On the Wake Structure in Streaming Complex Plasmas

The theoretical description of complex (dusty) plasmas requires multiscale concepts that adequately incorporate the correlated interplay of streaming electrons and ions, neutrals, and dust grains. Knowing the effective dust-dust interaction, the multiscale problem can be effectively reduced to a one-component plasma model of the dust subsystem. The goal of the present publication is a systematic evaluation of the electrostatic potential distribution around a dust grain in the presence of a streaming plasma environment by means of two complementary approaches: (i) a high precision computation of the dynamically screened Coulomb potential from the dynamic dielectric function, and (ii) full 3D particle-in-cell simulations, which self-consistently include dynamical grain charging and non-linear effects. The applicability of these two approaches is addressed

Interferometric Study of Ionospheric Plasma Irregularities in Regions of Phase Scintillations and HF Backscatter

We investigate the nature of small-scale irregularities observed in the cusp by the Twin Rockets to Investigate Cusp Electrodynamics-2 (TRICE-2) in regions of enhanced phase scintillations and high-frequency coherent radar backscatter. We take advantage of the fact that the irregularities were detected by spatially separated probes, and present an interferometric analysis of both the observed electron density and electric field fluctuations. We provide evidence that fluctuations spanning a few decameters to about a meter have low phase velocity in the plasma reference frame and are nondispersive, confirming that decameter-scale irregularities follow the E × B velocity. Furthermore, we show that these “spatial” structures are intermittent and prominent outside of regions with strongest precipitation. The observations are then discussed in the context of possible mechanisms for irregularity creation.publishedVersio

More than competition: exploring stakeholder identities at a grassroots cause-related sporting event

The purpose of this paper is to (a) explore stakeholder identities of a grassroots cause-related sporting event; and (b) gain a better understanding of how identities are related to stakeholder development, support of the event, and future intentions. We used a mixed methods research design that consisted of two studies: qualitative followed by quantitative. Study 1 explored stakeholder identities and how they are related to stakeholder development and support of the event, and Study 2 examined how future intentions regarding attendance, donations, and sponsor support differ based on levels of stakeholder identity. Sports marketing and non-profit management literature streams as well as identity theory and social capital theory informed our studies. The National Kidney Foundation Surf Festival was selected because it is a grassroots cause-related sporting event with financial success over the last two decades. In addition, a surf contest, an action sport, is a unique sport setting in the nonprofit sector, which offers insight to marketers seeking to target subcultures. The findings of the qualitative study revealed three identities relevant to participants: sport subculture, community, and cause. A framework emerged from the data that illustrated how these identities unite together to generate social capital, which is linked to effective volunteer and sponsorship management. Quantitative analysis through survey data provided further evidence of the impact of identification with a cause-related sport activity on consumer outcomes. Results indicated attendees with high surf-related identity are more likely to attend future Surf Festivals, have higher intentions to donate to the cause, and have higher sponsor purchase intentions compared to those with low self-identity with the sport subculture. The conclusion discusses implications, framing the findings through the intersection of the sports marketing and non-profit sector industries, and provides suggestions for future research.Ye

Modeling of multimodal urban public transport trips

Przesiadki w podróżach realizowanych transportem zbiorowym w miastach są oceniane przez pasażerów negatywnie, jako dodatkowa uciążliwość podróży. Sieci połączeń transportu zbiorowego oparte na przesiadkach mogą być jednak bardziej efektywne. W określonych przypadkach połączenia z przesiadkami mogą być bardziej komfortowe od bezpośrednich, także według subiektywnej oceny pasażerów. Ważne jest zatem zidentyfikowanie czynników determinujących wybór określonego rodzaju podróży i determinant wpływających na zmianę zachowań pasażerów poprzez akceptację podróży z przesiadkami. W artykule zaprezentowano metodę przeprowadzania badań marketingowych, których celem jest identyfikacja zachowań transportowych i preferencji podróżnych dotyczących połączeń z przesiadkami. Opisano badania przeprowadzone wśród studentów Politechniki Gdańskiej, a także wyniki analizy uzyskanych danych w postaci statystyki opisowej i analizy niezależności i zależności. Przedstawiono także model matematyczny oparty na regresji logistycznej, który umożliwia określenie, jakie warunki powinny być spełnione, aby podróż z przesiadką została zaakceptowana przez pasażerów. Wyniki przeprowadzonych badań wskazują, że najbardziej uciążliwymi cechami podróży z przesiadkami są: ryzyko spóźnienia się na przesiadkę oraz konieczność oczekiwania podczas przesiadki. Najlepszą rekompensatą za te uciążliwości jest skrócenie czasu podróży względem podróży bezpośredniej.Changes in travels realized by means of public transport in cities are judged by passengers negatively, as an additional inconvenience of the trip. However, the network of public transport connections based on transfer changes may be more efficient. In certain cases connecting trips may be more comfortable than the direct in the subjective opinion of passengers. It is therefore important to identify the factors determining passengers preferences in terms of trips with transfer changes comfort. The article describes original method of carrying out a research aimed at identifying travel behaviour and travellers preferences in the term of trips with changes. The research conducted among students of the Gdańsk University of Technology and results of obtained data analysis in the form of descriptive statistics and analysis of correlation and lack of correlation in transfers issue have been presented in the article. Also the mathematical model based on a logistic regression allowing to define a conditions that must be met to make a travel with changes acceptable by passengers has been described. The results of the study research indicates that the most onerous features of trips with transfers are: risk of being late to the transport connection and the necessity to wait during this transfer. The best compensation for this inconveniences is reduction of travel time in relation to direct travel

Experiments on wake structures behind a microparticle in a magnetized plasma flow

The wake behind a spherical microparticle in a magnetized ion flow is studied experimentally by analyzing the arrangement of a pair of particles. It is shown that there are two stable particle arrangements at intermediate magnetic inductions, whereas only oblique (horizontal) particle configurations are found at the highest magnetic field. Self-consistent collisional molecular dynamics simulations of the particle system show that the underlying mechanism of these arrangements is the weakening of attractive wake forces by the increasing magnetic field. Plasma instabilities provide a trigger for the onset of the transition between the two different arrangements. Furthermore, the course of the transition is qualitatively explained by the charge variation of the downstream particle in the wake of the upstream particle. In addition, a thorough analysis of the sheath by means of particle-in-cell simulations in combination with particle resonance measurements yields consistent values of the particle mass and charge, as well as the levitating electric field and ion flow velocity

Rules of engagement: a discrete choice analysis of sponsorship decision making

This paper draws on exchange and utility theories to propose and test a model of sponsorship decision making using discrete choice analysis. Grounded in prior sponsorship research and current management practice, the model describes sponsorship selection as a sequence of choices about sponsorship packages of differing value. The core thesis is that managers attempt to maximise their utility when selecting sponsorships by evaluating the various pay-offs from the alternatives available. This research applies a simulated choice-based experiment with 196 sponsorship managers to assess their preferences for a set of criteria likely to shape their future decisions about sponsorship selection. While perceptions of brand-image congruence and relationship quality significantly affect sponsor preferences, contrary to some evidence, short-term business arrangements appear more desirable than longer-term sponsorships