An experimental study of the impulse response of a vibro-impacting cantilever beam

The dynamics of a vibro-impacting cantilever beam experiment using an impact load cell is considered. The signal recorded from the cell produces spike train -type data. The issues related to the analysis of such data are discussed; particularly the sampling rate and threshold values. For vibro-impact motion of the beam, the duration of impacts is investigated by using a time of contact measure. The implications are discussed for vibro-impact systems mathematically modelled by using instantaneous impact assumptions (coefficient of restitution). Using the load cell to measure impact forces for the beam system is also considered. Then a delay reconstruction of the dynamics of the system by using interspike intervals is considered. It is demonstrated how this process is effected by the influence of noise and the data-acquision process using numerical simulations of the experimental data. It is shown how simple periodic motions can be identified by using a probability density approach and possible future research is highlighted

Intelligent configuration of social support networks around depressed persons

Helping someone who is depressed can be very important to the depressed person.A number of supportive family members or friends can often make a big difference.This paper addresses how a social support network can be formed, taking the needs of the support recipient and the possibilities of the potential support providers into account.To do so, dynamic models about the preferences and needs of both support providers and support recipients are exploited. The outcome of this is used as input for a configuration process of a support network. In a case study, it is show how such an intelligently formed network results in a reduced long term stress level

A discursive approach to narrative accounts of hearing voices and recovery

Substantive objective: To research the range of discursive constructions ‘recovered’ voice hearers employ to describe hearing voices and the implications for positioning and subjectivity (what can be thought and felt) using each construction. Methodological objective and method: To explore a ‘sympathetic’ application of Foucauldian discourse analysis, adapting Willig’s (2008 Willig, C. 2008. Introducing Qualitative Research in Psychology, Maidenhead: Open University Press. ) method, analysing two published accounts. Results and conclusions: Heterogeneous discursive constructions for talking about hearing voices were identified, including: ‘many-’selves’’, ‘taking-the-lead-in-your-own-recovery’, ‘voices-as-an-’imagined-world’’ and ‘voices-as-a-coping-strategy-for-dealing-with-trauma’. The discourse of the biomedical model was not prominent, suggesting alternate discursive constructions may create subjects with a greater capacity for ‘living with voices’ and create a subjectivity from which vantage point the experience holds meaning and value and can be integrated into life experiences. This research may have useful clinical applications for mental health services aiming to collaboratively explore service users’ ways of understanding hearing voices

Gravitational Collapse and Disk Formation in Magnetized Cores

We discuss the effects of the magnetic field observed in molecular clouds on the process of star formation, concentrating on the phase of gravitational collapse of low-mass dense cores, cradles of sunlike stars. We summarize recent analytic work and numerical simulations showing that a substantial level of magnetic field diffusion at high densities has to occur in order to form rotationally supported disks. Furthermore, newly formed accretion disks are threaded by the magnetic field dragged from the parent core during the gravitational collapse. These disks are expected to rotate with a sub-Keplerian speed because they are partially supported by magnetic tension against the gravity of the central star. We discuss how sub-Keplerian rotation makes it difficult to eject disk winds and accelerates the process of planet migration. Moreover, magnetic fields modify the Toomre criterion for gravitational instability via two opposing effects: magnetic tension and pressure increase the disk local stability, but sub-Keplerian rotation makes the disk more unstable. In general, magnetized disks are more stable than their nonmagnetic counterparts; thus, they can be more massive and less prone to the formation of giant planets by gravitational instability.Comment: Chapter 16 in "Magnetic Fields in Diffuse Media", Springer-Verlag, eds. de Gouveia Dal Pino, E., Lazarian, A., Melioli,

Physical Processes in Star Formation

© 2020 Springer-Verlag. The final publication is available at Springer via https://doi.org/10.1007/s11214-020-00693-8.Star formation is a complex multi-scale phenomenon that is of significant importance for astrophysics in general. Stars and star formation are key pillars in observational astronomy from local star forming regions in the Milky Way up to high-redshift galaxies. From a theoretical perspective, star formation and feedback processes (radiation, winds, and supernovae) play a pivotal role in advancing our understanding of the physical processes at work, both individually and of their interactions. In this review we will give an overview of the main processes that are important for the understanding of star formation. We start with an observationally motivated view on star formation from a global perspective and outline the general paradigm of the life-cycle of molecular clouds, in which star formation is the key process to close the cycle. After that we focus on the thermal and chemical aspects in star forming regions, discuss turbulence and magnetic fields as well as gravitational forces. Finally, we review the most important stellar feedback mechanisms.Peer reviewedFinal Accepted Versio

Pension reform, the stock market, capital formation and economic growth: a critical commentary on the World Bank's proposals

Abstract Proposing far-reaching reforms to the pension systems, the World Bank has recently suggested that the existing pay-as-you-go pension systems in many rich as well as poor countries, should be replaced by fully funded, mandatory, preferably private pensions, as the main pillars of the new system. It argues that these reforms will not only benefit the pensioners, but also enhance savings, promote capital formation and economic development. This paper provides a critical examination of the Bank's theses and concludes that it has adopted a one-sided view of the relationships between the key critical variables. The proposed reform may therefore neither protect the old nor achieve faster economic growth