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Navigation is an essential part of flying where crew keep track of the position of a moving aircraft relative to the Earth. Early in aviation history the tools for this were maps, compass, airspeed, indicator, clock, and astronavigation. Modern systems in the craft, on the ground and in space, have to a large degree automated this task and provides high accuracy and availability. There are now ground based navigation systems with area coverage, specialized systems for landing procedures, radio beacons, distance measuring equipment, radar and transponders, inertial navigation systems, and satellite navigation receivers. Equally important as these technical aids are air traffic control, maps, and procedures. Today the art of air navigation involves a working knowledge of all these systems.

A vital system on modern high-speed electric trains is the overhead catenary system and the pantograph current collector. As speed limits are increased, train operators and railway engineers need measures of system performance in a number of situations. In this work a laboratory model is built to study the pantograph behaviour on curved track running on a catenary system with large stiffness variation. The model is designed to be simple, yet exhibit the most characteristic dynamic properties of the real system. Another objective is the possibility to run the pantograph at speeds near the wave propagation velocity of the contact wire. The situation of several trailing pantographs, with even spacing, which excites the system to steady state, is considered. Effects of changes in design features such as tension in the contact wire and torsion and translation stiffness of components in the pantograph are studied for different speeds. The interaction is complex and the performance depends on the dynamic properties of both the catenary system and the pantograph. The results show that the pantograph configuration mainly affects the size of amplitudes in the system while the contact wire tension influences at which velocities large amplitudes and contact losses occur.

In a future society with limited access to fossil fuels, technologies for efficient on demand delivery of renewable energy are highly desirable. In this regard, methods that allow for solar energy storage and on demand solar driven energy generation are particularly relevant since the sun is the most abundant energy source. The talk will focus on the possibility to harness and store solar energy in chemical bonds by the use of photochromic molecules (molecular solar thermal energy storage, MOST). Photochromic molecules are capable of reversible isomerisation between two metastable isomers when exposed to light. These two isomers have distinct chemical and physical properties, such as HOMO and LUMO energy levels. In molecular solar thermal energy storage, photochromic molecules with a large difference in energy between the two isomers is used and the energy difference between these two isomers equals to the molar energy storage capacity of the system (Figure 1). Molecular solar thermal (MOST) is a concept for long term storage of solar energy in molecules and release of the energy as heat with full regeneration of the initial materials. The process is inherently closed cycle and emission free. Critical design parameters of the photochromic materials will in the talk be discussed and includes:1) The effect of the HOMO-LUMO gap of the low and high energy isomers on the solar harnessing capability and efficiency.2) The effect of the thermal energy barrier on the energy storage density.3) The effect of the thermal energy barrier on the storage lifetime. 4) The use of catalytic back conversion and energy extraction. 5) The use of triplet-triplet annihilation photon upconversion (TTA-UC) to enhance efficiency of energy conversion. Figure 1. Energy diagram explaining the enthalpy of energy storage (H storage ) and the activation energy of backisomerization (E a ) between the low (parent) and high (photoisomer) energy isomers.The Shockley and Queisser type limits set solar power conversion efficiency limitation on all single bandgap solar harvesting devices. A generic approach to circumvent the Shockley and Queisser limit is by photon upconversion. By transforming two low energy photons to one high energy photon, the 445 WD2.4 (Invited) 11:30 AM -11:45 AM 978-1-4577-1504-4/14/$26.00 ©2014 IEEE