Specific Interface Research Articles

Dowel-like morphology of Cu2Al3 enhances shear strength of interfacial layers in Cu-Al composites

Developing bimetallic interfaces with high interfacial bonding strength is important for metallic composites used under harsh service conditions. However, the formation of brittle intermetallic compounds is unavoidable for some interface combinations, resulting in a significant deterioration of bonding strength. In this work, we demonstrate the development of a Cu alloy/Al alloy interface with a shear strength of 126±15 MPa – a value almost twice that reported in previous studies. The exceptional interfacial bonding strength is attributed to a special interface structure, composed of brittle intermetallic compound layers connected internally by dowels of a metastable Cu2Al3 phase, achieved via alloy design and process control. During solid-liquid composite processing, a liquid diffusion layer forms at the interface between the Cu and Al alloys. A precursor Cu4Al7Ni phase then develops at the Cu side and transforms into a metastable Cu2Al3 phase with a banded structure. Finally, layers of Cu9Al4 and CuAl2 layers form, which are fully connected to the Cu2Al3 phase. The banded arrangement of the Cu2Al3 phase acts to block crack propagation and deflect cracks into the eutectic layer and Al alloy, resulting in an ultra-high interfacial bonding strength. This work demonstrates that high interfacial bonding strength can be achieved by tailoring the interface structure instead of by decreasing the interface thickness, and thus paves a new way for developing high-performance bimetallic interfaces.

Functionalization of Emulsion Interfaces: Surface Chemistry Made Liquid.

Disperse systems, and emulsions in particular, are currently massively used in fields as varied as food industry, cosmetics, health care and environmentally-friendly materials. To meet increasingly precise needs or targeted applications, these systems need to be endowed with new functionalities at their interfaces, in addition to their composition and structural properties. However, due to the fragility of drops and the low reactivity of their surface, conventional solid surface chemistry cannot be used for such a purpose. Several specific emulsion interface functionalization techniques have thus been developed for targeted systems and applications, but a general framework has yet to be drawn. In this review, we attempt to present these methods in a unified way through the prism of what we may call "liquid surface chemistry". We propose to categorize existing methods into drop-coating strategies, including layer-by-layer techniques and polymer coating, with a particular focus on polydopamine, and emulsifier-carrier approaches involving particles and/or amphiphilic molecules. They are discussed in a transversal way, highlighting the underlying physico-chemical principles and providing a comparative analysis of their advantages, current limitations and potential for improvement. We also propose future directions and opportunities, involving for instance DNA-based programmability or artificial intelligence, which could make liquid surface chemistry more versatile and controlled.

Influence of Sub-CMC Rhamnolipid Flushing on the Mobilization and Solubilization of Residual Dodecane in Saturated Porous Media

The potential of monorhamnolipid (monoRL) biosurfactant to enhance the removal of residual dodecane from a porous medium was investigated under monoRL concentration varying from sub-CMC to hyper-CMC conditions by one-dimension column experiments. In the immiscible displacement experiment, 76% of the total volume of dodecane is removed by flushing of 150 μM monoRL solution. The solubilization of dodecane could be enhanced by rhamnolipid even at monorhamnolipid concentrations as low as 50 μM/L. The higher solubilization concentration (500 μM/L) of monoRL solution results in higher solubilized dodecane concentration (160 μM/L) due to the larger quantity of micelle formation. Compared to solubilization, immiscible displacement, or mobilization, is far more effective in removing residual dodecane. The interfacial partitioning tracer tests (IPTT) method is applied to measure the variation in specific dodecane-water interface areas (Anw). The results showed that the flushing of monoRL increased the Anw from 2.04 to 3.54 cm2/cm3. This investigation implies that low-concentration monorhamnolipid flushing and subsequent micelle solubilization is an economic method to remediate NAPL-contaminated fields.

A fluorine-free bioinspired multifunctional slippery coating for ultra-long-term anticorrosion of Mg alloy, static/dynamic anti-icing, antibacterial and antifouling

Poor corrosion resistance limits the application of Mg alloy and it is meaningful to explore a surface coating technology for ultra-long-term corrosion protection of Mg alloy. Superhydrophobic surface (SHS) and smooth liquid-injected porous surface (SLIPS) have shown important application value in the field of Mg alloy corrosion protection. However, the unstable special interface of air layer or lubricant cannot act as stable corrosion barrier for the long term. Inspired by frog skin, a bionic fluorine-free multifunctional slippery coating (MSC) is prepared by one-step spraying a mixture of epoxy resin, silicone oil, modified nano TiO2 and modified micron mica powder. MSC exhibits a microstructure similar to frog skin, excellent slippery (sliding angle ∼ 3°) and strong lubricant retention. Different from anticorrosion mechanism of SHS and SLIPS by their special interface, MSC, storing silicone oil on the surface and inside the coating, demonstrates ultra-long-term anticorrosion to Mg alloy (both neutral salt spray and 3.5 wt% NaCl solution immersion for 60 days) due to excellent barrier effect throughout coating, and the scratch defect area of MSC is not significantly eroded after 14 days of salt spray. Moreover, MSC exhibits excellent static/dynamic anti-icing ability and low ice adhesion in a −20℃ environment, outstanding adhesion (level 4B), high hardness (3H), antibacterial (>94 %), antifouling, chemical stability and resistance to boiling water, ice water and UV radiation. All these excellent properties can promote the application of Mg alloy in a wider range of fields.

Modelling of high-velocity free-surface flows: a revised interfacial area approach

The specific interface area transport equation is derived from first principles, and a closure model for turbulent flow is proposed. The flow is modelled by a two-phase method providing velocities of both phases at the bubbly, spray and the intermediate large scale interface (LSI) regimes. The interface area is transported by the interface velocity – a linear combination of corresponding phase velocities and a turbulent drift velocity. The resulting equation includes the source terms due to the bubble (droplet) breakup and coalescence, and turbulent splashes at the interface. A model is proposed for the source term in the LSI regime. The model is implemented in the developer's version of the Simcenter STAR-CCM+ ® CFD code. The new model is applied to self-aerating water flows down stepped chutes; the results are in reasonable agreement with the experimental data.

The Trustworthiness Metric Model of Interface Based on Defects

The interface is a crucial element in component-based software, enabling the linkage of distinct components to facilitate interaction. Defects within the interface can significantly impact the overall trustworthiness of the system. Therefore, it is essential to assess the interface trustworthiness based on a defect-centric approach. This paper introduces a novel model for evaluating interface trustworthiness, anchored in defect analysis. First, the defect types are formalized based on interface specifications. Then, the comprehensive weight allocation method is established to characterize the importance degree of each interface defect type by combining the G1 and CRITIC methods. Subsequently, the attributes of the interface are evaluated by defect value analysis, and the trustworthiness measurement model of the interface is proposed based on these attributes. Furthermore, to evaluate the trustworthiness of the whole system, the trustworthiness measure models under different combination structure of components are established. Finally, the model’s’ applicability is demonstrated through an illustrative example. This trustworthiness evaluation from the interface view can guide interface designers to obtain high-quality interfaces and improve the trustworthiness of the entire software.

ROF-based antenna-PDM system employing DSM and DD-weight-pruning Volterra nonlinear equalization

The radio over fiber (ROF) system based on Delta-sigma modulation (DSM) can meet the requirements of the fronthaul system with its high signal fidelity and mature digital fronthaul interface specification. However, nonlinear impairments in ROF systems can seriously affect the performance of DSM signals. To reduce the impact of nonlinear effects on DSM signals with low complexity, we have designed a nonlinear equalizer based on the Volterra series. The complexity of the Volterra nonlinear equalizer (VNLE) is reduced through a weight pruning strategy. And by using directed decision instead of training sequences, we eliminate the redundancy introduced by VNLE while simultaneously ensuring its stability within the DSM system. Ultimately, we transmit one-bit single-carrier loaded DSM signals over 20 km of SMF-28 fiber and 3 m of wireless distance in an antenna polarization division multiplexing (APDM) intensity modulation and direct detection (IM/DD) system. For the first time, we add decision-directed weight-pruning Volterra nonlinear equalization (DD-PVNLE) algorithm in the APDM-IM/DD system to overcome the signal damage by the nonlinearity of the system. The BER of the Delta-sigma modulated on-off keying (DSM-OOK) signal reduces from 1 × 10−3 to 1.1 × 10−4. The high-fidelity 1024QAM, 2048QAM, and 4096QAM are recovered successfully whose BERs below the soft decision threshold 2.4 × 10−2 and hard decision threshold 3.8 × 10−3 respectively.

LIMIT: Learning Interfaces to Maximize Information Transfer

Robots can use auditory, visual, or haptic interfaces to convey information to human users. The way these interfaces select signals is typically pre-defined by the designer: for instance, a haptic wristband might vibrate when the robot is moving and squeeze when the robot stops. But different people interpret the same signals in different ways, so that what makes sense to one person might be confusing or unintuitive to another. In this article, we introduce a unified algorithmic formalism for learning co-adaptive interfaces from scratch . Our method does not need to know the human’s task (i.e., what the human is using these signals for). Instead, our insight is that interpretable interfaces should select signals that maximize correlation between the human’s actions and the information the interface is trying to convey. Applying this insight we develop Learning Interfaces to Maximize Information Transfer (LIMIT). LIMIT optimizes a tractable, real-time proxy of information gain in continuous spaces. The first time a person works with our system the signals may appear random; but over repeated interactions, the interface learns a one-to-one mapping between displayed signals and human responses. Our resulting approach is both personalized to the current user and not tied to any specific interface modality. We compare LIMIT to state-of-the-art baselines across controlled simulations, an online survey, and an in-person user study with auditory, visual, and haptic interfaces. Overall, our results suggest that LIMIT learns interfaces that enable users to complete the task more quickly and efficiently, and users subjectively prefer LIMIT to the alternatives. See videos here: https://youtu.be/IvQ3TM1_2fA .

Interface induced photoluminescence enhancement from heterojunction BaMoO4/HEAs phosphors: Experiment, theory and anti-counterfeiting application

The BaMoO4/FeCoNiCrMo (BMO/HEA(Mo)), BMO/FeCoNiCrTi (HEA(Ti)) and BMO/FeCoNiCrTiAl (HEA(Al)) phosphors were synthesized by an integrated technology. The structural characterization showed that except the main lattice phase, only the characteristic peak of high-entropy alloys (HEAs) appeared in BMO/HEAs phosphors and the existence of lattice distortion for [MoO4]2- in BMO. The microstructure analysis confirmed that there is a special interface contact between BMO and HEAs, which makes the metal in HEAs easy to have a certain connection with BMO, which causes the lattice distortion of [MoO4]2- to intensify, thus accelerating the recombination rate of charge carriers in BMO/HEAs phosphors. The BMO/HEAs phosphors have a strong emission peak at 445 nm under the excitation wavelength of 285 nm. Theoretical calculations and experiments confirmed that the luminescence of BMO/HEAs phosphor is caused by the lattice distortion of [MoO4]2-, the interface defect of BMO/HEAs and the recombination of charge carriers. The Mo in HEA(Mo) can accelerate the recombination rate of charge carriers between BMO and HEAs, thus enhancing the luminescence performance of BMO/HEA(Mo) phosphor and exhibit dynamic fluorescence anti-counterfeiting applications. However, the Ti in HEA(Ti) and Al in HEA(Al) can easily separate the charge carriers between BMO and HEAs, thus reducing the luminescence of BMO/HEA(Ti) and BMO/HEA(Al) phosphors.

Reconfigurable topological gradient metamaterials and potential applications

Elastic topological metamaterials are innovative fields of the fusion of physics and mechanics. Through novel microstructural designs, elastic topological metamaterials provide a pioneering approach to precisely manipulate elastic waves, maintaining robustness and efficiency in wave propagation even within complex environments. Recent advancements in reconfigurability and gradient features have significantly enriched the mechanical phenomena of wave manipulation, broadening the application potential of elastic topological metamaterials. In this study, we design the local resonant phononic crystal, employing a spiral support structure to ensure low-frequency characteristics and adjustable mass for flexible configuration. By utilizing the designed lattices with distinct topological phases, the topological valley edge states are constructed. The frequency and group velocity variation of the topological edge states under different stiffness and mass parameters are analyzed. Furthermore, we further constructed the mass and stiffness gradient metamaterial to analyze the transmission law of elastic waves in topological metamaterials. Additionally, the fluctuation features of the wave transmittance under disordered and impurity defects were discussed, confirming the robustness of waveguides within low-frequency topological metamaterials. Finally, we explored the potential applications of the designed metamaterials in energy localization and low-frequency reconfigurable waveguides. Numerical analysis showed that the topological gradient metamaterials can enhance the vibration energy at a specific interface, and low-frequency bend waveguide paths can be adjusted flexibly by configurable mass. In summary, this paper focuses on the low-frequency and gradient features of elastic topological metamaterials, aiming to unlock their application potential in vibrational energy harvesting, vibration suppression, and information transmission, which accelerate the practical implementation of topological metamaterials.

Impact of Wettability on CO2 Dynamic Dissolution in Three-Dimensional Porous Media: Pore-Scale Simulation Using the Lattice Boltzmann Method.

Understanding the dissolution behavior of supercritical CO2 (scCO2) in porous media is crucial for efficient CO2 storage. However, the precise modeling of dynamic dissolution behavior at this pore scale remains a huge challenge, and the impact of wettability on this process still needs to be clarified. In this study, the influence of rock wettability on CO2 dynamic dissolution in the three-dimensional porous media is investigated using the lattice Boltzmann method (LBM). The LBM is coupled with scCO2-water two-phase flow, solute transport, and heterogeneous and homogeneous reactions. The size, number, and dissolution pattern of scCO2 bubbles during the dissolution process are observed under strongly water-wet, weakly water-wet, intermediate-wet, and mixed-wet conditions. The CO2(aq) concentration and pH are investigated, followed by a quantitative investigation of the impact of wettability on the specific interface area and the mass transfer coefficient. An empirical relationship between the specific interface area and scCO2 saturation is established. The findings reveal that under weakly water-wet and intermediate-wet conditions, the sizes of scCO2 clusters and monomers are small and mostly distributed at the dead end of the pores. In contrast, under strongly water-wet and mixed-wet conditions, the clusters are larger and interconnected, and distributed in the center of the pore. This results in a greater scCO2-water interface area, consequently enhancing the dissolution rate. Furthermore, a strong linear correlation is observed between scCO2 saturation and specific interface area. It is noted that as the hydrophilicity of the rock increases, the mass transfer coefficient initially rises and then declines.

Computing Precise Control Interface Specifications

Verifying network programs is challenging because of how they divide labor: the control plane computes high level routes through the network and compiles them to device configurations, while the data plane uses these configurations to realize the desired forwarding behavior. In practice, the correctness of the data plane often assumes that the configurations generated by the control plane will satisfy complex specifications. Consequently, validation tools such as program verifiers, runtime monitors, fuzzers, and test-case generators must be aware of these control interface specifications (ci-specs) to avoid raising false alarms. In this paper, we propose the first algorithm for computing precise ci-specs for network data planes. Our specifications are designed to be efficiently monitorable —concretely, checking that a fixed configuration satisfies a ci-spec can be done in polynomial time. Our algorithm, based on modular program instrumentation, quantifier elimination, and a path-based analysis, is more expressive than prior work, and is applicable to practical network programs. We describe an implementation and show that ci-specs computed by our tool are useful for finding real bugs in real-world data plane programs.

Insights into Thermal Conductivity at the MOF-Polymer Interface.

Understanding the thermal conductivity in metal-organic framework (MOF)-polymer composites is crucial for optimizing their performance in applications involving heat transfer. In this work, several UiO66-polymer composites (where the polymer is either PEG, PVDF, PS, PIM-1, PP, or PMMA) are examined using molecular simulations. Our contribution highlights the interface's impact on thermal conductivity, observing an overall increasing trend attributable to the synergistic effect of MOF enhancing polymer thermal conductivity. Flexible polymers such as PEG and PVDF exhibit increased compatibility with the MOF, facilitating their integration with the MOF lattice. However, this integration leads to a moderated enhancement in thermal conductivity compared to polymers that remain separate from the MOF structure, such as PS or PP. This effect can be attributed to alterations in phonon transport pathways and shifts in interfacial interactions between the polymer and MOF. Specifically, the infiltration of the polymer like PEG and PVDF into the MOF disrupted the MOF's ordered network, introducing defects or barriers that hindered phonon propagation. In contrast, nonpolar and rigid polymers like PP, PMMA, PS, and PIM-1 exhibited greater improvements in thermal conductivity when combined with MOFs compared to the flexible polymers PVDF and PEG. Most notably, our analysis identifies a critical interface region within approximately 30-50 Å that profoundly influences thermal conductivity. The interface region, as indicated by the density profile and radius of gyration, is notably shorter but plays a pivotal role in modulating the thermal properties. The sensitivity of the system to these interface characteristics underscores the crucial role of this particular interface area in dictating the thermal conductivity. Our findings emphasize the sensitivity of thermal conductivity in polymer matrices to interface characteristics and highlight the critical role of a specific interface region in modulating thermal properties.

Supermind Ideator: How scaffolding Human-AI collaboration can increase creativity

Previous efforts to support creative problem-solving have included (a) techniques such as brainstorming and design thinking to stimulate creative ideas, and (b) software tools to record and share these ideas. Now, generative AI technologies can suggest new ideas that might never have occurred to the users, and users can then select from these ideas or use them to stimulate even more ideas. To explore these possibilities, we developed a system called Supermind Ideator that uses a large language model (LLM) and adds prompts, fine tuning, and a specialized user interface in order to help users reformulate their problem statements and generate possible solutions. This provides scaffolding to guide users through a set of creative problem-solving techniques, including some techniques specifically intended to help generate innovative ideas about designing groups of people and/or computers (“superminds”). In an experimental study, we found that people using Supermind Ideator generated significantly more innovative ideas than those generated by people using ChatGPT or people working alone. Thus our results suggest that the benefits of using LLMs for creative problem-solving can be substantially enhanced by scaffolding designed specifically for this purpose.

Gold nanoparticles decoration of zinc oxide nanowalls on flexible substrates

Metal oxide nanostructures decorated with noble metal nanoparticles are hybrid structures with a special interface that combines the unique properties of those two materials. Noble metal nanoparticles exhibit useful catalytic properties, and they can be functionalized with biomaterials. In this work, we use gold nanoparticles that can be functionalized using thiolated molecules bound to the metal surface. Zinc oxide nano-walls (NWs) are a high surface-to-volume ratio wide-bandgap semiconductor nanostructures that, due to their biocompatibility and non-toxicity characteristics, can be used in biosensing applications that involve contact with tissues and cells. ZnO nano-walls can be deposited from aqueous solutions at low temperatures, both on rigid and flexible substrates, using a simple and low-cost process that can be upscaled to high-volume production. In this work, we study the nucleation and growth of the ZnO nano-walls and we describe the gold nanoparticles decoration at three different schemes of surface functionalization. Among these schemes, we found that the process where ZnO nano-walls were deposited on polyimide substrates followed by activation using a self-assembled monolayer, resulted in a decoration with uniform size and distribution of gold nano-particles. That process was studied as a function of the growth temperature, solution concentration, and time. The morphology of the ZnO nano-walls was studied by Scanning Electron microscope imaging and the crystal structure was studied by X-ray diffraction.

Guardians of the aquifers: ehancing Rome’s groundwater monitoring network

This paper proposes a methodology for managing groundwater monitoring directly in the field through a specific data entry system installed on mobile devices and a relational geographic database that allows the visualization and querying of data via a specific web interface. The study area is the city of Rome, where a monitoring system of approximately 150 piezometers and wells, currently manually monitored twice a year. The proposed method uses the Enterprise cloud platform (ESRI, 2024) managed by ISPRA-SNPA, which guarantees the repository of the data collected in an online cloud system and the use of Web applications. The data of the time series of levels and chemical-physical parameters such as temperature, pH, conductivity are freely accessible through attribute tables, graphs, and viewer elements. The results highlight numerous possibilities for expanding the network of active wells, enabling the use of groundwater resources for adaptation measures to address ongoing climate change.

Multiciliated ependymal cells: an update on biology and pathology in the adult brain.

Mature multiciliated ependymal cells line the cerebral ventricles where they form a partial barrier between the cerebrospinal fluid (CSF) and brain parenchyma and regulate local CSF microcirculation through coordinated ciliary beating. Although the ependyma is a highly specialized brain interface with barrier, trophic, and perhaps even regenerative capacity, it remains a misfit in the canon of glial neurobiology. We provide an update to seminal reviews in the field by conducting a scoping review of the post-2010 mature multiciliated ependymal cell literature. We delineate how recent findings have either called into question or substantiated classical views of the ependymal cell. Beyond this synthesis, we document the basic methodologies and study characteristics used to describe multiciliated ependymal cells since 1980. Our review serves as a comprehensive resource for future investigations of mature multiciliated ependymal cells.

Effects of interfacial debonding on the stability of finitely strained periodic microstructured elastic composites.

Predicting failure initiation in nonlinear composite materials, often referred to as metamaterials, is a fundamental challenge in nonlinear solid mechanics. Microstructural failure mechanisms encompass fracture, decohesion, cavitation, compression-induced contact and instabilities, affecting their unconventional static and dynamic performances. To fully take advantage of these materials, especially in extreme applications, it is imperative to predict their nonlinear behaviour using reliable, accurate and computationally efficient numerical methodologies. This study presents an innovative nonlinear homogenization-based theoretical framework for characterizing the failure behaviour of periodic reinforced hyperelastic composites induced by reinforcement/matrix decohesion and interaction between contact mechanisms and microscopic instabilities. Debonding and unilateral contact between different phases are incorporated by employing an enhanced cohesive/contact model, which features a special nonlinear interface constitutive law and an accurate contact formulation within the context of finite strain continuum mechanics. The theoretical formulation is demonstrated using periodically layered composites subjected to macroscopic compressive loading conditions along the lamination direction. Numerical results illustrate the ways in which debonding phenomena, in conjunction with fibre microbuckling, may influence the critical loads of the examined composite solid. The sensitivity of the results obtained through the proposed contact-cohesive model at finite strain with respect to its implementation is also explored. This article is part of the theme issue 'Current developments in elastic and acoustic metamaterials science (Part 1)'.

An Implementation of Communication, Computing and Control Tasks for Neuromorphic Robotics on Conventional Low-Power CPU Hardware

Bioinspired approaches tend to mimic some biological functions for the purpose of creating more efficient and robust systems. These can be implemented in both software and hardware designs. A neuromorphic software part can include, for example, Spiking Neural Networks (SNNs) or event-based representations. Regarding the hardware part, we can find different sensory systems, such as Dynamic Vision Sensors, touch sensors, and actuators, which are linked together through specific interface boards. To run real-time SNN models, specialised hardware such as SpiNNaker, Loihi, and TrueNorth have been implemented. However, neuromorphic computing is still in development, and neuromorphic platforms are still not easily accessible to researchers. In addition, for Neuromorphic Robotics, we often need specially designed and fabricated PCBs for communication with peripheral components and sensors. Therefore, we developed an all-in-one neuromorphic system that emulates neuromorphic computing by running a Virtual Machine on a conventional low-power CPU. The Virtual Machine includes Python and Brian2 simulation packages, which allow the running of SNNs, emulating neuromorphic hardware. An additional, significant advantage of using conventional hardware such as Raspberry Pi in comparison to purpose-built neuromorphic hardware is that we can utilise the built-in physical input–output (GPIO) and USB ports to directly communicate with sensors. As a proof of concept platform, a robotic goalkeeper has been implemented, using a Raspberry Pi 5 board and SNN model in Brian2. All the sensors, namely DVS128, with an infrared module as the touch sensor and Futaba S9257 as the actuator, were linked to a Raspberry Pi 5 board. We show that it is possible to simulate SNNs on a conventional low-power CPU running real-time tasks for low-latency and low-power robotic applications. Furthermore, the system excels in the goalkeeper task, achieving an overall accuracy of 84% across various environmental conditions while maintaining a maximum power consumption of 20 W. Additionally, it reaches 88% accuracy in the online controlled setup and 80% in the offline setup, marking an improvement over previous results. This work demonstrates that the combination of a conventional low-power CPU running a Virtual Machine with only selected software is a viable competitor to neuromorphic computing hardware for robotic applications.

Heterochiral π-Stacking Dimerization of Helical Secondary Structures with Emerging Supramolecular Chirality.

A specific interface mode type was observed between helical secondary structures, in which a left-handed (M) helix binds specifically to a right-handed (P) helix along the helical axis, leading to the formation of discrete heterochiral helical dimers. Moreover, a concealed supramolecular chirality within the meso-supramolecular dimers was unexpectedly discovered by chiral induction, and was further underpinned by covalent meso-helix structures.