Tuning edge state localization in graphene nanoribbons by in-plane bending

The electronic properties of graphene are influenced by both geometric confinement and strain. We study the electronic structure of in-plane bent graphene nanoribbons, systems where confinement and strain are combined. To understand its electronic properties, we develop a tight-binding model that has a small computational cost and is based on exponentially decaying hopping and overlap parameters. Using this model, we show that the edge states in zigzag graphene nanoribbons are sensitive to bending and develop an effective dispersion that can be described by a one-dimensional atomic chain model. Because the velocity of the electrons at the edge is proportional to the slope of the dispersion, the edge states become gradually delocalized upon increasing the strength of bending.Comment: 11 pages, 8 figure

Brussels I bis in Relation to Other Instruments on the Global Level

This chapter will discuss the relationship between the Brussels Ibis Regulation and other international conventions which regulate the recognition and enforcement of foreign judgments or arbitral awards in civil and commercial matters. Since a number of such conventions are in force, a possible collision with the Brussels Ibis Regulation may occur. As to the preceding Brussels I Regulation, the Court of Justice has already addressed the problem of conventions that may concur with the Regulation. This raises the question whether this case law remains untouched by the entry into force of the Brussels Ibis Regulation. Also, the relationship of Brussels Ibis with the Hague Convention on Choice-of-Court Agreements of 2005 will be discussed, since this Convention has not been signed by Member States but instead by the Council on behalf of the European Union. Thus, a different approach to a possible collision between the two instrument may be required. Lastly, the position of the New York Arbitration Convention of 1958 will be dealt with. Though explicitly excluded from the substantive scope of Brussels Ibis, arbitration has still been subject to some debate vis-à-vis its position in light of the Brussels I regime. The recent Gazprom case is an interesting example in this respect, which will be looked at in more detail

Brussels Ibis in relation to other instruments on the global level

This chapter will discuss the relationship between the brussels ibis regulation and other international conventions which regulate the recognition and enforcement of foreign judgments or arbitral awards in civil and commercial matters. Since a number of such conventions are in force, a possible collision with the brussels ibis regulation may occur. As to the preceding brussels i regulation, the court of justice has already addressed the problem of conventions that may concur with the regulation. This raises the question whether this case law remains untouched by the entry into force of the brussels ibis regulation. Also, the relationship of brussels ibis with the hague convention on choice-of-court agreements of 2005 will be discussed, since this convention has not been signed by member states but instead by the council on behalf of the european union. Thus, a different approach to a possible collision between the two instrument may be required. Lastly, the position of the new york arbitration convention of 1958 will be dealt with. Though explicitly excluded from the substantive scope of brussels ibis, arbitration has still been subject to some debate vis-à-vis its position in light of the brussels i regime. The recent gazprom case is an interesting example in this respect, which will be looked at in more detail

Usability Evaluation of the Kinect in Aiding Surgeon Computer Interaction

Interest in Gesture-based interaction in the operating room (OR) environment is rising. The main advantage of introducing such an interface in the OR is that it enables direct interaction between computer and surgeon while ensuring asepsis, as opposed to asking an assistant to interact with the patient’s medical images. The purpose of this study was to determine whether a modern gesture-based interface using the Kinect is feasible and desirable during surgical procedures. After an extensive exploratory research phase including OR observations, interviews with surgeons and a questionnaire, a user-based usability evaluation was conducted with the open-source medical imaging toolkit MITO and the Microsoft Kinect. Healthcare professionals were asked to conduct prototypical tasks in a simulated OR environment in the University Medical Centre of Groningen. Obtained performance and usability measures were compared to a control condition where the participant gave instructions to an assistant, comparable to the current OR situation. Results of the usability evaluation indicated that surgeons were generally positive about gesture-based interaction and would like to use the tested system. Performance measures indicated that the current system was generally slower in executing the prototypical tasks compared to asking an assistant. However this was during their first encounter with such a novel technique; an expert user showed significant faster completion times. Another limitation of using the Kinect as gesture-based interaction technique is its reduced accuracy while conducting measurements on medical images for example. Due to the importance of accurate selection in clinical image viewers a second study was conducted on different selection techniques in order to determine which technique is most accurate and appropriate for gesture-based selection. Two popular selection techniques: ‘Dwell’ and ‘Push’ were compared to the current mouse condition. Furthermore two different spatial resolutions were compared due to the importance of a small interaction space above the patient. Results from this experiment indicated that the tested techniques are significantly less accurate and more time-costly than the mouse control condition. However there was a significant effect between the two different spatial resolutions, indicating the importance of higher resolution depth-cameras. Finally suggestions for usability improvements for the test-case system were proposed and important guidelines for future gesture-based interaction systems in the operating room. From these results we can conclude that the concept of gesture-based interaction using low-cost commercially available hardware, such as the Kinect, is feasible for operating room purposes. Although the accuracy is lower and execution times are slower compared to the current situation in which the surgeon directs an assistant, surgeons rate the usability of the tested system high, and would already prefer to use this system than asking an assistant due to the direct and sterile form of interaction. Furthermore training and future technological innovations such as higher resolution depth-camera’s can possibly improve the performance of gesture-based interaction.

Critical Casimir interactions between colloids around the critical point of binary solvents

Critical Casimir interactions between colloidal particles arise from the confinement of fluctuations of a near-critical solvent in the liquid gap between closely-spaced particles. So far, the comparison of theoretical predictions and experimental measurements of critical Casimir forces (CCFs) has focused on the critical solvent composition, while it has been lacking for off-critical compositions. We address this issue by investigating CCFs between spherical colloidal particles around the critical point of a binary solvent through a combination of experiments, previous Ising Monte Carlo simulation results and field-theoretical methods. By measuring the correlation length of the near-critical solvent and the pair potentials of the particles in terms of radial distribution functions and by determining the second virial coefficient, we test in detail theoretical predictions. Our results indicate that the critical Casimir theory gives quantitative correct predictions for the interaction potential between particles in a near critical binary mixture if weak preferential adsorption of the particle surface is taken into account