research Center, School of Mechanical, Aerospace and Civil Engineering, The University of Manchester, Manchester M60 1QD, United Kingdom
F. H. Stott
Corrosion and Protection Centre, School of Materials, The University of Manchester, Manchester M60 1QD, United Kingdom
Laser surface treatment of ceramics by melting and re...
JLA Vol:25 Iss:3 (Surface tension stabilized laser welding (donut laser welding)—A new laser welding technique)
Department of Engineering Sciences and Mathematics, Luleå University of Technology and Westinghouse Electric Sweden AB, SE-721 63 Va¨sterås, Sweden
Department of Engineering Sciences and Mathematics, Luleå University of Technology
A new laser welding process is presented which delivers a porosity free, spatter free weld. The process involves a donut shaped melt with a central hole of the same order of magnitude as the material thickness. The laser illuminates only the leading section of this melt. The hole is kept open by the melt surface tension.
JLA Vol:24 Iss:1 (Silicon(IV) phthalocyanine-loaded-nanoparticles for application in photodynamic process)
Andreza Ribeiro Simioni
Fernando L. Primo
Antonio Claudio Tedesco
The aim of this study was to evaluate the potential application of biodegradable nanoparticles containing a photosensitizer in photodynamic therapy. The poly (D,L lactic-co-glycolic acid) nanoparticles were studied by steady-state techniques, time-resolved fluorescence, and laser flash photolysis. The external morphology of the nanoparticles was established by scanning electron microscopy, and the biological activity was evaluated by in vitro cell culture by 3-(4,5 dimethyl-thiazol-2,5 biphenyl) tetrazolium bromide assay. The particles were spherical in shape exhibiting ...
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:16 Iss:3 (A procedure for the estimation of intrabeam hazard distances and optical density requirements under the ANSI Z136.1-2000 Standard)
Robert J. Thomas
Benjamin A. Rockwell
Air Force Research Laboratory, Brooks AFB, Texas 78235-5215
Wesley J. Marshall
USACHPPM, Aberdeen Proving Ground, Maryland 21010-5422
Robert C. Aldrich
Mary F. Gorschboth
Sheldon A. Zimmerman
Dahlgren Division, Naval Surface Warfare Center, Dahlgren, Virginia 22448-5100
R. James Rockwell
Rockwell Laser Industries, Cincinnati, Ohio 45243
Over the past few years, a comprehensive rewrite of the American National Standard for Safe Use of Lasers (ANSI Z136.1) has been conducted [American National Standards Institute, Z136.1-2000 America...
Politecnico di Milano, Dipartimento di Meccanica Via La Masa 1, I-20156 Milan, Italy
This paper studies the effect of different typologies of surface treatment by diode laser on the local formability of dual phase steel. An analytical thermal model allowed the temperature and cooling rate curves to be predicted and used to select the process parameter conditions. Microhardness measurements, microstructure observations, mechanical tensile test, and Erichsen cup test allowed the positive effect of the heat treatment on dual phase steel formability to be quantified.
B. S. Yilbas
A. Z. Al‐Garni
Mechanical Eng. Dept., KFUPM, P.O. Box 1913, Dhahran, Saudi Arabia
Laser induced heating processes are important when a laser is used as a machine tool in industry, since the quality of the machining process strongly depends on the heating mechanism. The present study examines a heat transfer model that provides useful information on the laser induced interaction mechanism. Steady state and time dependent heating models are introduced and temperature profiles inside the materials are predicted. Using appropriate assumptions, the time for the surface temperature to reach 90% of its steady state value is estimated. To valid...
Department of Mechanical Engineering, University of California, Santa Barbara, CA 93106
The photochromic flow visualization technique has been utilized to study several different liquid flows. The technique utilizes radiachromic dyes that can be dissolved in a number of liquids. The resulting dye‐solvent solutions remain colorless in the absence of ultraviolet radiation; however, the solutions turn dark blue when exposed to ultraviolet light. A nitrogen pulse laser has been constructed for use as source of ultraviolet radiation. When sharply focused, the emitted beam of ultraviolet light produces a very narrow, well define...
A. S. Salminen
V. P. Kujanpa¨a¨
Lappeenranta University of Technology, Laser Processing Centre, Tuotantokatur 2, FIN 53850 Lappeenranta, Finland
The utilization of the laser welding process with filler wire addition is often considered a complicated and difficult process which has too high accuracy demands for a work shop floor. This study shows the effect of some of the most important welding variables to the quality and efficiency of laser welding when welding with filler wire. The material used was a common structural steel St52/37 of 6 mm in thickness. The joint type used was a butt joint. Acceptable weld quality was achieved with most of the tested p...
JLA Vol:19 Iss:1 (Combining high-speed laser perforation and cold roll forming for the production of biomedical microfiltration membranes)
Laser Center University of Applied Sciences Muenster (LFM), Stegerwaldstrasse 39, 48565 Steinfurt, Germany
A. P. Hoult
SPI, 3 Wellington Park, Tollbar Way Hedge End, Southampton SO30 2QU, United Kingdom
A novel high speed two-step technique capable of performing large matrices of very small pores with micron dimensions in large sheets of thin stainless steel foils has been developed. This process combination is initiated by high-speed “on-the-fly” laser perforation. A 100 W fiber laser is capable of a very high drilling rate making it an attractive option for the creation of large drilling matrices ...
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