Continuous Phase Research Articles

Broadband, Wide-Angle, and Versatile Metasurface Illusions with Inverse Synthetic Aperture Radar Imaging.

Generation of controllable illusions has raised widespread interest. Over the past few decades, this field has been revolutionized by the emergence of metamaterials and metasurfaces. However, current efforts utilizing single-layer metasurfaces are limited to simple illusion demonstrations by reproducing electromagnetic field distributions, which also struggle to achieve both broad bandwidths and wide angular ranges. Here, a nontrivial multi-layer illusion strategy is proposed utilizing the inverse synthetic aperture radar imaging. The customization of illusions is facilitated by correlating the phase dispersion of meta-atoms within the target frequency interval with the positioning of the structure. The approach enables the creation of illusions across a broadband of 8 to 12 GHz and a wide angular range from -30° to 30°. As a proof of principle, several illusions are experimentally demonstrated, showcasing the diversity of the approach. This work presents a viable illusion strategy that is more feasible for practical applications in the microwave domain, paving the way for future advances of customizable illusions.

A Holistic Data-Driven Approach to Synthesis Predictions of Colloidal Nanocrystal Shapes.

The ability to precisely design colloidal nanocrystals (NCs) has far-reaching implications in optoelectronics, catalysis, biomedicine, and beyond. Achieving such control is generally based on a trial-and-error approach. Data-driven synthesis holds promise to advance both discovery and mechanistic knowledge. Herein, we contribute to advancing the current state of the art in the chemical synthesis of colloidal NCs by proposing a machine-learning toolbox that operates in a low-data regime, yet comprehensive of the most typical parameters relevant for colloidal NC synthesis. The developed toolbox predicts the NC shape given the reaction conditions and proposes reaction conditions given a target NC shape using Cu NCs as the model system. By classifying NC shapes on a continuous energy scale, we synthesize an unreported shape, which is the Cu rhombic dodecahedron. This holistic approach integrates data-driven and computational tools with materials chemistry. Such development is promising to greatly accelerate materials discovery and mechanistic understanding, thus advancing the field of tailored materials with atomic-scale precision tunability.

Proposing a feedback-feedforward neuro-fuzzy-PID controller to produce precise micro-droplets in a flow-focusing micro-channel

In this paper, a novel feedback-feedforward structure is proposed for precise droplet generation. An Adaptive Neuro-Fuzzy Inference System is used as an inverse model to predict the desired motor speed in the feedforward path, and a PID controller to compensate for the disturbances in the feedback path. The Neuro-Fuzzy model computes the desired droplet size based on the desired droplet size and flow characteristics. A flow-focusing microchannel is constructed using photolithography to generate micro-droplets. DI water as the discrete phase and oil as the continuous phase are mixed with accurate flow rates. The DI water flow rate is kept fixed and the flow rate of oil is controlled using the proposed controller. In the feedback loop, the micro droplets’ sizes are measured with an image processing of pictures captured with a high-speed camera. The performance of the closed-loop system is implemented experimentally in different desired sizes i.e., 82, 90, and 100 micrometers. It is shown that the performance of the system i.e., rise time, settling time, and accuracy is better in larger sizes. Moreover, due to the inverse neuro-fuzzy model in the feedforward loop, the rise time became small. The performance of the system in dealing with disturbances i.e., a 50% increase in discrete phase flow (water), has been considered. The results show that the closed-loop system is fast and robust against disturbances.

Tackling artefacts in the timing of relativistic pulsar binaries: Towards the SKA

Common signal-processing approximations produce artefacts when timing pulsars in relativistic binary systems, especially edge-on systems with tight orbits, such as the Double Pulsar. In this paper, we use extensive simulations to explore various patterns that arise from the inaccuracies of approximations made when correcting dispersion and Shapiro delay. In a relativistic binary, the velocity of the pulsar projected onto the line of sight varies significantly on short timescales, causing rapid changes in the apparent pulsar spin frequency, which is used to convert dispersive delays to pulsar rotational phase shifts. A well-known example of the consequences of this effect is the artificial variation of dispersion measure (DM) with binary phase, first observed in the Double Pulsar 20 years ago. We show that ignoring the Doppler shift of the spin frequency when computing the dispersive phase shift exactly reproduces the shape and magnitude of the reported DM variations. We also simulate and study two additional effects of much smaller magnitude, which are caused by the assumption that the spin frequency used to correct dispersion is constant over the duration of the sub-integration and over the observed bandwidth. We show that failure to account for these two effects leads to orbital phase-dependent dispersive smearing that leads to apparent orbital DM variations. The functional form of the variation depends on the orbital eccentricity. In addition, we find that a polynomial approximation of the timing model is unable to accurately describe the Shapiro delay of edge-on systems with orbits of less than four hours, which poses problems for the measurements of timing parameters, most notably the Shapiro delay. This will be a potential issue for sensitive facilities such as the Five-hundred-meter Aperture Spherical Telescope (FAST) and the forthcoming Square Kilometre Array (SKA); therefore, a more accurate phase predictor is indispensable.

Size, Shape and Composition Control of Metallic Colloidal Nanoparticles for the Design of Heterogeneous Catalysts

Metal supported catalysts play a pivotal role in various industrial processes, yet conventional preparation methods such as impregnation or coprecipitation lack precision in controlling critical parameters like particle size, morphology, and composition. The colloidal synthesis proved to be an excellent route for the rational adjustment of these parameters, allowing to establish structure‐performance correlations for smart catalyst design. This review explore the common strategies employed for the fine tuning of size, shape, and composition of colloidal nanoparticles used as heterogeneous catalysts. Since the colloidal route involves the use of stabilizing agents, different strategies for their removal are discussed together with insights into their effects in catalysis. Furthermore, common strategies for the deposition of preformed nanoparticles are presented. . In addition, the modifications in the geometric and electronic properties and their impact in the catalytic properties are described. To conclude, current applications, challenges, and future perspectives of metal supported nanoparticles as heterogenous catalysts are discussed.

All-optical measurement-device-free feedforward enabling ultra-fast quantum information processing

Utilizing feedforward to perform adaptive quantum operations on one entangled state according to the measurement result of the other state enables measurement-based quantum information processing (QIP). Until now, the bandwidth of feedforward in optical QIP has been limited to around 100 MHz by measurement with electronics. A potential alternative is the utilization of an optical parametric amplifier (OPA). This optical device eliminates the need for electronic measuring devices and enables all-optical broadband feedforward. In this paper, we demonstrate a variable squeezing gate with an operation bandwidth of 1.3 THz by all-optical measurement-device-free feedforward. We utilize a periodically poled lithium niobate waveguide as a broadband OPA and perform continuous phase locking in our optical system. Experimental results demonstrate that our all-optical QIP operates at a THz clock frequency, representing a major step toward the realization of an ultra-fast quantum computer.

Influence of Y2O3 Nano-Dispersoids on the Characteristics of AlCoCrFeNi2.1-Reinforced Tungsten Alloys via Mechanical Alloying and Low-Temperature Sintering

This study investigates the effects of nano-oxide dispersoids on microstructural evolution, phase formation, and mechanical properties of W-Mo-Ti alloys reinforced with AlCoCrFeNi2.1 during mechanical alloying. An EBSD/EDS analysis confirmed the formation of different phases, including the tungsten matrix, FCC reinforcement phase, Al2O3, and (Al,Cr) oxide. Y2O3 particles played a crucial role in refining the microstructure, promoting a uniform dispersion of the reinforcement phase and oxide particles in the tungsten model alloys. Mechanical testing demonstrates that the Y2O3-containing alloy exhibits improved hardness with prolonged milling, attributed to the refinement in the microstructure. In contrast, the Y2O3-free alloy shows reduced hardness due to the agglomeration of reinforcement phases surrounded by an (Al,Cr) oxide layer. The model tungsten alloys exhibit brittle behavior in compression tests, which can be attributed to the presence of (Al,Cr) oxide layers weakening the interfacial bonding and limiting plastic deformation.

Recent Advances in Plant-Based Edible Emulsion Gels for 3D-Printed Foods.

3D printing has emerged as a suitable technology for creating foodstuff with functional, sensorial, and nutritional attributes. There is growing interest in creating plant-based foods as alternatives to address current demands, especially to tailor consumer preferences. Consequently, plant-derived edible inks for additive manufacturing have emerged as suitable options, including emulsion gels (or emulgels). These gels can be formulated entirely from plant-derived lipids, proteins, polysaccharides, and/or other ingredients to form complex fluids that belong to the category of soft matter. This review summarizes the most recent advances in the areas of formation, structuring, properties, and applications of plant-based emulsion gels for 3D-printed food. These semisolid materials can be extruded to the set or solidified into structures with predesigned shapes, fidelity, and sensory attributes across the senses (taste, smell, sight, and touch) along with nutrition values. Emulsion gels can be formed by either solely gelling the continuous phase or combining this process with the formation of a particle network through aggregation and close packing. The current challenges facing the development of edible inks using plant-based materials are critically discussed to stimulate further advances in the rapidly growing field of personalized 3D-printed foods.

Rheology and printability of biopolymeric oil-in-water high internal phase Pickering emulsions: a review.

Biopolymeric oil-in-water (O/W) high internal phase Pickering emulsions (HIPPEs) due to their unique rheological behaviors of HIPPEs such as shear-thinning property, viscoelasticity, and thixotropic recovery have emerged as highly promising printing inks in the 3D printing process. O/W biopolymer-based HIPPEs are categorized as complex fluids, where rheological parameters are crucial for optimizing printability. However, existing reviews have not fully elucidated the interrelationship between rheology and printability for HIPPEs in enhancing the quality and performance of printed parts. This review delved into the influence factors of the continuous phase (e.g., biopolymer type, concentration, pH, and ionic strength) and the oil phase (e.g., oil type, volume fraction, and encapsulated components) on their rheology, to adjust their rheological behaviors in order to prepare more eligible HIPPEs as printing inks. Moreover, a spectrum of rheology-printability relationships, derived from empirical trends and rigorous analytical models, is examined to provide generalized rheological guidelines for achieving successful printability in O/W biopolymer-based HIPPEs. Furthermore, unique challenges and future perspectives on preparing their complex rheological behaviors suitable for additive manufacturing in O/W biopolymer-based HIPPEs were presented. Leveraging these insights significantly reduces reliance on trial-and-error methods in printing, thereby fostering the robust development of novel O/W biopolymer-based HIPPEs and enhancing the overall quality of printed products.

Confinement and wettability-driven dispersed phase hydrodynamics in cross-flow jets at low velocity and density ratios

The evolution characteristics of a low-velocity dispersed phase into continuous shear flow have numerous applications across biomedical devices, chemical processes, water management in fuel cells, spray systems, film deposition, and atomizing devices. The flow characteristics arise from a complex interplay of wettability, hydrodynamics, and interfacial properties, which, when constrained by confined geometries such as those in fuel cells, present a fascinating multiphase-multiphysics problem. This study investigates the impact of the chemical signature of a confined geometry and the velocity ratio between the dispersed and continuous phases on the evolution of the dispersed phase. The footprint and shape of the generated droplet guide the pressure distribution, deformation, and subsequent cross-flow-induced stretching. By systematically analyzing the dynamic effects of capillarity, inertia, air-shear, gravity, viscosity, wettability, and confinement, we classify the fate of a liquid droplet within classical flow regimes: jetting, threading, and dripping. These distinct flow regimes are mapped using classical non-dimensional numbers, and a quasi-universal characteristic is obtained relative to velocity ratios. The findings of this research contribute to precise control and prediction of dispersed-phase hydrodynamics, which play a pivotal role in enhancing the efficiency of fuel cells, droplet generation devices, water harvesting systems, film deposition techniques, coatings, and point-of-care diagnostic devices. The work underscores the relevance of integrating experimental and computational insights for optimizing interface-driven processes in interdisciplinary applications.

Fewer, but Better: On the Benefits of Surfactant‐Free Colloidal Syntheses of Nanomaterials

AbstractColloidal syntheses are common bottom‐up synthetic approaches to obtain various nanomaterials, e.g., gold nanoparticles, where a precursor, e.g., HAuCl4, is reduced in the presence of reducing agents in a solvent. It is often claimed, and almost dogmatically believed, that stabilizers, capping agents, ligands, surfactants, or other additives must be added to ensure the stability of the colloids. Although there is almost a systematic use of such chemicals in the literature, a range of surfactant‐free, or additive‐free, colloidal syntheses have been reported. In those syntheses, the solvent plays the role of source of reducing agents and/or stabilizers. Recently, the use of alkaline solutions of low‐viscosity mono‐alcohols, such as ethanol, has been shown to lead to stable surfactant‐free colloids for various metal nanoparticles. Here, with the example of gold nanoparticles obtained at room temperature, it is shown that adding commonly reported stabilizers, such as trisodium citrate, PVP, SDS, poly(NIPAM), CTAB, or chemicals such as hydroquinone, actually does not lead to any advantages compared to the surfactant‐free colloidal synthesis performed in an alkaline mixture of water and 20 vol.% ethanol. The results stress the potential of surfactant‐free approaches compared to more conventional surfactant‐ and additive‐assisted strategies to develop greener research studies and syntheses.

The role of stochasticity in fungal community assembly: explaining apparent stochasticity with field experiments.

Stochasticity is a main process in community assembly. However, experimental studies rarely target stochasticity in natural communities, and hence experimental validation of stochasticity estimates in observational studies is lacking. Here, we combine experimental and observational data to unravel the role of stochasticity in the assembly of wood-inhabiting fungi. We carried out a replicated field experiment where the natural colonization of a focal fungal species was simulated through inoculation, and the local fungal communities were monitored through DNA metabarcoding before and after the inoculations. The amount of stochasticity in fungal colonization was less pronounced than expected from the amount of unpredictability in observational data, suggesting that stochasticity may play a smaller role in fungal occurrence than previously anticipated, or that it may be a stronger influence in the dispersal and establishment phases than in colonization per se. Stochasticity was more prominent in the initial phase of community succession, with the earliest successional stage involving a higher level of stochasticity than the later stage after 2 years. We conclude that experimentally measuring the role of stochasticity in community assembly is feasible for species-rich communities under natural conditions and highlight the importance of experimentally testing the accuracy of stochasticity estimates based on observational data.

Effects of Temperature and Bimodal Microstructure on the Mechanical Properties and Fracture Mechanisms of High-Strength Al-Ni-Cu-Fe Alloy Fabricated through Laser Powder Bed Fusion

This study investigates the mechanical properties of an Al-Ni-Cu-Fe alloy fabricated using laser powder bed fusion (LPBF) technology, evaluated at temperatures ranging from room temperature to 300°C under various strain rates for potential aerospace and automotive applications. Aluminum alloys often face the challenges of maintaining high-temperature strength and stability, limiting their use in demanding environments. The results demonstrate that the LPBF Al-Ni-Cu-Fe alloy maintains strength above 300 MPa at standard strain rates and reaches up to 400 MPa at high strain rates at 300°C, indicating its suitability for lightweight, high-strength vehicles and thermal engineering systems. The high-temperature strengthening mechanisms are attributed to Al9FeNi submicron cellular eutectic walls that impede dislocation motion and precipitation strengthening from Al2Cu. Fracture analysis reveals that localized brittleness limits elongation to 3% at room temperature, with deformation distributed between coarse-grained (CG) and fine-grained (FG) regions. At elevated temperatures (300°C), partial homogenization of FG regions reduces melt pool constraints, promoting local deformation. Therefore, ductility increases significantly under high strain rates as the dispersed Al9FeNi phases become less effective in resisting instantaneous stresses, allowing deformation to overcome melt pool boundaries. At extreme strain rates during impact testing, twinning becomes the dominant deformation mechanism, contrasting with tensile testing. These findings confirm the potential of the LPBF Al-Ni-Cu-Fe alloy as a heat-resistant printed aluminum alloy for high-temperature applications and provide valuable insights into fracture mechanisms within the bimodal microstructure, guiding future alloy optimization.

Understanding Post‐Release Dispersal and Habitat Selection Helps Refine Management of Translocated Populations

ABSTRACTTranslocation outcomes in connected habitats are often uncertain, as individuals dispersing outside managed areas are exposed to threats. Post‐release monitoring can reduce uncertainty by revealing how dispersal and habitat selection influences establishment and population growth which inform future translocations. We undertook post‐release monitoring to identify habitat selection patterns following a translocation of toutouwai (North Island robin, Petroica longipes) to a large, contiguous forest habitat. Post‐release monitoring aimed to estimate survival, dispersal, and territory establishment to inform management decisions and future release site selection. We created species distribution models using monitoring data to identify differences in habitat selection during the post‐release dispersal and territory establishment phases. Toutouwai dispersed across 1312 ha but established territories within only 113 ha and 1 km from the release location. Site fidelity was higher than predicted, and there was no difference in dispersal or habitat selection across demographic groups. Critically, high site fidelity suggested that the extent of managed habitat was sufficient to protect dispersing individuals. Habitat selection preferences were stronger during territory establishment and were associated with lower slopes, higher water deficit and proximity to water reservoirs. Species distribution modelling allowed for predictions of high‐quality core habitat where dispersal and territory establishment were more likely, resulting in targeted management to improve population growth. Our results show that initial dispersal in connected habitats may be much larger than suggested by territory data alone, and that management may need to protect larger areas to support successful establishment. We demonstrate how effective post‐release monitoring can inform predictions of habitat quality and dispersal and guide management actions to improve translocations outcomes.

Multiscale modeling of nanofluid flow and enhanced heat transfer via a computational fluid dynamics–discrete element coupled approach

A new multiscale model, which directly considers the interaction between the macroscopic continuous base fluid phase and the microscopic discrete nanoparticle phase, is proposed to analyze the nanofluid flow and enhanced heat transfer. At the macroscale, the flow and heat transfer of nanofluids are modeled by the nonisothermal Navier–Stokes equations under the Eulerian framework. At the microscale, the motion and thermal state of each nanoparticle are governed by a group of ordinary differential equations derived from the Newton's second law and energy balance law under the Lagrangian framework. The models at different scales are coupled together through both interaction force and thermal parameters. To reduce the cost in calculating the interaction force between the two phases, the discrete element method is used. Compared to the existing models, the primary novelties of the present model are twofold. First, the collisions between nanoparticles and between nanoparticles and solid walls are considered to count the heat migration and exchange caused by collisions. Second, the effective thermal conductivity is calculated locally, which establishes the dependence of thermal conductivity on the local spatial distribution of nanoparticles. It is no doubt that these considerations will make the new model more realistic and accurate. To solve the model efficiently, a stable, accurate and decoupled numerical solver is designed by using the finite element method and characteristic-based split scheme. Numerical results show good accuracy of the proposed model and corresponding solver. In particularly, for the nonuniform nanoparticle distribution, the new method has an incomparable advantage over other methods.

Development of hot melt extruded Polycaprolactone (PCL) matrices for an oral ultra-long-lasting delivery of Galantamine for Alzheimer’s disease therapy

Galantamine Hydrobromide (GAL) is a tertiary alkaloid, acting as a competitive and reversible cholinesterase inhibitor. It is indicated for the symptomatic treatment of patients from mild to moderate dementia level of the Alzheimer’s disease (AD) type. For treatment of mild to moderate AD, GAL is generally combined with other drugs. The purpose of this work was development and characterization of hot melt extruded (HME) matrices based on polycaprolactone (PCL) for GAL oral ultra-long-lasting delivery. PCL is biodegradable polymer, biocompatibility, water-insoluble and excellent for HME process. From HME drug and polymer mixtures arms from 1 % up to 50 wt-% of GAL were obtained. The raw materials and the as-obtained HME arms were characterized by particle size distribution (PSD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), wide angle x-ray scattering (WAXS) and dissolution test. Our findings showed that GAL possesses crystalline form I polymorphic, it is thermodynamically stable, and remains their particle and crystalline form even after HME process. Crystallization temperature of PCL increases with GAL content, indicating strong heterogeneous nucleating effect of drug on polymer crystallization process. SEM morphological analysis indicates continuous polymeric phase on surface. However, higher amounts of GAL (50/50 wt-%) presented clusters and heterogeneity, especially in extruded cross-section. It may have influenced the drug release property, decreasing the sustained release ability, due to the transport of medium molecules through the bulk extrudates by GAL soluble clusters. The diffractograms (WAXS) showed patterns peaks of GAL and PCL, indicating that GAL remains its crystalline structure and PCL recrystallized. In the dissolution test, PCL/GAL 80/20 and 90/10 achieved 100% with over seven days and profiles that can be tuned by varying GAL concentration. Finally, we demonstrate the feasibility of using HME process based on the mixture of PCL and GAL as proposals for oral therapies for conditions of AD. This is the first report showing PCL-GAL polymer matrices that achieves several-days drug release.

Influence of continuous Cu-rich phase on the deformation mechanism in as-cast CoCrFeNiCu high-entropy alloy

Influence of continuous Cu-rich phase on the deformation mechanism in as-cast CoCrFeNiCu high-entropy alloy

Effects of cross-linked/acetylated tapioca starches on the gelling properties, rheological behaviors and microstructure of myofibrillar protein gels: Perspective on molecular interactions and phase transition

The present work mainly investigated the changes of gel characteristics, rheological properties and ultrastructure of myofibrillar protein (MP) gels with varying amounts (2, 4, 6, and 8 %, w/w) of cross-linked tapioca starch (CTS) or acetylated tapioca starch (ATS). The findings showed that CTS or ATS notably improved the gelling characteristics (such as gel strength and water retention) of mixed MP gels in a dose-dependent manner (P < 0.05), which was clearly verified by the results of rheological behavior tests under different modes. Moreover, compared to ATS, CTS rendered higher gel strength and promoted the formation of a more uniform and smoother mixed MP gel matrix, which was mainly attributed to the higher peak viscosity of CTS. Furthermore, the images of iodine staining indicated that in mixed MP gels, the continuous phase supported by MP was gradually transited to being starch supported as the amounts of CTS or ATS increased between 2 % and 8 %. Additionally, hydrophobic interactions and disulfide bonds were the principal chemical forces of mixed MP gels, which could promote the occurrence phase transition. Briefly, our present work provided some vital understanding of the molecular interactions between MP and modified tapioca starches, which could efficiently modulate the quality profiles of meat products.

Continuous phase modulation technology based on grating period interval for high grating coupling coefficient and precise wavelength control.

A novel, to the best of our knowledge, grating modulation technique for distributed feedback laser arrays is proposed and demonstrated. This method modifies the initial phase within each grating period, applying a total phase shift that increments in an arithmetic progression, realizing laser arrays with channel spacings of 0.493 nm, 0.949 nm, and 1.956 nm. This method maintains a coupling coefficient comparable to traditional uniform grating structures. Furthermore, the continuous phase modulation enhances the stability of the lasing wavelength of the primary mode, reducing sensitivity to fabrication errors. This improved tolerance to manufacturing inaccuracies represents a significant technological advancement, making this approach highly promising for applications requiring precise and stable wavelength control.

The evolution of electrical, optical, and mechanical properties of CsPbBr3 perovskites during continuous phase transitions

The evolution of electrical, optical, and mechanical properties of CsPbBr3 perovskites during continuous phase transitions