• JLA Vol:23 Iss:4 (Evaluation of the bone repair in defects grafted with hydroxyapatite and collagen membrane combined with laser therapy in rats)


    Authors:
    Marcelo Rodrigues da Cunha
    Luanda de Abreu Figueira
    Joa˜o Paulo Mardegan Issa
    Ricardo Alexandre Junqueira Calzzani
    Daniele Cristina do Prado Ribeiro
    Amilton Iatecola
    Mariane Silva Pettian
    Array


    Bone regeneration is the result of cellular events such as osteogenesis and neovascularization. However, implantation of autogenous grafts may be necessary in cases of bone mass loss due to high impact trauma. The disadvantages of the latter approach include morbidity of the donor area. Biomaterials represent an alternative for bone restoration. The most widely used compounds are collagen or hydroxyapat...

    $25.00

  • JLA Vol:6 Iss:2 (CO<sub>2</sub> shielding gas effects in laser welding mild steel)


    Authors:
    D. H. Abbott
    C. E. Albright



    The most widely used shielding gases for laser welding of steels are helium and argon. Helium produces significantly more penetration than argon in penetration&hyphen;mode laser beam welding. Another gas that has been proposed as an alternative to these inert gases is carbon dioxide. The benefits of using carbon dioxide as a shielding gas for laser welding are that it costs less than helium and argon and that it provides nearly the same penetration as helium. The major drawback to its use as a shielding gas for mild steel is that it can cause porosity and other weld discontinuities. In this investigation helium and carbon dioxide were...

    $25.00

  • JLA Vol:1 Iss:3 (CO<sub>2</sub> Laser Engraving System for Relief Plate to Print Corrugated Cardboard)


    Authors:
    K. Wakabayashi
    N. Sugishima
    NEC Corporation, Laser Equipment Div., 1120, Shimokuzawa, Sagamihara, JAPAN


    A very compact and economical CO2 laser engraving system to make relief plates for the purpose of printing corrugated cardboard has been developed. This system consists of a highly stable 500W CO2 laser and a high speed, easy handling image processing sub&hyphen;system. In this paper several new developments are described. This image processing technique for CO2 laser raster scanning and engraving has been newly developed. Every binary image is converted to the relief plate more easier than other reported engraving systems.

    $25.00

  • JLA Vol:14 Iss:1 (Physical&ndash;computational model to describe the interaction between a laser beam and a powder jet in laser surface processing)


    Authors:
    O. O. Diniz Neto
    Array

    R. Vilar
    Departamento de Engenharia de Materiais, Instituto Superior Te´cnico, 1049-001 Lisboa, Portugal


    Frequently laser surface treatments use a powder jet in conjunction with the laser beam. In this study we present a physical–computational model to describe the interaction between a laser beam and a powder jet. The model can be used to calculate the spatial distribution of particle temperature and laser beam attenuation at any moment and all over the region where the laser and particle beams interact. In calculating particle temperature, the attenuation of the laser beam by the particles themselves is taken into acc...

    $25.00

  • JLA Vol:18 Iss:2 (Fabrication of titanium microchannels using laser-assisted thermochemical wet etching)


    Authors:
    S. W. Son
    M. K. Lee
    K. H. Oh
    S. H. Jeong
    Department of Mechatronics, Gwangju Institute of Science and Technology, 1 Oryongdong Bukgu, Gwangju, 500-712 Republic of Korea


    A fabrication method of titanium microchannels of an aspect ratio up to 16 and channel width of 10–30 μm is developed using laser-assisted thermochemical wet etching. For the fabrication of deep channel, the workpiece was repeatedly etched over the same path with the control of process parameters. The cross-sectional profile of the microchannel varied between a V shape and a U shape, depending largely upon the laser beam power and etchant concentration. Bubb...

    $25.00

  • JLA Vol:8 Iss:2 (Recent progress in laser surface treatment: <emph type="4">II</emph>. Adopted processing for high efficiency and quality)


    Authors:
    W. Bloehs
    B. Gru¨nenwald
    F. Dausinger
    H. Hu¨gel
    Institut fu¨r Strahlwerkzeuge, Universita¨t Stuttgart, Pfaffenwaldring 43, 70569 Stuttgart, Germany


    In Part I of this contribution, energy coupling and transport mechanisms were considered in detail. The second part concentrates on the effect of the spatial distribution of the energy in the laser beam, which will be discussed in connection with applications of laser surface technologies. Along these lines, a variety of beam shaping facilities is presented for laser hardening and cladding. Their purpose is to adapt the irradiated area to the workpiece ge...

    $25.00

  • JLA Vol:2 Iss:3 (Energy Coupling in Surface Treatment Processes)


    Authors:
    Friedrich Dausinger
    Markus Beck
    Jae H. Lee
    Eckhard Meiners
    Thomas Rudlaff
    Jialin Shen
    Institut fu¨r Strahlwerkzeuge, University of Stuttgart, Federal Republic of Germany


    In cutting or welding processes with lasers, deep penetration mechanisms allow high energy coupling rates. In surface treatment processes such as martensitic hardening, cladding and alloying, deep penetration of the laser beam is mostly not applicable. This generally leads to insufficient coupling rates. In this contribution several ways of enhancing the coupling rate are summarized. Following some theoretical considerations, results of exp...

    $25.00

  • JLA Vol:16 Iss:2 (Laser short pulse heating of copper: Thermo&ndash;elasto&ndash;plastic analysis)


    Authors:
    A. F. M. Arif
    B. S. Yilbas
    ME Department, KFUPM. Dhahran, Saudi Arabia


    Laser short pulse heating of metallic substrates results in excessive electron temperatures in the surface vicinity. This gives rise to nonequilibrium energy transport in the region irradiated by a laser beam. Moreover, the thermomechanical coupling effect should be incorporated into the energy transport equation as lattice site temperature increases. In the present study, laser short pulse heating of copper is considered. The electron kinetic theory approach is employed to model the nonequilibrium heating process while thermomechanical coupling is introduced in the energy transport equation t...

    $25.00

  • JLA Vol:20 Iss:3 (Diode-pumped solid state laser light sources for confocal laser scanning fluorescence microscopy)


    Authors:
    Mårten Stjernstro¨m
    Department of Applied Physics, Royal Institute of Technology, SE-106 91 Stockholm, Sweden and Department of Chemistry, Royal Institute of Technology, SE-100 44 Stockholm, Sweden

    Fredrik Laurell
    Hjalmar Brismar
    Department of Applied Physics, Royal Institute of Technology, SE-106 91 Stockholm, Sweden


    Diode-pumped solid-state lasers (DPSSLs) have been integrated as light sources in confocal laser scanning microscopy (CLSM). The standard argon ion laser at 488 nm is compared with a DPSSL operating at 473 nm in terms of noise and CLSM image characteristics. The equally high fluorescence image quality togeth...

    $25.00

  • JLA Vol:24 Iss:3 (Investigation of the effects of basic laser material interaction parameters in laser welding)


    Authors:
    W. J. Suder
    S. W. Williams
    Welding Engineering and Laser Processing Centre, Cranfield University, MK43 0AL, United Kingdom


    The depth of penetration achieved in continuous wave (CW) laser welding results from a balance of many complicated phenomena, which are linked with the characteristics of the heat source. In this work, the laser welding process has been investigated in terms of basic laser material interaction parameters: power density and interaction time. It has been shown that these two parameters are insufficient to characterize the laser welding process. Thus, a third parameter, specific point energy, has been introduced, which along with the power densi...

    $25.00

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