Article
Mechanics
Tao Wang, He Yu, Yujian Fang, Ru Xiang, Nengqi Kan, Jing Yan
Summary: This paper assesses the geometrical structures and operating performance of volutes used in centrifugal pumps and proposes design principles and calculation processes to reduce hydraulic loss and increase pump efficiency. Numerical investigations reveal that the new volute design improves pump head and efficiency. This paper provides a new approach for designing energy-saving volutes in centrifugal pumps.
Article
Physics, Fluids & Plasmas
Lukas Oberreiter, Udo Seifert, Andre C. Barato
Summary: Biochemical clocks are crucial for all living systems and can only oscillate coherently for a limited number of times when isolated from external signals and subject to fluctuations. Moreover, these clocks can only oscillate if they consume free energy. We propose a universal bound that determines the minimum amount of free energy required for a certain number of coherent oscillations.
Article
Multidisciplinary Sciences
Ziga Kos, Joern Dunkel
Summary: In this study, the concept of nematic bits (nbits) is introduced in liquid crystals, and it is demonstrated through theory and simulations how single-bit operations can be implemented using electric fields and how universal classical logic gates and generalized logical functions can be realized using nematoelastic interactions.
Article
Energy & Fuels
Zachary E. Lee, K. Max Zhang
Summary: A new method for model identification and predictive control using smart thermostat and smart electricity meter, without the need for submetering, is proposed to overcome modeling challenges and hardware requirements, enabling scalable and efficient integration of residential heat pumps with the smart grid.
Article
Automation & Control Systems
Chang Hoon Song, Geonho Hwang, Jun Ho Lee, Myungjoo Kang
Summary: This study proves the universality of deep narrow RNNs and shows that the upper bound of the minimum width for universality can be independent of the length of the data. They also investigate the universality of other types of recurrent neural networks and bridge the gap between multi-layer perceptrons and RNNs, providing theoretical and technical support for further research on deep RNNs.
JOURNAL OF MACHINE LEARNING RESEARCH
(2023)
Article
Chemistry, Multidisciplinary
Thomas Guerin, Maxim Dolgushev, Olivier Benichou, Raphael Voituriez
Summary: The authors analyzed the kinetics of imperfect reactions in confining domains for diffusive or anomalous transport processes, and found that the full distribution of reaction times can be obtained from the mean reaction time in large confining volumes. They showed that the distribution of imperfect reactions is similar to that of perfect reactions, even in the regime of low reactivity where there are large fluctuations in reaction time. This was illustrated for both normal diffusion in domains of generic shapes and anomalous diffusion in complex environments, with predictions confirmed by numerical simulations.
COMMUNICATIONS CHEMISTRY
(2021)
Article
Mathematics
Benjamin Bakker, Yohan Brunebarbe, Jacob Tsimerman
Summary: In this paper, we prove Griffiths' conjecture on the quasi-projectivity of images of period maps using algebraization results from o-minimal geometry. We develop a theory of analytic spaces and coherent sheaves that are definable with respect to a given o-minimal structure, and prove a GAGA-type theorem algebraizing definable coherent sheaves on complex algebraic spaces. We then combine this with Artin's algebraization theorems to show that proper definable images of complex algebraic spaces are algebraic. Applying this to period maps, we conclude that the images of period maps are quasi-projective and that the restriction of the Griffiths bundle is ample.
INVENTIONES MATHEMATICAE
(2023)
Article
Astronomy & Astrophysics
Pedro Bargueno, Ernesto Contreras
Summary: In this work, we derive the Bekenstein-Hawking entropy formula, S = A/4l(p)(2), from minimal assumptions. These assumptions include the existence of a minimum area, A(min), proportional to l(p)(2); the event horizon area, A, being tessellated by distinguishable units; and these units having an infinite tower of internal levels. Our model-independent results can be realized as excitations of more fundamental entities, like strings or loop quantum gravity spin networks. When considering the microstates of the black hole as singlets within the infinite tower of states describing the whole event horizon, our model also yields the correction term - 3/2 log A. We also discuss the applicability of our model to extremal black holes and its potential relationships with spectral geometry and other approaches.
Article
Astronomy & Astrophysics
Ivan Kolar, Tomas Malek, Anupam Mazumdar
Summary: We study exact solutions of infinite derivative gravity with null radiation in almost universal Weyl type III/N Kundt spacetimes, where the convoluted field equations simplify to a single nonlocal, linear equation containing the Laplace operator on 2-dimensional spaces of constant curvature. We find nonlocal analogues of solutions describing gravitational waves generated by null sources, which can be exactly solvable using eigenfunction expansion or the heat kernel method in several examples. The nonlocal solutions are regular at the sources unlike the local solutions, and in the limit of infinite nonlocality, they become conformally flat.
Article
Mathematics, Applied
Derya Saglam
Summary: This paper investigates a characterization of minimal translation graphs as a generalization of minimal translation hypersurfaces in semi-Euclidean space.
Article
Multidisciplinary Sciences
Jonathan Keelan, James P. Hague
Summary: The study found that considering the full complexity of arterial trees is essential for determining the fundamental properties of vasculatures. Optimization-based arterial growth algorithms are stable against uncertainties in physiological parameters, while optimal bifurcation exponents are affected by the complexity of vascular networks and the boundary conditions dictated by organs.
SCIENTIFIC REPORTS
(2021)
Article
Computer Science, Information Systems
Yiran Yang, Xian Sun, Wenhui Diao, Xuee Rong, Shiyao Yan, Dongshuo Yin, Xinming Li
Summary: In this article, the authors propose an exquisite strategy for label assignment in object detection based on samples' joint scores. This strategy can be applied to both 2D and 3D monocular detectors. By formulating label assignment as an optimization problem and utilizing iterative Genetic Algorithm and GIoU auxiliary branch, the authors demonstrate the effectiveness and universality of the proposed strategy through extensive experiments on different datasets.
IEEE TRANSACTIONS ON MULTIMEDIA
(2023)
Article
Green & Sustainable Science & Technology
Mariacrocetta Sambito, Stefania Piazza, Gabriele Freni
Summary: A generic water system is made up of a series of works to collect, transport, store and distribute water to meet user needs. In areas with high altitude differences, the potential energy of water is high and needs to be dissipated. The study evaluates the results of using a stochastic approach to solve the multi-objective optimization problem of PATs in water systems, with different methods performing better in different contexts.
Article
Mathematics, Interdisciplinary Applications
Jean-Marc Ginoux, Riccardo Meucci, Stefano Euzzor, Eugenio Pugliese, Julien Clinton Sprott
Summary: This paper presents the jerk dynamics of a minimal universal model of laser with feedback, proving the derivation of two equivalent forms of the model and implementing an electronic circuit for the simpler dynamics.
INTERNATIONAL JOURNAL OF BIFURCATION AND CHAOS
(2022)
Article
Mechanics
Ruben Poehnl, William Uspal
Summary: The study investigates the motion of chemically active colloids in the form of rotating helices, revealing that the translational and rotational velocities of the particles depend on geometry and the distribution of catalytic activity on the surface. Both tangential and circumferential concentration gradients contribute to the particle velocity, with their relative importance impacting the motion of the particle. By selecting specific particle design parameters, it is possible to control and even suppress certain components of angular velocity, affecting the translation of the helix.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Physics, Fluids & Plasmas
Kevin Lippera, Michael Benzaquen, Sebastien Michelin
PHYSICAL REVIEW FLUIDS
(2020)
Article
Mechanics
Francois Nadal, Sebastien Michelin
JOURNAL OF FLUID MECHANICS
(2020)
Article
Mechanics
Panayiota Katsamba, Sebastien Michelin, Thomas D. Montenegro-Johnson
JOURNAL OF FLUID MECHANICS
(2020)
Article
Chemistry, Physical
Akash Choudhary, K. V. S. Chaithanya, Sebastien Michelin, S. Pushpavanam
Summary: This study examines the motion of chemically active Janus particles in weak confinement, investigating the effects of confining planar boundaries on phoretic and hydrodynamic interactions. New states such as channel-spanning oscillations and damped oscillations around the centerline were identified, expanding on previous analyses of single wall interactions. Insights also suggest that biological and artificial swimmers sense their surroundings through long-ranged interactions that can be altered by changing surface properties.
EUROPEAN PHYSICAL JOURNAL E
(2021)
Article
Mechanics
Francisco Rojas-Perez, Blaise Delmotte, Sebastien Michelin
Summary: The study demonstrates that chemically active colloids can self-propel by modifying the concentration of chemical solutes surrounding them, which generates chemical gradients and hydrodynamic flows that alter the trajectories of other particles. Therefore, the dynamics of suspensions with reactive particles is fundamentally governed by hydro-chemical interactions, posing challenges for solving detailed hydro-chemical problems with many particles. Most current methods rely on Green's functions of Laplace and Stokes operators to approximate particle behavior in the far field, which is only valid in very dilute conditions and simple geometries.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Francesco Picella, Sebastien Michelin
Summary: This study investigates the self-propulsion of isotropic colloids inside capillary tubes through numerical simulations. The results demonstrate that spatial confinement promotes the colloids' spontaneous motion and significantly affects the self-propulsion velocities.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Physics, Fluids & Plasmas
Nikhil Desai, Sebastien Michelin
Summary: Active droplets can swim in viscous flows due to convective transport of a chemical solute produced at their surface, with stability against nonaxisymmetric perturbations and emergence of self-propulsion along the wall. Reduction in the drop-wall separation destabilizes modes and promotes self-propulsion due to confinement-induced localization of chemical gradients. Quadrupolar states are more unstable than dipolar counterparts favoring stronger slip forcing on the drop surface.
PHYSICAL REVIEW FLUIDS
(2021)
Article
Mechanics
T. Traverso, S. Michelin
Summary: By studying autochemotactic Janus particles, this research reveals the effects of flow and chemical induction, as well as the influence of confinement, on collective behavior.
JOURNAL OF FLUID MECHANICS
(2022)
Review
Mechanics
Sebastien Michelin
Summary: Microscopic active droplets swim autonomously in viscous flows by exploiting solute transport and self-generated Marangoni flows. They are of great interest to physicists, chemists, biologists, and fluid dynamicists for analyzing self-propulsion and collective dynamics, developing cellular models, or performing biomedical and engineering applications. This review focuses on the recent developments of these fascinating droplets, including mathematical and physical modeling, experimental design, and characterization.
ANNUAL REVIEW OF FLUID MECHANICS
(2023)
Article
Physics, Fluids & Plasmas
Nikhil Desai, Sebastien Michelin
Summary: Active drops emit/absorb chemical solutes, creating concentration gradients and driving their own transport and propulsion. Despite their isotropy, active drops can achieve directed self-propulsion as long as the Peclet number is larger than a critical threshold. This study investigates the spontaneous motion and nonlinear saturation of an isotropic phoretic colloid confined along a rigid wall, revealing that reducing the particle-wall separation enhances the swimming speed through efficient rearrangement of solute concentration gradients.
PHYSICAL REVIEW FLUIDS
(2022)
Article
Chemistry, Physical
Kevin Lippera, Michael Benzaquen, Sebastien Michelin
Summary: For symmetric collisions, a systematic alignment of droplets' trajectories is observed, while for more generic collisions, complex and diverse dynamical regimes are observed, resulting in significant scattering.
Article
Physics, Fluids & Plasmas
Jean -Baptiste Thomazo, Lauga Eri, Benjamin Le Reverend, E. Wandersman, A. M. Prevost
Article
Chemistry, Physical
Sebastien Michelin, Simon Game, Eric Lauga, Eric Keaveny, Demetrios Papageorgiou
Article
Chemistry, Physical
Shang Yik Reigh, Mu-Jie Huang, Hartmut Loewen, Eric Lauga, Raymond Kapral
Article
Chemistry, Physical
Alexander Chamolly, Eric Lauga, Soichiro Tottori
