365 research outputs found
Aerodynamic Analysis of a Generic Fighter with a Chine Fuselage/Delta Wing Configuration Using Delayed Detached-Eddy Simulation
The Modular Transonic Vortex Investigation (MTVI) program at NASA Langley Research Center investigated the transonic characteristics of generic fighter configurations with chined fuselages and delta wings. Previous experiments show that the fuselage and leading edge vortex interactions are detrimental to the vehicle’s aerodynamic characteristics for angles of attack greater than 23º at low angles of sideslip. This is largely due to abrupt asymmetric vortex breakdown, which leads to pronounced pitch-up and significant nonlinearities in lateral stability that could result in roll departure. An improved understanding of the exact origins of this nonlinear behavior would improve future fighter design, and predictive capabilities of such nonlinearities could drastically reduce the cost associated with flight testing new or modified aircraft. The nonlinearities experienced by the MTVI configuration at 30 degrees angle of attack, Reynolds number of 2.68x106, and Mach number of 0.4 are computed using Delayed Detached-Eddy Simulation. Computational predictions of rolling moment compare very well with previous wind tunnel experiments at the same conditions, including the abrupt, nonlinear increase in rolling moment as a function of sideslip angle at small sideslip angles. A detailed investigation of the CFD data confirms that this nonlinearity is due to a rapid change in the flow field structures from symmetric to asymmetric vortex breakdown
Innovator resilience potential: A process perspective of individual resilience as influenced by innovation project termination
Innovation projects fail at an astonishing rate. Yet, the negative effects of innovation project failures on the team members of these projects have been largely neglected in research streams that deal with innovation project failures. After such setbacks, it is vital to maintain or even strengthen project members’ innovative capabilities for subsequent innovation projects. For this, the concept of resilience, i.e. project members’ potential to positively adjust (or even grow) after a setback such as an innovation project failure, is fundamental. We develop the second-order construct of innovator resilience potential, which consists of six components – self-efficacy, outcome expectancy, optimism, hope, self-esteem, and risk propensity – that are important for project members’ potential of innovative functioning in innovation projects subsequent to a failure. We illustrate our theoretical findings by means of a qualitative study of a terminated large-scale innovation project, and derive implications for research and management
How the Kano model contributes to Kansei engineering in services
Recent studies show that products and services hold great appeal if they are attractively designed to elicit emotional feelings from customers. Kansei engineering (KE) has good potential to provide a competitive advantage to those able to read and translate customer affect and emotion in actual product and services. This study introduces an integrative framework of the Kano model and KE, applied to services. The Kano model was used and inserted into KE to exhibit the relationship between service attribute performance and customer emotional response. Essentially, the Kano model categorises service attribute quality into three major groups (must-be [M], one-dimensional [O] and attractive [A]). The findings of a case study that involved 100 tourists who stayed in luxury 4- and 5-star hotels are presented. As a practical matter, this research provides insight on which service attributes deserve more attention with regard to their significant impact on customer emotional needs.
Statement of Relevance: Apart from cognitive evaluation, emotions and hedonism play a big role in service encounters. Through a focus on delighting qualities of service attributes, this research enables service providers and managers to establish the extent to which they prioritise their improvement efforts and to always satisfy their customer emotions beyond expectation.
Keywords:
Kansei engineering, emotional feelings, Kano model, service
A Dyson Sphere around a black hole
The search for extraterrestrial intelligence (SETI) has been conducted for
nearly 60 years. A Dyson Sphere, a spherical structure that surrounds a star
and transports its radiative energy outward as an energy source for an advanced
civilisation, is one of the main targets of SETI. In this study, we discuss
whether building a Dyson Sphere around a black hole is effective. We consider
six energy sources: (i) the cosmic microwave background, (ii) the Hawking
radiation, (iii) an accretion disk, (iv) Bondi accretion, (v) a corona, and
(vi) relativistic jets. To develop future civilisations (for example, a Type II
civilisation), () is expected to
be needed. Among (iii) to (vi), the largest luminosity can be collected from an
accretion disk, reaching , enough to maintain a Type
II civilisation. Moreover, if a Dyson Sphere collects not only the
electromagnetic radiation but also other types of energy (e.g., kinetic energy)
from the jets, the total collected energy would be approximately 5 times
larger. Considering the emission from a Dyson Sphere, our results show that the
Dyson Sphere around a stellar-mass black hole in the Milky Way (
away from us) is detectable in the ultraviolet,
optical, near-infrared(), and mid-infrared() wavelengths via the waste heat
radiation using current telescopes such as Galaxy Evolution Explorer
Ultraviolet Sky Surveys. Performing model fitting to observed spectral energy
distributions and measuring the variability of radial velocity may help us to
identify these possible artificial structures.Comment: This paper has been accepted for publication in MNRA
Nanoscale probing of electron-regulated structural transitions in silk proteins by near-field IR imaging and nano-spectroscopy
Silk protein fibres produced by silkworms and spiders are renowned for their unparalleled mechanical strength and extensibility arising from their high-β-sheet crystal contents as natural materials. Investigation of β-sheet-oriented conformational transitions in silk proteins at the nanoscale remains a challenge using conventional imaging techniques given their limitations in chemical sensitivity or limited spatial resolution. Here, we report on electron-regulated nanoscale polymorphic transitions in silk proteins revealed by near-field infrared imaging and nano-spectroscopy at resolutions approaching the molecular level. The ability to locally probe nanoscale protein structural transitions combined with nanometre-precision electron-beam lithography offers us the capability to finely control the structure of silk proteins in two and three dimensions. Our work paves the way for unlocking essential nanoscopic protein structures and critical conditions for electron-induced conformational transitions, offering new rules to design protein-based nanoarchitectures.National Science Foundation (U.S.) (1563422)National Science Foundation (U.S.) (1562915
Extreme damped Lyman- absorption in young star-forming galaxies at
The onset of galaxy formation is thought to be initiated by the infall of
neutral, pristine gas onto the first protogalactic halos. However, direct
constraints on the abundance of neutral atomic hydrogen (HI) in galaxies have
been difficult to obtain at early cosmic times. Here we present spectroscopic
observations with JWST of three galaxies at redshifts , about
Myr after the Big Bang, that show strong damped Lyman-
absorption ( cm) from HI in their local
surroundings, an order of magnitude in excess of the Lyman- absorption
caused by the neutral intergalactic medium at these redshifts. Consequently,
these early galaxies cannot be contributing significantly to reionization, at
least at their current evolutionary stages. Simulations of galaxy formation
show that such massive gas reservoirs surrounding young galaxies so early in
the history of the universe is a signature of galaxy formation in progress.Comment: Submitte
Recommended from our members
Understanding potential career changers’ experience of career confidence following a positive psychology based coaching programme
Changes in the labour market over the last decades have led to an increase in the number of career and job changes individuals are likely to face in their working lives. Previous research indicates that a high level of confidence can help individuals to make positive career changes, yet an agreed definition of confidence is not widely accepted, and the literature provides a limited evidence base for practice. This research involved five female participants who were contemplating a career change. They took part in a coaching programme which consisted of four positive psychology interventions based on a proposal of core confidence as a higher order construct composed of self-efficacy, hope, optimism and resilience. Data were gathered through semi-structured interviews and written reflections and an interpretative phenomenological analysis showed that participants perceived their career confidence before the programme as low, incorporating negative affect and self-doubt. After the programme, participants demonstrated increased career engagement, self-awareness and a positive and optimistic outlook. The analysis revealed that change was effected through the development of hope, change in cognitive processes and coaching as a catalyst. Implications for the definition of career confidence, and for positive psychology and career coaching practice are considered
- …