The Experts below are selected from a list of 41364 Experts worldwide ranked by ideXlab platform

Galeev R. - One of the best experts on this subject based on the ideXlab platform.

  • Numerical simulation of gas discharge CO 2 lasers with conic tubes
    2020
    Co-Authors: Galeev R., Safiullin R.
    Abstract:

    The results of numerical simulation for fast-axial-flow gas discharge CO 2 lasers are presented. Quasi-one-Dimensional Consideration of the processes for powerful CO 2 lasers with conic discharge tubes shows that laser operation may be more effective in the case of tubes which are narrowed down from anode to cathode provided that gas flow is directed towards the cathode. On the contrary, when tube is narrowed down from cathode to anode, no any advantage in the laser operation may be received. The calculated quantities are in satisfactory agreement with the available experimental data

  • Numerical simulation of the processes in fast flow gas discharge CO 2 lasers
    2020
    Co-Authors: Galeev R., Safioulline R.
    Abstract:

    In the report the results of numerical simulation of the processes in discharge chambers (DC) of fast flow CO 2 lasers, are presented. The investigations for longitudinal glow discharge (quasi-one-Dimensional and two-Dimensional flow) using four- and six-temperature models, were performed. Distributions of gas dynamic quantities, densities of charged parti cles, electric field strength, as well as vibrational temperatures of CO 2, N 2 and CO species, within the DC were calcu lated. Quasi-one-Dimensional Consideration of processes for powerful CO 2 lasers with conic discharge tubes has shown that narrowed along the gas flow tubes must be more effective for laser operation than cylindrical ones. The calculated quantities are in satisfactory agreement with available experimental data

Safiullin R. - One of the best experts on this subject based on the ideXlab platform.

  • Numerical simulation of gas discharge CO 2 lasers with conic tubes
    2020
    Co-Authors: Galeev R., Safiullin R.
    Abstract:

    The results of numerical simulation for fast-axial-flow gas discharge CO 2 lasers are presented. Quasi-one-Dimensional Consideration of the processes for powerful CO 2 lasers with conic discharge tubes shows that laser operation may be more effective in the case of tubes which are narrowed down from anode to cathode provided that gas flow is directed towards the cathode. On the contrary, when tube is narrowed down from cathode to anode, no any advantage in the laser operation may be received. The calculated quantities are in satisfactory agreement with the available experimental data

Safioulline R. - One of the best experts on this subject based on the ideXlab platform.

  • Numerical simulation of the processes in fast flow gas discharge CO 2 lasers
    2020
    Co-Authors: Galeev R., Safioulline R.
    Abstract:

    In the report the results of numerical simulation of the processes in discharge chambers (DC) of fast flow CO 2 lasers, are presented. The investigations for longitudinal glow discharge (quasi-one-Dimensional and two-Dimensional flow) using four- and six-temperature models, were performed. Distributions of gas dynamic quantities, densities of charged parti cles, electric field strength, as well as vibrational temperatures of CO 2, N 2 and CO species, within the DC were calcu lated. Quasi-one-Dimensional Consideration of processes for powerful CO 2 lasers with conic discharge tubes has shown that narrowed along the gas flow tubes must be more effective for laser operation than cylindrical ones. The calculated quantities are in satisfactory agreement with available experimental data

Shahzada Zaman Shuja - One of the best experts on this subject based on the ideXlab platform.

  • Three-Dimensional Consideration of jet impingement onto the kerf in relation to laser cutting process: Effect of jet velocity on heat transfer rates
    Optics and Lasers in Engineering, 2011
    Co-Authors: Omar A. Melhem, Bekir Sami Yilbas, Shahzada Zaman Shuja
    Abstract:

    Abstract In laser cutting process, an assisting gas is used to improve the mass removal rate from the cutting kerf and protect the kerf surfaces from the high temperature exothermic reactions, such as oxidation reactions, during the cutting process. Therefore, heat transfer rates from the kerf wall and the skin friction along the kerf surface are important for quality cutting. In the present study, jet emerging from a conical convergent nozzle and impinging onto the kerf surface is investigated in relation to the laser cutting process. The flow field in the kerf, the heat transfer rates from the kerf wall, and the skin friction along the kerf surface are computed for four average jet velocities at the nozzle exit and two kerf wall wedge angles. The ratio of the stand-off-distance (distance between the nozzle exit and the kerf top surface) to nozzle diameter is selected as H / D =2.2., where H is the stand-off-distance and D is the nozzle exit diameter. The kerf wall temperature is kept at 1500 K to resemble the laser cutting process. It is found that the Nusselt number increases sharply at the kerf inlet and decreases towards the kerf exit for the kerf wall angle of 0°. However, it increases gradually in this region for the kerf wedge angle of 4°. The skin friction decreases along the kerf surface.

Russell F Doolittle - One of the best experts on this subject based on the ideXlab platform.

  • a three Dimensional Consideration of variant human fibrinogens
    Thrombosis and Haemostasis, 1998
    Co-Authors: Stephen J Everse, Glen Spraggon, Russell F Doolittle
    Abstract:

    Recently reported X-ray structures for large core fragments derived from human fibrinogen and fibrin make it possible to correlate structural and functional anomalies of known genetic variants. Here we examine a variety of amino acid replacements previously reported for hereditary dysfibrinogenemias, most of which are associated with impaired fibrin polymerization. For many of these we have modeled in the mutant amino acid and considered the structural consequences. We have also examined the cases of a small deletion and a large insertion, as well as the impact of substitutions in the GPRPam ligand that was co-crystallized with fragment double-D.