119092 research outputs found
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Wind- und Solarstrom ergänzen sich
No full textErneuerbare Energien sind inzwischen die Basis der Stromerzeugung in Deutschland. Allein Wind und Sonne lagen im letzten Jahr bei über 45% des verbrauchten Stroms. Durch gegenläufige saisonale und tageszeitliche Schwankungen haben die beiden erneuerbaren Energiequellen hohes Synergiepotenzial. In den letzten drei Jahren gab es jedoch im Schnitt jeweils rund 15 Tage an denen ungünstige Bedingungen für Wind und Sonne zusammenfielen. An diesen Tagen können Reservekapazitäten und Stromimporte den Strombedarf in Deutschland decken. Die Analyse beleuchtet die Entwicklung in den letzten Jahren und zeigt verschiedene Maßnahmen für den Erhalt der Versorgungssicherheit angesichts des geplanten Ausstiegs aus der Kohleverstromung. Hierzu gehören die Flexibilisierung der Nachfrage, eine Angebotsglättung durch Batteriespeicher, eine Stärkung des europäischen Stromhandels sowie wasserstofffähige Gaskraftwerke
Market-based optimization of the Energy-to-Power ratio of a latent thermal energy storage unit based Carnot Battery
No full textThe volatile electricity generation from renewable energies creates the need for electricity storage technologies which, unlike the pumped hydroelectric energy storage established to date, are not tied to geographical conditions. The emerging technology of pumped thermal electricity storage (PTES) is one such alternative. PTESs belong to the group of Carnot Batteries.
Using a price-taker approach with perfect daily foresight, this study determines the achievable contribution margin of a 5MW generic storage in the German day-ahead market by exclusively exploiting daily price spreads. Based on real data from various phase change materials, the investment costs for PTES with a latent thermal energy storage (LTES) unit can be determined as a function of their energy-to-power ratio (E/P-ratio). By comparing the achievable contribution margins and investment costs, the most economical E/P-ratio can be identified. The result is a cost-optimal E/P-ratio that depends on the year, the round-trip efficiency, the coefficient of performance, and the powerrelated purchased equipment cost. For this purpose, both historical and future years were examined, whereby an agent-based market model was used to simulate the future electricity price time series. Oxalic acid dihydrate proved to be the optimal phase change material for all round-trip efficiencies investigated. It turned out that, under the assumed boundary conditions, no PTES enables an economically attractive operation at round-trip efficiencies between 30 % and 70 %. The configurations closest to an economically attractive operation have E/P-ratios of at least 4 h related to the charging duration at half discharging duration
Innovators and transformers – filling the void: informing operations management research and practice by applied neuroscience.
No full textTaxonomic, phylogenetic and functional diversity patterns of Saturniidae moth communities along a tropical forest recovery gradient in Ecuador
No full textConserving the remaining primary forests and restoring forests on former agricultural lands are two key strategies to conserve biodiversity in the tropics. Natural regrowth of forest following the abandonment of agricultural land use is one way of forest restoration and thus, it is important to understand how biodiversity shifts with ongoing recovery and whether communities become more similar over time to those in old‐growth forests. We studied patterns of taxonomic, functional and phylogenetic diversity as well as community composition of Saturniidae, as one of the most conspicuous and well‐studied families of moths. Our study covered a forest recovery gradient from active agriculture via early and advanced stages of regrowth to old‐growth rainforests in the lowland Chocó region of Ecuador. Saturniidae diversity patterns did not follow the hypothesized increase from agriculture to old‐growth forest, but instead, the highest taxonomic and functional diversity was found in early regrowth, and the highest phylogenetic diversity in active agriculture. Diversity differences along the forest recovery gradient were overall weak and occurred mainly when focusing on common and dominant species, but community composition showed a gradual turnover with the strongest differences between old‐growth forest and active agriculture. Our results show that diverse Saturniidae communities are found in naturally recovering tropical forests. But although Saturniidae have been recommended as indicator species due to their well‐documented taxonomy, our results suggest that they are not well suited as indicators of forest recovery. Nevertheless, due to their striking appearance, Saturniidae could serve as flagship species for the conservation of tropical forests
Information-theoretic multi-model fusion for target-oriented adaptive sampling in materials design
No full textTarget-oriented discovery under limited evaluation budgets requires making reliable progress in high-dimensional, heterogeneous design spaces where each new measurement is costly, whether experimental or high-fidelity simulation. We present an information-theoretic framework for target-oriented adaptive sampling that reframes optimization as trajectory discovery: instead of approximating the full response surface, the method maintains and refines a low-entropy information state that concentrates search on target-relevant directions. The approach couples data, model beliefs, and physics/structure priors through dimension-aware information budgeting, adaptive bootstrapped distillation over a heterogeneous surrogate reservoir, and structure-aware candidate manifold analysis with Kalman-inspired multi-model fusion to balance consensus-driven exploitation and disagreement-driven exploration. Evaluated under a single unified protocol without dataset-specific tuning, the framework improves sample efficiency and reliability across 14 single- and multi-objective materials design tasks spanning candidate pools from to and feature dimensions from to , typically reaching top-performing regions within 100 evaluations. Complementary 20-dimensional synthetic benchmarks (Ackley, Rastrigin, Schwefel) further demonstrate robustness to rugged and multimodal landscapes
Integrating intralogistics resource availability into adaptive production planning in flexible job shop environments
No full textA reliable provision of materials in production is a prerequisite for the timely fulfillment of customer orders. Especially in flexible job shop scheduling problems (FJSPs), it is essential to coordinate the use of intralogistics resources in a way that avoids bottlenecks in the production process. In this context, traceability systems offer promising opportunities to record the current location and status of load carriers and suitable means of transport. Established production scheduling approaches rarely consider dynamic information from in-house logistics systems. Consequently, this paper presents an adaptive production planning and control system which integrates the efficient distribution of intralogistics resources into the scheduling process. A model predictive controller using a genetic algorithm is implemented to generate coordinated production and logistics schedules based on process data in a real production environment. By this, a higher utilization of load carriers and means of transport is achieved leading to lower number and costs of required intralogistics resources compared to a planning scenario in which they are neglected
Spatially localized optical excitations in a doped solid using robust broadband composite pulses
No full textWe experimentally demonstrate spatial confinement of optically driven atomic excitation by broadband composite pulses in a rare-earth ion-doped Pr3+:Y2SiO5 crystal. The experimental data confirm that such sequences enable spatially localized excitation well below the diameter of the applied laser beam, with a substantial improvement compared to previous developments and applications of other classes of composite pulses. In particular, we derived and applied broadband composite sequences, which also work efficiently in inhomogeneously broadened media, while also maintaining robustness with regard to fluctuations of the driving laser intensity. We perform extensive measurements to assess and compare the performance of several classes of broadband composite sequences. The findings are confirmed by numerical simulations, which agree very well with the experimental data. As the concepts are also applicable to spatially confined excitations below the diffraction limit of the laser beam, the results serve as an important step towards high-resolution imaging, preparation and addressing in quantum technologies and classical applied optics
