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Several lines of evidence, including hydrous melt inclusions and unusually Cl-rich apatite, have been used to suggest that the reappearance of olivine and PGE-sulfide of the J-M Reef in the Stillwater Complex, Montana, is due to fluid infiltration and hydration melting. This study builds upon the hydration melting model using the programs MELTS and PELE with Stillwater bulk rock compositions for the original protolith. Cl-bearing phases are not modeled by MELTS and thus simple oxide mixtures of either a pure H2O or a H2O + Na2O "faux brine" are added to norite, gabbronorite, and melanorite protoliths at 1050 °C at 2 kbar pressure, conditions for which the nominally "dry" protolith is > 95% solid. Incongruent hydration melting results in up to 37% olivine produced in the melanorite. The olivine Fo content is a function of the partial melt retained on cooling, and ranges between 76 and 86, overlapping the natural range of olivine compositions observed in the rocks. Modeling with the PELE program, which includes a silicate liquid Cl component, sulfur species, and a more complex C-O–H-S fluid, suggests that, for CO2-rich fluids, fluid metal concentrations on the order of 25 ppm Pt, 75 ppm Pd, 0.03 wt.% Cu, and 0.20 wt.% Ni at a fluid/rock mass ratio of ~ 0.25 are needed to account for the observed ore grades. Sulfide and ore metals are readily remobilized for more H2O-rich fluids, consistent with heterogeneous distribution of sulfide and regionally variable ore grades. [ABSTRACT FROM AUTHOR]

Despite centuries of investigation, bubbles continue to unveil intriguing dynamics relevant to a multitude of practical applications, including industrial, biological, geophysical, and medical settings. Here we introduce bubbles that spontaneously start to 'gallop' along horizontal surfaces inside a vertically-vibrated fluid chamber, self-propelled by a resonant interaction between their shape oscillation modes. These active bubbles exhibit distinct trajectory regimes, including rectilinear, orbital, and run-and-tumble motions, which can be tuned dynamically via the external forcing. Through periodic body deformations, galloping bubbles swim leveraging inertial forces rather than vortex shedding, enabling them to maneuver even when viscous traction is not viable. The galloping symmetry breaking provides a robust self-propulsion mechanism, arising in bubbles whether separated from the wall by a liquid film or directly attached to it, and is captured by a minimal oscillator model, highlighting its universality. Through proof-of-concept demonstrations, we showcase the technological potential of the galloping locomotion for applications involving bubble generation and removal, transport and sorting, navigating complex fluid networks, and surface cleaning. The rich dynamics of galloping bubbles suggest exciting opportunities in heat transfer, microfluidic transport, probing and cleaning, bubble-based computing, soft robotics, and active matter. Bubbles, long studied for their diverse dynamics across industrial, biological, and medical applications, continue to reveal unexpected behaviors. This study introduces galloping bubbles, a novel self-propulsion mechanism driven by shape oscillations in a vibrated fluid chamber, offering potential for applications in fluid transport, cleaning, and active matter. [ABSTRACT FROM AUTHOR]

We present an optomechanical method for locally measuring the rheological properties of complex fluids in the ultra-high frequency range (UHF). A mechanical disk of microscale volume is used as an oscillating probe that monitors a liquid at rest, while the oscillation is optomechanically transduced. An analytical model for fluid-structure interactions is used to deduce the rheological properties of the liquid. This method is calibrated on liquid water, which despite pronounced compressibility effects remains Newtonian over the explored range. In contrast, liquid 1-decanol exhibits a non-Newtonian behavior, with a frequency-dependent viscosity showing two relaxation times of 797 and 151 picoseconds, associated to supramolecular and intramolecular processes. A shear elastic response appears at the highest frequencies, whose value allows determining the volume of a single liquid molecule. UHF optomechanical micro-rheology provides direct mechanical access to the fast molecular dynamics in a liquid, in a quantitative manner and within a sub-millisecond measurement time. An optomechanical probe measures the rheological properties of liquids in a microscopic volume. Operating at ultra-high frequency, it reveals compressibility effects in water, while unveiling non-Newtonian behavior in a long chain alcohol. [ABSTRACT FROM AUTHOR]

Foams improve mobility control in injection operations within geological settings. Nanoparticles, such as iron-oxide, have been shown to enhance the stability of foams when combined with surfactants. In this research, we leverage the magnetic properties of these nanoparticles to detect their presence as a surrogate for monitoring the geologic extent of injected fluids in the subsurface. The feasibility of using these nanoparticles for monitoring purposes stems from their detectability at low concentrations in subsurface environments. We developed two distinct methods to detect the presence of magnetite nanoparticles in complex fluids. To simulate complex subsurface fluids in a laboratory setting, we included various ions and surfactants and investigated their effects on the detection of nanoparticles. To this end, we designed an experimental setup and tested two magnetic detection methods: Induction Heating (IH) and Oscillator Frequency Shift (OFS). The IH method involves applying a high-frequency alternating magnetic field to a solution containing small amounts of magnetic nanoparticles and measuring the temperature response. We built an experimental setup to generate this magnetic field for different samples, with temperature changes recorded by an infrared camera. The results indicate that nanoparticle concentrations linearly affect the solution's temperature rise. However, the presence of ions and surfactants also influences the temperature response. The OFS method measures shifts in the resonance frequency of a circuit caused by changes in magnetic permeability inside a coil. This coil is part of a transistor oscillator circuit that produces a sinusoidal voltage waveform, with the oscillation frequency depending on the coil's inductance. The presence of nanoparticles causes a shift in resonance frequency, which were precisely measured for various samples. The drop in resonance frequency is a linear function of nanoparticle concentration, and both methods detect concentrations as low as 150 mg/L of Fe3O4 nanoparticles. [ABSTRACT FROM AUTHOR]

Planktonic organisms, despite their passive drift in the ocean, exhibit complex responses to fluid flow, including escape behaviors and larval settlement detection. But what flow signals can they perceive? This paper addresses this question by considering an organism covered with sensitive cilia and immersed in a background flow. The organism is modeled as a spherical particle in Stokes flow, with cilia assumed to measure the local shear at the particle surface. This study reveals that, while these organisms can always measure certain components of the flow strain, bottom-heaviness is necessary to measure the horizontal component of vorticity. These findings shed light on flow sensing by plankton, contributing to a better understanding of their behavior. [ABSTRACT FROM AUTHOR]

Several methods in nonadiabatic molecular dynamics are based on Madelung's hydrodynamic description of nuclear motion, while the electronic component is treated as a finite-dimensional quantum system. In this context, the quantum potential leads to severe computational challenges and one often seeks to neglect its contribution, thereby approximating nuclear motion as classical. The resulting model couples classical hydrodynamics for the nuclei to the quantum motion of the electronic component, leading to the structure of a complex fluid system. This type of mixed quantum–classical fluid models has also appeared in solvation dynamics to describe the coupling between liquid solvents and the quantum solute molecule. While these approaches represent a promising direction, their mathematical structure requires a certain care. In some cases, challenging higher-order gradients make these equations hardly tractable. In other cases, these models are based on phase-space formulations that suffer from well-known consistency issues. Here, we present a new complex fluid system that resolves these difficulties. Unlike common approaches, the current system is obtained by applying the fluid closure at the level of the action principle of the original phase-space model. As a result, the system inherits a Hamiltonian structure and retains energy/momentum balance. After discussing some of its structural properties and dynamical invariants, we illustrate the model in the case of pure-dephasing dynamics. We conclude by presenting some invariant planar models. [ABSTRACT FROM AUTHOR]

A plug flow reactor was constructed to scale the synthesis of metastable, phthalaldehyde-based polymers to achieve production rates of 1–2 kg per day. The flow-induced mixing and in-line polymerization quench and precipitation sequences resulted in improved polymer purity and long-term stability compared to the same materials made from a conventional batch process. Cryogenic rheology was used to probe the complex fluid dynamics encountered during the polymerization of PPA homopolymers. It is envisioned that this continuous flow manufacturing approach could be extended to other low ceiling temperature or aldehyde monomer systems to help implement and support a plastic circular economy. [ABSTRACT FROM AUTHOR]

Geophysical fluid dynamics (GFD) is an interdisciplinary field that studies the large-scale motion of fluids in the natural world. With a wide range of applications such as weather forecasts and climate prediction, GFD employs various research approaches including in-situ observations, satellite measurements, numerical simulations, theoretical analysis, artificial intelligence, and physical model experiments in laboratory. Among these approaches, rotating tank experiments provide a valuable tool for simulating naturally-occurring fluid motions in laboratories. With proportional scaling and proper techniques, scientists can reproduce multi-scale physical processes of stratified fluids in the rotation system, which allows for the simulation of essential characteristics of fluid motions in the atmosphere and oceans. In this review, rotating tanks of various scales in the world are introduced, as these tanks have been actively used to explore fundamental scientific questions in ocean and atmosphere dynamics. To illustrate the GFD experiments, three representative cases are presented to demonstrate the frontier achievements in the the GFD study by using rotating tank experiments: mesoscale eddies in the ocean, convection processes, and plume dynamics. Detailed references for the experimental procedures are provided. Future studies are encouraged to further explore the utilization of rotating tanks with improvements in experimental design and integration of other research methods. This is a promising direction of GFD to help enhance our understanding of the complex nature of fluid motions in the natural world and to address the challenges posed by global environmental changes. [ABSTRACT FROM AUTHOR]

This article demonstrates a mathematical model and theoretical analysis of the Micropolar fluid in the reverse roll coating process. It is important because micropolar fluids account for the microstructure and microrotation of particles within the fluid. These characteristics are significant for accurately describing the behavior of complex fluids such as polymer solutions, biological fluids, and colloidal suspensions. First, we modeled the flow equations using basic laws of fluid dynamics. The flow equations are made modified using low Reynolds number theory. The simplified equations are solved analytically. The exact expression for velocity and pressure gradient are obtained, while pressure is calculated numerically using Simpson Rule. Graphical depictions are carried out to comprehend the impact of the newly emerged physical constraints. The influence of micropolar and microrotation parameters on the velocity, pressure and pressure gradient are elaborated with the help of different graphs. [ABSTRACT FROM AUTHOR]

Jamming is an athermal transition between flowing and rigid states in amorphous systems such as granular matter, colloidal suspensions, complex fluids and cells. The jamming transition seems to display mixed aspects of a first-order transition, evidenced by a discontinuity in the coordination number, and a second-order transition, indicated by power-law scalings and diverging lengths. Here we demonstrate that jamming is a first-order transition with quenched disorder in cyclically sheared systems with quasistatic deformations, in two and three dimensions. Based on scaling analyses, we show that fluctuations of the jamming density in finite-sized systems have important consequences on the finite-size effects of various quantities, resulting in a square relationship between disconnected and connected susceptibilities, a key signature of the first-order transition with quenched disorder. This study puts the jamming transition into the category of a broad class of transitions in disordered systems where sample-to-sample fluctuations dominate over thermal fluctuations, suggesting that the nature and behavior of the jamming transition might be better understood within the developed theoretical framework of the athermally driven random-field Ising model. Jamming in amorphous systems is an athermal transition characterized by mixed first-order and second-order aspects. Authors demonstrate that jamming is a first-order transition with quenched disorder, revealing significant finite-size effects and a square relationship between disconnected and connected susceptibilities in cyclically sheared systems. [ABSTRACT FROM AUTHOR]

Polymer nanocomposites with tuning functions are exciting candidates for various applications, and most current research has focused on static mechanical reinforcement. Actually, under service conditions of complex dynamic interference, stable dynamic mechanical properties with high energy dissipation become more critical. However, nanocomposites often exhibit a trade-off between static and dynamic mechanics, because of their contradictory underlying physics between chain crosslinking and chain relaxation. Here, we report a general strategy for constructing ultra-stable dynamic mechanical complex fluid nanocomposites with high energy dissipation by infusing complex fluids into the nanoconfined space. The key is to tailor full-scale polymer dynamics across an exceptionally broad timescale by single-chain confinement. These materials exhibit stable storage modulus (100 ~ 102 MPa) with high energy dissipation (loss factor > 0.4) over a broad frequency range (10−1 ~ 107 Hz)/temperature range (−35 ~ 85°C). In the loss factor > 0.4 region, their dynamic mechanical stability (rate of modulus change versus temperature (k)) is 10 times higher than that of conventional polymer nanocomposites. Under service conditions of complex dynamic interference, stable dynamic mechanical properties with high energy dissipation becomes more critical but nanocomposites often exhibit a trade-off between static and dynamic mechanics. Here, the authors report a general strategy for constructing ultra-stable dynamic mechanical complex fluid nanocomposites with high energy dissipation by infusing complex fluids into the nanoconfined space. [ABSTRACT FROM AUTHOR]

Skyrmions are topologically protected, vortex-like structures found in various condensed-matter systems including helical ferromagnets and liquid crystals, typically arising from chiral interactions. Using extensive particle-based simulations, we demonstrate that non-chiral hard banana-shaped particles, governed solely by excluded-volume interactions, spontaneously stabilize skyrmion structures through the bend-flexoelectric effect. Under thin confinement, we observe the formation of quasi-2D layers of isolated skyrmions or dense skyrmion lattices. These structures, comprising a racemic mixture of left- and right-handed skyrmions, show resilience against thermal fluctuations while remaining responsive to external fields, offering intriguing possibilities for manipulation. We also find that the size of these skyrmions can be adjusted by the dimensions and curvature of the banana-shaped particles. In the absence of geometric frustration due to confinement, a blue phase III may emerge, characterized by a 3D network of chiral skyrmion filaments of the nematic director field within an isotropic background. Our findings provide valuable insights into stabilizing skyrmion lattices and blue phases, showcasing non-Gaussian fluid-like dynamics in systems of achiral hard particles. Furthermore, they highlight the remarkable capacity of these complex fluids in designing advanced functional materials with diverse applications in photonics and memory devices. In helical ferromagnets and liquid crystals, skyrmions arise due to chiral interactions. Using simulations, authors show that non-chiral hard banana shaped particles can form 2D or 3D skyrmion phases with potential applications in photonics and memory devices. [ABSTRACT FROM AUTHOR]

This paper presents simulations of dam-break flows of Herschel–Bulkley viscoplastic fluids over complex topographies using the shallow water equations (SWE). In particular, this study aims to assess the effects of rheological parameters: power-law index (n), consistency index (K), and yield stress ( τ c ), on flow height and velocity over different topographies. Three practical examples of dam-break flow cases are considered: a dam-break on an inclined flat surface, a dam-break over a non-flat topography, and a dam-break over a wet bed (downstream containing an initial fluid level). The effects of bed slope and depth ratios (the ratio between upstream and downstream fluid levels) on flow behaviour are also analyzed. The numerical results are compared with experimental data from the literature and are found to be in good agreement. Results show that for both dry and wet bed conditions, the fluid front position, peak height, and mean velocity decrease when any of the three rheological parameters are increased. However, based on a parametric sensitivity analysis, the power-law index appears to be the dominant factor in dictating fluid behaviour. Moreover, by increasing the bed slope and/or depth ratio, the wave-frontal position moves further downstream. Furthermore, the presence of an obstacle is observed to cause the formation of an upsurge that moves in the upstream direction, which increases by increasing any of the three rheological parameters. This study is useful for an in-depth understanding of the effects of rheology on catastrophic gravity-driven flows of non-Newtonian fluids (like lava or mud flows) for risk assessment and mitigation. [ABSTRACT FROM AUTHOR]

The paper presents results of finite element modeling, development of and experiments with the measuring cell based on a symmetric stripline for measuring coarse-grained soil permittivity. The wave impedance of the measuring cell section intended for filling with soil, is about 80 Ω to expand the frequency range. This allows reducing the width of the central strip and increasing the critical frequency, which cause the higher-order modes. Cell sections with the transfer from SMA connectors to measuring section are filled with a solid dielectric. The distance between outer conductors and the central strip width in these sections, are linearly increased to the size of the measuring section to provide the wave impedance of 50 Ω. The wave impedance growth in the measuring section is considered in the soil complex permittivity calculations. The complex permittivity is measured for five calibration liquids with the static permittivity of 2.27 (transformer oil) to 78.5 (water) and three soil samples with different moisture. It is shown that acceptable values of measurement error can be obtained if the real part of the complex permittivity does not exceed 23–25 units at a frequency of ~1 GHz. [ABSTRACT FROM AUTHOR]

Non-Newtonian fluid mechanics and computational rheology widely exploit elastic dumbbell models such as Oldroyd-B and FENE-P for a continuum description of viscoelastic fluid flows. However, these constitutive equations fail to accurately capture some characteristics of realistic polymers, such as the steady extension in simple shear and extensional flows, thus questioning the ability of continuum-level modeling to predict the hydrodynamic behavior of viscoelastic fluids in more complex flows. Here, we present seven elastic dumbbell models, which include different microstructurally inspired terms, i.e., (i) the finite polymer extensibility, (ii) the conformation-dependent friction coefficient, and (iii) the conformation-dependent non-affine deformation. We provide the expressions for the steady dumbbell extension in shear and extensional flows and the corresponding viscosities for various elastic dumbbell models incorporating different microscopic features. We show the necessity of including these microscopic features in a constitutive equation to reproduce the experimentally observed polymer extension in shear and extensional flows, highlighting their potential significance in accurately modeling viscoelastic channel flow with mixed kinematics. [ABSTRACT FROM AUTHOR]

The development of analytical chemistry relies on the ability for rapid and accurate determination of the substances and molecules. To date, tremendous efforts have been made to explore chemical and biological sensing systems for various related applications including chemical analysis, environmental monitoring, and medical care. Specifically, the rising of two-dimensional (2D) nanomaterials promotes the exploration of advanced sensing systems with high sensitivity and responsivity owing to the novel properties and functions. In recent years, metal organic frameworks (MOFs) with pristine merits on adjustable chemical structure, large specific surface area, and accessible surface engineering behaviors have been rapidly developed as highly desired sensing materials. For biological sensors, functional designed 2D MOFs and MOF-based nanomaterials usually possess high sensitivity and responsivity for a broad variety of analytes, which provided great feasibility as the building blocks to achieve specific applications. However, only limited 2D MOFs and MOF-based nanomaterials are reported with abnormalities to operate in biological systems due to complex working phenomenon restrain its intrinsic performance. Therefore, we contribute a timely review on the current developments and researches that attributed to various biosensors and different biological sensing approaches (electrochemical, photoelectrochemical, luminescence, etc.) are necessary. This review provides a brief overview on the current challenges and new frontiers of fabrication as well as design on biosensing 2D MOFs and MOF-based nanomaterials, which would guide the exploration of novel 2D materials that capable of high selectivity and sensitivity in complex biological fluids. [ABSTRACT FROM AUTHOR]

Dissipative structures often appear as an unstable counterpart of ordered structures owing to fluctuations that do not form a homogeneous phase. Even a multiphase mixture may simultaneously undergo one chemical reaction near equilibrium and another one that is far from equilibrium. Here, we observed in real time crystal seed formation and simultaneous nanocrystal aggregation proceeding from CeIV complexes to CeO2 nanoparticles in an acidic aqueous solution, and investigated the resultant hierarchical nanoarchitecture. The formed particles exhibited two very different size ranges, resulting in further pattern formation with opalescence. The hierarchically assembled structures in solutions were CeO2 colloids, viz. primary core clusters (1–3 nm) of crystalline ceria and secondary clusters (20–30 nm) assembled through surface ions. Such self-assembly is widespread in multi-component complex fluids, paradoxically moderating hierarchical reactions. Stability and instability are not only critical but also complementary for co-optimisation around the nearby free energy landscape prior to bifurcation. For atomically precise nanoparticle synthesis, it is crucial to understand hierarchical interactions during nanostructure formation. Here, the authors observe the crystal seed formation and simultaneous nanocrystal aggregation of ceria from aqueous solution in real time to understand hierarchically different intra- and interparticle interactions governing the particle shapes. [ABSTRACT FROM AUTHOR]

In quasi-two-dimensional conditions, different invasion patterns can be observed when a fluid displaces another fluid with a higher viscosity. The transition from interfacial instability to fracture during gas invasion remained poorly understood, and classification criteria for different invasion patterns demanded further improvement. In this study, single-point compressed gas injection experiments were conducted in magnesium lithium phyllosilicate (MLPS) suspensions in a rectangular Hele-Shaw cell. Interestingly, with the increase of the injection pressure and the decrease of the concentration of MLPS suspension, the gas invasion pattern underwent a transition from viscous elastic fracture, elastic fracture, elastic viscous fingering to viscous fingering, in which viscous elastic fracture was observed for the first times. We detailly discuss the characteristics and occurrence conditions of each invasion pattern. Furthermore, by analyzing the velocity field of each invasion pattern, it is found that the relationship between the velocity direction around the gas and the gas growth direction varies with different invasion patterns. A simple and effective quantitative indicator is constructed to distinguish the different invasion patterns. Following the identification of invasion patterns, a further investigation was conducted into the relationship between invasion patterns and experimental conditions. By utilizing the relationships among injection conditions and material rheological properties, two dimensionless numbers, Bingham number and Weissenberg number, are conducted, which have an impact on the various invasion patterns and invasion process. A unified phase diagram based on the Bingham number and Weissenberg number was also proposed to incorporate the possible gas invasion patterns in the MLPS suspension. [ABSTRACT FROM AUTHOR]

Oscillatory shear tests are frequently used to determine viscoelastic properties of complex fluids. Both the amplitude and frequency of the input signal can be independently varied, allowing rheologists to probe a wide range of material responses. Historically, most oscillatory tests have focused on the measurement and application of the total strain. However, the total strain is a composite parameter consisting of recoverable and unrecoverable components. Use of only the total strain therefore provides an incomplete description of the rheology. In this work, we provide a mathematical derivation for the determination of the recoverable and unrecoverable components in steady-state linear viscoelastic oscillatory flows via a simple experimental procedure. The relationship between the total strain and its components is fully explored and challenged in the context of how rheologists define moduli and common rheological models. These relations are demonstrated via experimental measurements on model viscoelastic and viscoplastic materials: wormlike micelles and Carbopol 980. Additionally, we show how the derived mathematics fully details the conditions where the Cox-Merz rules are valid in terms of recovery rheology. Finally, we demonstrate how a thorough understanding of the strain components can be used to create a simple nonlinear model that reproduces all common amplitude sweep behaviors. [ABSTRACT FROM AUTHOR]

Magnetoelastic (ME) effect-based sensors have been innovatively engineered for diverse applications, ranging from ensuring food safety to facilitating immunoassays and structural health monitoring. These cutting-edge devices leverage piezomagnetic/flexomagnetic plates to propagate waves, with the top surface of the plate frequently encountering contact with liquids. This article delves into the intricacies of analytically modeling the flexomagnetic effect, focusing on strain gradients within a finite-thickness plate. Additionally, it investigates the dispersion of shear horizontal (SH) waves within the same flexomagnetic plate when immersed in a Newtonian liquid region. The study meticulously considers the influences of plate thickness, flexomagnetic coefficient, and the viscosity of the liquid, particularly for a Cobalt-ferrite plate. The obtained dispersion equations are used to plot phase velocity spectra and frequency spectra. The implications of this research extend to optimizing surface acoustic wave sensors (SAW) designed for underwater applications, bio-sensing, and chemo-sensing. The comprehensive understanding of the dispersion characteristics of SH waves in piezomagnetic plates with flexomagnetic effect equips researchers and engineers to enhance the performance and efficiency of SAW devices across a spectrum of under-liquid scenarios. [ABSTRACT FROM AUTHOR]

In contrast to most fishes, salmonids exhibit the unique ability to hold their eggs for several days after ovulation without significant loss of viability. During this period, eggs are held in the body cavity in a biological fluid, the coelomic fluid (CF) that is responsible for preserving egg viability. To identify CF proteins responsible for preserving egg viability, a proteomic comparison was performed using 3 salmonid species and 3 non-salmonid species to identify salmonid-specific highly abundant proteins. In parallel, rainbow trout CF fractions were purified and used in a biological test to estimate their egg viability preservation potential. The most biologically active CF fractions were then subjected to mass spectrometry analysis. We identified 50 proteins overabundant in salmonids and present in analytical fractions with high egg viability preservation potential. The identity of these proteins illuminates the biological processes participating in egg viability preservation. Among identified proteins of interest, the ovarian-specific expression and abundance in CF at ovulation of N-acetylneuraminic acid synthase a (Nansa) suggest a previously unsuspected role. We show that salmonid CF is a complex biological fluid containing a diversity of proteins related to immunity, calcium binding, lipid metabolism, proteolysis, extracellular matrix and sialic acid metabolic pathway that are collectively responsible for preserving egg viability. [ABSTRACT FROM AUTHOR]

We derive explicit analytical expressions for the recurrence relations using the analytical matrix method for frequency response and the Bautista-Manero-Puig model for complex fluids. The BMP model is derived from the Extended Irreversible Thermodynamics formalism and has been shown to be useful in predicting the complex rheological behavior of self-associative systems. All harmonics of the alternating normal and shear stresses in oscillatory shear with various amplitude oscillatory regimes (AOS) can be calculated analytically, i.e., small amplitude oscillatory shear (SAOS), medium amplitude oscillatory shear (MAOS), and large amplitude oscillatory shear (LAOS). We show that incorporating the effects of the first and second normal stress differences for all AOS regimes leads to the emergence of higher harmonics. We establish the limits between the different AOS regimes based on criteria suggested by the analytical method. For some typical systems, such as CTAB-NaSal, we found a satisfactory quantitative agreement with the measured behavior of AOS. [ABSTRACT FROM AUTHOR]

Trained detection dogs have a unique ability to find the sources of target odors in complex fluid environments. How dogs derive information about the source of an odor from an odor plume comprised of odorants with different physical properties, such as diffusivity, is currently unknown. Two volatile chemicals associated with explosive detection, ammonia (NH3, derived from ammonium nitrate-based explosives) and 2-ethyl-1-hexanol (2E1H, associated with composition C4 plastic explosives) were used to ascertain the effects of the physical properties of odorants on the search behavior and motion of trained dogs. NH3 has a diffusivity 3.6 times that of 2E1H. Fourteen civilian detection dogs were recruited to train on each target odorant using controlled odor mimic permeation systems as training aids over 6 weeks and then tested in a controlled-environment search trial where behavior, motion, and search success were analyzed. Our results indicate the target-odorant influences search motion and time spent in the stages of searching, with dogs spending more time in larger areas while localizing NH3. This aligns with the greater diffusivity of NH3 driving diffusion-dominated odor transport when dogs are close to the odor source in contrast to the advection-driven transport of 2E1H at the same distances. [ABSTRACT FROM AUTHOR]

The annular flow of complex viscoelastic fluids, described by the generalised Phan-Thien–Tanner model, is studied. This model considers the Mittag-Leffler function instead of the usual linear or exponential functions of the trace of the stress tensor, and includes two new parameters that provide additional fitting flexibility. We derive a semi-analytical solution that provides a better understanding of the behaviour of this type of fluid in annular flows and also helps to improve the modelling of complex materials. [ABSTRACT FROM AUTHOR]

The concentration and temperature dependences of the solubility of natural pyrochlore and columbite and Ta and Nb oxides are experimentally studied in NaOH and (mNaF + mNaOH) alkaline aqueous solutions at 300–550°C and 50 and 100 MPa and low oxygen fugacity (Co–CoO and Ni–NiO buffers). The initial NaOH and NaF concentrations varied in the range of 0.01–2 m and 0.01–1 m, respectively. It is established that the Nb content in alkaline solutions within the entire concentration range is higher than the Ta content by approximately two and half orders of magnitude. The solubility of pyrochlore in alkaline Na solutions is significantly higher than that of columbite allowing us to consider that Nb forms complexes in alkaline fluids, whereas the Ta complexes are suppressed. The solubility of pyrochlore and columbite with increasing temperature decreases, and the presence of an F ion in form of low NaF content positively affects the solubility of Ta and Nb minerals and oxides at high temperatures (500–550°C). It is established that the lower oxygen fugacity (Co–CoO buffer) is favorable for the precipitation of Nb in NaOH fluids. The study of the pressure effect at 50 and 100 MPa on the solubility of pyrochlore, columbite, and Na and Nb oxides in alkaline Na solutions showed that the solubility of pyrochlore increases with increasing pressure, whereas that of columbite remains almost unchanged. Thus, the decrease in pressure favors the Nb precipitation in form of tantaloniobates at the dissolution of pyrochlore. No this correlation is observed for columbite. [ABSTRACT FROM AUTHOR]

Despite their aesthetic elegance, wavy or fingering patterns emerge when a fluid of low viscosity pushes another immiscible fluid of high viscosity in a porous medium, producing an incomplete sweep and hampering several crucial technologies. Some examples include chromatography, printing, coating flows, oil-well cementing, as well as large-scale technologies of groundwater and enhanced oil recovery. Controlling such fingering instabilities is notoriously challenging and unresolved for complex fluids of varying viscosity because the fluids' mobility contrast is often predetermined and yet the predominant drive in determining a stable, flat or unstable, wavy interface. Here we show, experimentally and theoretically, how to suppress or control the primary viscous fingering patterns of a common type of complex fluids (of shear-thinning with a low yield stress) using a radially tapered cell of linearly varying gap thickness, h(r). Experimentally, we displace a complex viscous (PAA) solution with gas under a constant flow rate (Q), varied between 0.02 and 2 slpm (standard liter per minute), in a radially converging cell with a constant gap-thickness gradient, α = d h / d r < 0 . A stable, uniform interface emerges at low Q and in a steeper cell (i.e., greater | α | ) for the complex fluids, whereas unstable fingering pattern at high Q and smaller | α | . Our theoretical predictions with a simplified linear stability analysis show an agreeable stability criterion with experimental data, quantitatively offering strategies to control complex fluid-fluid patterns and displacements in microfluidics and porous media. [ABSTRACT FROM AUTHOR]

Turbulent relaxation is the process of turbulent systems reaching the state of equilibrium, starting upon quenching the turbulence forcing acting on them. Such relaxation in binary fluids is instrumental for both fundamental science understanding and industrial applications, although potential differences in the relaxation of bulk and interface are still to be identified. Using direct numerical simulations of Cahn-Hilliard-Navier-Stokes equations, here we show that the bulk and the interface relax towards different states. However, both the relaxation channels can be accounted for via a universal pathway based on the recently proposed principle of vanishing nonlinear transfers. We find that the bulk of each fluid relaxes differently from the turbulent relaxation of a single hydrodynamic fluid. At the same time, the interface relaxes towards a Helmholtz-like pressure-balanced state. The present methodology can be directly applied to predict the turbulent relaxed states in active binary mixtures as well as other complex fluid systems. A turbulent binary fluid strives for a relaxed state after the forcing has been switched off. Using direct numerical simulations of the Cahn-Hilliard-NavierStokes system, it is found that the bulk of each fluid and the interface relax differently following a universal path of relaxation. [ABSTRACT FROM AUTHOR]

The paper reveals the problem of measuring reactive oxygen (ROS) and nitrogen (RNS) species' concentrations in plasma treated water Milli-Q. We investigate the features of the FOX method for hydrogen peroxide concentration measurement and the Griess method for nitrite ions concentration spectrophotometric measurement using two different ways of an aqueous solution treatment. In the first case, the electrode (non-conducting high-temperature ceramics) was above the aqueous solution and the discharge was in the gas phase. In the second case, the electrodes were fixed around the perimeter inside the cylindrical chamber filled with water, and working gas (air, argon) was injected into interelectrode space. Varying the duration of exposure (2–10 min) leads to changes in the chemical composition and biological activity of the liquid medium, and this approach is effective for proving of the methods in complex liquids. We found the erosion of the electrodes (stainless steel, duralumin) with the injection of argon and air. The erosion can affect reactions of the methods used, as a result, it makes a contribution to measured concentration. For further applications, it is necessary to consider these features to obtain the correct and reproducible results. When plasma exposure occurs with an electrode that is above the surface of the liquid and does not erode, both methods work in the proper way. But when erosion is present ions of eroded materials (iron, aluminum) contribute to the measurement of hydrogen peroxide concentration using the FOX method. A method with xylenol orange is proposed for taking this feature into account by measuring the concentration of metal ions. In the Griess assay it is possible to obtain strongly erroneous results due to visually similar color and close values of absorbance at the chosen wavelength (525 nm) for both low concentration of nitrites (within linear part of the calibration curve) of nitrites and high concentration (far beyond linear part of the calibration curve). In our research concentration of nitrites does drastically change in the experiment after changing material of the electrodes from stainless steel to duralumin. The Griess assay leads to the formation of a stable fluorescent complex when erosion of the metal electrodes is present. [ABSTRACT FROM AUTHOR]

Amniotic fluid is a complex biological medium that offers protection to the fetus and plays a key role in normal fetal nutrition, organogenesis, and potentially fetal programming. Amniotic fluid is also critically involved in longitudinally shaping the in utero milieu during pregnancy. Yet, the molecular mechanism(s) of action by which amniotic fluid regulates fetal development is ill-defined partly due to an incomplete understanding of the evolving composition of the amniotic fluid proteome. Prior research consisting of cross-sectional studies suggests that the amniotic fluid proteome changes as pregnancy advances, yet longitudinal alterations have not been confirmed because repeated sampling is prohibitive in humans. We therefore performed serial amniocenteses at early, mid, and late gestational time-points within the same pregnancies in a rhesus macaque model. Longitudinally-collected rhesus amniotic fluid samples were paired with gestational-age matched cross-sectional human samples. Utilizing LC–MS/MS isobaric labeling quantitative proteomics, we demonstrate considerable cross-species similarity between the amniotic fluid proteomes and large scale gestational-age associated changes in protein content throughout pregnancy. This is the first study to compare human and rhesus amniotic fluid proteomic profiles across gestation and establishes a reference amniotic fluid proteome. The non-human primate model holds promise as a translational platform for amniotic fluid studies. [ABSTRACT FROM AUTHOR]

Developments in the last century, and especially in the last 50 years, have advanced understanding of suspension rheology greatly. Here, a limited review of suspension work over this period is presented, emphasizing advances over the last three decades in understanding of the particle pressure and strong shear thickening, which were motivated by crucial experimental observations, computational advances, and a critical review, all from the 1980s. This review serves as a preview to some outstanding challenges in suspension mechanics. This article considers primarily dispersions of spherical particles, which serve not only as a model material for understanding the rheology of more complex fluids of practical relevance, but also as a basic system for the study of nonequilibrium statistical physics. [ABSTRACT FROM AUTHOR]

In this paper, a novel hydrogen-bonded liquid crystalline binary complex system was synthesized from pure mesogenic 4-(octyloxy)benzoic acid (8OBA) and non-mesogenic n-aminobenzoic acid (nABA, n = 3, 4) chemicals. Differential scanning calorimeter (DSC) experiments were performed to investigate the thermal properties of the synthesized samples, and polarized optical microscopy (POM) experiments were performed to investigate the mesogenic phase textures. The DSC and POM results showed that the phase sequence was Cr ↔ SmA ↔ SmC ↔ N ↔ I during continuous heating and cooling cycle. In addition, the thermal stability factor, phase transition entropy, and phase transition activation energy were calculated using DSC data. According to the calculated values, it was concluded that the mesogenic phases of the synthesized complexes occur regularly and the most stable phase is the SmC phase. Moreover, the optical tilt angle value for the SmC phase was measured and it was seen that the value increased up to 29° and 30° for 8OBA/4ABA and 8OBA/3ABA complexes, respectively. The formation of hydrogen bonds between the mesogenic and non-mesogenic molecules in the synthesized mesogenic structure was confirmed by Fourier-transformed infrared spectroscopy (FTIR). Furthermore, XRD results showed that the molecular ordering of the synthesized hydrogen-bonded 8OBA/4ABA and 8OBA/3ABA binary complexes occur in a monoclinic structure in the solid phase. [ABSTRACT FROM AUTHOR]

An overarching challenge in rheology is to develop constitutive models for complex fluids for which we lack accurate first principles theory. A further challenge is that most experiments probing dynamical structure and rheology do so only in very simple flow fields that are not characteristic of the complex deformation histories experienced by material in a processing application. A recently developed experimental methodology holds potential to overcome this challenge by incorporating a fluidic four-roll mill (FFoRM) into scanning small-angle X-ray scattering instrumentation (sSAXS) (Corona, P. T. et al. Sci. Rep.8, 15559 (2018); Corona, P. T. et al. Phys. Rev. Mater6, 045603 (2022)) to rapidly generate large data sets of scattering intensity for complex fluids along diverse Lagrangian flow histories. To exploit this uniquely rich FFoRM-sSAXS data, we propose a machine learning framework, Scattering-Informed Microstructure Prediction under Lagrangian Evolution (SIMPLE), which uses FFoRM-sSAXS data to learn an evolution equation for the scattering intensity and an associated tensorial differential constitutive equation for the stress. The framework incorporates material frame indifference and invariance to arbitrary rotations by data preprocessing. We use autoencoders to find an efficient reduced order model for the scattering intensity and neural network ordinary differential equations to predict the time evolution of the model coordinates. The framework is validated on a synthetic FFoRM-sSAXS data set for a dilute rigid rod suspension. The model accurately predicts microstructural evolution and rheology for flows that differ significantly from those used in training. SIMPLE is compatible with but does not require material-specific constraints or assumptions. [ABSTRACT FROM AUTHOR]

Developing constitutive models that can describe a complex fluid's response to an applied stimulus has been one of the critical pursuits of rheologists. The complexity of the models typically goes hand-in-hand with that of the observed behaviors and can quickly become prohibitive depending on the choice of materials and/or flow protocols. Therefore, reducing the number of fitting parameters by seeking compact representations of those constitutive models can obviate extra experimentation to confine the parameter space. To this end, fractional derivatives in which the differential response of matter accepts non-integer orders have shown promise. Here, we develop neural networks that are informed by a series of different fractional constitutive models. These fractional rheology-informed neural networks (RhINNs) are then used to recover the relevant parameters (fractional derivative orders) of three fractional viscoelastic constitutive models, i.e., fractional Maxwell, Kelvin-Voigt, and Zener models. We find that for all three studied models, RhINNs recover the observed behavior accurately, although in some cases, the fractional derivative order is recovered with significant deviations from what is known as ground truth. This suggests that extra fractional elements are redundant when the material response is relatively simple. Therefore, choosing a fractional constitutive model for a given material response is contingent upon the response complexity, as fractional elements embody a wide range of transient material behaviors. [ABSTRACT FROM AUTHOR]

This study introduces the Constitutive Neural Network (ConNN) model, a machine learning algorithm that accurately predicts the temporal response of complex fluids under specific deformations. The ConNN model utilizes a recurrent neural network architecture to capture the time dependent stress responses, and the recurrent units are specifically designed to reflect the characteristics of complex fluids (fading memory, finite elastic deformation, and relaxation spectrum), without presuming any equation of motion of the fluid. We demonstrate that the ConNN model can effectively replicate the temporal data generated by the Giesekus model and the Thixotropic-Elasto-Visco-Plastic (TEVP) fluid model under varying shear rates. To test the performance of the trained model, we subject it to an oscillatory shear flow, with periodic reversals in flow direction, which has not been trained on. The ConNN model successfully replicates the shear moduli of the original models, and the trained values of the recurrent parameters match the physical prediction of the original models. However, we do observe a slight deviation in the normal stresses, indicating that further improvements are necessary to achieve more rigorous physical symmetry and improve the model prediction. [ABSTRACT FROM AUTHOR]

This paper's goal is to investigate a mathematical model of Darcy Forchheimer flow of a tri-hybrid nanofluid consisting of pure blood as the base fluid and ZrO2, AA7072 and AA7075 as nanoparticles flowing via a porous channel, which might be used as a model for drug administration. Some appropriate transformations are implemented to transmute the governing system of partial differential equations and the relevant boundary conditions for computation. The NDsolve is employed to generate the numerical solution for the relevant system of differential expression. The properties of flow patterns of tri-hybrid nanofluids are simulated and investigated in great depth due to the variation in the changing factors, such as temperature, velocity, and profiles. ZrO2 + AA7072 + AA7075/blood, ZrO2 + AA7072/blood and ZrO2/blood have their rates, momentum, and heat transfer studied in detail, as have the effects of applicable limitations on these variables. Amongst the various findings of this study is the fact that elevating the Forchheimer number slows the flow velocity of the tri-hybrid nanofluid and enhances the temperature profile. This theoretical model is comprised of Forchheimer number that occurs through blood flow. It has a significant bearing on the magnetic delivery in blood, the therapeutic procedure of hyperthermia, magnetic endoscopy, understanding and regulating blood flow, transport of complex bio-waste fluids, and heat transfer in capillaries, amongst other things. [ABSTRACT FROM AUTHOR]

This study aims to examine the impact of planting strategies on improving thermal comfort in relation to the existing buildings within real high-rise residential complexes. Using numerical simulation via ENVI-met, we compare six planting scenarios characterized by two locational schemes—open-space planting and building-vicinity planting—and three tree quantities. The results highlight the importance of planting greater numbers of trees, and also of their locations, to moderate the thermal environment. The findings of the study demonstrated that increasing the number of trees in the open space by threefold of the advisory guidelines led to a significant reduction in the average air temperature by 0.87 °C, mean radiant temperature (MRT) by 11.00 °C, physiological equivalent temperature (PET) by 4.50 °C, and wind speed by 0.30 m/s. Planting the minimum number of trees under building-vicinity reduced air temperature by 0.07 °C, MRT by 2.48 °C, and PET by 0.92 °C, while showing a slight increase in wind speed of approximately 0.01 m/s. To achieve improvements in both thermal condition and air flow, we suggest planting rows of trees parallel to the prevailing wind direction in the ventilation corridors at some distance from buildings, to minimize overlap of shade from trees and from buildings. The findings of this study will provide useful guidelines for effective planting design in dense residential areas. [ABSTRACT FROM AUTHOR]

Membrane-based organic solvent separations are rapidly emerging as a promising class of technologies for enhancing the energy efficiency of existing separation and purification systems. Polymeric membranes have shown promise in the fractionation or splitting of complex mixtures of organic molecules such as crude oil. Determining the separation performance of a polymer membrane when challenged with a complex mixture has thus far occurred in an ad hoc manner, and methods to predict the performance based on mixture composition and polymer chemistry are unavailable. Here, we combine physics-informed machine learning algorithms (ML) and mass transport simulations to create an integrated predictive model for the separation of complex mixtures containing up to 400 components via any arbitrary linear polymer membrane. We experimentally demonstrate the effectiveness of the model by predicting the separation of two crude oils within 6-7% of the measurements. Integration of ML predictors of diffusion and sorption properties of molecules with transport simulators enables for the rapid screening of polymer membranes prior to physical experimentation for the separation of complex liquid mixtures. Membranes can be used for energy efficient organic liquid mixture separations. Here the authors use machine learning and transport simulations to predict the separation of complex mixtures such as crude oils by any linear polymer membrane. [ABSTRACT FROM AUTHOR]

Soft-matter nanoparticles are of great interest for their applications in biotechnology, therapeutic delivery, and in vivo imaging. Underpinning this is their biocompatibility, potential for selective targeting, attractive pharmacokinetic properties, and amenability to downstream functionalisation. Morphological diversity inherent to soft-matter particles can give rise to enhanced functionality. However, this diversity remains untapped in clinical and industrial settings, and only the simplest of particle architectures [spherical lipid vesicles and lipid/polymer nanoparticles (LNPs)] have been routinely exploited. This is partially due to a lack of appropriate methods for their synthesis. To address this, we have designed a scalable microfluidic hydrodynamic focusing (MHF) technology for the controllable, rapid, and continuous production of lyotropic liquid crystalline (LLC) nanoparticles (both cubosomes and hexosomes), colloidal dispersions of higher-order lipid assemblies with intricate internal structures of 3-D and 2-D symmetry. These particles have been proposed as the next generation of soft-matter nano-carriers, with unique fusogenic and physical properties. Crucially, unlike alternative approaches, our microfluidic method gives control over LLC size, a feature we go on to exploit in a fusogenic study with model cell membranes, where a dependency of fusion on particle diameter is evident. We believe our platform has the potential to serve as a tool for future studies involving non-lamellar soft nanoparticles, and anticipate it allowing for the rapid prototyping of LLC particles of diverse functionality, paving the way toward their eventual wide uptake at an industrial level. [ABSTRACT FROM AUTHOR]

In flows with re-entrant corners, polymeric fluids can exhibit a recirculation region along the wall upstream from the corner. In general, the formation of these vortices is controlled by both the extensional and shear rheology of the material. More importantly, these regions can only form for sufficiently elastic fluids and are often called "lip vortices". These elastic lip vortices have been observed in the flows of complex fluids in geometries with sharp bends. In this work, we characterize the roles played by elasticity and shear thinning in the formation of the lip vortices. Simulations of the Newtonian, Bird-Carreau, and Oldroyd-B models reveal that elasticity is a necessary element. A systematic study of the White-Metzner, finitely extensible non-linear elastic (FENE-P), Giesekus and Rolie-Poly models shows that the onset and size of the elastic lip vortex is governed by a combination of both the degree of shear thinning and the critical shear rate at which the thinning begins. (left) Contour plots of velocity magnitude for the FENE-P model showing the decrease in size of the elastic lip vortex as maximum extensibility decreases. (right) Length of the elastic vortex as a function of a modified Carreau number showing a modelindependent effect of the degree and onset of shear thinning. [ABSTRACT FROM AUTHOR]

Analytical ultracentrifugation (AUC) is a classical polymer and colloid analysis technique invented by Theodor Svedberg 100 years ago. Modern hard- and software and powerful computers make it now possible to develop the methodology beyond what was possible with this technique before. This perspective aims to describe new possibilities, which extend the possibilities of AUC beyond the classical repertoire of the determination of distributions of sedimentation coefficient, particle size, and molar mass as well as stoichiometries and interaction constants of interacting systems. High-resolution simultaneous characterization of particle size and optical property distributions, investigation of nucleation by reaction in the AUC cell, characterization of particle interactions at a very high concentration, and characterization of complex fluids or osmotic pressures over large concentration ranges even crossing phase boundaries are among the discussed topics. They show that even after 100 years of successful application, AUC still has much yet unexplored potential in colloid and polymer science. This perspective paper spans from the days of invention of analytical ultracentrifugation to now including nonmainstream methodology and instrumentation, which has a huge potential for the future. This includes multiwavelength detectors, high-resolution particle size distributions, chemical reactions in the ultracentrifuge, high-concentration work, osmotic pressure distributions, and characterization of complex fluids. [ABSTRACT FROM AUTHOR]

Liquid metal (LM) has gained increasing attention for a wide range of applications, such as flexible electronics, soft robots, and chip cooling devices, owing to its low melting temperature, good flexibility, and high electrical and thermal conductivity. In ambient conditions, LM is susceptible to the coverage of a thin oxide layer, resulting in unwanted adhesion with underlying substrates that undercuts its originally high mobility. Here, we discover an unusual phenomenon characterized by the complete rebound of LM droplets from the water layer with negligible adhesion. More counterintuitively, the restitution coefficient, defined as the ratio between the droplet velocities after and before impact, increases with water layer thickness. We reveal that the complete rebound of LM droplets originates from the trapping of a thinly low-viscosity water lubrication film that prevents droplet-solid contact with low viscous dissipation, and the restitution coefficient is modulated by the negative capillary pressure in the lubrication film as a result of the spontaneous spreading of water on the LM droplet. Our findings advance the fundamental understanding of complex fluids' droplet dynamics and provide insights for fluid control. Liquid metals are widely used in flexible electronics and soft robotics applications, but their adhesion to underlying solid substrates is unwanted. Dai et al. show that liquid metal droplets can overcome adhesion forces and bounce off from the surface covered with a water film with sufficient thickness. [ABSTRACT FROM AUTHOR]

Dynamic wetting of complex fluids is an integral component of several industrial operations ranging from surface coatings to the modern 3D printing. This multifaceted interfacial phenomenon has been reviewed in the past decades either from the perspective of the solid or the fluid. However, it is fundamentally governed by the interfacial interactions between the solid and fluid. In this mini-review, we attempt to propose a general framework for studying the contact line dynamics of complex fluids that is inclusive of these interfacial interactions stemming from solid properties, fluid properties and the macroscopic flow geometry. We critically examine two interfacial phenomena involving complex fluids—spreading/wetting of blood and polymers exhibiting rod-climbing to unveil the existing scientific challenges in the domain. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to present a rigorous analysis of streamline patterns and their bifurcation to a viscoplastic Bingham fluid model that involves heat and mass transfer in an electroosmotic flow through a complex wavy microchannel. The Bingham fluid act as a solid medium in the core layer, which divides the channel into three distinct sections utilized to model the problem as a switched dynamical system between these zones. To track multiple steady states (stagnation points) and related trapping phenomena, we perform both analytical and numerical bifurcation analysis of each subsystem with respect to different physical effects such as electrical double layer thickness and Helmholtz-Smoluchowski velocity. The key feature of the technique presented here is its ability to reveal the peristaltic transport characteristics of the Bingham fluid model in the presence or absence of symmetric flow properties. The primary novelty here is the ability to regulate the location and stability of the equilibrium points in the domain of interest. This leads to the detection of global bifurcations that reflect important dynamic elements of the model. Our results highlighted a new category of complex behavior that controls transitions between qualitatively different transport mechanisms, as well as a class of non-classical trapping phenomena. [ABSTRACT FROM AUTHOR]

We investigate a quasi-2D suspension of Brownian particles in an optical speckle field produced by holographic manipulation of a laser wavefront. This system was developed to study, in a systematic and controllable way, a distinctive instance of diffusion, called Fickian yet Non Gaussian diffusion (FnGD), observed, during the last decade, for colloidal particles in a variety of complex and biological fluids. Our setup generates an optical speckle field that behaves like a disordered set of optical traps. First, we describe the experimental setup and the dynamics of the particles, focusing on mean square displacements, displacement distributions and kurtosis. Then, we present Brownian Dynamics simulations of point-like particles in a complex energy landscape, mimicking that generated by the optical speckle field. We show that our simulations can capture the salient features of the experimental results, including the emergence of FnGD, also covering times longer than the ones so far achieved in experiments. Some deviations are observed at long time only, with the Gaussian restoring being slower in simulations than in experiments. Overall, the introduced numerical model might be exploited to guide the design of upcoming experiments targeted, for example, to fully monitor the recovery of Gaussianity. [ABSTRACT FROM AUTHOR]

The prime thrust of this proposed mathematical model is to investigate on Love type wave propagation in a visco-porous piezoelectric waveguide with complex fluid loaded on its surface, with loosely bonded common interfaces. To describe the fluid viscoelasticity the Maxwell and Kelvin–Voigt equations are incorporated, with the aid of varying Deborah number. Solving the equation of motion for different media, namely, complex fluid layer, visco-porous piezoelectric waveguide layer, and porous half-space, a direct Sturm–Liouville problem has been formulated, which is a salient feature of this analysis. Employing suitable boundary conditions an accurate generalized complex dispersion equation is derived. To validate the results, comparison has been done with a pre-established study as a particular case, and a strong agreement is revealed. Effect of several parameters viz. fluid viscosity (glycerol concentration), fluid layer thickness, waveguide layer thickness, and bonding parameters, on the phase velocity and attenuation of Love type wave has been delineated by means of graphs. The effect of glycerol concentration and thickness of the complex fluid layer is among the key outcome of the study. It is established that Kelvin–Voigt fluid model is most appropriate when the glycerol concentration is high, as compared to other models, in the case of rapid simulation, while the Newtonian fluid model may be preferred for problems involving varying thickness of the medium. The findings of this study may be utilized in the optimal design and development of viscosity sensors Love wave fluid sensing devices. [ABSTRACT FROM AUTHOR]

We consider the model problem of mixing of passive tracers by an incompressible viscous fluid. Addressing questions of optimal control in realistic geometric settings or alternatively the design of fluid-confining geometries that successfully effect mixing requires a meaningful norm in which to quantify mixing that is also suitable for easy and efficient computation (as is needed, e.g., for use in gradient-based optimization methods). We use the physically inspired reasonable surrogate of a negative index Sobolev norm over the complex fluid mixing domain Ω , a task which could be seen as computationally expensive since it requires the computation of an eigenbasis for L 2 (Ω) by definition. Instead, we compute a representant of the scalar concentration field in an appropriate Sobolev space in order to obtain an equivalent definition of the Sobolev surrogate norm. The representant, in turn, can be computed to high-order accuracy by a Padé approximation to certain fractional pseudo-differential operators, which naturally leads to a sequence of elliptic problems with an inhomogeneity related to snapshots of the time-varying concentration field. Fast and accurate potential theoretic methods are used to efficiently solve these problems, with rapid per-snapshot mix-norm computation made possible by recent advances in numerical methods for volume potentials. We couple the methodology to existing solvers for Stokes and advection equations to obtain a unified framework for simulating and quantifying mixing in arbitrary fluid domains. We provide numerical results demonstrating the convergence of the new approach as the approximation order is increased. [ABSTRACT FROM AUTHOR]

Superlubricating materials can greatly reduce the energy consumed and economic losses by unnecessary friction. However, a long pre-running-in period is indispensable for achieving superlubricity; this leads to severe wear on the surface of friction pairs and has become one of the important factors in the wear of superlubricating materials. In this study, a polyethylene glycol-tannic acid complex green liquid lubricant (PEG10000-TA) was designed to achieve macroscale superlubricity with an ultrashort running-in period of 9 s under a contact pressure of up to 410 MPa, and the wear rate was only 1.19 × 10−8 mm3·N−1·m−1. This is the shortest running-in time required to achieve superlubricity in Si3N4/glass (SiO2). The results show that the strong hydrogen bonds between PEG and TA molecules can significantly reduce the time required for the tribochemical reaction, allowing the lubricating material to reach the state of superlubrication rapidly. Furthermore, the strong hydrogen bond can share a large load while fixing free water molecules in the contact zone to reduce shear interaction. These findings will help advance the use of liquid superlubricity technology in industrial and biomedical. [ABSTRACT FROM AUTHOR]

Background noise due to nonspecific binding of biomolecules on the assay substrates is one of the most common challenges that limits the sensitivity of microarray-based immunoassays. Background signal intensity usually increases when complex biological fluids are used because they have a combination of molecules and vesicles that can adsorb onto substrate surfaces. Blocking strategies coupled with surface chemistries can reduce such nonspecific binding and improve assay sensitivity. In this paper, we conducted a systematic optimization of blocking strategies on a variety of commonly used substrates for protein measurement in complex biofluids. Four blocking strategies (BSA, non-fat milk, PEG, and a protein-free solution) coupled with four surface chemistries (3-glycidoxypropyltrimethoxysilane (GPS), poly-L-lysine (PLL), aminoalkylsilane (AAS), and nitrocellulose (NC)) were studied for their effect on background, microspot, and net signal intensities. We have also explored the effect that these blocking strategies have when proteins in complex samples (plasma, serum, cell culture media, and EV lysate) are measured. Irregular spot morphology could affect signal extraction using automated software. We found that the microspots with the best morphology were the ones printed on GPS glass surfaces for all immunoassays. On NC membrane, the protein-based blocking strategies yielded the highest net fluorescent intensity with the antigen contained in PBS, plasma, serum, and serum-free cell culture media. Differently, with EV lysate samples, Pierce™ protein-free blocker yielded the best net signal intensity on both GPS and NC surfaces. The choice of blocking strategies highly depends on the substrate. Moreover, the findings discovered in this study are not limited to microarray-based immunoassays but can provide insights for other assay formats. [ABSTRACT FROM AUTHOR]

Landfill leachates are highly contaminated liquids and complex to treat. Two of the processes which are promising for the treatment are the advanced oxidation and adsorption methods. With the combination of the Fenton and adsorption methods, practically all the organic load of leachates can be removed; however, this combination of processes is limited due to the soon clogging of adsorbent material, which leads to high operation costs. In the present work, the results of the regeneration of clogged activated carbon are shown after the application of the Fenton/adsorption process in leachates. This research consisted of four stages: sampling and leachate characterization, clogging of the carbon through the Fenton/adsorption process, carbon regeneration through the oxidative Fenton process, and lastly, evaluation of regenerated carbon adsorption through jar and column tests. In the experiments, HCl 3 M was used, and different concentration of hydrogen peroxide (0.15 M, 0.2 M, 0.25 M) were tested at different times (16 h and 30 h). The activated carbon regeneration through the Fenton process and the optimal peroxide dosage was 0.15 M for 16 h. The regeneration efficiency was obtained from comparing the adsorption efficiency between regenerated and virgin carbon, reaching 98.27% and can be applied up to 4 times without losing regeneration efficiency. These results prove that it is possible to restore the clogged activated carbon adsorption capacity during the Fenton/adsorption process. [ABSTRACT FROM AUTHOR]

Supervised machine learning and artificial neural network approaches can allow for the determination of selected material parameters or structures from a measurable signal without knowing the exact mathematical relationship between them. Here, we demonstrate that material nematic elastic constants and the initial structural material configuration can be found using sequential neural networks applied to the transmmited time-dependent light intensity through the nematic liquid crystal (NLC) sample under crossed polarizers. Specifically, we simulate multiple times the relaxation of the NLC from a random (qeunched) initial state to the equilibirum for random values of elastic constants and, simultaneously, the transmittance of the sample for monochromatic polarized light. The obtained time-dependent light transmittances and the corresponding elastic constants form a training data set on which the neural network is trained, which allows for the determination of the elastic constants, as well as the initial state of the director. Finally, we demonstrate that the neural network trained on numerically generated examples can also be used to determine elastic constants from experimentally measured data, finding good agreement between experiments and neural network predictions. [ABSTRACT FROM AUTHOR]