Israel Arzate-Vázquez

Damage Mechanisms in AISI 304 Borided Steel: Scratch and Daimler-Benz Adhesion Tests

In this study, damage mechanisms in the FeB/Fe2B coatings formed on the surface of AISI 304 steel are determined by adhesion tests. First, the boriding of the AISI 304 steel was carried out through the powder-pack method at 1223 K in the range from 2-10 h of exposure time. After treatment, Berkovich depth-sensing indentation test were conducted; the result showed tensil and compressive residual stresses in the FeB and Fe2B, respectively. The adhesion of borided steels was evaluated by the Daimler-Benz Rockwell-C and scratch test. Based on the scratch tracks, the chipping was the predominant mechanism at 2 and 6 h, with critical loads of 35 and 43 N, respectively; while spalliation was determined at 27 N for 10 h. Also, hertzian and tensil cracks, buckling and compressive delamination were determined in the AISI 304 borided steel by scanning electron microscope.

Indentation Technique: Overview and Applications in Food Science

Indentation technique also known as instrumented indentation testing (IIT) has been widely used for characterization of mechanical properties of materials of different nature and different levels. This technique has been mostly used in the field of metallic materials, although in recent years its use has expanded to the biological area, and recently has been also used in the area of food science. The aim of this chapter is to show the general aspects of the indentation technique such as definition, measurement methods and data analysis, measured mechanical parameters, and examples of using the indentation technique in biological materials and specifically in food science. The main contribution of this chapter is to offer the reader a basic understanding of the technique and to show its scope for its possible application in the characterization of food mechanical properties.

Characterization of Biodegradable Nanocomposite Films Prepared with Glutelin from Jatropha curcas L. by Response Surface Methodology and Infrared Spectroscopy

Abstract The water vapor permeability (WVP) and hardness of biodegradable nanocomposite films based on glutelin from Jatropha curcas L. were determined and the results were analyzed by response surface methodology (RSM). The effects of independent variables constituted by the plasticizer (glycerol), nanofiller (cloisite), and pH on the physical parameters were evaluated. The regression models obtained for each physical property adequately described the measurements used in the experimental design, with regression coefficients of 0.9513 and 0.9421 for WVP and hardness. The regression coefficients show that pH has the most significant effect on the WVP, whereas the cloisite content has the largest influence on the hardness of the nanocomposite film. Fourier transform infrared spectroscopy provided confirmation of the results obtained by RSM. Corroboration that the gluteline structure is in a similar form as the WVP and primarily influenced by pH was obtained using conventional and second derivative infrared spectra. However, the hardness of the film primarily depends on the cloisite content. This methodology may be useful for the design and elaboration of nanocomposite films based on J. curcas L. with specific barrier and mechanical properties.