Influence of shade, curing mode, and aging on the color stability of resin cements

The color stability of resin cements is essential for aesthetic restorations. Aim: To evaluate the influence of shade and aging time on the color stability of two light-cured and two dual-cured resin cements. Methods: The CIE-Lab color parameters (n=6) were measured immediately after sample preparation and at 7, 30 and 90 days of aging in distilled water. The color difference (ΔE) was calculated and then analyzed by three-way ANOVA for repeated measures and Tukey’s HSD test (α=0.05). Results: ΔE was higher for transparent resin colors, followed by dark and light colors. The mean values of ΔE were lower for both light-cured resin cements compared to the dual-cured cements. As the aging time increased, ΔE values increased. Conclusions: The light-cured resin cements showed greater color stability. The lighter shades of luting were more likely to display a greater color change.

Dimensional stability of an addition silicone after disinfection/sterilization

Poster presented at the “From Basic Sciences to Clinical Research” – First International Congress of CiiEM. Egas Moniz, Caparica, Portugal, 27-28 November 2015

Springboards into design : exploring multiple representations of interaction in a dental surgery

This paper demonstrates that in order to understand and design for interactions in complex work environments, a variety of representational artefacts must be developed and employed. A study was undertaken to explore the design of better interaction technologies to support patient record keeping in a dental surgery. The domain chosen is a challenging real context that exhibits problems that could potentially be solved by ubiquitous computing and multi-modal interaction technologies. Both transient and durable representations were used to develop design understandings. We describe the representations, the kinds of insights developed from the representations and the way that the multiple representations interact and carry forward in the design process.

A participatory design agenda for ubiquitous computing : a case study in dental practice

This paper reflects upon our attempts to bring a participatory design approach to design research into interfaces that better support dental practice. The project brought together design researchers, general and specialist dental practitioners, the CEO of a dental software company and, to a limited extent, dental patients. We explored the potential for deployment of speech and gesture technologies in the challenging and authentic context of dental practices. The paper describes the various motivations behind the project, the negotiation of access and the development of the participant relationships as seen from the researchers' perspectives. Conducting participatory design sessions with busy professionals demands preparation, improvisation, and clarity of purpose. The paper describes how we identified what went well and when to shift tactics. The contribution of the paper is in its description of what we learned in bringing participatory design principles to a project that spanned technical research interests, commercial objectives and placing demands upon the time of skilled professionals.

Maintaining human agency in the design on context-aware systems : Design games in a dental surgery

This paper describes a series of design games, specifically aimed at exploring shifts in human agency in order to inform the design of context-aware applications. The games focused on understanding information handling issues in dental practice with participants from a university dental school playing an active role in the activities. Participatory design activities help participants to reveal potential implicit technical resources that can be presented explicitly in technologies in order to assist humans in managing their interactions with and amidst technical systems gracefully.

Purity evaluation and influence of carbon nanotube on carbon nanotube/graphite thermal stability

High resolution thermogravimetry has been used to evaluate the carbonaceous content in a commercial sample of single-walled carbon nanotube (SWNT). The content of SWNTs in the sample was found to be at least 77mass% which was supported by images obtained with scanning and transmission electron microscopies (SEM and TEM). Furthermore, the influence of SWNT addition on the thermal stability of graphite in mixtures of SWNT/graphite at different proportions was investigated. The graphite stability decreased with the increased of SWNT content in the overall range of composition. This behavior could be due to the close contact between these carbonaceous species as determined by SEM analysis.

Static load modelling and voltage stability indices

This paper analyzes the performance of some of the widely used voltage stability indices, namely, singular value, eigenvalue, and loading margin with different static load models. Well-known ZIP model is used to represent loads having components with different power to voltage sensitivities. Studies are carried out on a 10-bus power system and the New England 39-bus power system models. The effects of variation of load model on the performance of the voltage stability indices are discussed. The choice of voltage stability index in the context of load modelling is also suggested in this paper.

Stability analysis and control of multiple converter based autonomous microgrid

In this paper, the stability of an autonomous microgrid with multiple distributed generators (DG) is studied through eigenvalue analysis. It is assumed that all the DGs are connected through Voltage Source Converter (VSC) and all connected loads are passive. The VSCs are controlled by state feedback controller to achieve desired voltage and current outputs that are decided by a droop controller. The state space models of each of the converters with its associated feedback are derived. These are then connected with the state space models of the droop, network and loads to form a homogeneous model, through which the eigenvalues are evaluated. The system stability is then investigated as a function of the droop controller real and reac-tive power coefficients. These observations are then verified through simulation studies using PSCAD/EMTDC. It will be shown that the simulation results closely agree with stability be-havior predicted by the eigenvalue analysis.

Sociometric stability and the behavioral correlates of peer acceptance in early childhood

This paper presents findings from an Australian study examining the behavioral correlates and stability of social status for preschool-aged children. The social status of an initial sample of 187 (94 boys and 93 girls) preschool children (mean age 62.4 months, SD = 4.22) was determined through sociometric assessment. Children classified as rejected, neglected and popular (n = 70) were selected for observation. Children were observed for a total of 25 minutes over a three-month period engaging in free play within their preschool centers. Results indicated that children classified as popular were more likely than rejected or neglected children to engage in cooperative play, ongoing connected conversation and to display positive affect. Popular children were less likely than rejected or neglected children to engage in parallel play, onlooker behavior or alone directed behavior. Six months after initial sociometric classification, sociometric interviews were repeated to test for stability and change. Results indicated that preschool-aged children’s social status classifications showed a moderate to high rate of stability for those children classified as popular, rejected and neglected.