JLA Vol:2 Iss:1 (On Laser Vibrometry of Rotating Targets: Effects of Torsional and In‐Plane Vibration)

Authors:
S. J. Rothberg
J. R. Baker
N. A. Halliwell
ISVR, University of Southampton, Highfield, Southampton S09 5NH, England

Vibration measurements on rotating surfaces are often referred to in the commercial literature as a major application of laser Doppler vibration transducers. This paper examines such use of these instruments and shows how the presence of a velocity component due to the rotation itself leads to spurious measurement dependence on both torsional vibration and motion perpendicular to the line of incidence of the laser beam. In addition, the scale of this dependence increases with both rotation speed and perpendicular distance between the l...

JLA Vol:16 Iss:4 (Microstructural aspects of laser dissimilar welds of hard metals to steels)

Authors:
A. Costa
IDMEC, Av. Rovisco Pais, 1049-001 Lisboa, Portugal

L. Quintino
IDMEC, Av. Rovisco Pais, 1049-001 Lisboa, Portugal and Instituto Superior Te´cnico, Secc¸a˜o de Tecnologia Mecaˆnica, Av. Rovisco Pais, 1049-001 Lisboa, Portugal

R. M. Miranda
IDMEC, Av. Rovisco Pais, 1049-001 Lisboa, Portugal and Universidade Aberta, R. Escola Polite´cnica 147, 1269-001 Lisboa, Portugal

Laser beam welding has been widely used in industry in the past decade. Recently, applications in dissimilar welds involving hard metals have been investigated. Hard metals are commonly used in tool manufacturing and this application...

JLA Vol:21 Iss:1 (Local susceptibility of the retina, formation and duration of afterimages in the case of Class 1 laser products, and disability glare arising from high-brightness light emitting diodes)

Authors:
Hans-Dieter Reidenbach
Cologne University of Applied Sciences, Research Laboratory on Medical Technology and Non-Ionizing Radiation, Betzdorfer Str 2, 50679 Koeln, Germany

According to the new European Directive on Artificial Optical Radiation, the employer has to determine the exposure and the assessment of risks and in addition, he shall give particular attention to any indirect effects, such as temporary blinding, when carrying out the risk assessment. Up to now, secondary effects such as temporary blinding have not been regarded in safety standards and there exist but a few data on this topic as far as modern artificial high-brightness (HB) light sources are concerned. Te...

JLA Vol:24 Iss:4 (Cellular reactions toward nanostructured silicon surfaces created by laser ablation)

Authors:
K. Wallat
Institute of Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen, Universitaetsstr. 5-7, 45117 Essen, Germany

D. Do¨rr
R. Le Harzic
F. Stracke
D. Sauer
Fraunhofer Institute for Biomedical Engineering (IBMT) and Chair for Molecular and Cellular Biotechnology (University of Saarbruecken), Ensheimer Str. 48, 66386 St. Ingbert, Germany

M. Neumeier
A. Kovtun
Institute of Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen, Universitaetsstr. 5-7, 45117 Essen, Germany

H. Zimm...

JLA Vol:4 Iss:3 (Recommendations for Safe and Appropriate Use of Lasers in Dentistry in Face of Rising Concerns)

Authors:
Leo J. Miserendino
Elliot Abt
David Harris
Harvey Wigdor
The Chicago Dental Laser Institute

JLA Vol:15 Iss:1 (Microstructure and corrosion behavior of high power diode laser deposited Inconel 625 coatings)

Authors:
J. Tuominen
Laser Application Laboratory, Tampere University of Technology, FIN-33101 Tampere, Finland

P. Vuoristo
T. Ma¨ntyla¨
Institute of Materials Science, Tampere University of Technology, FIN-33101 Tampere, Finland

J. Latokartano
J. Vihinen
Laser Application Laboratory, Tampere University of Technology, FIN-33101 Tampere, Finland

P. H. Andersson
Institute of Production Engineering, Tampere University of Technology, FIN-33101 Tampere, Finland

A series of experiments were performed to investigate the one-step laser cladding of Inconel 625 powder, injected off-axially onto m...

JLA Vol:25 Iss:3 (Evaluation of corneal and eye lens irradiance for optical aided viewing)

Authors:
Enrico Galbiati
GEST Labs, Via Kennedy, 20871 Vimercate, Italy

The use of a magnifying lens with a highly divergent laser beam may cause a big increase of the irradiance on the cornea and the eye lens. This study provides the analysis of several cases where the use of a lens lead to a corneal irradiance significantly higher than the naked-eye viewing. The examples analyzed in this study allow determining the factors that represent the increase of the corneal irradiance caused by the use of the lens. The results indicate that these factors of irradiance increase may be close to 100.

JLA Vol:19 Iss:2 (Welding of titanium and other refractory metals with a free pulse shaping laser)

Authors:
Karsten Richter
Lasag AG, Switzerland

Uwe Reisgen
Wilfried Behr
Forschungszentrum Ju¨lich GmbH, Germany

Ronald Holtz
Lasag AG, Switzerland

Refractory metals are used as construction materials for specific applications. Amongst the refractory metals, titanium has a special status due to its multi-faceted property profile and its comparatively low price. Titanium materials have outstanding properties, such as excellent resistance to corrosion and very high strength at low densities, which lead to their preferred use in chemical engineering and as a structural material in lightweight construction. Due to the high affin...

JLA Vol:23 Iss:1 (Review of laser microscale processing of silicon carbide)

Authors:
B. Pecholt
S. Gupta
P. Molian
Department of Mechanical Engineering, Laboratory for Lasers, MEMS and Nanotechnology, Iowa State University, Ames, Iowa 50011

A review of various laser techniques for microscale processing of SiC for microelectronics and microelectromechanical-system applications is presented. SiC is an excellent material for harsh environments due to its outstanding mechanical, thermal, and chemical properties. However, its extreme thermodynamic stability and inert properties created difficulties in conventional microfabrication methods which provided an opportunity for the exploration of laser processing as an alternative. Many aspects...

JLA Vol:7 Iss:3 (Characterization of chromium bearing surface alloys produced by laser alloying on low carbon steel substrates)

Authors:
G. L. Goswami
Dilip Kumar
A. L. Pappachan
A. K. Grover
K. Sridhar
Array

High‐chromium ferritic alloys were produced on mild steel substrates by laser surface alloying. For this, chromium‐plated mild steel samples were treated with a pulsed Nd:YAG laser (300 W maximum power) by varying the average power level from 21.6 W to 30.0 W. The chromium content of the surface alloys was in the range of 3.0–27.0 wt%, with fairly uniform depth of alloying. Microscopy showed very fine austenite needles within elongated/equiaxed ferrite grains in the laser‐alloyed zone (LAZ). X‐ray diffraction indi...