Tracing the journey of the sun and the solar siblings through the Milky Way

  This thesis is focused on studying the motion of the Sun and the Solar siblings through the Galaxy. The Solar siblings are stars that were born with the Sun in the same molecular cloud 4.6 Gyr ago. In the first part of the thesis, we present an efficient method to calculate the evolution of small systems embedded in larger systems. Generalizations of this method are used to calculate the motion of the Sun and the Solar siblings in an analytical potential containing a central bar and spiral arms. By integrating the orbit of the Sun backwards in time, we determine its birth radius and the amount of radial migration experienced by our star. The birth radius of the Sun is used to investigate the evolution and disruption of the Sun's birth cluster. Depending on the Galaxy model parameters, the present-day phase-space distribution of the Solar siblings might be quite different. We used these data to predict the regions in the Galaxy where it will be more likely to search for Solar siblings in the future. Finally, we compute the stellar encounters experienced by the Sun along its orbit and their role on the stability of the outer Solar System.  Gaia Research for European Astronomy Training (GREAT-ITN) networkSterrewacht - OU

Exploring intergroup conflict and community-based participatory research partnerships over time

Community-based participatory research (CBPR) is a growing practice by which academics and community partners conduct collaborative health-based research. While CBPR fosters productive partnerships, there is increasing research on interpersonal group dynamics and the ways that intersecting factors, such as gender and ethnicity, affect the social interactions within CBPR. This paper explores the tensions inherent in large interdisciplinary community-based participatory research partnerships, through the examination of a long-standing community–academic partnership focused on advancing public health. Nine qualitative interviews were conducted between November 2019 and January 2020 with steering committee members from a long-standing collaborative partnership that conducts research to inform public health action. While the collaborative process was generally positive, we also uncovered less pleasant aspects of CBPR projects that are infrequently discussed in the literature, such as role confusion and power dynamics. Leadership style was seen as the driving force shaping how other team concerns were perceived. Not having structures in place to facilitate relationship development, or clear documentation of procedures, rules and norms, led to team complications. Team members suggested that a renewed focus on organisational structure would contribute to role clarity and organisation. The results highlight the complexity of working on interdisciplinary mixed community–academic teams, specifically the ways in which interdisciplinary, collaborative research can be a complicated, meandering process, often without clear-cut answers to sometimes simple questions

A Cloud Based Data Integration Framework

Virtual enterprise (VE) relies on resource sharing and collaboration across geographically dispersed and dynamically allied businesses in order to better respond to market opportunities. It is generally considered that effective data integration and management is crucial to realise the value of VE. This paper describes a cloud-based data integration framework that can be used for supporting VE to discover, explore and respond more emerging business opportunities that require instant and easy resource access and flexible on-demand development in a customer-centric approach. Motivated by a case study discussing power incident management in the Spanish Electricity System, an effective on-demand application is also implemented to demonstrate how to use this framework to solve real world problems

Voltage dip generator for testing wind turbines connected to electrical networks

This paper describes a new voltage dip generator that allows the shape of the time profile of the voltage generated to be configured. The use of this device as a tool to test the fault ride-through capability of wind turbines connected to the electricity grid can provide some remarkable benefits: First, this system offers the possibility of adapting the main features of the time–voltage profile generated (dip depth, dip duration, the ramp slope during the recovery process after clearing fault, etc.) to the specific requirements set forth by the grid operation codes, in accordance with different network electrical systems standards. Second, another remarkable ability of this system is to provide sinusoidal voltage and current wave forms during the overall testing process without the presence of harmonic components. This is made possible by the absence of electronic converters. Finally, the paper includes results and a discussion on the experimental data obtained with the use of a reduced size laboratory prototype that was constructed to validate the operating features of this new device

Novel sources of Flavor Changed Neutral Currents in the 331RHN331_{RHN} model

Sources of Flavor Changed Neutral Currents (FCNC) naturally emerge from a well motivated framework called 3-3-1 with right-handed neutrinos model, $331_{RHN}$ for short, mediated by an extra neutral gauge boson $Z^{\prime}$. Following previous works we calculate these sources and in addition we derive new ones coming from CP-even and -odd neutral scalars which appear due to their non-diagonal interactions with the physical standard quarks. Furthermore we show that bounds related to the neutral mesons systems $K_L-K_S$ and $D_1^0 - D_2^0$ may be significantly strengthened in the presence of these new interactions allowing us to infer stronger constraints on the parameter space of the model.Comment: Published version. 10 pages, 6 figure

Computation of initial conditions for a thin disc as an extension of Dehnen algorithm

Galaxie

Radial migration of the Sun in the Milky Way: a statistical study

Computational astrophysic