• JLA Vol:18 Iss:4 (Threshold powers and delays for igniting propane and butane-air mixtures by cw laser-heated small particles)


    Authors:
    Thomas H. Dubaniewicz
    National Institute for Occupational Safety and Health, Pittsburgh Research Laboratory, 626 Cochrans Mill Road, Pittsburgh, Pennsylvania 15236


    The National Institute for Occupational Safety and Health, Pittsburgh Research Laboratory conducted a study of laser safety in potentially flammable environments. Researchers measured threshold igniting powers as a function of beam diameter for butane and propane-air mixtures by laser-heating targets placed on optical fiber tips using a 1064 nm laser. The minimum igniting powers for propane-air and butane-air were about 250 and 300 mW, respectively. Threshold igniting powers for propane-air were approxima...

    $25.00

  • JLA Vol:23 Iss:4 (Thermal diffusivity measurement of silver nanofluid by thermal lens technique)


    Authors:
    Reza Zamiri
    Department of Physics, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia

    B. Z. Azmi
    Department of Physics,Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia and Advanced Materials and Nanotechnology Laboratory, Institute of Advanced Technology, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia

    E. Shahriari
    Kazim Naghavi
    E. Saion
    Zahid Rizwan
    M. S. Husin
    Department of Physics, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia


    The thermal lens technique was utilized in silver nanofluid containing silver nanopartic...

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  • JLA Vol:6 Iss:1 (Amending the CDRH performance standard for laser products)


    Authors:
    Jerome E. Dennis
    Office of Compliance and Surveillance Center for Devices and Radiological Heath, US Food and Drug Administration, Silver Springs, MD, U.S.A.


    The most recent amendments to the Federal performance standard for laser products became effective in 1985 and 1986. At this time, the Center for Devices and Radiological Health (CDRH) is making public its intention to amend the standard again and is inviting suggestions and comments. The amendments that are now under consideration are based upon advances in the sciences of photobiology and hazard evaluation. They are also intended to harmonize with developments in international standards for similar products, and to cla...

    $25.00

  • JLA Vol:17 Iss:2 (Feedback control effects on dimensions and defects of H13 tool steel by direct metal deposition process)


    Authors:
    Y. Hua
    J. Choi
    Department of Mechanical and Aerospace Engineering and Engineering Mechanics, University of Missouri, Rolla, Missouri 65409-1060


    As a promising and novel manufacturing technology, laser aided direct metal deposition (DMD) process produces near-net-shape functional metal parts directly from the computer aided design (CAD) model. In-process feedback control has been recognized as a critical element to ensure the dimensional accuracy as well as near-net-shape production. Furthermore, process parameters should be delicately controlled to produce defect-free parts with superior mechanical properties. A closed loop real-time optical height control system...

    $25.00

  • JLA Vol:21 Iss:4 (Numerical model of a laser-sustained argon plasma)


    Authors:
    R. Akarapu
    A. R. Nassar
    Department of Engineering Science and Mechanics, Penn State University, University Park, Pennsylvania 16802-6812

    S. M. Copley
    Applied Research Laboratory and Department of Mechanical and Nuclear Engineering, Penn State University, University Park, Pennsylvania 16802-6812

    J. A. Todd
    Department of Engineering Science and Mechanics, Penn State University, University Park, Pennsylvania 16802-6812


    A steady state axi-symmetric model was developed to predict the size, shape and temperature of a laser-sustained plasma in flowing argon. The power of the carbon dioxide (CO2) laser and the free s...

    $25.00

  • JLA Vol:8 Iss:3 (Theoretical and experimental studies of thick‐section cutting with a chemical oxygen–iodine laser (COIL))


    Authors:
    A. Kar
    J. E. Scott
    W. P. Latham



    A simple mathematical model of thick‐section stainless steel cutting with a high power chemical oxygen–iodine laser (COIL) is presented and compared with experimental results obtained with a 10‐kilowatt COIL at the U.S. Air Force's Phillips Laboratory. This model uses a lumped‐parameter technique to relate the cutting kerf depth with various process parameters and can be used to predict scaled laser materials processing performance to very thick sections. The model is similar to an empirical model developed by researchers in Japan, but includes predictive capabilities for thick metal cutting...

    $25.00

  • JLA Vol:2 Iss:3 (Current State‐of‐the‐Art of Contouring Techniques in Manufacturing)


    Authors:
    Kevin G. Harding
    Industrial Technology Institute, Sensor Center for Improved Quality, Ann Arbor, Michigan 48106


    A manager with a major automobile manufacturer once made the comment that “the best thing we ever did to improve quality was give the guys on the floor a caliper to measure the parts”. As the tolerances on manufacturing become tighter, the need for accurate measurement has also increased. Hand fitting of parts to each other does not work in modern automated factories. Gauges in the past have been built to provide a fixed set of measurements of a known part. This practice too has been changing due to the trend toward flexible manufacturing. Now the gages...

    $25.00

  • JLA Vol:18 Iss:1 (Effect of oxygen in ambient atmosphere on penetration characteristics in single yttrium–aluminum–garnet laser and hybrid welding)


    Authors:
    Yasuaki Naito
    Masami Mizutani
    Seiji Katayama
    Joining and Welding Research Institute (JWRI), Osaka University, 11-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan


    Welding with a yttrium–aluminum–garnet (YAG) laser only or with hybrid source combined with a YAG laser and a TIG arc was carried out on Type 304 stainless steel plate with low S content in the air or in the chamber with Ar gas including 0%–15% oxygen gas. It was confirmed in both laser and hybrid welding that the penetration and geometry of welds depended upon the volume of the oxygen in the ambient atmosphere, and that a pronounced “nail head” disappeared in a weld...

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  • JLA Vol:22 Iss:3 (Evaluation criterion and closed-loop control of penetration status during laser-MIG hybrid welding)


    Authors:
    Yongqiang Zhang
    Shougang Research Institute of Technology, Beijing 100043, Peoples Republic of China

    Peng Wen
    Jiguo Shan
    Yuanqing Shuang
    Wuzhu Chen
    Department of Mechanical Engineering, Tsinghua University Beijing 100084, Peoples Republic of China


    Laser-MIG hybrid welding is an advanced joining process and is widely applied in various industries. It is important to make sure the plate is fully penetrated with an appropriate weld formation in practical applications. In this paper, 3 kW CO2 laser and pulse MIG machine were used to compose the laser-MIG hybrid welding equipment to make butt weld of stainless...

    $25.00

  • JLA Vol:8 Iss:6 (Laser surface alloying of magnesium base alloys)


    Authors:
    R. Galun
    A. Weisheit
    B. L. Mordike
    Institut fu¨r Werkstoffkunde und Werkstofftechnik, Technische Universita¨t Clausthal, Agricolastraße 6, D‐38678 Clausthal‐Zellerfeld, Germany


    The feasibility of the laser surface alloying of magnesium base alloys with aluminum, copper, nickel and silicon has been shown in this work. By laser alloying with these elements, using a 5 kW CO2‐laser, the hardness of several magnesium base alloys can be increased to values above 250 HV0.1. Melted depths from 700–1200 μm and alloying contents from 15–55 at % were achieved. The wear resistance of ...

    $25.00

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