JLA Vol:14 Iss:2 (Deformation behavior and microstructural changes of a hardened high carbon alloy steel in laser bending)

Authors:
K. C. Chan
J. Liang
Department of Manufacturing Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong

In this article, the deformation behavior and microstructure of a hardened high carbon steel in laser bending were examined. A CO₂ laser unit (TEM₀₀) was used to bend the samples at different laser powers, scanning velocities, and number of scans. A relatively linear relationship between bending angle and number of scans was obtained at laser powers of 150 and 200 W and at a scanning velocity of 30 mm/s. A threshold heat input of about 3.25 J/mm was observed, below which bending was unlikely to occur. The bending angle was al...

JLA Vol:18 Iss:3 (Femtosecond laser bulk micromachining of microfluid channels in poly(methylmethacrylate))

Authors:
Dave F. Farson
Hae Woon Choi
Department of Industrial, Welding and Systems Engineering, The Ohio State University, Columbus, Ohio 43221

Chunmeng Lu
L. James Lee
Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, Ohio 43221

Internal channels in a polymer are widely used in biotechnology applications such as DNA stretching and in devices such as micrototal analysis systems and lab on a chip systems. For manufacturing prototype devices, femtosecond pulsed laser energy has been used to implement a convenient direct write bulk-machining process in glass. In this technique, the laser beam is focu...

JLA Vol:26 Iss:1 (Two-dimensional simulation of laser ablation with 235 nanosecond pulses)

Authors:
Sousan Ghalamdaran
Iranian National Centre for Laser Science and Technology (INLC), PO Box 14665-576 Tehran, Iran and Department of Physics, Amir Kabir University of Technology, PO Box 15875-4413 Tehran, Iran

Parviz Parvin
Department of Physics, Amir Kabir University of Technology, PO Box 15875-4413 Tehran, Iran

Mohamad Javad Torkamany
Jamshid Sabbagh Zadeh
Iranian National Centre for Laser Science and Technology (INLC), PO Box 14665-576 Tehran, Iran

A two-dimensional thermal model of nanosecond pulsed laser ablation is developed to describe the physical processes, the plasma absorption, the crater profile, and the temp...

JLA Vol:9 Iss:6 (Amendments to the Center for Devices and Radiological Health Federal Performance Standard for laser products)

Authors:
Jerome E. Dennis
Center for Devices and Radiological Health, Food and Drug Administration, Rockville, MD, U.S.A.

Federal law requires that all laser products that are imported into or introduced into commerce in the United States comply with the performance standard published in the Code of Federal Regulations (CRF), Title 21, Parts 1040.10 and 1040.11, administered by the Center for Devices and Radiological Health (CDRH), US Food and Drug Administration. Although it contains somewhat different requirements for hazard classification, engineering controls and labeling, the ANSI Z136.1 standard defers to the CDRH standard. The CDRH standard became effective in August, 1976 and ...

JLA Vol:3 Iss:2 (Precision Limits of the Estimation of the Parameters of Fo¨rster Models of Fluorescence Waveforms)

Authors:
L. Jonathan Dowell
Los Alamos National Laboratory, Los Alamos, NM 87545

The author examined the precision of maximum‐likelihood‐derived, nonlinear least‐squared‐error algorithms that are suitable for laboratory implementation and that estimate the parameters of Fo¨rster models of fluorescence. The estimation precision for these parameters is limited by inherent noise in the fluorescence‐waveform measurement. This paper examines the Fo¨rster model and its recent applications and discusses parameter estimations for models of energy transfer by different wavefunction interactions. It presents the results of Monte Carlo simulation studi...

JLA Vol:16 Iss:4 (Laser assisted cleaning of oxide films on SUS409 stainless steel)

Authors:
H. Guo
Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802

R. Martukanitz
Applied Research Laboratory, The Pennsylvania State University, University Park, Pennsylvania 16802

T. DebRoy
Department of Materials Science and Engineering, The Pennsylvania State Univeristy, University Park, Pennsylvania 16802

Laser assisted cleaning of oxide films on SUS409 stainless steel plates was studied both experimentally and theoretically. The highly oxidized surfaces with oxide scales of about 25 μm thickness were irradiated with Q-switched pulsed Nd:yttritium–aluminu...

JLA Vol:21 Iss:2 (Partial growth of crack in laser scribing of glass)

Authors:
Koji Yamamoto
Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565–0871, Japan

Noboru Hasaka
Hideki Morita
Mitsuboshi Diamond Industrial Co., Ltd., 1-4-37 Minami-kaneden, Suita, Osaka 564–0044, Japan

Etsuji Ohmura
Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565–0871, Japan

The scribing of glass by a CO₂ laser is much more effective compared to the conventional mechanical technology in use because the strength of the cut glass is improved since microcracks and particles along the cut edge are lessened. However, the crack depth of ...

JLA Vol:1 Iss:2 (Laser Applications in Biomedicine. Part II: Clinical Applications)

Authors:
J. Stuart Nelson
Michael W. Berns
Beckman Laser Institute and Medical Clinic, University of California, Irvine, 1002 Health Sciences Road East, Irvine, California 92715

JLA Vol:24 Iss:2 (Temperature measurement of laser heated metals in highly oxidizing environment using 2D single-band and spectral pyrometry)

Authors:
Maryse Muller
Remy Fabbro
PIMM Laboratory (Arts et Me´tiers ParisTech—CNRS), 151 Bd.de l’Hoˆpital, 75013 Paris, France

Hazem El-Rabii
Institut Prime, CNRS-ENSMA-Universite´ de Poitiers, 1 Ave. Cle´ment Ader, BP 40109, 86961 Futuroscope Chasseneuil Cedex, France

Koji Hirano
Nippon Steel Corporation, Marunouchi Park Building, 2-6-1 Marunouchi, Chiyoda Ward, Tokyo 100-8071, Japan

Calibration and validation of two temperature measurement techniques both using optical pyrometry, usable in the framework of the study of the heated metals in highly oxidizing environments and more generally dur...

JLA Vol:6 Iss:3 (Laser express: Putting together a laser‐based road show)

Authors:
Steven S. Lympany
Laser & Electro‐Optics Technology, Central Carolina Community College, Lillington, NC 27546, U.S.A.

Laser technology has progressed to the point that most elementary through high school students are familiar with one or more laser applications. However, many of these students have not had the opportunity to witness a laser in acton where they can touch it and see it directly. In addition, most students are unaware of the career possibilities the field of laser technology has to offer. This paper presents the specifics of a successful laser‐based program that has been offered to K‐12 students and teachers in North Carolina over the la...