Effect of plasma nitriding treatment on structural, tribological and electrochemical properties of commercially pure titanium

In this study, plasma nitriding treatment was applied to commercially pure titanium (Grade 2). Structural properties, electrochemical and tribological behaviours of the nitrided pure titanium specimens were comparatively investigated. Microstructure and morphology of the plasma nitrided specimens were analysed by X-ray diffraction and scanning electron microscopy. Furthermore, corrosion tests were conducted in Ringer's solution, which represents a human body environment, to determine electrochemical properties. Then, tribological and frictional properties were investigated using pin-on-disc tribometer, and a micro-hardness tester was used to measure the hardness of the coatings. The results showed that plasma nitrided specimens exhibited higher surface hardness than the untreated specimens did. In addition, the plasma nitrided specimens at 700 degrees C presented significantly better performance than the other plasma nitrided specimens (at 500 degrees C and 600 degrees C) under dry wear conditions. Moreover, corrosion test results showed that corrosion behaviours of untreated and nitrided samples had similar characteristic

How Do Users Perceive a Design-in-Use Approach to Implementation?:A Healthcare Case

Part 5: Methods for User StudiesInternational audienceThe implementation of information systems in organizational settings is a protracted process that includes the mutual adaptation of system and organization to each other after the system has gone live. We investigate a design-in-use approach to this implementation process. Rather than a centrally run implementation process with preset goals, the management in the studied hospital tasked the individual departments with exploring and embracing the possibilities afforded by a network of interconnected electronic whiteboards. The responsibility for driving this process was assigned to local super users in the departments. On the basis of interviews with 17 clinicians we find that (a) they perceive the design-in-use approach in conflicting ways, (b) the super users are more positive about the approach than the end-users, (c) standardization across departments conflicts with design in use within departments, (d) intradepartmental change is perceived more positively, (e) the design-in-use process is inextricably sociotechnical, and (f) the clinicians’ perception of design in use is more about implementing change than about preparing it or about training and support. The conflicting perceptions of the design-in-use approach, for example, include whether it gained momentum, met local needs, and made for an engaging process. We discuss the implications of our findings for a design-in-use approach to implementation

Modification of titanium alloys surface properties by plasma electrolytic oxidation (PEO) and influence on biological response

Surface characteristics can mediate biological interaction improving or affecting the tissue integration after implantation of a biomaterial. Features such as topography, wettability, surface energy and chemistry can be key determinants for interactions between cells and materials. Plasma electrolytic oxidation (PEO) is a technique used to control this kind of parameters by the addition of chemical species and the production of different morphologies on the surfaces of titanium and its alloys. With the purpose to improve the biological response, surfaces of c.p titanium and Ti6Al4V were modified by using PEO. Different electrolytes, voltages, current densities and anodizing times were tested in order to obtain surfaces with different characteristics. The obtained materials were characterized by different techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM) and glow discharge optical emission spectroscopy (GDOES). Wettability of the obtained surfaces were measured and the corresponding surface energies were calculated. Superhydrophilic surfaces with contact angles of about 0 degrees were obtained without any other treatment but PEO and this condition in some cases remains stable after several weeks of anodizing; crystal phase composition (anatase-rutile) of the anodic surface appears to be critical for obtaining this property. Finally, in order to verify the biological effect of these surfaces, osteoblast were seeded on the samples. It was found that cell behavior improves as SFE (surface free energy) and coating porosity increases whereas it is affected negatively by roughness. Techniques for surface modification allow changes in the coatings such as surface energy, roughness and porosity. As a consequence of this, biological response can be altered. In this paper, surfaces of c.p Ti and Ti6Al4V were modified by using plasma electrolytic oxidation (PEO) in order to accelerate the cell adhesion processUniversidad de Antioquia. Vicerrectoría de investigación. Comité para el Desarrollo de la Investigación - CODIColombia. Ministerio de Ciencia, Tecnología e Innovación - MinCienciasCOL0015099COL000792