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Reviews and responses for Fast contrail estimation with OpenSky data
No full textContrails, formed under specific atmospheric conditions, have a noteworthy role in heat-trapping within the atmosphere. This study bridges the gap between theoretical contrail formation models and real-world data by employing flight information from OpenSky and meteorological data from the European Centre for Medium-Range Weather Forecasts. We introduce a computationally efficient contrail estimation module, leveraging a client-server architecture that allows on-demand weather data interpolation via an API, significantly reducing computational load and enhancing performance locally. The study also benchmarks the entire pipeline, from data acquisition to contrail prediction, offering a robust tool for future air traffic studies requiring interpolated weather data.Control & Simulatio
Effect of temperature on lanthanide charge transition levels and vacuum referred binding energies
No full textLocation of lanthanide levels in the bandgap, vacuum referred binding energy (VRBE) in the lanthanide ground state and energy of lanthanide charge transition levels (CTLs) are just three different namings for the same concept. A concept of importance for the performance of lanthanide activated compounds. Energy differences of CTLs with the conduction band bottom and valence band top are important when it concerns e.g. lanthanide luminescence, charge carrier trapping, and valence stability. Effect of temperature on CTL energy or VRBE has so far never been addressed despite that luminescence application and thermoluminescence studies may span a temperature range from 10 K to 1000 K. In this work information on the bandgap (or energy of host exciton creation) around 10 K and at RT in compounds is gathered to demonstrate that bandgap decreases by 0.1 eV to 0.3 eV when temperature increases to RT. A similar decrease will be demonstrated for the energy of electron transfer from the VB to a trivalent lanthanide. The findings have consequences for VRBE-diagram construction, i.e. the experimental parameters for such construction should all apply to the same temperature. They also have consequences on how to relate luminescence thermal quenching energy barriers and TL derived electron and hole trap depths with a VRBE diagram. By proper evaluating the effects of temperature, accuracy of VRBE diagrams and consistency with luminescence and thermoluminescence data can be improved.RST/Luminescence Material
Magnetocaloric properties of Mn<sub>5</sub>(Si,P)B<sub>2</sub> compounds for energy harvesting applications
No full textThe magnetocaloric properties of Mn5Si1-xPxB2 (0 ≤ x ≤ 1) compounds were studied for energy harvesting applications. The crystal structure and the magnetic structure were characterized by powder X-Ray Diffraction and powder Neutron Diffraction. The results indicate that these magnetocaloric materials crystallize in the tetragonal Cr5B3-type crystal structure. The introduction of P causes a stretching of the c axis and compression of the a-b plane, leading to a decrease in the unit-cell volume V. In the ferromagnetic state the magnetic moments align within the a-b plane, and the magnetic moment of the Mn1 atom on the 16 l site is larger than that of the Mn2 atom on the 4c site. The Curie temperature TC can be adjusted continuously from 305 K (x = 1) to 406 K (x = 0) by replacing Si with P. The corresponding magnetic entropy change varies from 1.90 Jkg−1K−1 (x = 0) to 1.35 Jkg−1K−1 (x = 1) for a magnetic field change of 1 T. The PM-FM transition in these compounds corresponds to a second-order phase transition. Mn5Si1-xPxB2 compounds exhibit a magnetization difference of 28.1 - 31.3 Am2kg−1 for a temperature span of 30 K around TC in an applied magnetic field of 1 T. The considerable change in magnetization, the tunable TC near and above room temperature and the absence of thermal hysteresis make these compounds promising candidates for magnetocaloric energy harvesting materials.RST/Fundamental Aspects of Materials and Energ
The SATA-Drive: A Modular Robotic Drive for Reusable Steerable Laparoscopic Instruments
No full textIntroduction: Most robotic instruments and their drives still risk residual contamination due to cleaning complexities, rendering them limited reusable, and tend to have larger instruments than the 5mm laparoscopic standard. The novel steerable laparoscopic SATA-LRS uses modularity for cleanability and exchangeability. The SATA-Drive: a robotic driver designed for the actuation of a 3mm scaled version of the SATA-LRS is presented. Methods: A modular, expandable gear mechanism was designed to efficiently rotate and translate the instrument shafts. The 3mm SATA-LRS is controlled as proof. An user-experiment is conducted to test the (de)coupling of the instrument to and from the drive. Results: A video shows the SATA-Driver successfully articulating, rotating and grasping the end-effector. End-effector dis- and reassembly is possible in 36 (13 SD) seconds, while complete instrument coupling requires 28(8 SD) seconds and de-coupling requires 16 (7 SD) seconds. Discussion: A non-surgical robot arm, mounted with the SATA-drive has effectively been transformed into a system similar to robot assisted laparoscopy. The modularity of the drive's segmented build can easily be adapted and could benefit the adoption of future instruments. The SATA-LRS's cleanability features and its end-effector changes without disassembly are expected to benefit medical robotics. The 3mm SATA-LRS shows the instrument's potential for mini-laparoscopy.Medical Instruments & Bio-Inspired Technolog
Simulating Quantum Scheduler Performance for an Entanglement Generation Switch
No full textThe quantum internet improves upon the classical internet with several new possibilities. However, to create such a quantum internet, metropolitan hubs (for this research we will use an Entanglement Generation Switch - EGS - as hub) are needed to avoid a scaling problem when connecting all end nodes individually with one another. These EGSs share resources for multiple end nodes. Hence, resource sharing protocols are needed to manage these resources. Unfortunately due to the probabilistic nature of end-to-end entanglement generation, classical resource sharing protocols will not suffice for implementation in a quantum network. Therefore the need to design quantum resource sharing protocols arises. These protocols, where we specifically investigate quantum schedulers, should be simple and predictable to provide a comprehensible addition to current research by incorporating more parameters into the current EGS model while still attempting optimal resource efficiency. In this research we have extended quantum network simulation software to be used in this research and following projects. We have implemented a classical Max Weight scheduler with a constant time window size to simulate the inefficiency of such a classical protocol in a quantum environment and improve upon this protocol by implementing a scheduler with a dynamic time window size which scales with the link length and the probability of a photon arriving at the EGS. We investigate the entanglement successes, idle time and entanglement rates when using these schedulers and compared these with each other and with a third scheduler without a time window size but using a cutoff timer instead, the Cutoff scheduler. These results show an optimality of entanglement successes, idle time and entanglement rates for the Cutoff scheduler over the Dynamic Time Window scheduler and for the Dynamic Time Window scheduler over the Max Weight scheduler with a constant time window size. Also a decrease in entanglement rate for all schedulers is shown when increasing the link length.Computer Scienc
Collective action lessons for the energy transition: learning from social movements of the past
No full textTo accelerate the energy transition and achieve the needed large-scale transformation to address climate change, different barriers including lock-ins and path dependencies, incumbent power structures and changing individual and collective norms, values, and behaviors around energy need to be addressed. In the face of these challenges, citizens are beginning to play a bigger role in the transformation of the energy system. For example, they are becoming prosumers (energy consumers who also produce energy) and are increasingly engaging in collective energy actions, including taking part in energy communities. In the latter instance, collective investment and consumption decisions are made together, and norms, understanding and behavior towards energy are shaped collectively. To better understand the roles that individuals and groups can play in confronting the challenges of the energy transition, we make use of and adapt Ostrom’s socio-ecological systems (SES) framework to analyze past examples of collective actions and to delve deeper into the causes and catalysts of collective actions. We show how this framework can be used to analyze collective actions across time and contexts, focusing on connecting individual and group behavior with changing societal norms and the corresponding barriers to change. By applying the adapted SES framework as a lens to analyze historical examples of collective actions that have resulted in a widespread transformation in social norms and structures, we identify similarities and differences between these case studies and the current energy transition. Confronting incumbents and the challenge of changing social norms and behaviors are among the similarities, but the specific tactics used to limit incumbents’ powers and the actions taken to influence the norms and behaviors differ. Lastly, we determine the key actors that influenced social and behavioral change, as one of the main outcomes of the analysis.Policy Analysi
Adaptive Visual Servoing Control for Quadrotors: A Bio-inspired Strategy Using Active Vision
No full textNew insights into the landing behavior of bumblebees show an adaptive strategy where the optical flow expansion of the landing target is step-wise regulated. In this article, the potential benefits of this approach are studied by replicating the landing experiment with a quadrotor. To this end, an open-loop switching method is developed, enabling fast steps in divergence. An adaptive control law is used to deal with non-linear system dynamics, where the control gain is scheduled based on the control effectiveness of the actuator inputs during the steps. It is demonstrated that the quadrotor can reliably land on the target from varying initial positions, and the switching strategy shows a slight reduction in landing time compared to a constant divergence strategy with the same average divergence over distance. This strategy also reduces the maximum velocity during the landing.Aerospace Engineerin
Design thinking in medical education to tackle real world healthcare problems: The MasterMinds Challenge
No full textEducational challenge: Medical education must equip future professionals with the necessary skills to navigate the complex healthcare landscape. Clinical knowledge is essential, and critical and creative thinking skills are vital to meet the challenges of the system. Design thinking offers a structured approach that integrates creativity and innovation, yet its application in medical education is absent. Solution and implementation: The compulsory MasterMinds Challenge course at Leiden University Medical Center utilizes design thinking principles to address real world healthcare challenges. Final-year medical students participated in a two-day program. The course encompassed empathizing with stakeholders, problem definition, ideation, prototyping, and refining solutions. Presentation skills were emphasized, culminating in a symposium where teams showcase their outcomes. Implementation of the MasterMinds Challenge course was successful with 33 sessions delivered to 1217 medical students. Challenges covered various healthcare topics, yielding creative yet practical outcomes. Students appreciate the real world healthcare challenge, team-based approach, and the applicability of design thinking principles. Challenge owners expressed satisfaction with students’ commitment, creativity, and empathizing abilities. Lessons learned and next steps: To further enhance the MasterMinds Challenge course, a more longitudinal format is being designed, enabling greater autonomy and emphasizing the refining and implementation phases. The course can be extended to medical postgraduate professionals and interdisciplinary collaborations, fostering innovative ideas beyond current practices. By developing problem-solving skills, the MasterMinds Challenge course contributes to a future-proof medical education program and prepares students to meet the evolving needs of healthcare.Delft Centre for Entrepreneurshi
Method for bandgap interpolation of perovskite's spectral complex refractive index
No full textLead halide perovskites are a promising class of materials for solar cell applications. The perovskite bandgap depends on the material composition and is highly tunable. Opto-electrical device modelling is commonly used to find the optimum perovskite bandgap that maximizes device efficiency or energy yield, either in single junction or multi-junction configuration. The first step in this calculation is the optical modelling of the spectral absorptance. This requires as input the perovskite's complex refractive index N as a function of wavelength λ. The complex refractive index consists of real part n(λ) and imaginary part k(λ). For the most commonly used perovskites, n and k curves are available from spectroscopic ellipsometry measurements, but usually only for a few discrete bandgap energies. For solar cell optimization, these curves are required for a continuous range of bandgap energies. We introduce new methods for generating the n and k curves for an arbitrary bandgap, based on interpolating measured complex refractive index data. First, different dispersion models (Cody-Lorentz, Ullrich-Lorentz and Forouhi-Bloomer) are used to fit the measured data. Then, a linear regression is applied to the fit parameters with respect to the bandgap energy. From the interpolated parameters, the refractive index curve of perovskite with any desired bandgap energy is finally reconstructed. To validate our method, we compare our results with methods from literature and then use it to simulate the absorptance of a single junction perovskite and a perovskite/silicon tandem cell. This shows that our method based on the Forouhi-Bloomer model is more accurate than existing methods in predicting the complex refractive index of perovskite for arbitrary bandgaps.Photovoltaic Materials and Device
Multi-trait analysis characterizes the genetics of thyroid function and identifies causal associations with clinical implications
No full textTo date only a fraction of the genetic footprint of thyroid function has been clarified. We report a genome-wide association study meta-analysis of thyroid function in up to 271,040 individuals of European ancestry, including reference range thyrotropin (TSH), free thyroxine (FT4), free and total triiodothyronine (T3), proxies for metabolism (T3/FT4 ratio) as well as dichotomized high and low TSH levels. We revealed 259 independent significant associations for TSH (61% novel), 85 for FT4 (67% novel), and 62 novel signals for the T3 related traits. The loci explained 14.1%, 6.0%, 9.5% and 1.1% of the total variation in TSH, FT4, total T3 and free T3 concentrations, respectively. Genetic correlations indicate that TSH associated loci reflect the thyroid function determined by free T3, whereas the FT4 associations represent the thyroid hormone metabolism. Polygenic risk score and Mendelian randomization analyses showed the effects of genetically determined variation in thyroid function on various clinical outcomes, including cardiovascular risk factors and diseases, autoimmune diseases, and cancer. In conclusion, our results improve the understanding of thyroid hormone physiology and highlight the pleiotropic effects of thyroid function on various diseases.Pattern Recognition and Bioinformatic
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