Mechanical Properties and Fracture Dynamics of Silicene Membranes

As graphene became one of the most important materials today, there is a renewed interest on others similar structures. One example is silicene, the silicon analogue of graphene. It share some the remarkable graphene properties, such as the Dirac cone, but presents some distinct ones, such as a pronounced structural buckling. We have investigated, through density functional based tight-binding (DFTB), as well as reactive molecular dynamics (using ReaxFF), the mechanical properties of suspended single-layer silicene. We calculated the elastic constants, analyzed the fracture patterns and edge reconstructions. We also addressed the stress distributions, unbuckling mechanisms and the fracture dependence on the temperature. We analysed the differences due to distinct edge morphologies, namely zigzag and armchair

Circles of Peace. A Video Analysis of Situational Group Formation and Collective Third-Party Intervention in Violent Incidents

We seek to understand collective third-party intervention in violent incidents. Based on analyses of 131 video clips captured on mobile phones, we argue that bodily alignment between bystanders creates situational groups that encourage collective de-escalatory action. Qualitative analysis reveals that third parties generate situational groups when they create circular formations, providing greater opportunities to notice each other’s monitoring of the situation while separating those focused on the incident from others just passing by. Statistical analysis shows that the formation of situational groups facilitates the collectivization of de-escalatory action. In contrast to popular but outdated ideas about the dangerous influence of assemblies on individual behaviour (allegedly leading to disorder or apathy), our findings emphasize the self-regulatory, defusing capacity of gatherings

Supernova Remnants in the Magellanic Clouds. IV. X-Ray Emission from the Largest SNR in the LMC

We present the first X-ray detection of SNR 0450-70.9 the largest known supernova remnant (SNR) in the Large Magellanic Cloud. To study the physical conditions of this SNR, we have obtained XMM-Newton X-ray observations, optical images and high-dispersion spectra, and radio continuum maps. Optical images of SNR 0450-70.9 show a large, irregular elliptical shell with bright filaments along the eastern and western rims and within the shell interior. The interior filaments have higher [S II]/Halpha ratios and form an apparent inner shell morphology. The X-ray emission region is smaller than the full extent of the optical shell, with the brightest X-ray emission found within the small interior shell and on the western rim of the large shell. The expansion velocity of the small shell is ~220 km/s, while the large shell is ~120 km/s. The radio image shows central brightening and a fairly flat radio spectral index over the SNR. However, no point X-ray or radio source corresponding to a pulsar is detected and the X-ray emission is predominantly thermal. Therefore, these phenomena can be most reasonably explained in terms of the advanced age of the large SNR. Using hydrodynamic models combined with a nonequilibrium ionization model for thermal X-ray emission, we derived a lower limit on the SNR age of about 45,000 yr, well into the later stages of SNR evolution. Despite this, the temperature and density derived from spectral fits to the X-ray emission indicate that the remnant is still overpressured, and thus that the development is largely driven by hot gas in the SNR interior.Comment: Accepted for publication in The Astrophysical Journa

A top-down methodology to calculate the CO2-footprint for terminal operations; the 6-step approach

There is an increasing need for green and effective operations at terminals and in port due to existing and upcoming stricter air quality standards and regulations. At the same time there is an increasing awareness of the need to reduce energy consumption of ports and terminals and to focus on the carbon footprint which is dependent not only on equipment and operations, but also the energy mix and the management of energy consumption. This is an important objective for the terminals but also for a wide variety of stakeholders, such as port authorities and transport service clients. Sustainable terminal operations require a good insight in terminal configurations, the use of equipment and the availability of reliable data about the energy consumption on the terminal. This information is in many cases not available for a variety of reasons, such as the very competitive environment and the competition between terminals, sometimes simply because the information is not known. In this deliverable an innovative top-down approach is presented to calculate the CO2-emissions of terminals. This methodology is named ‘the 6-step-approach’. This approach can be considered as an easy applicable tool to get a brief and coherent overview of the total energy consumption of a terminal. The 6-step approach is a standardised methodology which is coherent with CEN standard CEN 16258 “Methodology for calculation and declaration of energy consumption and GHG emissions of transport services (freight and passengers)”. The CEN standard contributes to the standardisation, comprehensiveness, transparency, consistency, generalization and predetermination. __The methodology consists of 6 steps:__ 1- the operations on the terminal (what is actually happening?) 2- the construction of an analytical model of activities 3- the development of an algorithm based on the analytical model 4- application of the model (preferably with real data, presently mostly based on estimations) 5- valorisation of the outcomes of the model 6- policy recommendations In coherence with the consumption scheme based on the GHG Protocol or to ISO 14064 standard and the CEN EN 16258 standard, the methodology concentrates on three domains of energy consumption: the terminal operations and related equipment, the consumption of reefers and the lighting of the yard. These three elements cover more than 95% of all energy consumption at a terminal. An important contribution of the 6-step approach to the port community is the fact that the model delivers outcomes that can function as the basis for tailor made recommendations that cover almost all activities. Therefore the main objective of the tool is that it can function as a benchmark tool for companies, port authorities, E.U., WorldBank/IMF/OECD, etc. (policy investment). Furthermore the application of tool can be considered as a basis for evaluation (rising awareness and motivation to use energy competently and thoughtfully), organizational investments (modifying operations to increase productivity versus energy consumption), technical modification investments (modifying equipment and systems to reduce consumption/increase productivity), technical purchase investments (put new equipment/systems into operation). But overall, the 6-step approach is a source for inspiration, it gives structure to process and the methodology recognizes the new challenges: to apply the model as a a pro-active methodology that addresses the economic (profit), environmental (planet), and social objectives (people) in one coherent strategy. By doing this, the 6-step approach offers an opportunity for cooperation and interaction between the private firms su

The Tone from Above:The Effect of Communicating a Supportive Regulatory Strategy on Reporting Quality

In collaboration with the Authority for the Financial Markets in the Netherlands, we manipulate the content of official letters that instruct financial intermediaries to submit a mandatory self-assessment. As part of the Registered Report Process, we submitted our hypotheses, experimental procedure, and planned statistical analyses before data collection. We predicted that a request indicating a supportive regulatory attitude has a positive effect on reporting quality on average. We also predicted this effect to be stronger for small firms and for firms with a long-term orientation, and to become negative for firms with a short-term orientation. Planned analyses show that a supportive letter reduced reporting quality unless firms had a long-term orientation, supporting the moderating influence of time horizon, but providing no support for the expected average effect or for moderation by firm size

Interplay of superconductivity and magnetism in strong coupling

A model is introduced describing the interplay between superconductivity and spin-ordering. It is characterized by on-site repulsive electron-electron interactions, causing antiferromagnetism, and nearest-neighbor attractive interactions, giving rise to d-wave superconductivity. Due to a special choice for the lattice, this model has a strong-coupling limit where the superconductivity can be described by a bosonic theory, similar to the strongly coupled negative U Hubbard model. This limit is analyzed in the present paper. A rich mean-field phase diagram is found and the leading quantum corrections to the mean-field results are calculated. The first-order line between the antiferromagnetic- and the superconducting phase is found to terminate at a tricritical point, where two second-order lines originate. At these lines, the system undergoes a transition to- and from a phase exhibiting both antiferromagnetic order and superconductivity. At finite temperatures above the spin-disordering line, quantum-critical behavior is found. For specific values of the model parameters, it is possible to obtain SO(5) symmetry involving the spin- and the phase-sector at the tricritical point. Although this symmetry is explicitly broken by the projection to the lower Hubbard band, it survives on the mean-field level, and modes related to a spontaneously broken SO(5) symmetry are present on the level of the random phase approximation in the superconducting phase.Comment: 16 pages Revtex, 5 figure