Article
Physics, Fluids & Plasmas
Anton Peshkov, S. Teitel
Summary: Numerical study of compressing athermal, overdamped, frictionless spheres reveals critical behavior at the jamming transition, showing a critical scaling relation for pressure as a function of packing fraction phi and compression rate. Bulk viscosity diverges upon jamming, and analysis determines critical exponents associated with the compression-driven jamming transition. Results suggest stress-isotropic, compression-driven jamming may share universality class with stress-anisotropic, shear-driven jamming.
Article
Chemistry, Physical
Stefan Luding, Kianoosh Taghizadeh, Chao Cheng, Lou Kondic
Summary: This study examines the evolution of dense granular systems in three dimensions during slow compression and decompression. It finds that the transitions in the system involve both smooth and continuous reversible events, as well as fast and discontinuous irreversible events. The analysis using persistent homology reveals that kinetic energy is correlated with the strength of rearrangements, while global mechanical measures, such as pressure, are strongly correlated with the evolution of topological measures quantifying loops in the force network. Surprisingly, some transitions are detected by persistent homology even when particle motion or rearrangement is weak or not observed at all.
Article
Physics, Multidisciplinary
Norihiro Oyama, Takeshi Kawasaki, Kuniyasu Saitoh
Summary: This study uses molecular dynamics simulations to investigate the mechanical responses of dense packings of soft athermal spheres under finite-rate shear, focusing on the fluctuations in shear stress and interparticle contact number. By defining susceptibility as the ratio of global to local fluctuations, ridges reminiscent of Widom lines around the critical point in an equilibrium phase transition are observed on the volume fraction-shear rate plane.
FRONTIERS IN PHYSICS
(2021)
Article
Chemistry, Physical
Johnathan Hoggarth, Jean-Christophe Ono-dit-biot, Kari Dalnoki-Veress
Summary: When a pile of sand is poured out of a funnel onto a surface, the friction between the grains allows the pile to grow taller and spread out. In this study, we investigated a similar process using a two-dimensional pile of oil droplets. Unlike sand, the droplets have buoyancy and adhesion, and friction is negligible. As the pile grows, it reaches a critical height at which it spreads out across the boundary. Interestingly, although the behavior is granular, the growth process is similar to that of a continuous liquid. This can be described by a granular capillary length, which determines the critical height of the pile based on the balance between buoyancy and adhesion.
Article
Physics, Fluids & Plasmas
Pappu Acharya, Debankur Das, Kabir Ramola
Summary: The paper introduces a perturbation expansion method for athermal systems to determine displacement fields in response to disorder, showing interesting self-similar properties at every order. Force-balance equations are used for order-by-order determination of displacement fields, with nonlinear corrections introduced by interactions between defects at higher orders. The exact results are verified with displacement fields obtained from energy minimized configurations of soft disks.
Article
Physics, Fluids & Plasmas
Jerry Zhang, Dong Wang, Weiwei Jin, Annie Xia, Nidhi Pashine, Rebecca Kramer-Bottiglio, Mark D. Shattuck, Corey S. O'Hern
Summary: Granular metamaterials with tessellated structure can be used to design soft materials with specified mechanical properties.
Article
Physics, Fluids & Plasmas
Anton Peshkov, S. Teitel
Summary: Using a simplified model, this study examines the response of non-Brownian suspension in two dimensions to compression and shear. It shows that compression and shear induce jamming at different packing fractions. Furthermore, a critical analysis reveals consistent scaling behavior among compression, shear, and pure shearing. The study also investigates the anisotropy of force and contact networks using orientational order parameters.
News Item
Physics, Multidisciplinary
Nick Oikonomeas-Koppasis, Peter Schall
Summary: A proposed van der Waals-like model provides a unified framework for describing the dynamic solid-liquid transition in mechanically probed soft materials, addressing the current lack of understanding in this area.
Article
Multidisciplinary Sciences
Ngoc Tam Lam, Ian Howard, Lei Cui
Summary: The study developed a path-planning algorithm based on the breadth-first-search algorithm to generate a shortest path for each Platonic solid to reach a desired pose. In addition, the authors chose Penrose tiling as the method for regular-pentagon tiling.
Article
Physics, Multidisciplinary
Orest Hryhorchak, Andrij Rovenchak
Summary: We have analyzed the higher multipole moments in the expansion of the electrostatic potential generated by various distributions of charges over Platonic solids. The lowest non-zero multipole moment for the tetrahedron is the octupole, while for the octahedron and cube it is the hexadecapole. For the icosahedron and dodecahedron, non-zero elements appear first in the 2(6)-pole moment tensors.
Article
Thermodynamics
Eliton Fontana, Ricardo Persi de Souza, Claudia Angela Capeletto
Summary: This study examines natural convection in 3D convex regular polyhedra by using the number of faces as a parameter. It is found that the dodecahedron and icosahedron have similar behavior and are more efficient in improving convection heat transfer, while the tetrahedron is less efficient due to its structure. Increasing the number of faces tends to enhance fluid recirculation and increase the average Nusselt number.
NUMERICAL HEAT TRANSFER PART A-APPLICATIONS
(2023)
Article
Mathematics
Andre Vallieres, Dominic Rochon
Summary: This paper focuses on the dynamics of the eight tridimensional principal slices of the tricomplex Mandelbrot set and establishes a geometrical classification of these slices. It proves that the Firebrot is a regular tetrahedron and constructs the so-called Stella octangula as a tricomplex dynamical system. It also demonstrates that one of the 3D slices corresponds to a cube.
Article
Engineering, Chemical
Celine Ruscher, Joerg Rottler
Summary: The study focused on the statistical properties of the yielding transition in model amorphous solids under slow, athermal deformation, revealing plastic flow through a combination of elastic loading and collective avalanches. The spatial extent of avalanches and degree of stress correlations change as deformation progresses. It was found that the statistics of stress and energy drops only become comparable for large events in the steady flow regime.
Article
Physics, Fluids & Plasmas
Varghese Babu, Srikanth Sastry
Summary: This study numerically investigates the critical behavior and marginal stability of the shear jamming transition of frictionless soft spheres, finding that they occur over a finite range of densities and are similar to the isotropic jamming transition.
Article
Mathematics, Applied
Carlos Garcia-Azpeitia, Luis C. Garcia-Naranjo
Summary: We investigate the N-vortex problem on the sphere assuming equal strengths for all vortices and develop a theoretical framework to analyze solutions of the equations of motion with prescribed symmetries. Our results demonstrate the existence of several 1-parameter families of periodic orbits and are applied to show the existence of families of small nonlinear oscillations emanating from the Platonic solid equilibria.
JOURNAL OF NONLINEAR SCIENCE
(2022)
Article
Energy & Fuels
Mostafa Abuseada, Chuyu Wei, R. Mitchell Spearrin, Timothy S. Fisher
Summary: We report a process that converts methane to high-value graphitic carbon and hydrogen gas using simulated solar irradiation. The process involves capturing solid carbon in an easily extractable form through localized solar heating, while maintaining active deposition site density until flow is blocked. This method achieves high methane conversion and hydrogen yield.
Article
Thermodynamics
Akshay Bharadwaj Krishna, Kaiyuan Jin, Portonovo S. Ayyaswamy, Ivan Catton, Timothy S. Fisher
Summary: Heat exchangers are essential in supercritical CO2 Brayton cycles for waste heat recovery. These cycles operate at high temperatures and pressures to achieve higher energy density and thermal efficiency. Accurate estimation of heat exchanger performance is crucial for the design and optimization of sCO2 systems.
JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME
(2022)
Article
Thermodynamics
Akshay Bharadwaj Krishna, Kaiyuan Jin, Portonovo S. Ayyaswamy, Ivan Catton, Timothy S. Fisher
Summary: This paper focuses on the performance modeling and correlations of heat exchangers in high-temperature supercritical CO2 Brayton cycles. The developed correlations for heat transfer and friction characteristics offer superior accuracy and versatility. The study validates the correlations using experimental and computational fluid dynamics data and demonstrates their applicability to supercritical CO2 heat exchangers.
JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME
(2022)
Article
Thermodynamics
Yuan Hu, Mostafa Abuseada, Abdalla Alghfeli, Saurin Holdheim, Timothy S. Fisher
Summary: This study presents a method for measuring the thermal diffusivity of thin disk samples at high temperatures using a modified angstrom ngstrom's method, along with nondestructive temperature measurements using an infrared camera. The results demonstrate excellent agreement with reference values obtained by other methods, validating the accuracy of the proposed method.
JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME
(2022)
Article
Physics, Applied
Sizhe Liu, Kyle C. Smith
Summary: This study introduces a method that combines the efficiency of machine-learning models with the accuracy of ab initio calculations to elucidate the importance of Prussian blue analogs in aqueous electrochemical separations and energy storage, analyzing the structural stability and electrochemical activity of nickel hexacyanoferrate.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Nanoscience & Nanotechnology
Aniruddh Shrivastava, Vu Q. Do, Kyle C. Smith
Summary: NASICON materials, particularly sodium titanium vanadium phosphate (NTVP), show promising selectivity for the reversible capture of sodium ions compared to other alkali and alkaline-earth metal ions. The electrochemical performance of the NTVP electrode demonstrates its potential for applications in Faradaic deionization (FDI) and selective lithium recovery.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Physics, Fluids & Plasmas
Majed A. Alrefae, Gayathri Shivkumar, Alina A. Alexeenko, Sergey O. Macheret, Timothy S. Fisher
Summary: In this study, nanocrystalline graphitic films were successfully deposited on Cu foil in a roll-to-roll plasma-enhanced chemical vapor deposition system. The influence of discharge modes on the synthesis of graphitic films was investigated, and electrical and spectroscopic characterizations supported with modeling were performed. It was found that by adjusting the discharge modes, different qualities of nanocrystalline graphitic films could be produced without supplemental heating.
IEEE TRANSACTIONS ON PLASMA SCIENCE
(2022)
Article
Mechanics
Suryadev Pratap Singh, Manojit Ghosh, Meheboob Alam
Summary: Inertial transitions in a suspension Taylor-Couette flow are explored for the first time via experiments. Different vortex states can coexist under different particle loadings, and the particle loading affects the amplitude and wavelength of the vortices as well as the rotation frequency of the spiral vortices.
JOURNAL OF FLUID MECHANICS
(2022)
Correction
Instruments & Instrumentation
Mostafa Abuseada, Abdalla Alghfeli, Timothy S. Fisher
REVIEW OF SCIENTIFIC INSTRUMENTS
(2022)
Article
Materials Science, Multidisciplinary
Mostafa Abuseada, Abdalla Alghfeli, Timothy S. Fisher
Summary: This paper introduces a method to enhance heat spreading capabilities by synthesizing thin graphitic layers on organic substrates through a vacuum deposition process. The use of a light source that can be replaced with solar power enables rapid heating and improves growth rates over larger areas compared to laser processing, mitigating the issue of porosity in graphitic layers. Analysis of the enhanced organic substrates confirms graphitic conversion.
Article
Multidisciplinary Sciences
Meheboob Alam, Manojit Ghosh
Summary: This study reports torque measurements for the Taylor-Couette flow of a neutrally buoyant non-colloidal suspension in the counter-rotation regime up to a particle volume fraction of =0.2. A unified scaling relation for the dimensionless torque is shown to hold over a range of Taylor numbers Tac1 <= Ta <= 106 that covers primary, secondary, and tertiary bifurcating states. The effects of flow transitions and inhomogeneous particle distribution on torque scaling are discussed.
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2023)
Article
Chemistry, Physical
Mostafa Abuseada, R. Mitchell Spearrin, Timothy S. Fisher
Summary: This article introduces a new solar-thermal methane pyrolysis process that produces hydrogen gas and high-value graphitic carbon product in a fibrous carbon medium. The process reaches steady-state operation quickly and the graphitic product can be easily extracted from the solar reactor.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2023)
Article
Chemistry, Multidisciplinary
Vu Q. Do, Erik R. Reale, Irwin C. Loud, Paul G. Rozzi, Haosen Tan, David A. Willis, Kyle C. Smith
Summary: Faradaic deionization (FDI) is a promising technology for energy-efficient water desalination. By using porous electrodes containing redox-active materials, a symmetric FDI flow cell demonstrated the capability to produce freshwater from concentrated brackish water, reduce the salinity of hypersaline brine, and produce effluent near freshwater salinity from seawater-level salinity. These achievements were enabled by using flow-through electrodes with high areal-loading of nickel hexacyanoferrate (NiHCF) Prussian Blue analogue intercalation material and embedding micro-interdigitated flow fields in the electrodes to minimize active-material loss.
ENERGY & ENVIRONMENTAL SCIENCE
(2023)
Article
Engineering, Multidisciplinary
Yuan Hu, Mostafa Abuseada, Abdalla Alghfeli, Saurin Holdheim, Timothy S. Fisher
Summary: This study proposes a Bayesian analysis method that uses a parametric surrogate model in the form of polynomial chaos to accelerate the thermal diffusivity physical model for high-temperature determination. The No-U-Turn sampler is employed to improve the efficiency of the MCMC sampler.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2024)
Article
Energy & Fuels
Mostafa Abuseada, Timothy S. Fisher
Summary: This study presents a scalable route for continuous solar-thermal methane pyrolysis, using a roll-to-roll mode of operation with a fibrous carbon substrate. It converts natural gas into hydrogen and high-quality carbon product with virtually no CO2 emission, offering a promising solution to decarbonize fossil fuels.