NachhaltigF: Angewandte InformatikS: TC Freyung
J. Schmidt, K. Gruber, M. Klingler, C. Klöckl, Luis Ramirez Camargo, P. Regner, O. Turkovska, S. Wehrle, E. Wetterlund
A new perspective on global renewable energy systems: why trade in energy carriers matters
Energy & Environmental Science, vol. 12, no. 7, pp. 2022-2029
Recent global modelling studies suggest a decline of long-distance trade in energy carriers in future global renewable energy systems, compared to today's fossil fuel based system. In contrast, we identify four drivers that facilitate trade of renewable energy carriers. These drivers may lead to trade volumes remaining at current levels or even to an increase during the transition to an energy system with very high shares of renewables. First, new land-efficient technologies for renewable fuel production become increasingly available and technically allow for long-distance trade in renewables. Second, regional differences in social acceptance and land availability for energy infrastructure support the development of renewable fuel import and export streams. Third, the economics of renewable energy systems, i.e. the different production conditions globally and the high costs of fully renewable regional electricity systems, will create opportunities for spatial arbitrage. Fourth, a reduction of stranded investments in the fossil fuel sector is possible by switching from fossil fuels to renewable fuel trade. The impact of these drivers on trade in renewable energy carriers is currently under-investigated by the global energy systems research community. The importance of the topic, in particular as trade can redistribute profits and losses of decarbonization and may hence support finding new partners in climate change mitigation negotiations, warrants further research efforts in this area therefore.
Anton Schmailzl, B. Quandt, M. Schmidt, S. Hierl
In-Situ process monitoring during laser transmission welding of PA6-GF30
Procedia CIRP, vol. 74, pp. 524-527
Quasi-simultaneous laser transmission welding is preferably used for packaging sensors and electronics. In order to protect the components from moisture, a hermetic encapsulation is needed. However, local weld seam interruptions cannot be identified with the commonly used set-path monitoring. By using a pyrometer, coaxially integrated into a 3D-scanner, gaps between the joining partners can be allocated on basis of the measured temperature. However, the scattering of the heat radiation, especially caused by the fiber reinforcement of the plastics, leads to a reduction of the accessible heat radiation, which makes the identification of gaps considerably more difficult. The herein used experimental setup is characterized by a small detection spot and only by a slight weakening of the heat radiation inside the scanner. Hence, for welding PA6-GF30, the detection of small sized gaps is possible, even if a glass fiber content of 30 percent (wt.) and a weld seam width with approximately 1 mm are given.
GesundF: Europan Campus Rottal-Inn
A. Kupferberg, M. Iacoboni, V. Flanagin, M. Huber, Anna-Maria Kasparbauer, T. Baumgartner, G. Hasler, F. Schmidt, C. Borst, S. Glasauer
Fronto-parietal Coding of Goal-Directed Actions Performed by Artificial Agents
Human Brain Mapping, vol. 33, no. 3, pp. 1145-1162
With advances in technology, artificial agents such as humanoid robots will soon become a part of our daily lives. For safe and intuitive collaboration, it is important to understand the goals behind their motor actions. In humans, this process is mediated by changes in activity in fronto-parietal brain areas. The extent to which these areas are activated when observing artificial agents indicates the naturalness and easiness of interaction. Previous studies indicated that fronto-parietal activity does not depend on whether the agent is human or artificial. However, it is unknown whether this activity is modulated by observing grasping (self-related action) and pointing actions (other-related action) performed by an artificial agent depending on the action goal. Therefore, we designed an experiment in which subjects observed human and artificial agents perform pointing and grasping actions aimed at two different object categories suggesting different goals. We found a signal increase in the bilateral inferior parietal lobule and the premotor cortex when tool versus food items were pointed to or grasped by both agents, probably reflecting the association of hand actions with the functional use of tools. Our results show that goal attribution engages the fronto-parietal network not only for observing a human but also a robotic agent for both self-related and social actions. The debriefing after the experiment has shown that actions of human-like artificial agents can be perceived as being goal-directed. Therefore, humans will be able to interact with service robots intuitively in various domains such as education, healthcare, public service, and entertainment.
MobilNachhaltigS: TC Plattling MoMo
W. Schmidt, P. Bottke, Michael Sternad, P. Gollob, V. Hennige, M. Wilkening
Small Change—Great Effect: Steep Increase of Li Ion Dynamics in Li 4 Ti 5 O 12 at the Early Stages of Chemical Li Insertion
Chemistry of Materials, vol. 27, no. 5, pp. 1740-1750
Lithium titanate (LTO) is one of the most promising anode materials for large-scale stationary electrochemical storage of energy produced from renewable sources. Besides many other aspects, such as negligible formation of passivation layers and no volume expansion during lithiation, the success of LTO is mainly based on its ability to easily accommodate and release Li ions in a fully reversible way. This feature is tightly connected with Li self-diffusion. As yet, little information is available about microscopic Li diffusion properties and elementary steps of Li hopping at low intercalation levels, i.e., at values of x being significantly smaller than 1. Here, we used 7Li spin-locking NMR relaxometry to probe absolute hopping rates of LTO (homogeneous) solid solutions in quasi-thermodynamic equilibrium. As a result, the largest increase of Li diffusivity is observed when small amounts of Li are inserted. Strong Coulomb repulsions caused by the simultaneous occupation of neighboring 8a and 16c sites serve as an explanation for the enhanced Li diffusivity found. At even larger values of x, Li mobility slows down but is still much faster than in the host material with x = 0. Our results experimentally corroborate the outcome of recently published calculations on the DFT level focusing on both dynamic and structural aspects. The findings favor the formation of LTO solid solutions upon chemical lithiation; the steep increase in Li diffusivity found might also help with understanding the flat insertion potential observed.
DigitalF: Angewandte Informatik
Beitrag (Sammelband oder Tagungsband)
J. Paulus, G. Michelson, Marcus Barkowsky, J. Hornegger, B. Eskofier, M. Schmidt
Measurement of Individual Changes in the Performance of Human Stereoscopic Vision for Disparities at the Limits of the Zone of Comfortable Viewing
2013 International Conference on 3D Vision (3DV 2013)
3D displays enable immersive visual impressions but the impact on the human perception still is not fully understood. Viewing conditions like the convergence-accommodation (C-A) conflict have an unnatural influence on the visual system and might even lead to visual discomfort. As visual perception is individual we assumed the impact of simulated 3D content on the visual system to be as well. In this study we aimed to analyze the stereoscopic visual performance of 17 subjects for disparities inside and outside the in literature defined zone of comfortable viewing to provide an individual evaluation of the impact of increased disparities on the performance of the visual system. Stereoscopic stimuli were presented in a four-alternative forced choice (4AFC) setup in different disparities. The response times as well as the correct decision rates indicated the performance of stereoscopic vision. The results showed that increased disparities lead to a decline in performance. Further, the impact of the presented disparities is dependent on the difficulty of the task. The decline of performance as well as the deciding disparities for the decline were subject dependent.
NachhaltigF: Europan Campus Rottal-Inn
G. Wittstock, G. Denuault, Stefan Mátéfi-Tempfli, H. Bülter, M. Mátéfi-Tempfli, A. Lesch, I. Schmidt, C. Dosche, M. Ahlf, K. Al-Shamery, A. Fanget, L. Forró
Oxygen evolution at vertically aligned core-shell iron-iron oxide nanowire arrays
24th ECS Meeting: Photoelectrochemistry and Photoassisted Electrocatalysis, San Francisco, CA, USA
F: Elektrotechnik und Medientechnik
C. Bornkessel, M. Schubert, Matthias Wuschek, P. Schmidt
Determination of the General Public Exposure Around GSM and UMTS Base Stations
Radiation Protection Dosimetry, vol. 124, no. 1, pp. 40-47
This paper summarises two studies, in which measurement and calculation methods to determine the exposure of the general public around GSM and UMTS base stations have been developed and applied to different scenarios. The electromagnetic field variations around the stations in space and time are accounted for by appropriate maximisation techniques. Measurements show a bandwidth of exposures from 0.01% to more than 10% of field strength exposure limits. The distance to the station is not a main influencing factor, whereas the orientation to the main lobe and the sight conditions greatly influence exposure. Several commercially available numerical simulation tools were tested for their applicability on exposure forecast. In line-of-sight scenarios, all programs are able to predict the exposure accurately, whereas in non-line-of-sight situations, free space models overestimate the real exposure by some orders of magnitude.
F: Elektrotechnik und Medientechnik
Reinhard Schlosser, H. Schmidt, M. Leghissa, M. Meinert
Development of High‑Temperature Superconducting Transformers for Railway Applications
IEEE Transactions on Appiled Superconductivity, vol. 13, no. 2, pp. 2325-2330
We describe the high-temperature superconducting (HTS) transformer project run by Siemens. The project started in October 1996 and ended in September 2001. The aim of the project was to show the future prospects for superconducting railway transformers. To study the principle behavior of such a transformer, as a first step we designed, constructed and tested a nominal single-phase transformer of 100 kVA, 50 Hz, 5.5 kV/1.1 kV. After this was successfully tested, we started the design and construction of a single-phase transformer of 1 MVA, 50 Hz, 25 kV/1.4 kV. This unit already has the full ratings of a commercial transformer in many respects, e.g., power range, nominal voltage, 2-limb core with horizontal orientation, two secondary windings and an impedance of 25% at nominal current. Further innovative features are transposed conductor and a closed cooling cycle with sub-cooled nitrogen. The report describes the 1-MVA transformer's detailed design, and presents the results of electrical and thermal transformer routine tests (e.g., measurement of load losses and no-load losses). The conclusion highlights the future perspective of HTS transformers for railway applications.
F: Elektrotechnik und Medientechnik
M. Meinert, M. Leghissa, Reinhard Schlosser, H. Schmidt
System test of a 1‑MVA‑HTS-transformer connected to a converter-fed drive for present rail vehicles
IEEE Transactions on Appiled Superconductivity, vol. 13, no. 2, pp. 2348-2351
Railway companies aim to realize environmentally friendly revenue operations with high efficiency. High Temperature Superconducting (HTS)-transformers offer advantages regarding less mass and volume and considerably higher efficiency in drive systems. Siemens has developed a 1-MVA-HTS-transformer with typical characteristics for railway applications. For a successful introduction in the market, it is essential to guarantee the operational behavior of drive systems in well-known manner. So, Siemens realized the 1st operation of an AC-converter fed by a HTS-transformer. System test measurements of losses, tests of cooling redundancy as well as drive cycle operation were performed to compare the converter operation to sinusoidal operation, to analyze the losses depending on the harmonics of nonsinusoidal current and to investigate the behavior of the whole system under realistic drive cycles of a current rail vehicle.
F: Elektrotechnik und Medientechnik
M. Leghissa, B. Gromoll, J. Rieger, M. Oomen, H.-W. Neumüller, Reinhard Schlosser, H. Schmidt, W. Knorr, M. Meinert, U. Henning
Development and Application of Superconducting Transformers
Physica C: Superconductivity and its Applications, vol. 372-376, no. Part 3, pp. 1688-1693
Superconducting transformers are an important innovation for future power transmission and transportation systems. Powerful, lightweight, energy-saving and environmentally friendly they offer enormous benefits compared to their conventional counterparts. Siemens is developing a 1-MVA demonstrator transformer for laboratory testing, exhibiting innovative features like horizontal design, cabled-conductor windings and a closed cooling cycle with sub-cooled nitrogen. Being one of the most promising applications Siemens has started a programme towards the development of on-board transformers for electrical rail vehicles. This paper summarises world-wide efforts in the development of superconducting transformers and reports on the progress achieved at Siemens.