Fatih GÜNDÜZ 030060144 (7th week)

Grinding Whell:

The grinding whell has abrasive grains enveloped in a matrix of bonding material. These grains are of irregular sahpe and ramdonly dispersed within the matrix. Owing to this random dispersion, three mechanisms of interactions exist between the grains and the workpiece: cutting, plowing, and rubbing. Only cutting causes material removal, while plowing only causes deformation of the surface.

(Manufacturing: Design, Production, Automation and Integration, Benhabib B., Dekker M., p.224)

Impregnation:

Catalist preparation by Impregnation is carried out by cantacting the support with a solution containing the precursors of the active phases. Two different aproaches can be followed: incipient-wetness Impregnation and excess-solution Impregnation. In the former, the carbon support is wetted with a solution of the precursor, drop by drop, in the proper amount to just fill its pores. A slurry is formed with the pore volume filled with the solution, which is finally dried to remove the solvent, leaving the precursor of the active phase deposite on the pore walls. The second approach consist of the use of a volume of solution much larger than pore volume of the support. A slurry is formed from which, after a given period of time, yhe excess solvent is removed by evaporation or the impragnated solid is separated by filtration or decantation. This method does not permit precise control of the amount of catalyst precursor loaded unless a previous study is carried out the determine the adsorption isotherms. thus, it is likely that some of the catalist precursor will remain in the liquid phase after filtration.

(Carbon materials for catalysis Yazar, Serp P., Figueiredo L. J., p.138)

Norton's Tumbler Gear:

This has only one cone gear which is mounted on the input shaft I. Transmission is accomplished by using a pair of meshed gears. The smaller one is mounted on the output (driven) shaft(II) and can be slid axially, on shaft II. This gear meshes permanently, with an intermediate gear, mounted on an arm that is swivelable, around output shaft. the swivel is used to engage (mesh) and disengage (unmesh) the intermediate idler gear, with any of the cone gears mounted on the input shaft. While pivoting away from the axis of the input shaft, unmeshes the intermediate gear, pivoting towards it, meshes the intermediate gear. Thus axial adjustments of the driven gear, and swiveling adjustment of the intermediate gear, allow the intermediate gear to mesh with any of the cone gears, and transmit motion from driving shaft I to driving shaft II. The transmssion ratio can be changed suitably, by enmeshing the intermediate gear with a suitable gear on the cone.

(Machine tools handbook: design and operation, Joshi P. H. , p.243)

Surface roughening:

As shown shematically Fig. 7.1b, roughening of epitaxial layer surface allows atomic bonds near the surface to relax towards their equilibrium length and orientation. The basic energetic competition in this process is between the surface energy of the epitaxial layer (representing an increase in the system energy as surface roughening increases the total surface area of the epitaxial layer) and elastic energy (which is reduced by raughening, therefore representing a decrease in the system energy).

(Thin Films: heteroepitaxial systems Liu W.K., Santos M.B., p.304)