This paper gives the results of a detailed examination of the particles ejected from the cut zone during CO2 laser cutting of mild and stainless steels. Cuts were carried out over a range of material thickness at the optimum speed for each at a laser power of 900 Watts. Particles ejected from the cut zone were collected and analyzed to establish their chemical and physical characteristics. Analysis techniques included Scanning Electron Microscopy, wet chemical analysis, optical microscopy, metallography and particle sizing. The results from this extensive analysis have enabled the authors to estimate the...
JLA Vol:17 Iss:2 (Improved adsorption of human plasma fibronectin on magnesia partially stabilized zirconia (MgO–PSZ) bioceramic resulting from CO<sub>2</sub> laser irradiation)
Manufacturing Engineering Division, School of Mechanical & Production Engineering, Nanyang Technological University (NTU), Singapore 639798
The adsorption of proteins onto a biomaterial surface from the surrounding fluid phase is rapid, with the surface properties of the biomaterial determining the type, amount, and conformation of the adsorbed proteins. Magnesia partially stabilized zirconia (MgO–PSZ), a bioinert ceramic used at the high-load bearing sites, does not naturally form a direct bond with bone. It is believed that a favorable adsorption of the fibronectin could promote cell adhesion and subsequently the bonding between the...
Department of Forest Products, Faculty of Forestry, Bogor Agricultural University, Kampus IPB Darmaga, Bogor 16680, Indonesia
LABOMAP-ENSAM, rue Porte de Paris, 71250 Cluny, France
IREPA LASER, Poˆle API, 67400 Illkirch, France
Department of Natural Resources, Faculty of Science and Engineering, Shimane University, Matsue 690-8504, Japan
The interest of high speed steel (HSS) for wood cutting tools remains very important because of their good tool edge accura...
JLA Vol:8 Iss:3 (Laser shock processing of materials, physical processes involved and examples of applications)
Laser shock processing (LSP) consists of irradiating a metallic target with a short (about 20 ns) and intense (>1013W m−2) laser light in order to generate, through a high pressure surface plasma (>1 GPa), a plastic deformation and a surface strengthening within materials. This paper initially reviews the physical processes involved in the analytical modeling of the generation pressure mechanism in a confined plasma regime. Limiting factors such as the dielectric breakdown in the confining medium are also discussed together with current research directions aimed...
Dept. of Mechanical Engineering, Ibaraki College of Technology, Katsuta 312, Japan
Dept. of Mech. Eng. and Applied Mech., University of Michigan, Ann Arbor, Michigan 48109
Some recently developed optical methods for the measurement, control and shape recognition of particle flow are presented including motion control of micro‐particles by optical pressure, identification of particle groups by matched spatial filters, bidirectional light scattering/image processing, bidirectional light scattering/real time measurement, dual beam type particle counter, and speckle photography.
Thomas H. Dubaniewicz
Kenneth L. Cashdollar
Gregory M. Green
National Institute for Occupational Safety and Health, Pittsburgh Research Laboratory, P.O. Box 18070, Pittsburgh, Pennsylvania 15236
Laser-based instruments are used in areas where coal dust ignition presents a safety hazard. The National Institute for Occupational Safety and Health, Pittsburgh Research Laboratory (NIOSH, PRL) is conducting a study to help determine when an optical beam may be considered a potential ignition source in underground coal mines or coal storage facilities. Researchers conducted experiments to determine threshold igniting powers for Pittsburgh seam bituminous co...
JLA Vol:25 Iss:5 (Laser-induced thermoelectric voltage in La<sub>0.9</sub>Pr<sub>0.1</sub>MnO<sub>3</sub> thin films)
Beijing Key Laboratory for Nano-Photonics and Nano-Structure, Capital Normal University, Beijing 100048, People's Republic of China
The laser-induced thermoelectric voltage (LITV) was observed in La0.9Pr0.1MnO3 thin films grown on the vicinal cut LaAlO3 substrate by pulsed laser deposition for the first time. The detected signals were demonstrated to be originated from the anisotropic Seebeck effect. The largest peak value of the voltage is about 2.4 V, the full width at half-maximum of the temporal voltage peak and the rising time are 300–500 and 40–50 n...
R. W. McVey
R. M. Melnychuk
Department of Engineering Science and Mechanics and the Applied Research Laboratory, Pennsylvania State University, University Park, Pennsylvania 16801
J. A. Todd
Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, Pennsylvania 16801
R. P. Martukanitz
Applied Research Laboratory, Pennsylvania State University, State College, Pennsylvania 16803
An analytical relationship was derived to describe the amount of energy absorbed within preplaced powder during the laser deposition process. The relationship, which reflects an exponential decay of Beer&ndas...
Particle based near-field nanostructuring is an excellent possibility to overcome the optical diffraction limit in laser based material processing. In the near-field of microspheres which are irradiated with pulsed laser radiation, it is possible to generate nanoholes with diameters below 100 nm using a laser wavelength of 800 nm. To improve this approach, it is possible to position the microparticles with an optical trap to generate arbitrary structure geometries. In this paper, the authors describe the basic principle of optical trap assisted na...
Laser Microwave Division, U.S. Army Environmental Hygiene Agency
A tutorial guide is presented to provide uniform guidance when performing radiometric measurements upon laser systems to perform a hazard evaluation. This guide was requested by and presented to the Department of Defense (DOD) Laser System Safety Working Group (LSSWG) to serve as a standardized method when performing hazard evaluations primarily upon tactical and training military laser systems including laser rangefinders and designators. Technical information is provided in detail to select a suitable detector, preform radiometric measurements, assess laser system pointing errors, calculate laser p...
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