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See detailEffects of topological band structure on thermoelectric transport of bismuthene
Gaffar, Muhammad; Wella, Sasfan Arman; Hasdeo, Eddwi Hesky UL

in Physical Review. B (2021), 104(20), 205105

Two-dimensional bismuth (Bi) layer, known as bismuthene, exhibits Z2 topological bulk states due to large spin-orbit coupling that inverts the bands. Using the tight-binding method, we calculate the band ... [more ▼]

Two-dimensional bismuth (Bi) layer, known as bismuthene, exhibits Z2 topological bulk states due to large spin-orbit coupling that inverts the bands. Using the tight-binding method, we calculate the band structure of buckled bismuthene to understand its topological and trivial phases. We determine the thermoelectric properties for some considered phases, incorporating the edge states contribution, by using the linearized Boltzmann transport equation with a constant relaxation time approximation. It is shown that the thermoelectric figure of merit, ZT, actually drops in undoped topological bismuthene due to the edge effects. Surprisingly, the topological edge states enhance ZT at large doping with the Fermi energy near the bottom of bulk bands when bismuthene is nearly metallic. [less ▲]

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See detailNetwork model and four-terminal transport in minimally twisted bilayer graphene
De Beule, Christophe UL; Dominguez, Fernando; Recher, Patrik

in Physical Review. B (2021), 104

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See detailMachine learning and health inequalities
Leist, Anja UL

Presentation (2021, November 08)

Detailed reference viewed: 25 (1 UL)
Peer Reviewed
See detailCentrality and city size effects on NO2 ground and tropospheric concentrations within European cities
Wei, Yufei UL; Caruso, Geoffrey UL; Lemoy, Rémi

Scientific Conference (2021, November 05)

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See detailЛюксембургские военнопленные в СССР и советские военнопленные в Люксембурге
Ganschow, Inna UL

Speeches/Talks (2021)

Presentation of a special course in which students of the Luxembourg and Tambov universities participate. Students of both countries are working on digitizing objects of war life, collecting information ... [more ▼]

Presentation of a special course in which students of the Luxembourg and Tambov universities participate. Students of both countries are working on digitizing objects of war life, collecting information at a microhistorical level, as well as immersing themselves in different aspects of war. [less ▲]

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See detailStable Electrospinning of Core-Functionalized Coaxial Fibers Enabled by the Minimum-Energy Interface Given by Partial Core− Sheath Miscibility
Vats, Shameek UL; Lagerwall, Jan UL; Anyfantakis, Emmanouil UL

in Langmuir (2021), 37(45), 1326513277

Core−sheath electrospinning is a powerful tool for producing composite fibers with one or multiple encapsulated functional materials, but many material combinations are difficult or even impossible to ... [more ▼]

Core−sheath electrospinning is a powerful tool for producing composite fibers with one or multiple encapsulated functional materials, but many material combinations are difficult or even impossible to spin together. We show that the key to success is to ensure a well-defined core−sheath interface while also maintaining a constant and minimal interfacial energy across this interface. Using a thermotropic liquid crystal as a model functional core and polyacrylic acid or styrene-butadiene-styrene block copolymer as a sheath polymer, we study the effects of using water, ethanol, or tetrahydrofuran as polymer solvent. We find that the ideal core and sheath materials are partially miscible, with their phase diagram exhibiting an inner miscibility gap. Complete immiscibility yields a relatively high interfacial tension that causes core breakup, even preventing the core from entering the fiber- producing jet, whereas the lack of a well-defined interface in the case of complete miscibility eliminates the core−sheath morphology, and it turns the core into a coagulation bath for the sheath solution, causing premature gelation in the Taylor cone. Moreover, to minimize Marangoni flows in the Taylor cone due to local interfacial tension variations, a small amount of the sheath solvent should be added to the core prior to spinning. Our findings resolve a long-standing confusion regarding guidelines for selecting core and sheath fluids in core−sheath electrospinning. These discoveries can be applied to many other material combinations than those studied here, enabling new functional composites of large interest and application potential. [less ▲]

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See detailIntroduction to Digital History
Zaagsma, Gerben UL

Presentation (2021, November 03)

Introduction to digital history for C²DH internal training program, focusing on the history of digital history and the ways in which digitised and digital heritage affects historical research (politics of ... [more ▼]

Introduction to digital history for C²DH internal training program, focusing on the history of digital history and the ways in which digitised and digital heritage affects historical research (politics of digitisation). [less ▲]

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See detailDevice simulation of all-perovskite four-terminal tandem solar cells: towards 33% efficiency
Singh, Ajay UL; Gagliardi, Alessio

in EPJ Photovoltaics (2021), 12(4),

Inorganic–organic hybrid perovskites offer wide optical absorption, long charge carrier diffusion length, and high optical-to-electrical conversion, enabling more than 25% efficiency of single-junction ... [more ▼]

Inorganic–organic hybrid perovskites offer wide optical absorption, long charge carrier diffusion length, and high optical-to-electrical conversion, enabling more than 25% efficiency of single-junction perovskite solar cells. All-perovskite four-terminal (4T) tandem solar cells have gained great attention because of solution-processability and potentially high efficiency without a need for current-matching between subcells. To make the best use of a tandem architecture, the subcell bandgaps and thicknesses must be optimized. This study presents a drift-diffusion simulation model to find optimum device parameters for a 4T tandem cell exceeding 33% of efficiency. Optimized subcell bandgaps and thicknesses, contact workfunctions, charge transport layer doping and perovskite surface modification are investigated for all-perovskite 4T tandem solar cells. Also, using real material and device parameters, the impact of bulk and interface traps is investigated. It is observed that, despite high recombination losses, the 4T device can achieve very high efficiencies for a broad range of bandgap combinations. We obtained the best efficiency for top and bottom cell bandgaps close to 1.55 eV and 0.9 eV, respectively. The optimum thickness of the top and bottom cells are found to be about 250 nm and 450 nm, respectively. Furthermore, we investigated that doping in the hole transport layers in both the subcells can significantly improve tandem cell efficiency. The present study will provide the experimentalists an optimum device with optimized bandgaps, thicknesses, contact workfunctions, perovskite surface modification and doping in subcells, enabling high-efficiency all-perovskite 4T tandem solar cells. [less ▲]

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See detailAnalysis of flow induced texturing in complex fluids with Brillouin Rheology - a proof of concept
Lehr, Claudius Moritz UL

Doctoral thesis (2021)

The aim of this work is to study the flow induced texturing of molecules (complex fluids) in a shear field. This is done by measuring phonons with photons [1] in a commercially available rotational ... [more ▼]

The aim of this work is to study the flow induced texturing of molecules (complex fluids) in a shear field. This is done by measuring phonons with photons [1] in a commercially available rotational rheometer. The optical experimental method of transferring momentum and energy between phonons and photons is generally known as Inelastic Light Scattering (ILS) [2]. Brillouin Light Scattering (BLS) [3] has a quite small energy transfer compared to Raman spectroscopy [4] but with a high performance multi-pass Vernier tandem Fabry-Perot interferometer [5] and a sophisticated optical set-up, it is possible to achieve information about the texture (like entanglement of molecules) of complex fluids inside a rheometer gap while shearing. This can be acquired for any position in the sample, in contrast to the rheological experiments were an average over a whole sample is used. Here we successfully demonstrate an optical set-up that couples a BLS with rotational rheology in order to simultaneously measure the high-frequency longitudinal elastic modulus in a classical rheometer along with the zero-shear viscosity during the flow of complex fluids. BLS gives the possibility for contactless determination of local elastic properties, while the designed optical set-up is introduced as boundary conditions to control temperature gradients in the sample, and the position and dimension of the scattering volume. This method was tested for a range of temperatures, and well as for an applied shear field and different radial positions of the scattering volume in the sample using a plate-plate rheometer geometry. Measurements of a dilute polymer system suggest a homogeneous orientation of polymer molecules throughout the sample as soon as a critical shear rate has been reached at one spatial position. [less ▲]

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See detailComparing software frameworks of Augmented Reality solutions for manufacturing
Kolla, Sri Sudha Vijay Keshav UL; Sanchez, Andre UL; Plapper, Peter UL

in Procedia Manufacturing (2021, November 03), 55

Augmented reality (AR) is a technology that allows overlaying of virtual elements on top of the physical environment. This enhances the perception and conveys additional information to the user. With the ... [more ▼]

Augmented reality (AR) is a technology that allows overlaying of virtual elements on top of the physical environment. This enhances the perception and conveys additional information to the user. With the emergence of industry 4.0 concepts in manufacturing landscape, AR found its way to improve existing Human-Machine Interfaces (HMI) on the shop-floor. The industrial setting has a wide variety of application opportunities from AR, ranging from training and digital work instructions to quality inspection and remote maintenance. Even though its implementation in the industry is rising in popularity, it is still mainly restricted to large companies due the limited availability of resources in Small and Medium Size Enterprises (SME). However, SMEs can benefit from AR solutions in its production processes. Therefore, this research aims to develop and present the results of comparison of two simple and cost-effective AR software frameworks for Hand Held Device (HHD) and a Head Mounted Device (HMD), which can be applied for developing AR applications for manufacturing. Two AR applications are developed using these software frameworks which are presented in the case study section. Android device is chosen as a HHD and HoloLens is the HMD used in the case study. The development structure can be reproduced by a wider range of enterprises with diverse needs and resource availability. [less ▲]

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See detailWARCnet WG2 activities: a report
Schafer, Valerie UL

Scientific Conference (2021, November 03)

Detailed reference viewed: 44 (2 UL)
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See detailCANMatch: A Fully Automated Tool for CAN Bus Reverse Engineering based on Frame Matching
Buscemi, Alessio UL; Turcanu, Ion; Castignani, German et al

in IEEE Transactions on Vehicular Technology (2021)

Controller Area Network (CAN) is the most frequently used in-vehicle communication system in the automotive industry today. The communication inside the CAN bus is typically encoded using proprietary ... [more ▼]

Controller Area Network (CAN) is the most frequently used in-vehicle communication system in the automotive industry today. The communication inside the CAN bus is typically encoded using proprietary formats in order to prevent easy access to the information exchanged on the bus. However, it is still possible to decode this information through reverse engineering, performed either manually or via automated tools. Existing automated CAN bus reverse engineering methods are still time-consuming and require some manual effort, i.e., to inject diagnostic messages in order to trigger specific responses. In this paper, we propose CANMatch a fully automated CAN bus reverse engineering framework that does not require any manual effort and significantly decreases the execution time by exploiting the reuse of CAN frames across different vehicle models. We evaluate the proposed solution on a dataset of CAN logs, or traces, related to 479 vehicles from 29 different automotive manufacturers, demonstrating its improved performance with respect to the state of the art. [less ▲]

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See detailAutomatic Integration of Numerical Formats Examined with Frequency-tagged EEG
Marinova, Mila UL; Georges, Carrie UL; Guillaume, Mathieu et al

in Scientific Reports (2021)

How humans integrate and abstract numerical information across different formats is one of the most debated questions in human cognition. We addressed the neuronal signatures of the numerical integration ... [more ▼]

How humans integrate and abstract numerical information across different formats is one of the most debated questions in human cognition. We addressed the neuronal signatures of the numerical integration using an EEG technique tagged at the frequency of visual stimulation. In an oddball design, participants were stimulated with standard sequences of numbers (<5) depicted in single (digits, dots, number words) or mixed notation (dots – digits, number words – dots, digits – number words), presented at 10Hz. Periodically, a deviant stimulus (>5) was inserted at 1.25 Hz. We observed significant oddball amplitudes for all single notations, showing for the first time using this EEG technique, that the magnitude information is spontaneously and unintentionally abstracted, irrespectively of the numerical format. Significant amplitudes were also observed for digits – number words and number words – dots, but not for digits – dots, suggesting an automatic integration across some numerical formats. These results imply that direct and indirect neuro-cognitive links exist across the different numerical formats. [less ▲]

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See detailActive matter in infinite dimensions: Fokker–Planck equation and dynamical mean-field theory at low density
Manacorda, Alessandro UL

in Journal of Chemical Physics (2021)

We investigate the behavior of self-propelled particles in infinite space dimensions by comparing two powerful approaches in many-body dynamics: the Fokker-Planck equation and dynamical mean-field theory ... [more ▼]

We investigate the behavior of self-propelled particles in infinite space dimensions by comparing two powerful approaches in many-body dynamics: the Fokker-Planck equation and dynamical mean-field theory. The dynamics of the particles at low densities and infinite persistence time is solved in the steady-state with both methods, thereby proving the consistency of the two approaches in a paradigmatic out-of-equilibrium system. We obtain the analytic expression for the pair distribution function and the effective self-propulsion to first order in the density, confirming the results obtained in a previous paper and extending them to the case of a non-monotonous interaction potential. Furthermore, we obtain the transient behavior of active hard spheres when relaxing from equilibrium to the nonequilibrium steady-state. Our results show how collective dynamics is affected by interactions to first order in the density, and point out future directions for further analytical and numerical solutions of this problem. [less ▲]

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See detailAnisotropic Interlayer Force Field for Transition Metal Dichalcogenides: The Case of Molybdenum Disulfide
Wengen, Ouyang; Reut, Sofer; Xiang, Gao et al

in Journal of Chemical Theory and Computation (2021)

Detailed reference viewed: 30 (0 UL)
See detailMara's song
Aleksic, Gabrijela UL

Book published by Self-published (2021)

This book is a book I wrote for preschool immigrant children who struggle with learning a new language. Mara is a girl who comes to a new country and feels isolated in the school. She finds answers in the ... [more ▼]

This book is a book I wrote for preschool immigrant children who struggle with learning a new language. Mara is a girl who comes to a new country and feels isolated in the school. She finds answers in the nature and a refuge in music that she shares with her teacher and classmates in the end. [less ▲]

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See detailMaras Lied
Aleksic, Gabrijela UL

Book published by Self-published (2021)

This book is a book I wrote for preschool immigrant children who struggle with learning a new language. Mara is a girl who comes to a new country and feels isolated in the school. She finds answers in the ... [more ▼]

This book is a book I wrote for preschool immigrant children who struggle with learning a new language. Mara is a girl who comes to a new country and feels isolated in the school. She finds answers in the nature and a refuge in music that she shares with her teacher and classmates in the end. [less ▲]

Detailed reference viewed: 39 (1 UL)