Article
Mechanics
J. S. Kern, M. Beneitez, A. Hanifi, D. S. Henningson
Summary: This study investigates the transient and time-asymptotic linear stability of pulsating Poiseuille flow using the optimally time-dependent (OTD) modes framework, revealing that structures akin to Tollmien-Schlichting waves are dominant over a wide range of pulsation frequencies but disappear at low pulsation frequencies. Additionally, the existence of subharmonic perturbation cycles compared to the base flow pulsation is documented for the first time in pulsating Poiseuille flow.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Byron Guerrero, Martin F. Lambert, Rey C. Chin
Summary: This study investigates the time response and transient turbulence dynamics of rapidly decelerating turbulent pipe flows. Through statistical analysis of direct numerical simulations, it is found that turbulent flows undergo four transitional stages: inertial, friction recovery, turbulence decay, and core relaxation. The FIK identity is used to understand the time response of the skin friction coefficient.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Chemistry, Physical
Anael Lemaitre
Summary: The study compares local stress autocorrelation in fragile and strong glasses, showing that silica exhibits a high degree of hyperuniformity in local stress fluctuations compared to the KA binary mixture. The relevance of power-law stress correlation may constitute a key discriminating feature between strong and fragile glasses.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Operations Research & Management Science
Narayanan C. Viswanath
Summary: This paper applies the external uniformization (EU) method to study the transient behavior of continuous-time Markov chain models. The method uses an exponential clock to observe the Markov chain and calculates the approximate transient probability of being in a particular state using absorption probabilities. The results show that the EU method produces highly accurate results and requires less computational time compared to the uniformization/randomization (U/R) method.
OPERATIONAL RESEARCH
(2022)
Article
Mechanics
Duo Xu, Baofang Song
Summary: This article shows that turbulent bands are transient in nature, with a stochastic and exponentially distributed lifetime. The mean lifetime of turbulent bands increases with both the Reynolds number and the band length, indicating a size dependence that may have implications for the relationship between channel flow transition and directed percolation universality class.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Materials Science, Multidisciplinary
Nicolas Vidal-Silva, Roberto E. Troncoso
Summary: In this study, collinear magnets in honeycomb lattices under the action of time-dependent strains are investigated. An effective Floquet theory for spin systems is derived for high-frequency periodically varying deformations, resulting in the emergence of a spin chirality. The coupling between magnons and spin chirality depends on the details of the strain, and magnonic fluctuations can be driven into topologically protected phases by spatially homogeneous strains. Certain uniform strain fields can play the role of an out-of-plane nearest-neighbor Dzyaloshinskii-Moriya interaction. Additionally, confinement of magnon states can be achieved by applying nonuniform strains.
Article
Materials Science, Multidisciplinary
Gaia Forghieri, Paolo Bordone, Andrea Bertoni
Summary: Graphene nanoribbons serve as an ideal platform for electronic interferometry in the integer quantum Hall regime. By solving the time-dependent Schrodinger equation for single carriers in graphene, the study reveals the effects of carrier localization on their transport characteristics in pn junctions. Two types of Mach-Zender interferometers are simulated, showing expected and unexpected phenomena.
Article
Engineering, Civil
Wei Wang, Quanrong Wang, Zhitao Xiong, Si Chen, Wenjun Huang, Wenguang Shi, Shuai Wang, Shengde Yu
Summary: This study develops an ADR model considering transient flow fields, time-dependent source concentrations, and arbitrary initial conditions, with a general analytical solution derived by Green's function method. The robustness of the new analytical models is tested using laboratory-controlled experimental data. Findings suggest that flow velocity, initial conditions, and source concentrations significantly influence the model results of subsurface reactive transport.
JOURNAL OF HYDROLOGY
(2021)
Article
Mechanics
Martin Ndi Azese, Valjacques Nyemb Nsoga, Barbare J. Avouna Mvondo, Oluwole Daniel Makinde, Gilbert Batjom Batjom, Hollandine Sami Kouaji
Summary: This study analytically explores the flow of a Newtonian liquid forced into a narrow tube by an unsteady pressure gradient and an external force dependent on the encroachment rate. The findings have important implications for medicine and the printing industry. By comparing rectangular and circular channels, interesting similarities are discovered. The study also highlights the early and long-term dynamic characteristics.
Article
Mathematics, Applied
Fabio Pusateri, Israel Michael Sigal
Summary: The density functional theory (DFT) is a successful theory in describing the electronic structure of matter, with the Kohn-Sham (KS) equation as its foundation. The paper focuses on the time-dependent behavior of the KS equation, proving global existence and scattering in the full short-range regime with new and simple techniques that are compatible with the structure of DFT. These techniques involve commutator vector fields and non-abelian versions of Sobolev-Klainerman-type spaces and inequalities.
ARCHIVE FOR RATIONAL MECHANICS AND ANALYSIS
(2021)
Article
Engineering, Civil
M. J. Watts, A. Amin, R. Gilbert
Summary: The addition of steel or polypropylene fibres can significantly improve the serviceability performance of structural concrete. However, there is limited guidance or expressions available for predicting the long-term serviceability behavior of fibre reinforced concrete (FRC), which hinders the full utilization of FRC in design practice. An experimental program was conducted to quantify the time-dependent deformation and cracking behavior of FRC flexural members. The results showed that the dosage of steel fibres used in this study greatly improved the time-dependent behavior of concrete structures by reducing long-term deformations and cracking severity.
ENGINEERING STRUCTURES
(2022)
Article
Quantum Science & Technology
Karen V. Hovhannisyan, Somayyeh Nemati, Carsten Henkel, Janet Anders
Summary: When two initially thermal many-body systems start to interact strongly, their transient states quickly become non-Gibbsian, even if the systems eventually equilibrate. To understand the structure during the transient regime, a refined notion of thermality called g-local is used. Numerical demonstration shows that for two harmonic lattices with long-range interactions, each lattice remains g-locally thermal at all times, including the transient regime. The equilibrium is described by the generalized Gibbs ensemble, with special treatment required for three-dimensional lattices due to their extended set of conserved charges. Comparison with the two-temperature model reveals the partial salvage of the model at strong coupling by adopting the concept of a g-local temperature.
Article
Computer Science, Interdisciplinary Applications
Shaghayegh Zamani Ashtiani, Mujeeb R. Malik, Hessam Babaee
Summary: In this work, an in situ compression technique is presented to significantly reduce the size of data storage generated by large-scale simulations of time-dependent problems. The technique is based on time-dependent subspaces and uses an adaptive strategy to control the compression error.
JOURNAL OF COMPUTATIONAL PHYSICS
(2022)
Article
Energy & Fuels
Fei Song, Alfonso Rodriguez-Dono, Patricio Sanchez Farfan
Summary: This article presents an alternative anisotropic time-dependent constitutive model, which can predict the coupling between anisotropic behavior and time-dependent behavior. The model has been implemented in finite element method software and validated through comparisons with experimental data and analytical solutions.
GEOMECHANICS AND GEOPHYSICS FOR GEO-ENERGY AND GEO-RESOURCES
(2022)
Article
Chemistry, Physical
Davood Dar, Saswata Roy, Neepa T. Maitra
Summary: The adiabatic approximation in time-dependent density functional theory can lead to unphysical divergences in excited state-to-state transition probabilities and hyperpolarizabilities due to an incorrect pole structure in the quadratic response function. This study presents the exact form of the quadratic response kernel and proposes a practical and accurate approximation to solve the divergence issue. The results are demonstrated on excited state-to-state transition probabilities of a model system and the LiH molecule.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Physical
M. A. Lara-Pena, A. Licea-Claverie, I. Zapata-Gonzalez, M. Laurati
Summary: The study investigates the linear and non-linear rheological response of suspensions of soft core-shell particles. It reveals a transition from a fluid to a jammed glass state, with distinct regimes of linear storage modulus and yield stress associated with particle contacts evolution. The yielding of jammed suspensions occurs in two-steps, with increasing shear rate or frequency leading to increased yield strains and stresses.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2021)
Article
Chemistry, Multidisciplinary
Ivany Romero-Sanchez, Ilian Pihlajamaa, Natasa Adzic, Laura E. Castellano, Emmanuel Stiakakis, Christos N. Likos, Marco Laurati
Summary: In this study, we investigate the effects of crowding on the conformations and assembly of confined, highly charged, and thick polyelectrolyte brushes. Particle tracking experiments and theoretical simulations reveal that aggregation and re-entrant ordering occur due to the combined effect of osmotic pressure and short-range attraction. The attraction is caused by blunt-end interactions between stretched DNA fragments of neighboring brushes.
Article
Chemistry, Physical
Saswati Ganguly, Gaurav Prakash Shrivastav, Shang-Chun Lin, Johannes Haering, Rudolf Haussmann, Gerhard Kahl, Martin Oettel, Matthias Fuchs
Summary: Different types of defects play a significant role in the mechanical response of complex crystals close to melting or at finite temperatures. Conventional elasticity theory fails to explain the motion of point defects in ordered crystalline structures. In this study, a first principles theoretical framework derived from microscopic equations of motion is used to investigate the elastic properties of a crystal with a high concentration of point defects. Predictions about the mechanical properties are validated through deformation experiments in molecular dynamics simulations.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Polymer Science
Rodrigo Rivas-Barbosa, Jose Ruiz-Franco, Mayra A. Lara-Pena, Jacopo Cardellini, Angel Licea-Claverie, Fabrizio Camerin, Emanuela Zaccarelli, Marco Laurati
Summary: This study investigates the internal structure and interactions of composite microgels using small-angle scattering experiments and simulations. The results show that the conformation of PEG chains inside the microgels has a profound effect on the interparticle interactions and the structure of the microgels.
Article
Polymer Science
Ivany C. Romero-Sanchez, Laura E. Castellano, Marco Laurati
Summary: This study experimentally investigates the mechanisms to control the blunt-end induced effective attractions between densely packed spherical dsDNA brushes. By analyzing the effects of parameters such as functionality, salinity, and dsDNA fragment length on the brush and dsDNA fragment conformation, it is found that a decrease in functionality or an increase in salt content leads to the reduction of effective attractions.
Article
Environmental Sciences
Tiziana Di Lorenzo, Serena Benedetta Cabigliera, Tania Martellini, Marco Laurati, David Chelazzi, Diana Maria Paola Galassi, Alessandra Cincinelli
Summary: This study evaluated the ingestion of microplastics and textile cellulose by meiofaunal taxa and functional guilds in a first-order stream in Florence, Italy using a tandem microscopy approach. The results showed high concentrations of microplastics and textile cellulose particles in almost all organisms and functional guilds.
Article
Chemistry, Physical
Juliana Caspers, Nikolas Ditz, Karthika Krishna Kumar, Felix Ginot, Clemens Bechinger, Matthias Fuchs, Matthias Krueger
Summary: The motion of a colloidal probe in a viscoelastic fluid is determined by friction or mobility. The Einstein relation, which applies to Newtonian solvents, and the concept of time-dependent memory kernels are generalized to viscoelastic fluids. By investigating two observables - recoil and equilibrium mean squared displacement (MSD) - we establish a relation between the two based on linear response theory. However, MSD and recoil show distinct behaviors with increasing concentration due to different behaviors of the two kernels. Theoretical models reveal a Volterra relation between the two kernels, explaining the varying timescales in friction and mobility kernels with changing concentration.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Thomas Bissinger, Matthias Fuchs
Summary: We investigate the impact of particle mobility on phase transitions in a two-dimensional spin fluid. By using computer simulations, we demonstrate the existence of a BKT universality class phase transition in an off-lattice model of repulsive particles. The results show a critical spin wave region with a nonuniversal exponent eta(T) that follows the shape predicted by BKT theory. The transition from power-law decay to exponential decay at the critical temperature T-BKT is supported by finite-size scaling analysis.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Physics, Multidisciplinary
Florian Vogel, Matthias Fuchs
Summary: We study the vibrational properties of topologically disordered materials by analyzing particles that oscillate harmonically around random positions. Utilizing classical field theory in the thermodynamic limit, we establish a self-consistent model that takes into account nonplanar diagrams for multiple local scattering events. This allows us to accurately predict anomalies in athermal disordered materials, including the boson peak, sound softening, and Rayleigh damping of sound. The vibrational density of states exhibits Debye's law for small frequencies and an excess starting as co4 in the low frequency limit, attributed to (quasi-) localized modes.
PHYSICAL REVIEW LETTERS
(2023)
Article
Polymer Science
Fernando Soto-Bustamante, Gavino Bassu, Emiliano Fratini, Marco Laurati
Summary: This article reports the synthesis and characterization of PVA/CT cryogels for the uptake and entrapment of particulate and bacterial colonies. The network and pore structures of the gels were investigated as a function of CT content and freeze-thaw times using SAXS, SEM, and confocal microscopy. The results show that CT incorporation leads to a more homogeneous network structure and a decrease in the size of heterogeneities associated with PVA crystallites. The overall porosity remains almost unchanged due to the suppression of smaller pores in the PVA network with the progressive incorporation of the more homogeneous CT network.
Article
Chemistry, Physical
Victoria Ariel Bjornestad, Fernando Soto-Bustamante, Giancarlo Tria, Marco Laurati, Reidar Lund
Summary: This study investigates the structural pathways and metastable structures involved in the solubilization of lipid membranes using the non-ionic detergent Triton X-100. The findings reveal a unique ripple phase of ordered rippled bilamellar disc structures formed when moderate amounts of detergent are added to lipid vesicles, suggesting a combination of water structure destabilization and osmotic pressure causing interbilayer attraction. The study highlights the diversity in assembly pathways of simple lipids and detergents and their implications for membrane solubilization.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2023)
Article
Chemistry, Physical
Jose Ruiz-Franco, Rodrigo Rivas-Barbosa, Mayra A. A. Lara-Pena, Jose R. Villanueva-Valencia, Angel Licea-Claverie, Emanuela Zaccarelli, Marco Laurati
Summary: We investigated the interactions and inter-particle arrangements of concentrated dispersions of PNIPAM-PEGMA microgels during the volume phase transition. The scattering data of moderately concentrated dispersions were accurately modeled using a star polymer form factor and static structure factors calculated from simulations. The presence of charges in the system due to the use of an ionic initiator in the synthesis caused the radius of gyration and blob size of the particles to decrease with increasing effective packing fraction below the VPT temperature.
Article
Physics, Fluids & Plasmas
Florian Miserez, Saswati Ganguly, Rudolf Haussmann, Matthias Fuchs
Summary: We present a microscopic derivation of the laws of continuum mechanics of nonideal ordered solids including dissipation, defect diffusion, and heat transport using the Zwanzig-Mori projection operator formalism. The approach connects microscopic fluctuations to thermodynamic derivatives and transport coefficients, and provides a basis for measurements in atomistic simulations or colloidal experiments.
Article
Physics, Fluids & Plasmas
Niklas Grimm, Annette Zippelius, Matthias Fuchs
Summary: This article characterizes the effect of collision rules on velocity correlations in a system of hard spheres. The results show that there are long-range correlations between velocities in a nonequilibrium state, which is consistent with previous research findings.
Article
Chemistry, Physical
Jan Hansen, Rajeevann Uthayakumar, Jan Skov Pedersen, Stefan U. Egelhaaf, Florian Platten
Summary: Ethanol affects the phase behavior and interactions of protein solutions, as well as altering the dielectric properties of solutions. The observed trends in cloud-point temperatures can be explained using changes in B-2, which quantitatively agree with experimental results. Interactions between proteins, described by the DLVO potential, along with consideration of dielectric solution properties and electrostatic screening, play a key role in these effects.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
