• 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...

    $25.00

  • 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


    $25.00

  • 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...

    $25.00

  • JLA Vol:23 Iss:2 (Experimental investigation of laser shock peening using femtosecond laser pulses)


    Authors:
    Dongkyun Lee
    Elijah Kannatey-Asibu
    Department of Mechanical Engineering, The University of Michigan, Ann Arbor, Michigan 48105-2125


    In this study, the feasibility of laser shock peening using ultrafast laser pulses was experimentally investigated. A top coating of zinc with a water confining layer was applied in the investigation. The zinc coating was used for the thermoprotective effect. A high numerical aperture (NA≅0.5) aspheric lens was used to minimize the optical breakdown of water. Microhardness measurements were made on the top surface of the shock peened specimen and compared with the original material hardness. The results provide useful insight on...

    $25.00

  • JLA Vol:7 Iss:3 (Laser beam surveying, refractive index measurements and the making of a 360° reflection hologram)


    Authors:
    David Foster
    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.

    $25.00

  • 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...

    $25.00

  • 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 ...

    $25.00

  • 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 ...

    $25.00

  • 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...

    $25.00

  • JLA Vol:17 Iss:3 (Experimental study of CO<sub>2</sub> laser welding inside a groove&mdash; Application to high thickness laser welding)


    Authors:
    M. Hamadou
    R. Fabbro
    F. Coste
    S. Slimani
    GIP GERAILP/LALP (CNRS) 16 bis, Av. Prieur de la Coˆte d’Or 94114 Arcueil, France


    Laser welding inside a groove has to be considered when a high thickness material is welded. The use of a groove shape allows the access of the laser beam to the lower part of the groove. The choice of the groove geometry (groove width, depth, or aperture angle), as well as the assist gas setup (leading, trailing or backside protection) are then significant operating parameters for the process control. In this study, U- and V-shaped groove welding with a CO2 laser was investigated. The U-shaped ...

    $25.00

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