JLA Vol:7 Iss:3 (Laser beam surveying, refractive index measurements and the making of a 360° reflection hologram)
Notre Dame High School, 596 South Second St., San Jose, California 95112, U.S.A.
Triangulation measurements, using a laser to find the height of a room and of buildings, will be described first. This will be followed by triangulation and laser beam divergence measurements for range finding. The use of a hollow prism to hold liquids, whose refractive indicies are to be found, will then be described. The final topic will describe how a 360° reflection hologram was made at Notre Dame High School, utilizing three lasers and beam spreaders and four lasers and beam spreaders. The 360° hologram, made by a student, will be available for viewing.
JLA Vol:16 Iss:1 (Influence of surface preparation and process parameters on the porosity generation in aluminum alloys)
CLFA, avenue Prieur de la Côte d’or, 94114 Arcueil, France
A. B. Vannes
Ecole Centrale de Lyon, Ecully, France
The 4 kW cw Nd:yttrium–aluminum–garnet laser welding of solid solution hardened A5083 (5% Mg) and precipitation-hardened A356 (7% Si) alloys, sensitive to porosity formation was carried out at different welding speeds, under He gas shielding, and for partial penetration conditions, on bead on plate configuration. The porosity formation was examined through observation and evaluation of weld beads, based on x-ray radiography inspection coupled with image analysis, and quantification of gas...
JLA Vol:20 Iss:2 (Design and validation of a hybrid laser/water-jet machining system for brittle materials)
Department of Mechanical Engineering, Laboratory for Lasers, MEMS and Nanotechnology, Iowa State University, Ames, Iowa 50011-2161
A unique laser/water-jet (LWJ) cutting head has been designed, built, and interfaced with a CO2 laser for cutting and scribing of hard and brittle ceramic materials. Alumina samples were used to validate the effectiveness of the LWJ cutting head in thermal fracture mode. The results were compared with vaporization mode (focused beam) as well as thermal fracture mode (defocused beam) of air-assisted laser c...
JLA Vol:9 Iss:6 (Amendments to the Center for Devices and Radiological Health Federal Performance Standard for laser products)
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)
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:14 Iss:2 (Deformation behavior and microstructural changes of a hardened high carbon alloy steel in laser bending)
K. C. Chan
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))
Dave F. Farson
Hae Woon Choi
Department of Industrial, Welding and Systems Engineering, The Ohio State University, Columbus, Ohio 43221
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...
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
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:24 Iss:2 (Temperature measurement of laser heated metals in highly oxidizing environment using 2D single-band and spectral pyrometry)
PIMM Laboratory (Arts et Me´tiers ParisTech—CNRS), 151 Bd.de l’Hoˆpital, 75013 Paris, France
Institut Prime, CNRS-ENSMA-Universite´ de Poitiers, 1 Ave. Cle´ment Ader, BP 40109, 86961 Futuroscope Chasseneuil Cedex, France
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...
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...
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