27 research outputs found
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