Sökning: "Seyed Hosseini"

Hittade 5 avhandlingar innehållade orden Seyed Hosseini.

  1. 1. Characterization of White Layers induced by Hard Turning of AISI 52100 Steel

    Författare :Seyed Hosseini; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; white layer; hard turning; IR-pyrometer; nano-sized grains; martensite; cutting temperature; bainite; cubic boron nitride; residual stress; retained austenite; cutting forces;

    Sammanfattning : Hard turning is a machining process applied to metallic materials with hardness above 45 HRC. The process offers high production flexibility and sustainable manufacturing since it allows performing both rough and finishing machining of complex geometries in one single setup. LÄS MER

  3. 2. Physicochemical studies of oxide zinc mineral flotation

    Författare :Seyed Hamid Hosseini; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Mineralteknik; Mineral Processing;

    Sammanfattning : At the present, zinc is produced mostly from zinc sulphide ores because the sulphides are easy to separate from the gangue and to concentrate by conventional flotation techniques but in the case of oxide zinc ores, the recovery of zinc is not enough high. The objective of the present study is to investigate the influence of different cationic, anionic and mixed collectors on the flotation of smithsonite mineral and an oxide zinc ore at various concentrations and pH values. LÄS MER

  4. 3. On stability, transition and turbulence in three-dimensional boundary-layer flows

    Författare :Seyed Mohammd Hosseini; Ardeshir Hanifi; Spencer Sherwin; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Receptivity; stability; optimal growth; three-dimensional bound- ary layers; crossflow instability; roughness control; freestream turbulence; sec- ondary instability; transition; turbulence;

    Sammanfattning : A lot has changed since that day on December 17, 1903 when the Wright brothers made the first powered manned flight. Even though the concepts behind flying are unaltered, appearance of stat-of-the-art modern aircrafts has undergone a massive evolution. LÄS MER

  5. 4. White Layer Formation during Hard Turning of Through-Hardened Martensitic and Bainitic AISI 52100 Steel

    Författare :Seyed Hosseini; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; white layers; residual stresses; phase transformation; dynamic recovery; bainite; dynamic recrystallization; carbide deformation; retained austenite; steel; martensite;

    Sammanfattning : Increased demands for flexible manufacturing lines, shorter cycle times and reduced impact on the environment drives the need for optimization of today’s manufacturing. For machining of hardened steel parts (>45 HRC), grinding has been the obvious choice for many decades. However, hard turning has often been considered as a replacement due to e. LÄS MER

  7. 5. Stability and transition of three-dimensional boundary layers

    Författare :Seyed Mohammad Hosseini; Ardeshir Hanifi; Vassilios Theofilis; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Receptivity; stability; optimal growth; three-dimensional boundary layers; crossflow instability; roughness control; freestream turbulence; secondary instability;

    Sammanfattning : A focus has been put on the stability characteristics of different flow types existing on air vehicles. Flow passing over wings and different junctions on an aircraft face numerous local features, ranging from different pressure gradients, to interacting boundary layers. LÄS MER