Electro-impulse de-icing testing analysis and design

Electro-Impulse De-Icing (EIDI) is a method of ice removal by sharp blows delivered by a transient electromagnetic field. Detailed results are given for studies of the electrodynamic phenomena. Structural dynamic tests and computations are described. Also reported are ten sets of tests at NASA's Icing Research Tunnel and flight tests by NASA and Cessna Aircraft Company. Fabrication of system components are described and illustrated. Fatigue and electromagnetic interference tests are reported. Here, the necessary information for the design of an EIDI system for aircraft is provided

Effect of top reinforcing on the fire performance of continuous reinforced concrete beams

This paper examines the behaviour of continuous reinforced concrete beams exposed to fire on three sides, in order to investigate the effect of different lengths of the top reinforcing bars over the supports. The study was performed with 2D finite element analysis using SAFIR. The effect of continuity was investigated with rectangular crosssection beams spanning over two and three bays subjected to the ISO 834 fire. Compared to a single span beam, the continuous beams resisted the fire exposure for a longer period of time. It was found that different lengths of the top reinforcing bars resulted in different failure mechanisms, but did not greatly affect the fire resistance of the beams . The influence of the full process of fire development was analysed using the ISO fire for 30, 60 and 90 minutes followed by a decay phase. Structural failure only occurred if the fully developed phase of the fire continued until very close to the failure time reached with no decay phase

Leveraging For-Cause Physical Activity Events for Physical Activity Promotion: An Investigation Using Self-Determination Theory

Motivating individuals to live active lifestyles remains a challenging but important public health issue. For-cause physical activity events reach large groups of people, many of whom are not regularly active. However, little research has applied established health behavior theories to explain participation in for-cause events. Therefore, the purpose of this dissertation was to investigate participation in for-cause events through the lens of Self-Determination Theory (SDT). The first study recruited participants (n=207) registered in a for-cause PA event (i.e., 5K distance or shorter) to complete online surveys that assessed need satisfaction for autonomy, competence, and relatedness; intrinsic motivation; altruism; PA behavior; and intention to repeat participation in future for-cause events. Analyses assessed change in need satisfaction for autonomy, competence, and relatedness from exercise before and after completing the event. Additional analyses assessed the associations of these three needs, intrinsic motivation, and altruism on intention to repeat participation in future for-cause events and PA behaviors. Results revealed a significant increase in competence satisfaction (p = 0.04) and decrease in relatedness satisfaction (p = 0.04). The increase in autonomy satisfaction was not statistically significant (p = 0.25). In addition, participants with higher post-event relatedness satisfaction were more likely to intend to repeat participation in a future for-cause event. Lastly, higher levels of post-event autonomy, competence, and relatedness satisfaction and intrinsic motivation were associated with greater post-event PA and higher levels of post-event competence and relatedness satisfaction and intrinsic motivation were associated with meeting PA guidelines. The second study assessed participants’ (n=18) experiences in for-cause events through semi-structured interviews. Constructs of Self-Determination Theory, altruism, and intention for PA were applied when coding, with the addition of emergent coding methods to assess additional themes in responses. Participants described their experiences in line with the three needs of SDT, especially competence and relatedness. Participants also described motivations for exercise aligning with identified (i.e., motive to exercise to meet personal goals) and intrinsic motivation (i.e., motive to exercise is inherent in performing the behavior). Responses often highlighted altruistic motives suggesting a potential fourth need in the context of for-cause events. Lastly, participants referred to the importance of a strong community formed through these events. Participants’ desire to join and support the cause helped explain their intention to remain active and involved in for-cause events. This mixed methods dissertation provides initial support for the application of SDT to participation in for-cause events. These events enlist large numbers of participants and may help reach and motivate those who are not regularly active. This study’s findings support how individuals may initially participate in a for-cause event to support the cause rather than do PA, suggesting new ways to promote events, reach participants, and motivate them to do PA. This dissertation highlights potential leverage points of for-cause events to promote PA, particularly by satisfying participants’ needs for altruism, competence, relatedness

Quantum entanglement between a nonlinear nanomechanical resonator and a microwave field

We consider a theoretical model for a nonlinear nanomechanical resonator coupled to a superconducting microwave resonator. The nanomechanical resonator is driven parametrically at twice its resonance frequency, while the superconducting microwave resonator is driven with two tones that differ in frequency by an amount equal to the parametric driving frequency. We show that the semi-classical approximation of this system has an interesting fixed point bifurcation structure. In the semi-classical dynamics a transition from stable fixed points to limit cycles is observed as one moves from positive to negative detuning. We show that signatures of this bifurcation structure are also present in the full dissipative quantum system and further show that it leads to mixed state entanglement between the nanomechanical resonator and the microwave cavity in the dissipative quantum system that is a maximum close to the semi-classical bifurcation. Quantum signatures of the semi-classical limit-cycles are presented.Comment: 36 pages, 18 figure

Optimal strategies for a game on amenable semigroups

The semigroup game is a two-person zero-sum game defined on a semigroup S as follows: Players 1 and 2 choose elements x and y in S, respectively, and player 1 receives a payoff f(xy) defined by a function f from S to [-1,1]. If the semigroup is amenable in the sense of Day and von Neumann, one can extend the set of classical strategies, namely countably additive probability measures on S, to include some finitely additive measures in a natural way. This extended game has a value and the players have optimal strategies. This theorem extends previous results for the multiplication game on a compact group or on the positive integers with a specific payoff. We also prove that the procedure of extending the set of allowed strategies preserves classical solutions: if a semigroup game has a classical solution, this solution solves also the extended game.Comment: 17 pages. To appear in International Journal of Game Theor

The Vienna RNA Websuite

The Vienna RNA Websuite is a comprehensive collection of tools for folding, design and analysis of RNA sequences. It provides a web interface to the most commonly used programs of the Vienna RNA package. Among them, we find folding of single and aligned sequences, prediction of RNA–RNA interactions, and design of sequences with a given structure. Additionally, we provide analysis of folding landscapes using the barriers program and structural RNA alignments using LocARNA. The web server together with software packages for download is freely accessible at http://rna.tbi.univie.ac.at/

Probing the electronic transport on the reconstructed Au/Ge(001) surface

By using scanning tunnelling potentiometry we characterized the lateral variation of the electrochemical potential $\mu _{ec}$ on the gold-induced Ge(001)-c(8 × 2)-Au surface reconstruction while a lateral current flows through the sample. On the reconstruction and across domain boundaries we find that $\mu _{ec}$ shows a constant gradient as a function of the position between the contacts. In addition, nanoscale Au clusters on the surface do not show an electronic coupling to the gold-induced surface reconstruction. In combination with high resolution scanning electron microscopy and transmission electron microscopy, we conclude that an additional transport channel buried about 2 nm underneath the surface represents a major transport channel for electrons

Freiburg RNA Tools: a web server integrating IntaRNA, ExpaRNA and LocARNA

The Freiburg RNA tools web server integrates three tools for the advanced analysis of RNA in a common web-based user interface. The tools IntaRNA, ExpaRNA and LocARNA support the prediction of RNA–RNA interaction, exact RNA matching and alignment of RNA, respectively. The Freiburg RNA tools web server and the software packages of the stand-alone tools are freely accessible at http://rna.informatik.uni-freiburg.de