Conventional Structure Research Articles

Sustainable Recycling of Perovskite Solar Cells: Green Solvent‐Based Recovery of ITO Substrates

ABSTRACTPerovskite solar cells (PSCs) emerge as a leading next‐generation photovoltaic (PV) technology, with power conversion efficiencies (PCEs) reaching 26.7% for single cells and 36.1% for hybrid tandem cells. As commercialization progresses, the inverted (p–i–n) structure of PSCs gains attention due to its enhanced thermal stability, lower moisture sensitivity, and reduced processing temperatures compared to the conventional (n–i–p) structure. However, sustainability concerns, particularly regarding production costs and end‐of‐life disposal, become increasingly critical. Recycling PSCs provides a viable solution to these challenges by recovering valuable indium tin oxide (ITO) substrates, which significantly impact material costs. Existing recycling methods for conventional PSCs often use toxic solvents like chlorobenzene (CB) and N,N‐dimethylformamide (DMF), posing environmental and health risks. This study introduces an eco‐friendly recycling process for ITO‐based inverted PSCs using acetone as a green solvent. The results show that recycled ITO substrates maintain their physical, electrical, and optical properties without significant degradation in PSC performance, even after multiple recycling cycles. This green solvent‐based approach not only preserves device efficiency but also supports future environmental regulations, highlighting its potential in promoting sustainable and cost‐effective PV technologies.

A Coplanar Crystalline InGaO Thin Film Transistor with SiO2 Gate Insulator on ZrO2 Ferroelectric Layer: A New Ferroelectric TFT Structure

AbstractFerroelectric transistors with a large memory window (MW) and operational stability have been of increasing interest recently. In this study, a ferroelectric thin‐film transistor (FE‐TFT) with a novel metal‐insulator‐semiconductor‐ferroelectric (MISF) structure is proposed. With the ferroelectric layer located under the semiconductor, the TFT process can be similar to a conventional coplanar structure with a SiO2 gate insulator (GI). In this work, both FE and active semiconductors are deposited by spray pyrolysis which is beneficial for large‐area and low‐cost manufacturing. The FE ZrO2 by spray pyrolysis has a nanocrystalline phase, and the semiconductor InGaO shows a polycrystalline structure. The TFT exhibits a MW of 5.6 V with an operating voltage range of −10–10 V. The device shows a low leakage current of 10−12 A, and thus the on/off ratio is >107 at VDS = 1.0 V. The device shows stable performance with increasing temperatures up to 80 °C. The endurance of the device is 5000 cycles at 0.1 Hz pulse with a negligible variation of MW less than 0.1 V, indicating excellent operational stability.

4D printed shape memory alloy binary bits for unconventional information processing

ABSTRACT Unconventional information processing techniques leveraging advanced materials and structures have recently gained widespread attention. Bistable structures offer innovative methods for information processing due to their binary physical states, which directly correspond to electronic binary signals. However, conventional bistable structures typically require external driving elements, complicating the system. In this study, we fabricated intelligent bistable bits (IBBs) using 4D printing technology. Simulation and experimental results demonstrate that the proposed IBBs can sense environmental changes and autonomously achieve configuration transformation. Building on this, the tunable energy barriers and ‘time-sequence’ deformation properties of the IBBs are realised through simple stacking of structures and stimulation at different positions. Furthermore, this paper presents a design example of environment-responsive mechanical metamaterials based on IBBs, highlighting their potential in unconventional data storage. This work provides new insights into the design of IBBs adapted to complex environments and holds significant value for developing similar intelligent devices.

Stereolithography 3D printing gyroid triply periodic minimal surface vitrified bond diamond grinding wheel

The pores of vitrified bond diamond grinding wheel play a key role in the grinding process. However, uneven pore distribution and low porosity affect the grinding performance of the wheel significantly. Stereolithography based additive manufacturing provides an effective method to fabricate vitrified bond diamond grinding wheels with a uniform distribution and an interconnected pore structure. The key to high-performance grinding wheel via stereolithography 3D printing lies in the preparation of the slurry with high solid loading, low viscosity and uniform stability. In this study, the dispersion and stability of vitrified bond and diamond slurries were investigated systematically. The effects of resin monomers, surface modifiers, and solid loading on the dispersion, rheological behavior and stability of slurries were studied in detail. Finally, an optimal vitrified bond and diamond slurry for stereolithography based additive manufacturing was obtained, and complex-shaped gyroid triply periodic minimal surface grinding wheel were fabricated. By grinding the SiC ceramics, the material removal rate, grinding temperature, and surface roughness were compared to those achieved using a conventional solid structure grinding wheel. The results show that the gyroid porous grinding wheel can achieve better surface roughness and lower the grinding temperature.

Enhancing core loss and thermal performance for wireless EV charging with a cross-laminated core structure

This paper explores the implementation of laminated cores in inductive power transfer (IPT) systems for wireless EV charging. Two conventional structures are initially evaluated: the horizontally laminated core (H-cores) and the vertically laminated cores (V-cores). Fe-based nanocrystalline materials are applied for these structures due to their excellent core loss properties. The study introduces material modelling and loss analysis methods that combine toroidal measurements with eddy current losses from norm flux. Finite Element Method (FEM) simulations reveal that both structures experience significant flux density and thermal imbalances, creating operational challenges for IPT systems. To address these issues, a cross-laminated structure is proposed, combining the benefits of both horizontal and vertical laminations to reduce thermal imbalances. Simulation results show improved system performance, confirmed by experimental tests. Using the cross-lamination approach, the operational duration of IPT systems can be extended, and the maximum equilibrium temperature at an output current of 10 A is reduced by over 40°C, from 90.4 °C to 47.2 °C. Additionally, efficiency improves by over 0.4 % at 11.1 kW output power. This innovative core design provides a practical solution for implementing laminated cores in high-power wireless EV charging applications, enhancing efficiency and thermal performance.

Unveiling Trigonal Anti-Prismatic Structure and Stacking Sequences in InTe.

Polymorphic phases of 2D van der Waals layered materials attract significant research interest due to their diverse properties. There is a growing need to synthesize novel polymorphs and explore their atomic-level structures. In this study, molecular beam epitaxy (MBE) is used to grow indium telluride, a III-VI metal chalcogenide with promising applications, on graphene substrates. Atomic resolution scanning transmission electron microscopy reveals that the grown layers exhibit both the well-known trigonal prismatic structure and a less common trigonal anti-prismatic structure, leading to novel stacking sequences. The stability of this unconventional structure is further analyzed using density functional theory calculations, and its potential topological properties are investigated. These findings indicate that III-VI metal chalcogenides are capable of forming polymorphs with diverse symmetries and topological phases beyond their conventional structures. Furthermore, MBE proves to be a viable method for synthesizing such polymorph.

Thermal performance evaluation of a novel solar-driven pyrolysis reactor

Utilizing concentrated radiation from the sun to drive solid waste pyrolysis can address the carbon-emission issue during the heating process. This study proposed a novel directly irradiated solar-driven pyrolysis reactor with a simplified structure, consisting of alumina insulation, quartz glass tubes, and porous ceramics. The reactor's numerical model, considering the radiative heat transfer at short-wavelength radiation and long-wavelength infrared radiation, was developed for its thermal performance evaluation. The effects of operating conditions (gas inlet velocity and lamp power) and porous media structural parameters (pore size and porosity) on the reactor's thermal performance were investigated to guide the practical application of the solar-driven pyrolysis reactor. The present study also found that using SiC as a porous skeleton increased the energy absorption of porous media from 17.8 % to 30.0 % due to the higher absorptivity of SiC compared to Al2O3 for solar radiation. The findings revealed the superior thermal performance of the novel reactor structure proposed in the present study, given that the energy absorbed by the porous media was three times that of the directly irradiated reactor with a conventional structure using SiC porous ceramics. This study might broaden the solar thermal utilization pathway and offer the possibility of commercializing solar-driven pyrolysis.

Rational design of static wetting on roughness-engineered heterogeneous surfaces

Surface roughness and chemical composition are crucial in controlling the static wetting properties of surfaces. Here, conventional surface structuring methods used in Si microfabrication are used as a reference to analyze the impact of precisely engineered surface roughness. The static wettability of rough chemically heterogeneous surfaces is experimentally studied through contact angle measurements and compared against computational simulations to categorize the wetting behavior of water droplets. Heterogeneous samples are observed to already show significant dependence on the surface fraction covered by each material. Furthermore, owing to the presence of a resist layer on top of the Si pillars, intermediate states between the Wenzel (W) and Cassie–Baxter (CB) models are observed. Consistent with these models, we find that local chemical modifications of microstructured surfaces are crucial for controlling their surface wettability properties. Additionally, a comparison of equivalent microstructures made of Si or polydimethylsiloxane (PDMS) reveals the quantitative impact of the hydrophilic/hydrophobic nature of the material on the evolution of the wetting properties with increasing roughness factors. While Si surfaces behave according to the W model, PDMS surfaces show intermediate wetting states at significantly lower roughness levels. Bubbles trapped beneath water droplets demonstrate the existence of intermediate states that cannot be defined by either the W or CB models. By combining experimental results with finite element simulations, we not only demonstrate wettability control through specific roughness and chemical modifications but also provide insight into how these parameters interact to accurately predict and adjust static wetting properties.

Apocalyptic Becoming: Virus, Borders and Symbiosis in Butler’s Clay’s Ark

In Octavia E. Butler’s 1984 novel Clay’s Ark, an extraterrestrial microorganism causes transformative effects on human bodies and societies. Set against the backdrop of an impending large-scale infection, the novel deconstructs societal hierarchies faced by marginalized people. By employing Deleuze and Guattari’s generative thoughts, this paper examines different communities like enclaves, car family, and ranch to highlight how viral outbreaks catalyze significant changes. The Clayark virus functions as a vector of escape, breaking away from conventional norms and structures, and fostering the emergence of more rhizomatic communities. Haraway’s concept of “companion species” is employed to investigate the symbiotic relationship between humans and viruses, envisioning a brighter posthuman society. Butler’s writings challenge conventional science fiction clichés, examining how individuals on the margins navigate and resist systemic oppression, and presenting a symbiotic solution to transcend barriers in the apocalyptic setting.

Simplified circuit model of novel bypass diode based PV array for circulating current and power loss minimization under partial shading

Purpose This study aims to propose a new connection technique of bypass diode (BD) in photovoltaic (PV) array, which reduces the circulating current (CC) within PV modules as well as conduction loss in partial shaded condition (PSC). Design/methodology/approach Linearized circuit model of PV panel is proposed for calculating the CC and power loss of novel BD arrangements in PV array. From the analysis the best BD arrangement is applied in series parallel, TCT and honeycomb (HC) PV array structure for simulation and hardware verification. The hardware verification is performed in a 3 × 3 PV array, where individual panel capacity is 200 W. Findings The proposed BD arrangement reduces the power loss due to CC under PSC by almost 3% compared to conventional BD structure in a PV array. Originality/value The proposed BD arrangement is simple and useful in large PV power plants to reduce the CC-based extra power loss under PSC.

A SET‐tolerant StrongARM comparator with improved performance

AbstractIn this paper, a radiation hardened by design StrongARM comparator is proposed to mitigate the radiation effects. With 12 additional transistors compared to the conventional one, the proposed structure shows much higher immunity to single‐event transients. During the amplification phase, when the input differential voltage is 10 mV, the proposed structure can withstand up to 18fC free charge, 45x far surpassing the conventional structure. During the regeneration phase, every sensitive node in the proposed structure can withstand a 200 fC‐injected charge. Compared to other redundant structures with performance deterioration, the proposed architecture exhibits high‐speed characteristics. When the differential voltage between two inputs is 1 mV, the delay of the new structure is 168.26 ps and the speed improvement is 118.02% over the conventional structure.

Unit Cell Optimization of Groove Gap Waveguide for High Bandwidth Microwave Applications

Recently, groove gap waveguides (GGWs) have shown significant potential in power handling and bandwidth enhancement compared to conventional waveguides. In this research work, we designed and developed an innovative mushroom-unit-cell-based groove gap waveguide (MGGW) that has shown improved bandwidth compared to conventional GGW structures. The dispersion characteristics of the MGGW were analyzed through the eigenmode solver feature of Microwave Studio CST, which showed that the bandwidth was improved by 8% compared to conventional unit cells in the microwave spectrum. To validate our proposed method for the physical dimensions of unit cell structures, we developed an MGGW structure for the S band, which shows similar trends aligning with the simulation results. The measurement results are promising as a reflection coefficient of less than −20 dB was achieved over the entire band for the WR284 Electronic Industries Alliance (EIA) standard waveguide adapter. The proposed MGGW structure with improved bandwidth will open new doors for researchers to develop ultra-wide bandwidth microwave applications, i.e., filters, transmission lines, resonators, attenuators, etc.

THE BOLIVIAN ORGANIC QUINOA IN THE FAIRTRADE MARKET, IMPLICATIONS FOR THE WEAKEST LINK IN THE VALUE CHAIN: SMALL-SCALE FARMERS

<p><strong>Background: </strong>The fair trade model seeks to redress the imbalance of power in global supply chains. Unlike conventional trade structures, this commercial alternative purport to benefit small farmers and workers in developing countries. In the real world, however, small-scale producers are often excluded from the benefits. <strong>Objective</strong>: To analyzes organic Bolivian quinoa as a Fairtrade product and the impacts and challenges that Bolivian quinoa farmers face in the marketing chain. <strong>Methodology: </strong>A documentary analysis of the production system, application of qualitative techniques with local actors involved in the supply chain of Bolivian quinoa, and field work in regional markets were carried out. <strong>Results</strong>: The economic conditions of smallholder quinoa producers are improving under this certification system. However, global oversupply and increased competition are having a significant impact on retail prices and Bolivian sales to foreign markets. The retail price is more than a third higher than the Fairtrade price, maximizing profits at the expense of fair trade. <strong>Implications</strong>: Organic and Fairtrade certified Bolivian quinoa may not be a suitable product for the Fairtrade model. Being a landlocked country and commercial competition from Peru are the two main challenges for small quinoa producers. <strong>Conclusions</strong>: The Bolivian organic Fairtrade quinoa value chain involves several intermediaries, similar to conventional trade. Organic certification is a time-consuming and costly process because farmers cannot cover the costs. The almost non-existent governance structures imply that most decisions are based on the buyer-driven commodity chain, demonstrating the weak bargaining position of farmers. An alternative certification for small quinoa producers could be the Small Producers' Symbol label.</p>

Demonstration of a three-active-section DFB laser with photon-photon resonance and detuned loading effects to obtain enhanced bandwidth and maintained high output power

Enhancement of the modulation bandwidth of the directly modulated semiconductor laser has attracted tremendous attention for applications in optical fiber communication and optical interconnects. However, modulation bandwidth is enhanced by some special technology such as integrating the active region or passive region regularly, which lead to low power and complex fabrication. Here we design and demonstrate a monolithic integrated three-active-section distributed feedback (TAS-DFB) laser with enhanced bandwidth theoretically and experimentally. The laser includes three sections: the DFB section, feedback section and active phase section. The three sections share the same multiple quantum-well structure. To enhance the modulation bandwidth beyond the intrinsic modulation bandwidth, both photon-photon resonance (PPR) and detuned loading (DL) effects are utilized to achieve over 55 GHz. The active phase section shows promise in achieving high bandwidth with PPR and relatively high output power of ∼ 10 mW at 25 °C under continuous-wave (CW) operation simultaneously. The fabrication process of the TAS-DFB laser is simplified due to the conventional and identical active layer structure.

МАКРОСТРУКТУРА АНГЛОМОВНИХ НАУКОВИХ СТАТЕЙ УКРАЇНСЬКОГО АВТОРСТВА У ГАЛУЗІ НАУК ПРО ЖИТТЯ

The study addresses macrostructure patterns of research articles in the life sciences published by Ukrainian journals by analyzing section and subsection heading designation and ordering. The study corpus comprised 60 original research articles (RAs) written in English and published in fi ve scientifi c journals in the fi eld of biology and environmental sciences in Ukraine in 2023–2024. The headings recorded were classifi ed according to their type. Functional headings were processed quantitatively; content headings were subjected to a key word analysis. Based on section labelling, composition and ordering, their structural patterns were constructed and compared. The study revealed that the examined articles followed the conventional structuring standards based on the Introduction-Methods-Results-Discussion (IMRD) pattern. Most section headings were of the standard functional type, while subsection headings were mostly of content type. The dominant macrostructure patterns were I_Mat & M_R & D_C and I_Mat & M_R_D_C with subheadings included in the Mat & M or R&D sections. No major deviations from the international standards of research article structuring were found. Key words: research article, macrostructure pattern, section heading, sub-heading, IMRD structure.

Experimental and numerical analysis of geometry on joint strength in GFRP-aluminum alloy adhesive joints

Enhancing the bonding strength between composites and metals is one of the urgent challenges that needs to be addressed. One of the methods to improve the strength of adhesive joints is to change the geometry of the joints. In this paper, four different types of aluminum alloy sleeves were developed by designing grooves with varying angles and shapes. Glass fiber reinforced polymer rods were adhesively bonded to these sleeves, resulting in the preparation of five different types of adhesive joints, including a conventional structure. The mechanical performance and failure mechanisms of these joints were analyzed experimentally and numerically. The results indicate that, compared to conventional adhesive joints, the load-bearing capacity of the four designed adhesive joints has been significantly improved, with a maximum increase of 49.6% and a minimum increase of 35.6%. The axial angle of the groove structures designed within the joint is a factor that influences the ultimate load capacity of the joint. Furthermore, the shear stress in the adhesive layer is identified as the primary cause of adhesive layer failure. The designed mechanical interlocking structures can not only increase the interfacial bonding force between the adhesive layer and the substrate but also delay the complete failure of the adhesive layer, thereby improving the load-bearing strength of the joint. This work is expected to provide new insights for the design of composite and metal joints.

Experimental study and numerical modelling of post-tensioning systems on the transverse direction of composite steel deck-concrete structures

This study introduces the first investigation into the impact of post-tensioning layouts on the specific transverse direction of steel-deck concrete structures due to the significant limitations of current practice. The experimental work investigates the flexural capacity, structural failures, and crack characteristics of post-tensioned composite (PTC) systems using different tendon profiles and anchorage positions. Three specimens were tested under the four-point bending tests, in which one specimen employed a straight tendon and the remaining two used a profiled tendon (parabolic) with different anchorage positions. The specimens failed due to flexural failure with heavy crushing of concrete and without any damage to the steel sheeting. As compared to conventional concrete structures, the testing revealed a unique crack pattern in the composite system, with cracks initiating 90 degrees at the top edge of the ribs instead of the bottom face of the concrete. The load capacity of specimens using profiled tendon was higher by 15.2 % in the service stage and 17.3 % in the ultimate stage than that of straight tendon. The anchorage positioned at the mid-depth of the section brings the most effective placement to the PTC specimens, where the stress losses can be reduced by 2 % to 4 % and the bending stiffness increased by 4 %. The proposed finite element (FE) models of the PTC specimens were developed and validated against experimental results, ensuring the use of modelling techniques available in the software package ABAQUS.

LetsGo: Large-Scale Garage Modeling and Rendering via LiDAR-Assisted Gaussian Primitives

Large garages are ubiquitous yet intricate scenes that present unique challenges due to their monotonous colors, repetitive patterns, reflective surfaces, and transparent vehicle glass. Conventional Structure from Motion (SfM) methods for camera pose estimation and 3D reconstruction often fail in these environments due to poor correspondence construction. To address these challenges, we introduce LetsGo, a LiDAR-assisted Gaussian splatting framework for large-scale garage modeling and rendering. We develop a handheld scanner, Polar, equipped with IMU, LiDAR, and a fisheye camera, to facilitate accurate data acquisition. Using this Polar device, we present the GarageWorld dataset, consisting of eight expansive garage scenes with diverse geometric structures, which will be made publicly available for further research. Our approach demonstrates that LiDAR point clouds collected by the Polar device significantly enhance a suite of 3D Gaussian splatting algorithms for garage scene modeling and rendering. We introduce a novel depth regularizer that effectively eliminates floating artifacts in rendered images. Additionally, we propose a multi-resolution 3D Gaussian representation designed for Level-of-Detail (LOD) rendering. This includes adapted scaling factors for individual levels and a random-resolution-level training scheme to optimize the Gaussians across different resolutions. This representation enables efficient rendering of large-scale garage scenes on lightweight devices via a web-based renderer. Experimental results on our GarageWorld dataset, as well as on ScanNet++ and KITTI-360, demonstrate the superiority of our method in terms of rendering quality and resource efficiency.

High-voltage FinFET with floating poly and high-k material for enhanced intrinsic gain and safe operating area

We propose a new drain-extended FinFET (DeFinFET) that can improve the intrinsic gain (gm/gds) and the electrical safe operating area (SOA). This structure features a novel utilization of the drain potential by using a floating poly (FP) and split high-k material (HK) on the drain and drift regions. This method effectively controls the potential drop profile within the drift region, which makes a uniform electric field distribution in the gate-on state. The evenly distributed electric field significantly increases the on-state breakdown voltage (7.33 V) compared to a conventional structure (5.89 V). In addition, it prevents the device from operating in an undesirable quasi-saturation mode, even after space charge modulation. This operation distinguishes our results from other studies, showing a notable improvement in gm/gds. Moreover, electron accumulation is induced in the drift region, leading to a significant decrease in the on-resistance. As a result, the proposed device demonstrates clear advantages in high-voltage applications with a 45% expanded electrical SOA over conventional DeFinFET.

Analysis of the Radial Force of a Piezoelectric Actuator with Interdigitated Spiral Electrodes.

The actuator is a critical component of the micromanipulator. By utilizing the properties of expansion and contraction, the piezoelectric actuator enables the manipulator to handle and grasp miniature objects during micromanipulation. However, in piezoelectric ceramic disc actuators with conventional surface electrode configurations, the actuating force generated in the radial direction is relatively limited. When used as the actuation element of the manipulator, achieving regulation over a wide range of operating strokes becomes challenging. Therefore, altering the electrode structure is necessary to generate a greater radial force, thus enhancing the positioning and grasping capabilities of the operating arm. This paper investigates a piezoelectric actuator with interdigitated spiral electrodes, featuring a constant pitch between adjacent electrodes. The radial force was tested under mechanical clamping conditions, and the influence of the electrical signal was examined. The characteristics of the electrode structure were described, and the working principles of the piezoelectric actuators were analyzed. Theoretical equations were derived for the macroscopic characterization of the radial clamping force of the actuator, based on the piezoelectric constitutive equation, geometric principles, and Bond matrix transformation relationships. A finite element model was developed, reflecting the features of the electrode structure, and finite element simulations were employed to verify the theoretical equations for radial force. To prepare the samples, encircled interdigitated spiral electrode lines were printed on the PZT-52 piezoelectric ceramic disc using a screen printing method. The clamping force experimental platform was established, and experiments on the clamping radial force were conducted with electrical signals of varying waveforms, frequencies, and voltages. The experimental results show that the piezoelectric ceramic disc actuator with an interdigitated spiral electrode line structure, when excited by a stable sine wave operating at 200 V and 0.2 Hz, generated a peak force of 0.37 N. It was 1.76 times greater than that produced by a previously utilized piezoelectric disc with conventional electrode structures.