Surface Hardening Characterization Of Transmission Gears

This paper is presented to compare the transmission gear products from SME (UKM gear) and national scale manufacturer (OEM gear) especially on the surface hardening characterization. Both gears were heat treated with different methods. The gear product of SME was heat treated by pack carburizing and quenching whereas the OEM gear was predicted to be heat treated using induction heating with high frequency. The surface hardening characterization was conducted by investigating the hardening thickness, the hardness number and the microstructure observation on the gear surfaces. The result of the hardening thickness investigation reveals a distinction on the depth of hardening penetration. The heat treatment using long interval pack carburizing of UKM gear produces a deeper penetration and the higher hardness number on the gear surface whereas the OEM gear has a thin hardness penetration and lower hardness number. The microstructure of the both gears depicts the different types of phase. The SME gear shows the present of the carbon infiltration on the martensitic phase structure boundary whereas the OEM gear exhibits lower bainite phase on the gear surface. With this condition the OEM gear is predicted to behave a better contact stress distribution during operation

Stochastic analysis of surface roughness

For the characterization of surface height profiles we present a new stochastic approach which is based on the theory of Markov processes. With this analysis we achieve a characterization of the complexity of the surface roughness by means of a Fokker-Planck or Langevin equation, providing the complete stochastic information of multiscale joint probabilities. The method was applied to different road surface profiles which were measured with high resolution. Evidence of Markov properties is shown. Estimations for the parameters of the Fokker-Planck equation are based on pure, parameter free data analysis

Ab-initio density functional study of O on the Ag(001) surface

The adsorption of oxygen on the Ag(001) is investigated by means of density functional techniques. Starting from a characterization of the clean silver surfaces oxygen adsorption in several modifications (molecularly, on-surface, sub-surface, Ag$_2$O) for varying coverage was studied. Besides structural parameters and adsorption energies also work-function changes, vibrational frequencies and core level energies were calculated for a better characterization of the adsorption structures and an easier comparison to the rich experimental data.Comment: 26 pages, 8 figures, Surf. Sci. accepte

A nonstandard characterization of regular surfaces

In the present work we approach the study of surfaces using Nonstandard Analysis, by providing first a nonstandard characterization of a surface. Further, the tangent space to a surface is defined as well.CEOCFCTFEDER/POCT

Surface Acoustic Waves in Thin Films Nanometrology

Thin films nanometrology is an emerging field in nanoscience as the synthesis, processing and applications of nanostructured thin films require an in-depth knowledge of their elastic constants. The elastic energy of a surface acoustic wave propagating in a solid medium, is concentrated at the interface between the solid and air (or a sufficiently rarified medium); consequently, high frequency surface acoustic waves with sub-micrometer wavelengths are an extraordinary tool for a qualitative and quantitative elastic characterization of thin films. In this article, a short review is presented to describe the main ultrasound techniques based on surface acoustic waves for thin films characterization and to highlight the probing limits of acoustic nanometrology