| 1. |
- Donahue, N. M., et al.
(author)
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Aging of biogenic secondary organic aerosol via gas-phase OH radical reactions
- 2012
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In: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 109:34, s. 13503-13508
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Journal article (peer-reviewed)abstract
- The Multiple Chamber Aerosol Chemical Aging Study (MUCHACHAS) tested the hypothesis that hydroxyl radical (OH) aging significantly increases the concentration of first-generation biogenic secondary organic aerosol (SOA). OH is the dominant atmospheric oxidant, and MUCHACHAS employed environmental chambers of very different designs, using multiple OH sources to explore a range of chemical conditions and potential sources of systematic error. We isolated the effect of OH aging, confirming our hypothesis while observing corresponding changes in SOA properties. The mass increases are consistent with an existing gap between global SOA sources and those predicted in models, and can be described by a mechanism suitable for implementation in those models.
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| 2. |
- Schneider, J., et al.
(author)
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The seasonal cycle of ice-nucleating particles linked to the abundance of biogenic aerosol in boreal forests
- 2021
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In: Atmospheric Chemistry and Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 21:5, s. 3899-3918
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Journal article (peer-reviewed)abstract
- Ice-nucleating particles (INPs) trigger the formation of cloud ice crystals in the atmosphere. Therefore, they strongly influence cloud microphysical and optical properties and precipitation and the life cycle of clouds. Improving weather forecasting and climate projection requires an appropriate formulation of atmospheric INP concentrations. This remains challenging as the global INP distribution and variability depend on a variety of aerosol types and sources, and neither their short-term variability nor their long-term seasonal cycles are well covered by continuous measurements. Here, we provide the first year-long set of observations with a pronounced INP seasonal cycle in a boreal forest environment. Besides the observed seasonal cycle in INP concentrations with a minimum in wintertime and maxima in early and late summer, we also provide indications for a seasonal variation in the prevalent INP type. We show that the seasonal dependency of INP concentrations and prevalent INP types is most likely driven by the abundance of biogenic aerosol. As current parameterizations do not reproduce this variability, we suggest a new mechanistic description for boreal forest environments which considers the seasonal variation in INP concentrations. For this, we use the ambient air temperature measured close to the ground at 4.2 m height as a proxy for the season, which appears to affect the source strength of biogenic emissions and, thus, the INP abundance over the boreal forest. Furthermore, we provide new INP parameterizations based on the Ice Nucleation Active Surface Site (INAS) approach, which specifically describes the ice nucleation activity of boreal aerosols particles prevalent in different seasons. Our results characterize the boreal forest as an important but variable INP source and provide new perspectives to describe these new findings in atmospheric models.
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| 3. |
- Scheffle, M., et al.
(author)
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Low cost large area panel processing of MCM-D substrates and packages
- 2001
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In: Proceedings of IPACK’01. ; , s. -8
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Conference paper (peer-reviewed)abstract
- The paper describes the results of the EU research project LAP that had the target to develop and to demonstrate a low-cost high-density substrate manufacturing technology for 1st-level die assemblies. The cost target of 1€€/in2 had to be obtained by increasing toady’s 4x4in2 panel sizes to panels upto 24x24in2. The results focus on RF characterization (integrated antennas up to 83GHz, inductors up a Q value of 50), novel packaging strategies (integration of substrate and package), and cost achievements (approaching the cost target). The technology capabilities have been demonstrated with a 9:4 satellite switch operating up to 2.4GHz and readout electronics for physics experiments.
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| 4. |
- Arridge, Christopher S., et al.
(author)
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Uranus Pathfinder : exploring the origins and evolution of Ice Giant planets
- 2012
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In: Experimental astronomy. - : Springer Science and Business Media LLC. - 0922-6435 .- 1572-9508. ; 33:2-3, s. 753-791
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Journal article (peer-reviewed)abstract
- The "Ice Giants" Uranus and Neptune are a different class of planet compared to Jupiter and Saturn. Studying these objects is important for furthering our understanding of the formation and evolution of the planets, and unravelling the fundamental physical and chemical processes in the Solar System. The importance of filling these gaps in our knowledge of the Solar System is particularly acute when trying to apply our understanding to the numerous planetary systems that have been discovered around other stars. The Uranus Pathfinder (UP) mission thus represents the quintessential aspects of the objectives of the European planetary community as expressed in ESA's Cosmic Vision 2015-2025. UP was proposed to the European Space Agency's M3 call for medium-class missions in 2010 and proposed to be the first orbiter of an Ice Giant planet. As the most accessible Ice Giant within the M-class mission envelope Uranus was identified as the mission target. Although not selected for this call the UP mission concept provides a baseline framework for the exploration of Uranus with existing low-cost platforms and underlines the need to develop power sources suitable for the outer Solar System. The UP science case is based around exploring the origins, evolution, and processes at work in Ice Giant planetary systems. Three broad themes were identified: (1) Uranus as an Ice Giant, (2) An Ice Giant planetary system, and (3) An asymmetric magnetosphere. Due to the long interplanetary transfer from Earth to Uranus a significant cruise-phase science theme was also developed. The UP mission concept calls for the use of a Mars Express/Rosetta-type platform to launch on a Soyuz-Fregat in 2021 and entering into an eccentric polar orbit around Uranus in the 2036-2037 timeframe. The science payload has a strong heritage in Europe and beyond and requires no significant technology developments.
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| 5. |
- Belov, Ilja, et al.
(author)
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Application of CFD Modelling for Energy Efficient Humidity Mangement of an Electronics Enclosure in Storage under Severe Climatic Conditions
- 2008
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In: International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Micro-Systems, 2008. - : IEEE. - 9781424421275 ; , s. 430-437
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Conference paper (peer-reviewed)abstract
- A CFD modelling methodology including experimental validation has been developed and applied for investigation of anti-moisture measures in a non- hermetic electronics enclosure containing a number of printed circuit boards, and placed in a severe storage environment. In the climatic test the temperature and the relative humidity have been varried from +33degC to +71degC and from 14% to 80%, respectively. Enclosure heater solutions have been parametrically studied by simulation. A heating strategy involving various power levels has been determined, which is just sufficient to maintain the internal relative humidity below 60%, thereby reducing the risk for dew formation on the electronics assembly.
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