Layer Design Research Articles

Accelerating Plastic Pollution Mitigation through Sustainable Urban Infrastructure Development

Plastic waste plagues both land and aquatic environments. The surface layer refers to the road pavement layer that comes into direct contact with a vehicle's wheel surface. The surface layer distributes wheel load far more evenly than the layer underneath. The surface layer design incorporates top-notch materials that can be used as additives to enhance the quality of the asphalt mixture. This study evaluates the asphalt mixture's durability using Marshall characteristics and Cantabria tests carried out in a lab setting. An ideal asphalt concentration of 5.25% is obtained. Low Density Polyethylene (LDPE) is added to the asphalt mixture at various contents, 0%, 2%, 4%, 6%, and 8%. The study's findings indicate that adding plastic waste to the asphalt mixture can enhance its performance. The two main mitigating actions are probably plastic prohibition laws and public awareness campaigns. To evaluate the possible environmental effects and resources utilized over the course of a plastic product's life span, researchers stress the importance of its life cycle assessment and circularity. Innovations are necessary to minimize, reuse, recycle, recover, and develop environmentally friendly plastic substitutes. By empowering and educating communities and citizens on how to reduce plastic pollution and use alternative plastic solutions, governments must enforce and promote collective action. This research must prioritize addressing plastic waste as a global issue.

Design of a LiF-rich solid electrolyte interphase layer through a fluorinated carbon (CFX) complex separator for stable lithium metal batteries

The formation of a stable solid electrolyte interphase (SEI) layer is very important for improving the cycling stability and safety of lithium metal batteries (LMBs). However, since the reactivity of lithium metal anodes (LMAs) is very high, controlling the movement of Li+ at the anode/electrolyte interface remains challenging. In this study, an approach involving coating a fluorine functional-controlled fluorinated carbon (CFX) layer onto a commercial PE separator to form a stable SEI layer was proposed. The strong reaction between the fluorine functional groups constituting CFX and Li+ facilitated the rapid formation of a LiF-rich SEI layer in the resting and initial cycling stages. This initial stable SEI layer promoted a subsequent homogeneous Li+ flux, thus improving the LMA stability. In addition, the mechanism by which the total amount of fluorine and the fluorine functional groups control the Li+ dynamics through the CFX-coated PE separator with controlled fluorine functional groups was used to identify the mechanism by which the total amount of fluorine and the fluorine functional groups provide the advantage of the creation of a stable SEI layer. Therefore, this study contributes to the energy storage field by solving the cycling stability problem related to LMAs and emphasizes that a stable SEI layer can be formed based on the important interface control according to the type of fluorine functional group.

Achieving 31.16 % efficiency in perovskite solar cells via synergistic Dion-Jacobson 2D-3D layer design

Among environmental friendly energy sources solar energy is prominent one that can be harnessed via photovoltaic (PV) cells. The hybrid organic & inorganic perovskite solar cells (PSCs), have shown appealing PV performance. Halide-based perovskites (PVSK) offer several advantages, including low cost, high efficiency, and ease of fabrication. However, there are stability issues with these 3D perovskite materials. The solar device based on 2D PVSK materials are being used more and more in modern applications to address these problems. Ruddlesden-Popper (RP) & Dion-Jacobson (DJ) phases are the two main forms of 2D PVSK. These materials offer significantly greater stability compared to 3D perovskites, making them a promising alternative. In this study, we combine 2D and 3D perovskites to strengthen both reliability as well as efficiency of 3D PSCs. The present work explores the combined effect of DJ 2D-3D PVSK layers on device performance. The DJ 2D material used is PeDAMA4Pb5I16, while the 3D material is the lead-free, stable CsGeI3-xBrx (with x = 1). The optimized solar cell structure developed in this work consists of (Au/Cu2O/PeDAMA4Pb5I16/CsGeI3-xBrx/PCBM/FTO). A thorough analysis was performed on the impact of various ETLs and HTLs, as well as factors such as defect density (Nt), 2D-3D layer thickness, shallow acceptor density (NA), series (RS) and shunt resistances (RSh), and temperature variations. In the present work, PCE has significantly improved, reaching an amazing 31.16 %. Other noteworthy metrics include a JSC 22.55 mA.cm−2, FF 88.47 % and VOC 1.5617 V, all demonstrating exceptional performance. These results demonstrate the effectiveness of our approach in strengthening the efficiency and performance of DJ 2D-3D PSCs, highlighting their potential for future applications.

A Multi-scale Patch Mixer Network for Time Series Anomaly Detection

With the development of Internet of Things (IoT) technology, a large amount of data with temporal characteristics is collected and stored. How to efficiently and accurately identify anomalies from these data is a major challenge. At present, there are many problems in the application of anomaly detection, including non-stationary data, complex and difficult-to-collect anomalies, the need for real-time detection and the limitation of computing resources. But few methods can comprehensively consider these issues. To overcome these challenges, we propose a lightweight neural network, Multi-scale Patch Mixer Network (MP-MixerNet). It is mainly composed of a Mixer Block based on fully connected layer design, which contains a Temporal-Mixer and a Spatial-Mixer, and can simultaneously model the intra- and inter-series dependencies of multivariate time series. We also perform multi-scale patch segmentation based on frequency analysis, which helps the model extract robust features from multiple period views. In addition, we design an Input Stabilization module to help the model deal with data distribution shift. Experimental results on a public time series anomaly detection dataset show that we are able to achieve higher comprehensive performance with fewer parameters and inference time.

Construction and performance study of interface layer of carbon fiber/epoxy composites by electrostatic adsorption

AbstractElectrostatic adsorption was used to self‐assemble layers of polymers and nanoparticles with varying charges onto the carbon fiber (CF) surface. This process created two distinct ionic crosslinked network layers: (3‐aminopropyl) triethoxysilane‐phytic acid‐polyethyleneimine (APTES‐PA‐PEI) and (3‐aminopropyl) triethoxysilane‐phytic acid‐nano‐silica (APTES‐PA‐SiO2). Fourier transform infrared spectrophotometer (FTIR) and X‐ray photoelectron spectroscopy (XPS) were used to confirm the presence of ionic interactions. The modified carbon fibers (CFs) exhibited increased surface roughness, higher concentration of functional groups, and improved wettability. Compared to untreated CF composites, the interfacial shear strength (IFSS) and the transverse tensile strength test (TFBT) of CF‐APTES‐PA‐PEI/epoxy composites increased by 67.8% and 62%, respectively. In contrast, the IFSS and TFBT of CF‐APTES‐PA‐SiO2/epoxy composites increased by 63.3% and 52.8%, respectively. The observed strengthening is attributed to the combined effects of ionic crosslinked networks, covalent and hydrogen bonding interactions, enhanced wettability, and the relatively roughened fiber surface. The interfacial layer design approach proposed in this study is both straightforward and effective, demonstrating significant potential for functionalizing CFs. This method is expected to be adaptable for other high‐performance fibers.Highlights The ionic cross‐linked network interface layers were designed. IFSS and TFBT were significantly improved. The enhancement mechanism was elaborated.

Influence of biofilm growth on permeability evolution in gravel layers of leachate collection system: A pore-scale analysis using Darcy-Brinkman-Stokes approach

Biofilm formation within the gravel layer of leachate collection systems (LCS) poses a significant challenge by reducing permeability, potentially leading to clogging. Understanding the impact of biofilm growth on the hydraulic performance of LCS is essential for optimizing gravel layer design. This study utilized the Navier-Stokes-Brinkman equations to develop a numerical model that describes fluid flow at the pore scale within both biofilm-covered and open pore regions of the LCS gravel layer. The model was validated using previous experimental and numerical results. A geometric model of a porous network composed of randomly packed spherical particles, reflecting actual particle sizes in LCS, was then established. This model was used to investigate the evolution of the flow field and changes in permeability under varying conditions of particle size, biofilm thickness, and permeability characteristics. The results showed that increasing biofilm thickness reduced channel cross-sectional area, elevated flow velocity, increased pressure drop, and caused an exponential decrease in permeability. The study also confirmed that the permeability and porosity of the biofilm significantly influenced the extent of permeability reduction in the LCS gravel layer. Additionally, smaller particle size combinations had a more pronounced effect on permeability reduction. These findings provide valuable insights at the pore scale, helping to predict the impact of biofilm growth on gravel layer permeability in LCS and offering essential guidance for future design and management strategies.

Multiple conformal-contact transfer of large-area crack-free transition metal dichalcogenide stacks

Abstract Atomically-thin two-dimensional (2D) transition metal dichalcogenides (TMDs) have emerged as an ideal platform for both physics investigation and device applications. By stacking different layers into homo- or hetero-structures, an extra degree of freedom is involved in further tuning their properties, thereby boosting scenarios in twistronics, moiré photonics and optoelectronics. However, interfacial imperfections such as contaminations and cracks, frequently occur during the layer stacking sequence and accumulate layer by layer, greatly degenerating the interface quality. In this study, we developed a multiple conformal-contact transfer method to construct TMD stacks with crack-free intrinsic interfaces. The design of a deformable buffer layer is crucial to guarantee the conformal contact and intact transfer of each layer, contributing to the successful construction of centimetre-scale TMD stacks up to 8 layers. Precise control over spatial location and interlayer twist angle is also feasibly achieved, evidenced by the stacking-dependent interlayer exciton (IE) effects in WS2-WSe2 heterostructures. This work provides a facile and precise approach for architecting 2D stacks with perfect interfaces, which will further accelerate the customized design for their device functionalization.

Highly durable MXene-based pressure sensor enabled by homogeneous interfacial locking

Pressure sensors with linear high sensitivity and a broad response range enable the capture of subtle pressure changes across various scenarios, making them essential for accurate detection. Conventional methods typically employ porous and layered designs to boost sensitivity but they can compromise stability due to mechanical mismatches and interface incompatibilities between diverse materials. To address these issues, we propose a homogeneous interfacial locking strategy that simultaneously improves the linear response range and stability of the sensor. This approach uses aqueous polyurethane (WPU) as the interface-locking material, which matches the material properties of the substrate polyurethane (PU) sponge. This compatibility anchors the deposited MXene nanosheets to the sponge framework, establishing a robust mechanical and electrical interface. Additionally, the partial filling of the sponge’s pores with WPU enhances its mechanical compressibility. As a result, the sensor achieves high sensitivity (6226 kPa−1), a wide detection range (up to 146 kPa) and excellent durability (over 100,000 cycles), making it suitable for long-term human posture monitoring and analysis. This strategy offers a promising pathway for developing pressure sensors with high sensing performance and improved stability.

Performance of dual-band infrared photodetectors based on M-structure superlattices

Abstract The mainstream dual-band photodetector structures are complex, requiring careful design of each absorption layer, making it difficult to customize according to specific requirements. We simplified the structure and proposed an alternative design, which based on the nBn barrier structure combined with the M-structure superlattice (M-SL). With the utmost consideration for lattice matching, we have enabled tailored design and arbitrary adjustment of the absorption coefficients for both detection bands and the overall absorption characteristics as needed. This manuscript presents a series of dual-band photodetectors. The performance of these devices was simulated at 77K, with quantum efficiency exceeding 22% in the MWIR band of the MWIR-LWIR detector, and normalized detectivity reaching 1011 cm · Hz / W . Quantum efficiency in the LWIR to VLWIR bands surpasses 19%, with normalized detectivity reaching 1011 cm · Hz / W .

K/Ka‐Band–GaN–High‐Electron‐Mobility Transistors Technology with 700 mS mm−1 Extrinsic Transconductance

In this study, the impacts of fabrication technology and epitaxial layer design on the transconductance (gm) of radio frequency AlGaN/GaN high‐electron‐mobility transistors (HEMTs) are examined. Optimization of the SiNx passivation and AlGaN barrier design of 150 nm gate HEMTs enhances the extrinsic (at Vds = 10 V) and intrinsic (at Vds = 15 V) transconductance from ≈0.47/0.65 to ≈0.62/1.1 S mm−1. Notably, an extrinsic gm of 0.70 S mm−1 at Vds = 5 V is achieved, setting a new benchmark for the extrinsic transconductance of AlGaN/GaN HEMTs designed for the K/Ka frequency range with a breakdown voltage exceeding 100 V.

Improved Thermal Dissipation in a MoS2 Field-Effect Transistor by Hybrid High-k Dielectric Layers.

Transition metal dichalcogenides like MoS2 have been considered as crucial channel materials beyond silicon to continuously advance transistor scaling down owing to their two-dimensional structure and exceptional electrical properties. However, the undesirable interface morphology and vibrational phonon frequency mismatch between MoS2 and the dielectric layer induce low thermal boundary conductance, resulting in overheating issues and impeding electrical performance improvement in the MoS2 field-effect transistors. Here, we employed hybrid high-k dielectric layers of Al2O3/HfO2 to simultaneously reduce the interfacial thermal resistance and improve device electrical performance. The enhanced contact, greater vibrational phonon overlapping region, and stronger interfacial bonding force between the top Al2O3 layer and MoS2 promote the heat removal efficiency across the interface to the substrate. Under the same input power density, the temperature profile of the MoS2 transistor on the Al2O3/HfO2 has been largely reduced compared to that of the device on HfO2, with a maximum reduction of 49.5 °C. In addition, the field-effect mobility and current of MoS2 devices on the Al2O3/HfO2 high-k dielectric layers have been significantly improved, attributed to the depressed electron scattering and trap states at the interface. The design of the hybrid high-k dielectric layers provides an efficient solution to simultaneously improve the thermal and electrical performance of the two-dimensional devices.

Gaze-Contingent Layered Optical See-Through Displays with a Confidence-Driven View Volume.

The vergence-accommodation conflict (VAC) presents a major perceptual challenge for head-mounted displays with a fixed image plane. Varifocal and layered display designs can mitigate the VAC. However, the image quality of varifocal displays is affected by imprecise eye tracking, whereas layered displays suffer from reduced image contrast as the distance between layers increases. Combined designs support a larger workspace and tolerate some eye-tracking error. However, any layered design with a fixed layer spacing restricts the amount of error compensation and limits the in-focus contrast. We extend previous hybrid designs by introducing confidence-driven volume control, which adjusts the size of the view volume at runtime. We use the eye tracker's confidence to control the spacing of display layers and optimize the trade-off between the display's view volume and the amount of eye tracking error the display can compensate. In the case of high-quality focus point estimation, our approach provides high in-focus contrast, whereas low-quality eye tracking increases the view volume to tolerate the error. We describe our design, present its implementation as an optical-see head-mounted display using a multiplicative layer combination, and present an evaluation comparing our design with previous approaches.

Composition design of fullerene-based hybrid electron transport layer for efficient and stable wide-bandgap perovskite solar cells

Fullerene derivatives [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) has been routinely used as the electron transport layer (ETL) in perovskite solar cells due to its suitable energy levels and good solution processability. However, its electron mobility and conductivity still need to be further enhanced for constructing high performance perovskite solar cells (PSCs). Herein, by doping the PC61BM with a p-type polymer PM6 and n-type molecule ITIC, efficient wide-bandgap perovskite solar cells with improved efficiency and operational/storage stability are obtained. Further spectroscopy and electric measurements indicate PM6 and ITIC can both passivate defects at the perovskite/ETL interface, meanwhile ITIC can elevate the Fermi level of PC61BM to enhance conductivity and PM6 can improve the photo-induced electron mobility of the ETL, facilitating charge extraction and reducing charge recombination. As the results, Cs0.17FA0.83Pb(I0.83Br0.17)3 wide-bandgap PSCs with PM6:PC61BM:ITIC as the ETL demonstrates a superior efficiency of 22.95%, compared to 20.89% of the PC61BM assisted device.

Bimetallic coordination polymers synthesized from pyrazine dicarboxylic acid serve as efficient electrocatalysts for enhancing the oxygen evolution reaction

The pursuit of cost-effective and efficient electrocatalysts for water oxidation is crucial for various applications for the storage and conversion of electrochemical energy. Coordination polymers (CPs) have garnered significant interest as potential electrocatalysts, as their catalytic efficiency can be precisely tuned through the design of coordination layers that boast highly accessible and highly reactive metal sites. However, CP-based catalysts face substantial challenges for their application in electrocatalytic oxidation processes because of their limited activity and poor stability. In this study, we employed a mixed-metal approach to develop CoxNi1-x-PDAs incorporating two functional sites specifically designed for facilitating the oxidation of water. The presence of both Co and Ni enhances electron transport through synergistic effects within the CoxNi1-x-PDAs structure. By adjusting the metal ratios in these coordination polymers, an optimized Co3/4Ni1/4-PDA demonstrated impressive performance in water oxidation under alkaline conditions during oxygen evolution reactions, a current density of 10 mA cm−2 was achieved with an overpotential of 322 mV, along with a Tafel slope measured at 87 mV dec−1. This approach involving mixed metals seeks to exploit the synergistic effects among various metal centers, which could result in efficient electrocatalysts for the oxidation of small molecules. Our findings present a promising avenue for utilizing CPs materials within the realm of electrocatalysis.

Biaxial tubular hybrid braided structures with supreme tensile performance: Experimental and statistical assessments

Biaxial tubular braided structures are increasingly being recognized as superior alternatives to traditional materials in structural engineering due to their enhanced tensile properties and durability. In this study, the mechanical characteristics of these structures are examined, focusing on the influence of braiding angle, yarn hybridization, and layer configurations on tensile behavior. Sixteen diverse specimens, crafted from polyester and basalt yarns using a 32-carrier vertical braiding machine, are explored, incorporating variations across four braiding angles, three hybridizations, and both single and dual-layer setups. Each specimen underwent rigorous uniaxial tensile testing, revealing critical insights into the relationships between structural configuration and mechanical performance. It was found that increasing the braiding angle significantly enhances elongation, strain, and energy absorption capacities. Additionally, a higher basalt yarn content was observed to amplify tensile strength, suggesting potential for tailored structural optimization. Notably, dual-layer configurations were found to outperform single layers in tensile efficiency, underscoring the advantage of layered designs in engineering applications. A significant gap in current literature is filled by this study, as a detailed analysis of biaxial tubular hybrid braids is provided, paving the way for their informed application in advanced composite structures.

Sustainable package design for efficient pomegranate cold chain: Enhancing storage space, sea freight efficiency, material sustainability, and energy conservation

This study evaluated the performance of a novel fabricated dual layer ventilated packaging (carton) design for pomegranate fruit. The study argues that higher process throughput, storage space usage (higher cargo density) and packaging material usage can be achieved through systematic design of packaging. The mechanical strength, fruit cooling speeds, and quality preservation characteristics of the new and existing carton designs were evaluated in a controlled laboratory environment. The new carton design achieved 22 % above minimum recommended industry compression strength, confirming its stacking safety during palletization. Fruit packed inside both carton designs attained an average respiration rate of 5.66 ± 1.23 mL CO2 kg−1 h−1 during cold storage. Fruit decay incidence (average 5.5 %), colour changes and sensory attributes were also similar in both carton designs after 12 weeks cold storage and 2 weeks ambient storage period. Finally, fresh pomegranate fruit (cv. Wonderful) were packed in the new and commercial package designs, palletized, containerized and exported from South Africa to Germany. The novel dual layer design had a higher freight density (1720 kg more fruit per reefer) compared to the commercial counterpart. It also improved the precooling process throughput (13 % faster), reduced carton material usage (40 %), and reduced energy usage (13 %). These advantages of the new dual layer ventilated packaging can be implemented with considerable sustainability benefits.

Binder-free tin (IV) oxide coated vertically aligned carbon nanotubes as anode for lithium-ion batteries

Despite the tremendous potential of tin oxide (SnO2) as an anode material, irreversible capacity loss due to the sluggish kinetics and structural pulverization as a result of the substantial volume alteration during redox reactions limits its use in lithium-ion batteries. The typical layered design of an electrode consisting of binder and conductive additive can lower the practical capacity of high-capacity electrode materials. We synthesized a binder and conductive additive-free, self-standing core-shell vertically-aligned carbon nanotubes (VACNTs)-SnO2 anode (SnO2-VACNTs) on 3D nickel foam using plasma-enhanced chemical vapor deposition and wet chemical method. The SnO2-VACNTs exhibited excellent cyclability with a specific capacity of 1512 mAh g−1 at 0.1 A g−1 after 100 cycles and 800 mAh g−1 at 1 A g−1 after 200 cycles. The ultra-fine SnO2 particles (<5 nm) shortened the Li+ diffusion paths into the bulk electrode and alleviated the volume alteration by lowering the strains during the redox reactions. Also, proper inter-tube distance between individual SnO2-VACNTs buffered the volume instability and offered better electrolyte accessibility. Direct connection of VACNTs with the current collector ensured an uninterrupted electron conducting path between the current collector and active material, thus offering more efficient charge transportation kinetics at the electrode/electrolyte interfaces.

Design of electron blocking layer and its influence on the radial hole transport in GaN-based vertical cavity surface emitting laser diodes

Design of electron blocking layer and its influence on the radial hole transport in GaN-based vertical cavity surface emitting laser diodes

Influence of initial state and residual stresses on the modulus-density relationship of geomaterials: insights from multiple experimental setups

ABSTRACT Quality control in pavement construction traditionally relies on density measurements of geomaterials. With the introduction of modulus measurement methods, a shift has occurred due to the operational advantages of modulus-estimating devices over conventional density measurement techniques. Modulus-based methods also provide valuable information for the mechanistic-empirical (ME) design of pavement layers. However, a challenge emerges as a single modulus measurement does not directly correspond to a specific density measurement, leading to concerns about replacing density measurements in quality control processes. While it is generally accepted that a geomaterial's modulus primarily depends on its moisture content and density or void ratio, this study explores the complex relationship between modulus and density, particularly in field scenarios with consistent moisture content. Using three different laboratory-scale test set-ups, characterised by unique loading and boundary conditions, the research highlights the significant role of a geomaterial's initial state in obtaining accurate modulus estimates. The results reveal that identical densities can exhibit variations in modulus due to differences in initial densities and the development of residual lateral stresses. These variations in field conditions often stem from different paving or spreading techniques, emphasising the need for a comprehensive approach when establishing density-modulus correlations..

Bayesian-neural-network accelerated design of multispectral-compatible camouflage layer with wide-band microwave absorption, customized infrared emission and visible transparency

Metasurfaces with customizable multi-spectrum compatibility have attracted a great deal of attention due to the increasing applications of stealth and camouflage. Compared with single-spectrum and fixed-scene camouflage metasurfaces, a camouflage metasurface with the designability and spectral-independence can adapt to more complex environments. However, this drastically increases the design complexity and time cost of metasurfaces. Here, we propose a method to design multispectral compatible function layer of camouflage which can achieve customizable wideband microwave absorption, visible transparency and selective infrared emission, simultaneously. The design of the camouflage layer is optimized and accelerated by Bayesian-neural network, which can be implemented based on a very limited amount of prior data and can greatly reduce the design complexity and time. To verify our method, an optical-transparent metasurface with digital infrared camouflage and low backward scattering was designed and fabricated. The simulation and experimental results well demonstrate the performance of multispectral compatible camouflage of the metasurface. We further explore the angular stability of the camouflage layer to the incident angle varying from 0 to 60° at microwaves. Our proposed design scheme provides a novel method to design spectrum-individual and devisable metasurfaces, which can be applied to camouflage in complex spectrum background.