28 research outputs found
Sustainable AI:Tools for moving toward Green AI
No full textIn the era of big data and even bigger machine learning models powering the current generative AI revolution, the environmental footprint of these developments can no longer be ignored. This much-needed guide confronts the challenge head-on, offering a groundbreaking exploration into making deep learning (DL) both efficient and accessible. Author Raghavendra Selvan exposes the high costs—both environmental and economic—of traditional DL methods and presents practical solutions that pave the way for a more sustainable AI. This essential read is for anyone in the machine learning field, from the academic researcher to the industry practitioner, who wants to make a meaningful impact on both their work and the world. This book enables readers to be agents of change toward a more sustainable and inclusive technological future
Organometallic Lanthanide Bismuth Cluster Single-Molecule Magnets
No full textSingle-molecule magnets (SMMs) are molecules that can retain magnetic polarization in the absence of an external magnetic field and embody the ultimate size limit for spin-based information storage and processing. Multimetallic lanthanide complexes lacking magnetic exchange coupling enable fast relaxation pathways that attenuate the full potential of these species. Employment of diamagnetic heavy main group elements with diffuse orbitals may lead to unprecedented strong coupling. Herein, two bismuth cluster bridged lanthanide complexes, [K(THF)4]2[Cp*2Ln2Bi6] (Cp* = pentamethylcyclopentadienyl; 1-Ln, Ln = Tb, Dy), were synthesized via a solution organometallic approach. The neutral [Ln2Bi6] heterometallocubane core features lanthanide centers that are bridged by a rare Bi66- Zintl ion which supports strong ferromagnetic interactions between lanthanides. This affords the rare observation of magnetic blocking and open hysteresis loops for superexchange-coupled SMMs comprising solely lanthanide ions. Both compounds constitute the first SMMs containing bismuth donors paving the way for promising synthetic targets for quantum computation
Organometallic Lanthanide Bismuth Cluster Single-Molecule Magnets
No full textSingle-molecule magnets (SMMs) are molecules that can retain magnetic polarization in the absence of an external magnetic field and embody the ultimate size limit for spin-based information storage and processing. Multimetallic lanthanide complexes lacking magnetic exchange coupling enable fast relaxation pathways that attenuate the full potential of these species. Employment of diamagnetic heavy main group elements with diffuse orbitals may lead to unprecedented strong coupling. Herein, two bismuth cluster bridged lanthanide complexes, [K(THF)4]2[Cp*2Ln2Bi6] (Cp* = pentamethylcyclopentadienyl; 1-Ln, Ln = Tb, Dy), were synthesized via a solution organometallic approach. The neutral [Ln2Bi6] heterometallocubane core features lanthanide centers that are bridged by a rare Bi66- Zintl ion which supports strong ferromagnetic interactions between lanthanides. This affords the rare observation of magnetic blocking and open hysteresis loops for superexchange-coupled SMMs comprising solely lanthanide ions. Both compounds constitute the first SMMs containing bismuth donors paving the way for promising synthetic targets for quantum computation
Organometallic Lanthanide Bismuth Cluster Single-Molecule Magnets
No full textSingle-molecule magnets (SMMs) are molecules that can retain magnetic polarization in the absence of an external magnetic field and embody the ultimate size limit for spin-based information storage and processing. Multimetallic lanthanide complexes lacking magnetic exchange coupling enable fast relaxation pathways that attenuate the full potential of these species. Employment of diamagnetic heavy main group elements with diffuse orbitals may lead to unprecedented strong coupling. Herein, two bismuth cluster bridged lanthanide complexes, [K(THF)4]2[Cp*2Ln2Bi6] (Cp* = pentamethylcyclopentadienyl; 1-Ln, Ln = Tb, Dy), were synthesized via a solution organometallic approach. The neutral [Ln2Bi6] heterometallocubane core features lanthanide centers that are bridged by a rare Bi66- Zintl ion which supports strong ferromagnetic interactions between lanthanides. This affords the rare observation of magnetic blocking and open hysteresis loops for superexchange-coupled SMMs comprising solely lanthanide ions. Both compounds constitute the first SMMs containing bismuth donors paving the way for promising synthetic targets for quantum computation
Simulation of optic flow based flight control for a flapping wing micro aerial vehicle
No full textBio-inspired flying micro drones, formally known as Flapping Wing Micro Aerial Vehicles (FWMAV) are a booming class of robots in today's world. Navigation and flight control of these drones is an interesting area of research that has become popular among roboticists and engineers due to its challenges. A bio-inspired optic flow based flight control system for FWMAV using six optic sensor was proposed earlier. However, there is not enough evidence to validate the control methodology discussed. This thesis presents a validation in the form of a flight simulator to test the optic flow based control strategy. The simulator consists of functional modules such as a kinematic module to generate the motion of the FWMAV based on inertia, external forces and torques, an optic sensor system module to generate the optic flow as perceived by the six optic sensor configuration, a flying environment to test the flight of the FWMAV and an optic flow based controller module to stabilise the aircraft in three dimensional space. Simulation results show that the optic flow based controller can successfully stabilise the FWMAV under normal flying conditions.Embedded SystemsSoftware and Computer TechnologyElectrical Engineering, Mathematics and Computer Scienc
Author response: Teaching NeuroImages: RCVS causing simultaneous convexity subarachnoid hemorrhage and hemimedullary infarction
No full textMulti-Objective Optimization of Hybrid Heat Sinks with Phase Change Materials
No full textA passive method with phase change material (PCM) is an appropriate technique in electronic cooling. But, due to its poor thermal conductivity, many enhancers are employed to reduce the thermal resistance offered by the PCM. A partial filling strategy to reduce the cost and weight of foams with fins is used in this study. A hybrid heat sink with a combination of fins placed at the sidewalls of the enclosure and foams filled at certain heights such as 10, 20, and 30 mm is considered in this present work. A two-dimensional numerical model with n-eicosane as PCM is developed in ANSYS Fluent 19. A multi-objective optimization is carried out using a reliable multi criteria decision making approach. Different weightage is distributed to the objective functions in this method depending on the choice of the user. The pore size and density vary for various filling heights, and 60 cases are investigated for both charging and discharging cycles. The pore size of 0.8-0.95 and pore density of 5-25 pores per inch with a broad range is considered. From the discussions, guidelines for selecting a preferable pore size and pore density can be determined based on the filling height and applied weightage.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Process and Energ
Extensive analysis of PCM-based heat sink with different fin arrangements under varying load conditions and variable aspect ratio
No full textThe present study compares a modified variable height fin heat sink with the conventional constant height fin heat sink. The two heat sinks are filled with an equal volume of PCM (n-eicosane) and a fin volume fraction of 8 %. The experiments are performed for constant loads and also different power surge conditions. The pulsed heat loads are applied for two scenarios: 1. Constant load 4 W - power surge and constant load 4 W - power surge - 1800 s no-load condition, and 2. Power surge (50 s, 100 s, and 150 s) - no-load conditions of 1800 s. During experiments, the proposed variable height fin heat sinks possess better thermal performance for all load scenarios. Further, a 3D computational model is developed using ANSYS Fluent 19 to assess not only the effect of fin arrangement for different aspect ratios but also the impact of fin shape. The enclosure aspect ratio employed for the given study ranges from 0.3 to 0.8 for both the heat sinks. Regarding the fin structure in a heat sink, four types of fin shapes are adopted: square, circular, diamond, and triangular. The contour images of temperature and the liquid fraction are shown for the charging process. For the discharging process, the time required for the heat sinks to completely solidify the PCM is discussed. From the outcomes, variable height fin heat sinks provide enhanced melting/solidification for all the aspect ratios and fin shapes considered. As the aspect ratio increases, the time difference between the heat sink for the completion of the discharging cycle is reduced. Moreover, the triangular shaped fin shows a higher enhancement percentage of 2.29 % and 1.43 % during melting and 6.25 % and 12.5 % during solidification for both the heat sinks, respectively.Process and Energ
Numerical analysis of multiple phase change materials based heat sink with angled thermal conductivity enhancer
No full textPhase change materials (PCM) RT-28HC, RT-35HC, and RT-44HC with three different melting temperatures, 29 °C, 36 °C, and 44 °C, with similar thermal properties, are considered. The PCM is oriented from the left to right side of the heat sink in its increasing order. The fins are attached to the heat sink longitudinally, and its orientation effects are studied low (100–500 W/m2) and high (1000–5000 W/m2) heat fluxes applied on the horizontal bottom surface of the heat sink. A 2D model is developed using ANSYS Fluent 19, and the fin orientation effects are investigated numerically. The orientation of fins at different angles such as 0°, +15°, +30°, +45°, +60°,-15°,-30°,-45°, −60° are considered. The effect of fins on the charging cycle is assessed by comparing a single and double PCM heat sink. Three initial conditions are investigated by altering the initial temperature 300 K, 303 K, and 310 K. At increasing heat input, the negative angled fins possess a higher melting rate. For different initial conditions, −60° provides higher enhancement, and +60° possesses prolonged melting for almost all cases. The performance of a triple PCM design is compared with single and double PCM counterparts under similar conditions.Process and Energ
Numerical analysis of fluid flow and heat transfer during melting inside a cylindrical container for thermal energy storage system
No full text
