9,823 research outputs found
Control of Cavity-Induced Drag Using Steady Jets
Separated shear layer oscillations in open cavities can
induce drag, noise and vibration. This issue has many
aerospace applications such as Landing gears and control
surfaces [1]. Recently, phase-cancellation [1] and offinstability
frequency excitation [2] & [3] approaches have
been incorporated in different open-loop and feedback control
systems. Despite the high control performance of these
systems, further enhancement is still possible.
In this study, steady jets, as shown in fig. 1, are forced
through 2mm, two-dimensional slots at the leading and trailing
edges of the cavity. In order to study the performance of this
novel approach, different cases will be examined, including:
jet combination (blowing from cavity leading edge, suction
from cavity leading edge and blowing-suction), jet angle
(parallel or deflected jet) and jet-to-free stream velocity
factor /.
Theory of Bubble Nucleation and Cooperativity in DNA Melting
The onset of intermediate states (denaturation bubbles) and their role during
the melting transition of DNA are studied using the Peyrard-Bishop-Daxuois
model by Monte Carlo simulations with no adjustable parameters. Comparison is
made with previously published experimental results finding excellent
agreement. Melting curves, critical DNA segment length for stability of bubbles
and the possibility of a two states transition are studied.Comment: 4 figures. Accepted for publication in Physical Review Letter
Drivers, barriers and development needs for LCA in the Nordic building sector - A survey among professionals
Simulation of transition dynamics to high confinement in fusion plasmas
The transition dynamics from the low (L) to the high (H) confinement mode in
magnetically confined plasmas is investigated using a first-principles
four-field fluid model. Numerical results are in close agreement with
measurements from the Experimental Advanced Superconducting Tokamak - EAST.
Particularly, the slow transition with an intermediate dithering phase is well
reproduced by the numerical solutions. Additionally, the model reproduces the
experimentally determined L-H transition power threshold scaling that the ion
power threshold increases with increasing particle density. The results hold
promise for developing predictive models of the transition, essential for
understanding and optimizing future fusion power reactors
Structurally specific thermal fluctuations identify functional sites for DNA transcription
We report results showing that thermally-induced openings of double stranded
DNA coincide with the location of functionally relevant sites for
transcription. Investigating both viral and bacterial DNA gene promoter
segments, we found that the most probable opening occurs at the transcription
start site. Minor openings appear to be related to other regulatory sites. Our
results suggest that coherent thermal fluctuations play an important role in
the initiation of transcription. Essential elements of the dynamics, in
addition to sequence specificity, are nonlinearity and entropy, provided by
local base-pair constraints
Abrupt changes in alpha decay systematics as a manifestation of collective nuclear modes
An abrupt change in decay systematics around the N=126 neutron shell
closure is discussed. It is explained as a sudden hindrance of the clustering
of the nucleons that eventually form the particle. This is because the
clustering induced by the pairing mode acting upon the four nucleons is
inhibited if the configuration space does not allow a proper manifestation of
the pairing collectivity.Comment: 6 pages, 3 figures, submitted to Phys. Rev. C, a few new references
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Exploring attitudinal factors influencing modal shift:a latent class analysis of Danish commuters
Governments advocate for a modal shift from motorized transport modes to active modes. Various political approaches can be adopted to affect travel behavior and patterns. However, interventions spread across the entire population offer limited opportunities to achieve behavioral change. Furthermore, attitude has been shown to cut across demographic characteristics and strongly influence the conducted travel behavior. Therefore, a latent class analysis including significant sociodemographic variables and value-based attitudes concerning factors influencing transport, settlement, and additional priorities was performed. The study objectively identified five classes of Danish commuters with the same preconditions in terms of commuting distance but with clear differences in attitude and transport modes. Each latent class represents a unique combination of characteristics, which indicates the need to design target group-specific interventions to optimize the chances of influencing travel behavior. In particular, a group of malcontented motorists demonstrating a high intention to change exhibit negative feelings toward car travel and thus appear to act in contravention of their attitudes. In contrast, a class of immovable motorists was found, a class of beneficial commuters and finally two cycling dominated classes of passionate cyclists and environmentalist cyclists. Finally, this study has emphasized that similar attitudes can lead to dissimilar behaviors and that the same behavior can be exhibited for various reasons. We deduced how transport mode choice is influenced by various factors, with habit as one of the strongest, as those with strong habits seem disinclined to information about alternatives and call for âharderâ policy interventions. The findings emphasize the importance of targeted interventions tailored to specific commuter groups to encourage modal shifts towards sustainable transportation.</p
Control of Cavity-Induced Drag Using Steady Jets
Separated shear layer oscillations in open cavities can
induce drag, noise and vibration. This issue has many
aerospace applications such as Landing gears and control
surfaces [1]. Recently, phase-cancellation [1] and offinstability
frequency excitation [2] & [3] approaches have
been incorporated in different open-loop and feedback control
systems. Despite the high control performance of these
systems, further enhancement is still possible.
In this study, steady jets, as shown in fig. 1, are forced
through 2mm, two-dimensional slots at the leading and trailing
edges of the cavity. In order to study the performance of this
novel approach, different cases will be examined, including:
jet combination (blowing from cavity leading edge, suction
from cavity leading edge and blowing-suction), jet angle
(parallel or deflected jet) and jet-to-free stream velocity
factor /.
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