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Despite the widespread applications of high-pressure plasma in semiconductor and display industry, such as deposition and ashing process, the use of cutoff probes for diagnosing high-pressure plasma was rarely studied. In this study, we investigated a method of measuring electron density in a cutoff probe using the resonance peak in a high-pressure plasma environment. This method is validated through both electromagnetic wave simulations and experimental methodologies. Our findings reveal that the proposed method demonstrates discrepancies of less than 1.47% compared to the input plasma frequency in the results of electromagnetic wave simulations at a gas pressure of 10 mTorr, while at 2.5 Torr, it exhibited a maximum discrepancy of 13.3% when selecting resonance frequencies lower than the electron–neutral collision frequency. This discrepancy at high pressure is reduced to within 1.92% by selecting a resonance frequency higher than the electron–neutral collision frequency. Also, the feasibility of these electron density measurements has been confirmed under conditions of high gas pressure where the cutoff frequency is not measurable, as evidenced by both simulation and experimental results. Our research on the diagnostic methods in high-pressure plasmas could significantly enhance the measurement and interpretation of plasma parameters in various industrial processes. [ABSTRACT FROM AUTHOR]

Time-resolved photoemission electron microscopy (PEEM) has established itself as a versatile experimental technique to unravel the ultrafast electron dynamics of materials with nanometer-scale resolution. However, the approach of performing PEEM-based, pixel-by-pixel lifetime mapping has not been reported thus far. Herein, we describe in detail the data pre-processing procedure and an algorithm to perform time-trace fittings of each pixel. We impose an energy cutoff for each pixel prior to spectral integration to enhance the robustness of our approach. With the energy cutoff, the energy-integrated time traces show improved statistics and lower fitting errors, thus resulting in a more accurate determination of the fit parameters, e.g., decay time constants. Our work allows us to reliably construct PEEM-based lifetime maps, which potentially shed light on the effects of local microenvironment on the ultrafast processes of the material and allow spatial distributions of lifetimes to be correlated with observables obtained from complementary microscopic techniques, hence enabling a more comprehensive characterization of the material. [ABSTRACT FROM AUTHOR]

Small angle x-ray scattering (SAXS) is a widely recognized solution for measuring complex nanostructures. With the increasing demand for accurately assessing structural characteristics and optimizing manufacturing processes, uncertainty quantification in SAXS inverse problems has become a critical issue. However, traditional methods face challenges such as slow computation speed and inaccurate estimation of multidimensional parameters. To overcome these issues, we propose an uncertainty quantification approach suitable for SAXS measurement that approximates the posterior using Bayesian deep learning. The effectiveness and reliability of our method are illustrated by assessing structural parameters of synthetic 2D Si grating samples. The uncertainty quantification takes only about 2.3 s, thousands of times faster than the conventional Markov Chain Monte Carlo (MCMC) methods. Also, our method has superior repeatability for parameter measurement compared to the MCMC approaches. It provides the potential of efficient and reliable SAXS measurement in increasingly intricate semiconductor manufacturing. [ABSTRACT FROM AUTHOR]

The microstructure plays a crucial role in the manufacturing and application of polyacrylonitrile fibers, which serve as precursors for carbon fibers. Synchrotron radiation small angle x-ray scattering (SR-SAXS) is a non-destructive and precise technique for analyzing fiber structures. This study employed one-dimensional SR-SAXS mapping to extract key structural parameters such as periodicity, lamellae thickness, and the extent of amorphous regions, as well as the directional orientation in γ-irradiated, pre-oxidized polyacrylonitrile fibers. The analysis revealed a three-layered structure comprising a surface skin, a transitional layer, and a central core. Notably, the lamellar thickness exhibits a "U"-shaped distribution, while the long-period structures, amorphous regions, and orientational properties demonstrate a "wave-like" pattern. Within this structure, the skin exhibits a higher level of orientation, with the orientation decreasing progressively from the skin toward the core layer. The structure of the layered crystal was further corroborated by the morphological analysis. In addition, molecular simulations were performed to propose the mechanisms underlying the formation of this layered structure. This comprehensive investigation using SR-SAXS and one-dimensional mapping provides detailed insights into the microstructural and morphological characteristics of polyacrylonitrile fibers, which can inform future advancements in material processing and refinement techniques for the production of advanced fibers. [ABSTRACT FROM AUTHOR]

We present a novel method for generating optical vortex needle beams (focused optical vortices with extended depth-of-focus) using a compact flat multilevel diffractive lens (MDL). Our experiments demonstrate that the MDL can produce focused optical vortices (FOVs) with topological charges l = 1 − 4 (extendable to other l values), maintaining focus over distances significantly longer than conventional optical vortices. Specifically, FOVs exhibit non-diffracting behavior with a depth-of-focus (DOF) extended beyond 5 cm, compared to conventional optical vortices, which show continuous size increase due to diffraction. When the MDL is illuminated by an optical vortex of 3 mm diameter, it achieves a transmission efficiency of approximately 90 % and extends the DOF several times beyond that of traditional lenses. Increasing the size of the input optical vortex further extends the DOF but introduces additional rings, with their number increasing proportionally to the value of l. Our approach, validated by both experimental results and numerical simulations, proves effective for beams such as optical vortex and Hermite-Gaussian modes and holds potential applications in high-resolution imaging, material processing, optical coherence tomography, and three-dimensional optical tweezers, offering a simple and efficient solution for generating non-diffracting beams. [ABSTRACT FROM AUTHOR]

In approaches to analyze material composition or in processing tasks using ultra-short laser ablation, it is of particular interest how ablated materials are distributed across the solid angle in front of the interaction region. We found that with our sub-10-fs laser in the regime from 10 14 W / c m 2 to 10 17 W / c m 2 , the solid angle of the ablation cone decreases significantly along with the laser intensity in a vacuum environment. For this observation, we used ion-beam analysis to investigate the distribution of tungsten collected on silicon catcher plates arranged across the solid angle of the laser-ablation cone. Moreover, we used other post-mortem tools, such as scanning electron microscopy and confocal laser scanning microscopy, to determine the ablation threshold of F t h = 468 mJ / c m 2 of our tungsten samples. Here, clearly, two laser intensity-dependent ablation regimes can be observed in the detection of a crater depth and a ablation cone angle. [ABSTRACT FROM AUTHOR]

We study the impedance behavior of two ferrofluids, of a similar magnetic material, one constituted by spherical nanoparticles and the other constituted by cubes, both suspended in kerosene. The ferrofluid constituted by cubic nanoparticles has 10% doping of a rare earth ion. The samples were inserted between two parallel disk-like electrodes of area S = 2.3 c m 2 made of surgical steel, separated by d = 127 μ m. The impedance was measured by applying a sinusoidal voltage of amplitude V 0 = 30 mV, from 1 mHz to 100 kHz. To analyze the experimental data, we use a model based on the Poisson–Nernst–Planck equations, with Ohmic boundary conditions. In the analysis, we assume that the ferrofluids contain free ions, originated from the manufacturing process, released by the stabilization layer around the magnetic nanoparticles dispersed in kerosene. The corresponding nanoparticles are charged of opposite signs with respect to these free ions. In the high frequency region, the effective diffusion coefficient coincides with that from the free diffusion coefficients, defined as the mathematical average between the diffusion coefficients of the nanoparticles and the free ions. In the low frequency region, we found the ambipolar diffusion coefficient, defined as their harmonic average. The effect of the electrodes is taken into account by means of surface conductivity to describe the conduction current across the electrode, assumed to be proportional to the surface electric field. In this model, the role of the electrodes is important just in the low frequency region. On the contrary, in the high frequency region, where the electric current is dominated by the displacement current, the role of the electrodes is negligible. The results show that the nanoparticles of the magnetic material have no effects on the higher-frequency range of the impedance spectra. In the low frequency region, our results indicate a difference in the electric response of the two ferrofluids. Due to their similar dimensions and, hence, similar ambipolar diffusion coefficients, we impute the observed different behavior to the charge transfer from the bulk to the external circuit included in the surface conductivity. [ABSTRACT FROM AUTHOR]

The freezing/melting transition is at the heart of many natural and industrial processes. In the classical picture, the transition proceeds via the nucleation of the new phase, which has to overcome a barrier associated with the free energy cost of the growing nucleus. The total nucleation rate is also influenced by a kinetic factor, which somehow depends on the number of attempts to create a nucleus, that translates into a significant density of proto-nuclei in the system. These transient tiny nuclei are not accessible to experiments, but they can be observed in molecular simulations, and their number and size distributions can be acquired and analyzed. The number distributions are carefully characterized as a function of the system size, showing the expected behavior, with limited spurious effects due to the finite simulation box. It is also shown that the proto-nuclei do exist even in the stable phase, in agreement with the fact that the (unfavorable) volume contribution to their free energy is negligible in the first stages of nucleation. Moreover, the number and size distributions evolve continuously between the stable and the metastable phases, in particular when crossing the coexistence temperature. The size distributions associated with any nucleus and with the largest one have also been calculated, and their relationship recently established for bubbles in a liquid [Puibasset, J. Chem. Phys. 157, 191102 (2022)] has been shown to apply here. This is an important relation for free energy barrier calculations with biased molecular simulations. [ABSTRACT FROM AUTHOR]

Metal-organic frameworks (MOFs) are promising candidate materials for photo-driven processes. Their crystalline and tunable structure makes them well-suited for placing photoactive molecules at controlled distances and orientations that support processes such as light harvesting and photocatalysis. In order to optimize their performance, it is important to understand how these molecules evolve shortly after photoexcitation. Here, we use resonance Raman intensity analysis (RRIA) to quantify the excited state nuclear distortions of four modified UiO-68 MOFs. We find that stretching vibrations localized on the central ring within the terphenyl linker are most distorted upon interaction with light. We use a combined computational and experimental approach to create a picture of the early excited state structure of the MOFs upon photoactivation. Overall, we show that RRIA is an effective method to probe the excited state structure of photoactive MOFs and can guide the synthesis and optimization of photoactive designs. [ABSTRACT FROM AUTHOR]

Manganese–rhodium (Mn–Rh) nanoparticles have emerged as a promising candidate for catalytic applications in the production of syngas, a critical precursor for a wide range of industrial processes. This study employs a comprehensive, theoretical, and computational approach to investigate the structural and electronic properties of Mn–Rh nanoparticles, with a specific focus on their interaction with titanium oxide (TiO2) surfaces and their potential as catalysts for syngas reactions. The density functional theory calculations are employed to explore the adsorption behavior of Mn–Rh nanoparticles on TiO2 surfaces. By analyzing the adsorption energies, geometries, and electronic structure at the nanoscale interface, we provide valuable insights into the stability and reactivity of Mn–Rh nanoparticles when immobilized on TiO2 supports. Furthermore, the catalytic performance of Mn–Rh nanoparticles in syngas production is thoroughly examined. Through detailed reaction mechanism studies and kinetic analysis, we elucidate the role of Mn and Rh in promoting syngas generation via carbon dioxide reforming and partial oxidation reactions. The findings demonstrate the potential of Mn–Rh nanoparticles as efficient catalysts for these crucial syngas reactions. This research work not only enhances our understanding of the fundamental properties of Mn–Rh nanoparticles but also highlights their application as catalysts for sustainable and industrially significant syngas production. [ABSTRACT FROM AUTHOR]

A novel bilateral impact-ionization-avalanche-transit-time (BIMPATT) diode based on AlGaN/GaN two-dimensional electron gas is proposed in this article. The BIMPATT is compatible with the available GaN high electron mobility transistor (HEMT) manufacturing process and has a shorter actual electron transit distance than existing HEMT-like IMPATT (HIMPATT) diodes. Compared with the same-sized HIMPATT, the optimum frequency of BIMPATT rises from 320 to 420 GHz and possesses a far wider operating frequency band, especially in the near 0.9 THz range. The maximum DC-RF conversion efficiency rises from 12.9% to 17.6%. The maximum RF power of BIMPATT is 3.18 W/mm, which is similar to 3.12 W/mm of the HIMPATT. Furthermore, our simulation demonstrated that the characteristics of BIMPATT are significantly affected by the length of anode and the thickness of the AlGaN barrier layer. The effects of ohmic contact resistance and background impurities on BIMPATT are also taken into account. This paper provides a reference for the design and characteristics enhancement of the lateral IMPATT devices. [ABSTRACT FROM AUTHOR]

The nucleation of ice from aqueous solutions is a process essential to myriad environmental and industrial processes, but the physical factors affecting the capacity of different solutes to depress the homogeneous nucleation temperature of ice are yet poorly understood. In this work, we demonstrate that for many binary aqueous solutions of non-ionic solutes, this depression is dominated by the entropy of the liquid phase. Employing the classic Turnbull interpretation of the interfacial free energy γ ∼ T S l i q u i d − S s o l i d and estimating solution entropies with a Flory-style modification of the ideal entropy of mixing that accounts for solute size effects, we demonstrate that mixing entropy alone predicts experimental homogeneous nucleation temperatures across a wide variety of non-ionic solutions. We anticipate that this physical insight will not only enhance a fundamental understanding of homogeneous nucleation processes across fields but also open new avenues to the rational design of aqueous solutions for desired nucleation behaviors. [ABSTRACT FROM AUTHOR]

The technological landscape for industrial processes handling asphaltene is evolving at a rapid pace due to the increase in the extraction of heavy crude oil. The main underlying challenges in this regard are the flow assurance, the recovery of the spent solvent, and the sophisticated extractor setup required to develop the process to an industrial scale. The number of studies focused on the handling of the asphaltene at the atomic and molecular scales is growing enormously in order to identify new sustainable solvents for the effective extraction of asphaltene from heavy crude oil or oil-bearing sands. This Perspective focuses on the importance of density functional theory and molecular dynamics simulations to explore the broader range of asphaltene inhibitors, e.g., nanoparticles, ionic liquids, and deep eutectic solvents, to prevent asphaltene precipitation. We provide a concise overview of the major accomplishments, analyze the aspects that require attention, and highlight the path-breaking studies having a significant impact on the process of chemical enhanced oil recovery from heavy crude oil reservoirs primarily based on atomistic and molecular simulations. [ABSTRACT FROM AUTHOR]

Polymer blends are critical in many commercial products and industrial processes and their phase behavior is therefore of paramount importance. In most circumstances, such blends are formulated with samples of high dispersity, which have generally only been studied at the mean-field level. Here, we extend the renormalized one-loop theory of concentration fluctuations to account for blends of disperse polymers. Analyzing the short and long length-scale fluctuations in a consistent manner, various measures of polymer molecular weight and dispersity arise naturally in the free energy. Thermodynamic analysis in terms of moments of the molecular weight distribution(s) provides exact results for the inverse susceptibility and demonstrates that the theory is not formally renormalizable. However, physically motivated approximations allow for an "effective" renormalization, yielding (1) an effective interaction parameter, χe, which depends directly on the sample dispersities (i.e., Mw/Mn) and leaves the form of the mean-field spinodal unchanged, and (2) an apparent interaction parameter χa that depends on higher-order dispersity indices, for instance Mz/Mw, and characterizes the true limits of blend stability accounting for long-range off-critical fluctuations. We demonstrate the importance of dispersity on several example systems, including both "toy" models that may be realized in computer simulation and more realistic industrially relevant blends. We find that the effects of long-range fluctuations are particularly prominent in blends where the component dispersities are mismatched, especially when there is a small quantity of the high-dispersity species. This can be understood as a consequence of the shift in the critical concentration(s) from the monodisperse value(s). [ABSTRACT FROM AUTHOR]

SnO2 is a prototypical transparent conducting oxide that finds widespread applications as transparent electrodes, gas sensors, and transparent thin-film devices. Hydrogen impurities in SnO2 give rise to unintentional n-type behavior and unexpected changes to conductivity. Interstitial H (Hi) and H at an oxygen vacancy (HO) are both shallow donors in SnO2. An O–H vibrational line at 3155 cm−1, that can be produced by a thermal anneal at 500 °C followed by a rapid quench, has been assigned to the Hi center and is unstable at room temperature on a timescale of weeks. An IR absorption study of the decay kinetics of the 3155 cm−1 O–H line has been performed. The disappearance of Hi upon annealing has been found to follow second-order kinetics. Measurements of the decay rate for a range of temperatures have determined an activation energy for the diffusion of interstitial H in SnO2. These results provide fundamental information about how unintentional hydrogen impurities and their reactions can change the conductivity of SnO2 device materials in processes as simple as thermal annealing in an inert ambient. [ABSTRACT FROM AUTHOR]

SnO2 is a prototypical transparent conducting oxide that finds widespread applications as transparent electrodes, gas sensors, and transparent thin-film devices. Hydrogen impurities in SnO2 give rise to unintentional n-type behavior and unexpected changes to conductivity. Interstitial H (Hi) and H at an oxygen vacancy (HO) are both shallow donors in SnO2. An O–H vibrational line at 3155 cm−1, that can be produced by a thermal anneal at 500 °C followed by a rapid quench, has been assigned to the Hi center and is unstable at room temperature on a timescale of weeks. An IR absorption study of the decay kinetics of the 3155 cm−1 O–H line has been performed. The disappearance of Hi upon annealing has been found to follow second-order kinetics. Measurements of the decay rate for a range of temperatures have determined an activation energy for the diffusion of interstitial H in SnO2. These results provide fundamental information about how unintentional hydrogen impurities and their reactions can change the conductivity of SnO2 device materials in processes as simple as thermal annealing in an inert ambient. [ABSTRACT FROM AUTHOR]

The study of granular avalanches in rotating drums is not only essential to understanding various complex behaviors of interest in granular media from a scientific perspective; it also has valuable applications in regard to industrial processes and geological catastrophes. Despite decades of research studies on avalanches, a proper understanding of their dynamic properties still remains a great challenge to scientists due to a lack of state-of-the-art techniques. In this study, we accurately predict the avalanche dynamic features of three-dimensional granular materials in rotating drums, by using graph neural networks on the basis of their initial static microstructures alone. We find that our method is robust to changes in various model parameters, such as the interaction potential, size polydispersity, and noise in particle coordinates. In addition, with the grain-scale velocities obtained either from our network or from numerical simulations, we find an approximately equal and strong correlation between the global velocity and global velocity fluctuation in our 3D granular avalanche systems, which further demonstrates the predictive power of our trained graph neural networks to uncover the fundamental physics of granular avalanches. We expect our method to provide more insight into the avalanche dynamics of granular materials and other amorphous systems in the future. [ABSTRACT FROM AUTHOR]

Solid-state reactions proceeding from an initial microstructure enable the synthesis of complex materials in a wide variety of applications. However, despite the importance of such reactions in materials' processing, the connection between an initial, reactant microstructure and the ensuing transformation kinetics has been relatively little studied. In this work, we employ computer simulation of a reaction–diffusion model and a quantitative analysis of the associated kinetic equations to examine the propagation and interaction of evolving fronts in a prototypical system transforming via a solid-state reaction. It is found that the interaction between fronts dictates transformation kinetics. We then use our results to describe the kinetics of phase formation in the Co–Ti–O system, which contains the entropy-stabilized line compound cobalt dititanate, CoTi 2 O 5. This system is of particular interest as it has been shown that the solid-state synthesis may be exploited to produce single-crystal cobalt dititanate. [ABSTRACT FROM AUTHOR]

In material processing and handling processes, premixed interlayer often replace the ideal Ni/Al interface, which would become a new origin of alloying reaction. This work investigates shock-induced reaction mechanism and kinetics of premixed Ni/Al nanolaminates with molecular dynamics simulations and theoretical analysis. The reaction is found to be driven by the crystallization evolution in premixed interlayer and the diffusion of premixed atoms. Among them, multi-stage reaction patterns are strongly manifested by the crystallization evolution characteristics. Specifically, "crystallization-dissolution-secondary growth" and "crystallization-dissolution" of B2 phase respectively correspond to the solid-state and solid-liquid reaction cases, where crystallizations are fitted well by Johnson–Mehl–Avrami kinetics model. Interestingly, the different growth mechanisms of B2 grain are revealed, namely nuclei coalescence and atomic diffusion. Moreover, the analysis of microscopic diffusion theory indicates a certain non-random diffusion nature for solid-state reaction initiation, but near-purely random diffusion for solid-liquid reaction initiation. The diffused Al atoms possess a limited diffusion coefficient and enhanced diffusion correlation, resulting in extremely slow mixing rate in Ni layer. In addition, the influence law of Ni concentration in premixed interlayer on reactivity parameters can be quantitatively described by a quadratic function. [ABSTRACT FROM AUTHOR]

The air fabrication of bulk LREBa2Cu3O7−δ [where LRE can be Nd, Sm, Eu, Gd, or combinations such as (Y,Gd), (Y,Er), (Sm,Eu,Gd), (Nd,Eu,Gd), and (Nd,Sm,Gd)] holds the potential to revolutionize the cost-effective production of high-temperature superconductors. This method enables batch processing on an industrial scale, opening up a range of applications across various fields with enhanced superconducting performance. In this study, we fabricated large single-domain (Sm,Eu,Gd)Ba2Cu3O7−δ using the top-seeded infiltration growth process in air. To suppress the RE/Ba substitutions, BaO2 was added in the secondary (Sm,Eu,Gd)2BaCuO5 (SEG-211) phase with various BaO2 weight percentages. The optimized sample achieved an onset critical temperature Tc(onset) of 94.57 K and a transition width of ΔTc < 1 K, representing a 71% improvement in ΔTc over the reference sample. Furthermore, the self-field critical current density Jc of the BaO2-optimized sample was 33.55 kA/cm2 at 77 K and 62.26 kA/cm2 at 65 K, H//c-axis. The addition of Ag2O to the BaO2-optimized sample yielded an onset critical temperature of Tc(onset) > 93 K and a transition width of ΔTc < 1.5 K. Significant improvement in high-field critical current density was observed in the Ag2O-added sample, with a Jc value of 18.14 kA/cm2 at 77 K and 1 T, and 50.54 kA/cm2 at 65 K and 3 T, H//c-axis. These results indicate that ternary (Sm,Eu,Gd)Ba2Cu3O7−δ can be produced in air using the IG process with optimal BaO2 and Ag2O, which is crucial for batch production in air. [ABSTRACT FROM AUTHOR]

The stability of the flow induced by a linearly stretched, flat sheet with a temperature gradient between the sheet and the free stream is investigated via a complementary numerical and large Reynolds number lower-branch asymptotic analysis. This analysis involves the derivation of new basic flow solutions which extend the exact analytical solutions of Crane, by coupling the energy and momentum equations with a temperature-dependent viscosity. In the most extreme case considered, the Reynolds number at which instabilities are observed is approximately halved compared to the isothermal case, thereby justifying its consideration as a physically meaningful flow variable of interest with potential implications for industrial extrusion processes. [ABSTRACT FROM AUTHOR]

The transport of discontinuous oil phases in constricted microchannels is a significant issue within the domains of the petroleum industry, bioengineering, and other industrial processes. During the transport, there is a pressure obstructing the drop flow through the narrow throat, which is named the Jamin effect. In this study, computational fluid dynamics technique is employed to observe and analyze the pressure drop of the discontinuous oil phase during its passage through a constricted microchannel and provides a quantitative analysis for the Jamin effect. The results show that the discontinuous oil phase undergoes five stages during its migration in the constricted microchannel, namely, the preparatory stage, the development stage of the forward meniscus, the quasi-stable stage, the regression stage of the rear meniscus, and the stable stage. Moreover, the composition of resistance in the Jamin effect is not solely due to capillary pressure, as traditional scholars believe. The analysis indicates that the equivalent viscosity of the discontinuous oil phase remains consistent during both the preparatory stage and the stable stage, demonstrating that the magnitude of the equivalent viscosity is unaffected by the profile of the oil phase. Additionally, the effects of oil phase saturation, viscosity, and capillary number on the Jamin effect also have been discussed. [ABSTRACT FROM AUTHOR]

This study investigated the sedimentation of two oscillating cold circular particles within a confined heated channel using the lattice Boltzmann method. The main objective was to investigate the effects of mixed convection, initial particle positioning, and wall confinement on particle behavior under different thermal regimes. In particular, this work sought to explain the mutual interactions between particles in the presence of these effects. Such an investigation is highly significant due to its widespread relevance in various natural and industrial processes involving particle transport. The four-way coupled model was validated against several classical benchmarks, including the drafting-kissing-tumbling interaction. The results demonstrated the critical role of initial particle positioning in promoting oscillatory motion. The reattachment of particle wakes leads to pronounced oscillations and vortex shedding in the trailing particle, especially when the particles are close. While these oscillations enhance the heat transfer coefficient, inter-particle collisions tend to suppress it. The results further revealed a decrease in the average Nusselt number for both particles below two, suggesting potential overestimation in the literature's correlation models. Furthermore, the Magnus force increasingly dominates drag forces as the Grashoff number increases. Notably, the influence of the trailing particle on the leading particle was observed exclusively during particle-wall collisions when close to the leading particle. Overall, this study highlighted the significant impact of thermal forces with wall confinement on particle motion across various thermal regimes, providing valuable insights into complex particle behavior and sedimentation patterns. [ABSTRACT FROM AUTHOR]

This study explores the impact dynamics of emulsion droplets, with a dispersed phase of either silicone oil, toluene, or heptane, and water as the continuous phase, on both smooth and microstructured surfaces fabricated via photolithography. By preparing emulsions without surfactants, we isolated the effects of surface morphology and liquid properties on droplet behavior. We characterized the rheology of the emulsions and their droplet size distributions. The impact dynamics were recorded using a high-speed camera in a shadowgraph configuration, with analysis performed through image processing techniques. Our results indicate that at higher impact velocities, water exhibits the largest spreading diameter ( d max ) on smooth surfaces, while emulsions with higher dispersed phase concentrations show reduced spreading due to increased energy dissipation. On microstructured surfaces, denser structures enhance resistance to spreading and trigger complex phenomena such as Worthington jets and secondary droplets, which are not observed on smooth surfaces. Additionally, we observed a transition in bouncing behavior for the silicone oil 50 cSt 20 v/v% emulsion on Glaco-coated surfaces, attributed to the infiltration of silicone oil into the Glaco microstructure, creating a suction force that prevents bouncing. These findings offer valuable insights for optimizing industrial processes like inkjet printing and pesticide application, where precise control of droplet behavior is crucial. [ABSTRACT FROM AUTHOR]

The development of miniaturized electronic devices is highly dependent on precision manufacturing techniques. To achieve device miniaturization, material removal and processing accuracy down to the submicrometer or even nanometer level are required. The precision machining of the mass block, a key component of the silicon micro-gyroscope, is taken as a reference. To achieve the precision positioning function of the micro-gyroscope, the mass at a certain position of the Si-based mass block must be precisely controlled. Therefore, the ultra-fine quantitative removal process of silicon materials is studied. A femtosecond laser processing system is constructed, and the evolution of micro–nanostructure and etching depth on the silicon surface is explored. An ultra-fine quantitative removal process is developed to achieve quantitative removal of different etching depths on the silicon surface. The experimental results show that the minimum removal thickness can be 0.502 µm. The processing index requirement for a silicon surface removal thickness of less than 0.001 mm has been fulfilled. It is critical to resolve the issue of high-quality manufacturing of miniaturized silicon-based devices. [ABSTRACT FROM AUTHOR]

Poly acrylic acid (PAA) is a polymer and a derivative of acrylic acid that is a superabsorbent, being able to absorb and retain water, and swell many times beyond its original volume. This property classifies it into a group of polymers called hydrogels. Hydrogels are being investigated in emerging applications such as drug delivery, biosensors, tissue engineering, wound healing bandages, and more. The ability to lithographically pattern hydrogel materials to specific dimensions at the micro and nanoscales can be very useful in devices and sensors. Limited work has been done on characterizing PAA for lithographic purposes, and so, this work investigates the ability to pattern PAA by electron beam lithography (EBL). PAA is interesting in that its carrier solvent, developer, and remover are all water alone, which may make it attractive for processes or materials that cannot tolerate solvents, acids, and bases used with other common EBL resists. PAA behaves as a negative tone resist with a relatively low base dose of 75 μC/cm2 at 100 kV acceleration voltage. The resolution is limited to 1.8 μm due to a low contrast of 1.29. However, PAA may still have many uses at that resolution where the positioning and dimension control of a hydrogel could be useful. Furthermore, PAA can successfully be used for pattern transfer with either a metal liftoff process or a silicon plasma etch. [ABSTRACT FROM AUTHOR]

In area-selective processes, such as area-selective atomic layer deposition (AS-ALD), there is renewed interest in designing surface modification schemes allowing to tune the reactivity of the nongrowth (NG) substrates. Many efforts are directed toward small molecule inhibitors or atomic layers, which would modify selected surfaces to delay nucleation and provide NG properties in the target AS-ALD processes allowing for the manufacturing of smaller sized features than those produced with alternative approaches. Bromine termination of silicon surfaces, specifically Si(100) and Si(111), is evaluated as a potential pathway to design NG substrates for the deposition of metal oxides, and TiO2 (from cycles of sequential exposures of tetrakis-dimethylamido-titanium and water) is tested as a prototypical deposition material. Nucleation delays on the surfaces produced are comparable to those on H-terminated silicon that is commonly used as an NG substrate. However, the silicon surfaces produced by bromination are more stable, and even oxidation does not change their chemical reactivity substantially. Once the NG surface is eventually overgrown after a large number of ALD cycles, bromine remains at the interface between silicon and TiO2. The NG behavior of different crystal faces of silicon appears to be similar, albeit not identical, despite different arrangements and coverage of bromine atoms. [ABSTRACT FROM AUTHOR]

The rapid growth of wearable electronics, health monitoring, and the Internet of Things has created a tremendous demand for flexible semiconductors and gadgets. Thermoelectric (TE) semiconductors that enable direct conversion between heat and electricity have been utilized as power generators, but their intrinsic brittleness inhibits the application for powering flexible/wearable electronics. The plastic inorganic semiconductors discovered in recent years offer a different option for flexible TE technologies when these materials combine good plasticity and high TE performance at room temperature. In this Perspective, we discuss how room-temperature plasticity affects the manufacturing process and real-world uses in flexible electronics, the trade-off between plasticity and thermoelectric performance, and the underlying deformation mechanisms. Further outlook on the discovery of viable plastic inorganic semiconductors is proposed. [ABSTRACT FROM AUTHOR]

In this study, we propose a novel modified pipe hydrodynamic model with a partial relaxation approach and develop a corresponding numerical algorithm within the framework of the finite volume method for its computation to enable robust, accurate, and comprehensive pipe modeling. The proposed numerical model provides some key improvements compared to existing numerical schemes for simulating mixed pipe flows: (1) it is capable of preserving both moving- and stationary-water steady states, and (2) it effectively reduces post-bore oscillations while maintaining second-order accuracy in the non-pressurized regime for unsteady pipe flows. Such improvements have been verified against theoretical and experimental data through tests involving both smooth and sharp-gradient steady and unsteady flows across various regimes in straight and locally bent circular pipes, which are fundamental elements of stormwater drainage, sewage networks, and industrial process pipelines. The proposed pipe flow model can be further improved regarding post-pore stability by utilizing specific post-bore oscillation suppression techniques, and it can be integrated into a practical hydraulic modeling tool for pipeline networks in future work. [ABSTRACT FROM AUTHOR]

This paper presents a novel method for history matching and production prediction for fractured horizontal wells by combining the data space inversion method (DSI) with the embedded discrete fracture model (EDFM), referred to as DSI-EDFM. In this approach, several initial numerical models with varying reservoir geological and fracture geometry parameters, but identical production schedules, are generated through random sampling and then run using the EDFM. The DSI method is subsequently employed to process the production data, creating a proxy model that matches actual historical data and predicts production performance by solving a quadratic optimization problem. A key improvement over the original DSI method is introduced, providing and proving the conditions under which the optimization problem derived from DSI is a positive definite quadratic optimization problem. With these conditions, the optimal solution can be directly obtained using the Newton method without any iterations. Furthermore, it is identified that overfitting issues frequently arise when using the Newton method for DSI. However, the simultaneous perturbation stochastic approximation algorithm effectively mitigates this problem, allowing the proposed DSI-EDFM to handle real reservoirs and uncertainty parameters efficiently. Three numerical examples are implemented to validate the method, including depleting development, water flooding operations, and the flush stage of fractured horizontal wells. The results demonstrate that the proposed DSI-EDFM achieves high accuracy in conducting history matching and performance prediction for fractured horizontal wells, even under complex flow model conditions and with a limited number of initial models. Additionally, the accuracy improves as the number of initial models increases. [ABSTRACT FROM AUTHOR]

In fluid dynamics, the generation and bursting of surface bubble liquid films in surfactant-laden environments involve complex phenomena, one of which is marginal pinching at the film's foot—a crucial yet inadequately understood aspect due to experimental limitations. Considering its profound impact on liquid film drainage and lifetime, we utilize high-resolution numerical simulations incorporating a weakly compressible scheme and adaptive mesh refinement to dissect the marginal pinching dynamics with unprecedented detail. Our approach elucidates the pinching dynamics and tracks the evolution of film thickness during the critical late-stage drainage process. By leveraging detailed geometric data from pinched regions, we significantly refine existing drainage models, enhancing their predictive accuracy regarding rupture thickness and film lifetime across various viscosities, surfactant concentrations, and bubble sizes. This refined model demonstrates robust alignment with our simulation results. Furthermore, we establish a quantifiable relationship between the prefactor governing reverse flow induced by the Marangoni effect and surfactant concentration. The methodologies and findings of this study provide foundational knowledge that paves the way for optimized industrial processes and an enhanced understanding of natural phenomena. [ABSTRACT FROM AUTHOR]

Large bubbles (1–5 mm radius) are important in a wide range of situations, including air-sea gas transfer, aerosol production as they burst at water surfaces, and the aeration of liquids in bioreactors and other industrial processes. When rising through turbulent flow, these bubbles are commonly distorted and may fragment to form daughter bubbles if their radius exceeds the Hinze scale (at which the restoring force due to surface tension is equal to the forces causing bubble distortion). Here, we present the results of laboratory experiments with fragmentation resulting from bubbles rising through a sheared and turbulent flow. The effects of water temperature, surface tension, local shear rate, and viscous dissipation rate of turbulent kinetic energy were assessed. Passive acoustical methods produce robust measurements of bubble fragmentation processes, allowing for rapid data collection to generate large data sets. In our experiments, even for bubbles very close to the Hinze scale, the dominant fragmentation mechanism is the capillary-driven fragmentation of elongated bubble filaments. The probability distribution of daughter bubble sizes from a single fragmentation event was independent of temperature, surface tension, and rate of viscous dissipation of turbulent kinetic energy. The overwhelming majority of fragmentation events resulted in one very large and one very small bubble, even for Hinze-scale parent bubbles and low Weber numbers (We < 5.3). Our results suggest that in a turbulent flow, there may be a link between the shear induced by large scale structures and the size of the smallest bubbles produced underneath a breaking wave. [ABSTRACT FROM AUTHOR]

Elastoviscoplastic (EVP) fluids, which exhibit both solid-like and liquid-like behaviors depending on the applied stress, are critical in industrial processes involving complex geometries such as porous media and wavy channels. In this study, we investigate how flow characteristics and channel design affect EVP fluid flow through a wavy channel, using numerical simulations supported by microfluidic experiments. Our results reveal that elasticity significantly influences flow dynamics, reducing pressure drops and expanding unyielded regions. Notably, we find that even minimal elasticity can shift the flow from steady to time-dependent regimes, a transition less pronounced in viscoelastic fluids. Additionally, we show that the development of stagnation regions can be prevented when using a modified EVP fluid with enhanced elasticity, thus providing a full global yielding of the material. This study elucidates the role of elasticity in modifying flow patterns and stress distribution within EVP fluids, offering insights into the optimization of industrial applications, such as the displacement of yield stress fluids in enhanced oil recovery, gas extraction, cementing, and other processes where flow efficiency is critical. [ABSTRACT FROM AUTHOR]

The heat and mass transfer phenomenon due to non-Newtonian nanofluids presents essential applications in various industrial and engineering processes like polymer solutions, manufacturing processes, food processing, pharmaceutical applications, extrusion processes, oil recovery, cooling systems, etc. In order to address the heat and mass transfer phenomenon, the suspension of nanofluids with different non-Newtonian materials has been studied. The objective of the current analysis is to endorse heat and mass transfer prediction due to a Casson–micropolar nanofluid over a bidirectional moving electromagnetic Riga surface. The suspension of micro-organisms is also utilized to predict the significant applications of the bioconvection phenomenon. The investigated analysis is supported with an external heat generation source and activation energy. The enhancement and fluctuation in heat transfer are captured with the addition of thermal radiation impact. The thermal, concentration, and velocity slip effects are utilized to investigate the thermal phenomenon. The shooting algorithm is applied for calculating the numerical simulations. The physical onset behind the variation of parameters is tested and claimed graphically. Current results offer applications in the heat transfer phenomenon, energy systems, solar collectors, manufacturing processes, cooling systems, thermal processes, automotive engineering, etc. [ABSTRACT FROM AUTHOR]

We report results in the development and testing of a low resource tophat electrostatic analyzer (ESA) for space plasma measurements. This device has been additively manufactured (3D-printed) using fused deposition modeling. The classic tophat design is composed of four plastic pieces, without any surface coatings. The three conducting electrodes are printed from carbon nanotube infused polyether ether ketone (CNT-PEEK). The fourth piece, an insulating electrode support, uses pure PEEK. This ESA is designed to detect electrons in space from 10 eV up to 30 keV. We demonstrate that the printed CNT-PEEK is sufficiently electrically conductive to support the fast high voltage slewing often required for high time resolution measurements. The plastic ESA has been successfully vibrated beyond standard pre-flight levels, tested under keV electron beam illumination over a wide range of temperatures, and tested under UV illumination, simulating the solar Ly-α flux. In comparison with an identical machined aluminum ESA, our CNT-PEEK ESA provides nominal energy/angle bandpasses, closely matching simulation. These bandpasses imply minimal impact from surface charging at beam energies of 2–3 keV, although more investigation is needed. We also find that the CNT-PEEK ESA provides far superior out-of-band electron rejection and UV photon rejection compared to the machined aluminum ESA. We do not detect any problems with trapped gases or outgassing. This development offers the potential for significant mass savings, implementation of otherwise unattainable geometric configurations, and dramatic simplification in manufacturing and assembly processes required for the development of space plasma instruments. [ABSTRACT FROM AUTHOR]

Ellipsometry is widely used to characterize the thickness and optical parameters of thin films deposited, for example, in industrial processes. It is based on the measurement of polarization change upon reflection of, for example, visible light at a material sample. Commercially available devices are designed for stationary applications and often rely on precise geometric adjustment of the optical setup to maximize the measurement precision. In this work, a simplified spectral ellipsometer is proposed and tested with the aim of flexible implementation in space-limited applications in thermonuclear fusion research: on the one hand, as a hand-held device for large thickness scans of coatings deposited on first-wall components inside the vacuum vessel of fusion experiments and, on the other hand, for in situ monitoring of plasma deposited coatings on diagnostic vacuum windows, reducing their transmission in the optical spectral range, which hampers spectroscopic diagnostics in long-pulse plasma experiments. The simplicity of the hardware setup is partially compensated by complex Bayesian inference of the coating parameters, which incorporates all uncertainties of the measurement and the model and provides a quantitative assessment of the final uncertainties of inferred coating parameters. The Bayesian inference based on synthetic observations is also used to optimize the diagnostic design, identifying the limiting parameters and quantifying their impact on final accuracy. For real-time analysis of layer thickness on first-wall components in fusion devices measured with the hand-held device, a neural network based analysis has been implemented, and promising test results are presented. [ABSTRACT FROM AUTHOR]