Influence of firing conditions and production methods on fracture strength of titanium-based metal ceramic crowns

Objectives: This study evaluated the effect of argon atmosphere compared with vacuum during porcelain firing on the fracture strength of crowns made of porcelain and electron beam melted (EBM) Ti-6Al-4 V, cast commercially pure titanium or milled commercially pure titanium. Methods: Sixty crown copings of c. p. titanium, Ti-6Al-4 V alloy and porcelain were fabricated using three production techniques. The copings were fired either under vacuum or in an argon gas atmosphere. Specimens were subdivided into groups of cast c. p. titanium, milled c. p. titanium and EBM Ti-6Al-4 V which were further subdivided according to firing modes employing either vacuum or argon gas. The 60 specimens were subjected to cyclic preloading and thermocycling, and were then individually loaded until interface fractured. Differences between the group mean values were calculated using the one-way ANOVA and Tukey’s range test. Two fractured samples from each group were cut with a diamond blade and examined using SEM and EDS for visualization and chemical composition analysis of the fractured interface. Results: The highest mean fracture strength values, though not significant, were recorded for the groups fired in argon atmosphere, and the lowest mean fracture strength values were recorded for the groups fired in vacuum, with one exception. Comparing the two main groups of firing atmosphere, no significant difference could be documented. SEM and EDS analysis indicated clear differences in composition and structure between the groups included in the study. Conclusions: Firing in argon atmosphere does not significantly improve the fracture strength of porcelain bonded to titanium.     

Orange to green switching anthraquinone-based electrochromic material

An easily accessible anthraquinone-benzodithiophene-based high bandgap polymer (PTAq) was synthesized by Stille coupling reactions in remarkably high yield (96.5%). The highest occupied molecular orbital energy level of the polymer was estimated from the onset of oxidation in a cyclic voltammetry study to be −5.7 eV. PTAq showed an orange-to-green color switching with the application of a 1.0-V external potential to the polymer film, which was visible to the naked eye. The optical behavior change was also monitored using ultraviolet–visible absorption spectroscopy and revealed a respectable 75% transmittance change when the polymer film was subjected to a 1.0-V external potential. The high color contrast observed makes PTAq one of the most promising materials for electrochromic device applications. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47729.     

Optimal Power Flow of Multiple Energy Carriers

This paper presents an approach for combined optimization of coupled power flows of different energy infrastructures such as electricity, gas, and district heating systems. A steady state power flow model is presented that includes conversion and transmission of an arbitrary number of energy carriers. The couplings between the different infrastructures are explicitly taken into account based on the new concept of energy hubs. With this model, combined economic dispatch and optimal power flow problems are stated covering transmission and conversion of energy. A general optimality condition for optimal dispatch of multiple energy carriers is derived, and the approach is compared with the standard method used for electrical power systems. Finally, the developed tools are demonstrated in examples     

Influence of Molecular Weight on the Performance of Organic Solar Cells Based on a Fluorene Derivative

The performance of organic photovoltaic (OPV) bulk‐heterojunction blends comprising a liquid‐crystalline fluorene derivative and a small‐molecular fullerene is found to increase asymptotically with the degree of polymerization of the former. Similar to various thermodynamic transition temperatures as well as the light absorbance of the fluorene moiety, the photocurrent extracted from OPV devices is found to strongly vary with increasing oligomer size up to a number average molecular weight, M_n ≈ 10 kg mol^?1, but is rendered less chain‐length dependent for higher M_n as the fluorene derivative gradually adopts polymeric behavior.     

Provably good multiprocessor scheduling with resource sharing

We present a 12(1+3R/(4m)) competitive algorithm for scheduling implicit-deadline sporadic tasks on a platform comprising m processors, where a task may request one of R shared resources.     

Voltage stability indices for stressed power systems

The use of static voltage stability indices based on a singular value decomposition of the power flow Jacobian matrix and matrices derived from the Jacobian matrix is discussed. It is shown that such indices, together with the singular vectors, contain substantial and important information about the proximity to voltage instability and also about critical buses and disturbances from a voltage instability point of view. This is done by a theoretical analysis of the linear power flow equations and an analysis from model power systems as well as realistic power systems (1033 nodes). It is argued that indices based on these matrices are useful for the system analyst in planning and operations planning     

SenToy in FantasyA: Designing an Affective Sympathetic Interface to a Computer Game

We describe the design process of an affective control toy, named SenToy, used to control a synthetic character in a computer game. SenToy allows players to influence the emotions of a synthetic character placed in FantasyA, a 3D virtual game. By expressing gestures associated with anger, fear, surprise, sadness and joy through SenToy, players influence the emotions of the character they control in the game. When designing SenToy we hypothesized that players would manipulate the toy to express emotions using a particular set of gestures. Those gestures were drawn from literature on how we express emotions through bodily movements and from emotion theories. To evaluate our idea we performed a Wizard Of Oz study [1]. The results of the study show that there are behaviours that players easily pick up for expressing emotions through the gestures with the toy, though not necessarily the ones extracted from literature. The study also provided some indication on what type of toy we should build, in particular, its ‘look and feel’. Correspondence to: Ms A. Paiva, IST & Instituto de Engenharia de Sistemas e Computadores, Rua Alves Redol 9, 1000 Lisboa, Portugal. Email: Ana.Paiva@inesc.pt