Conventional Design Research Articles

Data-enhanced design charts for efficient reliability-based design of geotechnical systems

This paper proposes a new design chart approach for reliability assessment, which enables clear visualization of the representative soil shear strength parameters under various reliability levels and effective stress levels. Utilizing the design charts, reliability assessment or reliability-based design can be performed with significantly reduced numbers of evaluations of the geotechnical system response. The design charts are established solely based on the probability distributions of soil parameters, and are applicable to a variety of geotechnical problems involving the same soil type. For practical illustration of the proposed approach, design charts are produced from the shear strength databases of saprolitic soils and colluvial soils in Hong Kong, and then applied to the reliability-based design of a slope with soil nail reinforcements. The ensuing design solutions require much fewer soil nails compared to the conventional design practice, while also achieving a better system reliability. The same charts are then applied to the reliability-based design of a retaining wall, where a series of design options are identified with equivalent reliability index against overturning failure and pullout failure. Through the proposed approach, the use of design charts promotes efficient reliability-based design of geotechnical systems with rational incorporation of reliability concepts.

Switching figure-of-merit, optimal design, and power loss limit of (ultra-) wide bandgap power devices: A perspective

Power semiconductor devices are utilized as solid-state switches in power electronics systems, and their overarching design target is to minimize the conduction and switching losses. However, the unipolar figure-of-merit (FOM) commonly used for power device optimization does not directly capture the switching loss. In this Perspective paper, we explore three interdependent open questions for unipolar power devices based on a variety of wide bandgap (WBG) and ultra-wide bandgap (UWBG) materials: (1) What is the appropriate switching FOM for device benchmarking and optimization? (2) What is the optimal drift layer design for the total loss minimization? (3) How does the device power loss compare between WBG and UWBG materials? This paper starts from an overview of switching FOMs proposed in the literature. We then dive into the drift region optimization in 1D vertical devices based on a hard-switching FOM. The punch-through design is found to be optimal for minimizing the hard-switching FOM, with reduced doping concentration and thickness compared to the conventional designs optimized for static FOM. Moreover, we analyze the minimal power loss density for target voltage and frequency, which provides an essential reference for developing device- and package-level thermal management. Overall, this paper underscores the importance of considering switching performance early in power device optimization and emphasizes the inevitable higher density of power loss in WBG and UWBG devices despite their superior performance. Knowledge gaps and research opportunities in the relevant field are also discussed.

Machine learning for nanozyme development in anti‐inflammatory applications

AbstractReactive oxygen species (ROS) play pivotal roles in diverse physiological processes, exerting a significant influence on various organ systems within the human body. Recently, there has been a notable upswing in the design of nanomaterials based on natural enzymes with the ability to scavenge ROS. These nanomaterials hold promise as potent alternatives to conventional antioxidants. However, the conventional design of these materials has often relied on empirical and trial‐and‐error methods, posing challenges in capturing the intricate conformational relationships of nanozymes. This comprehensive review aims to consolidate rational design strategies and applications of nanozymes. Primarily, it advocates for an in‐depth exploration of nanozyme mechanisms to facilitate precise design. Four rational design strategies: biomimetic design, experimental laws‐driven design, computation‐driven design, and data‐driven design are scrutinized while considering their respective advantages, disadvantages, and application conditions. The review subsequently delves into the diverse applications of nanozymes across fields such as inflammatory diseases treatment, disease diagnosis, and environmental applications. Finally, the review outlines the challenges and prospects associated with the rational design of nanozymes while providing a comprehensive overview of this burgeoning area of research.

The novel stereoscopic cooling plate designs and performance analysis for battery thermal management systems

This study explores the design and performance of liquid cooling plate-based battery thermal management system for lithium-ion battery packs through numerical simulation. We first assess traditional straight-channel cooling plates with three different placement strategies. The conventional design with bottom-mounted cooling plates demonstrates the most effective thermal management at the same total coolant mass flow rate. This suggests that the influence of reducing coolant flow velocity on the cooling performance outweighs the influence of increasing the heat exchange area under our simulated conditions. Advanced stereoscopic cooling plate structures, referred to as 3DCP-A and 3DCP-B, are then introduced, significantly enhancing battery thermal management performance. To achieve a maximum temperature difference ≤ 5.0 K for the most discharge process, the required mass flow rate of the 3DCP-B decreases by 30.0 g∙s−1 and 10.0 g∙s−1 compared to the conventional bottom-mounted cooling plate and 3DCP-A, respectively, and the pressure drop reduces by 75.9 % and 44.3 %, respectively. The power consumption for the 3DCP-B design is only 6.0 % of that for the traditional design. Finally, the effects of key operating temperatures on the cooling performance of the optimal 3DCP-B design are discussed. The insights obtained in this study provide valuable guidance for developing more efficient and effective pack-level liquid cooling plate-based battery thermal management system, essential for improving the reliability and performance of electric vehicles.

Area-Efficient Mixed-Signal Time-to-Digital Converter Integration for Time-Resolved Photon Counting.

Digital histogram generation for time-resolved measurements with single-photon avalanche diode (SPAD) sensors requires the storage of many timestamp signals. This work presents a mixed-signal time-to-digital converter (TDC) that uses analog storage to achieve an area-efficient design that can be integrated in large SPAD arrays. Fabricated using a 150 nm CMOS process, the prototype occupies an area of only 18.3 µm × 36.5 µm, a notable size reduction compared to conventional designs. The experimental results demonstrated high performance, with an integral nonlinearity (INL) of 0.35/0.14 least significant bit (LSB) and a differential nonlinearity (DNL) of 0.14/-0.12 LSB. In addition, the proposed TDC can support the construction of histograms comprising up to 512 bins, making it an effective solution to accommodate a wide range of resolution requirements. Validated in a point-of-care (PoC) device for fluorescence lifetime measurements, it distinguished between lifetimes of approximately 4.1 ns, 3.6 ns and 80 ns with the Alexa Fluor (AF) 546 and 568 dyes and Quantum Dot (QD) 705, respectively. The analog storage design and area-efficient architecture offer a novel approach to integrating TDCs in SPAD-based systems, with potential applications in medical diagnostics and beyond.

Advanced Analysis of Structural Performance in Novel Steel-Plate Concrete Containment Structures

This paper investigates the structural performance of novel steel-plate concrete containment structures, focusing on third-generation nuclear power plants. To address the challenges of increased complexities and costs associated with double-layer containment designs, this study explores the potential of steel-plate concrete structures to enhance safety, economic efficiency, and construction simplicity. The steel-plate concrete structure, characterized by its core concrete and dual steel plates, shows superior compressive strength, bending resistance, and elastoplasticity. Extensive numerical analyses, including finite element modeling and thermal-stress coupling, were conducted under various load conditions. Under structural integrity test conditions, the maximum radial displacement observed was 24.59 mm. Under design basis conditions, the maximum radial displacement was 47.61 mm; under severe accident conditions, it was 53.83 mm. The ultimate bearing capacity was 0.91 MPa, 2.17 times the design pressure. This study concludes that the steel-plate concrete containment structure maintains a high safety margin under all tested conditions, with stress and strain well within acceptable limits. It can effectively serve as a robust barrier against radioactive leakage and malicious impacts, providing a viable alternative to conventional containment designs.

Research on Aerodynamic Performance of Asynchronous-Hybrid Dual-Rotor Vertical-Axis Wind Turbines

This study analyzes the performance degradation of traditional hybrid wind turbines under high blade-tip-speed ratio conditions and proposes solutions through two-dimensional Computational Fluid Dynamics (CFD) simulations. It also introduces the design of two innovative asynchronous-hybrid dual-rotor wind turbines. The results indicate a remarkable 98.5% enhancement in torque performance at low blade-tip-speed ratios with the hybrid wind turbine model. However, as the blade-tip-speed ratio increases, it leads to negative torque generation within the inner rotor of the conventional design, resulting in a reduction of the power coefficient by up to 13.1%. The introduction of the new wind turbine design addresses this challenge by eliminating negative torque at high blade-tip-speed ratios through adjustments in the inner rotor’s operating range. This modification not only rectifies the negative torque issue but also enhances the performance of the outer rotor in the leeward region, consequently boosting the overall power coefficient. Moreover, the optimized inner rotor configuration effectively disrupts and shortens the wake length by 16.7%, with this effect intensifying as the rotational speed increases. This optimization is pivotal for enhancing the efficiency of multi-machine operations within wind farms.

Mid-infrared photodetector spectrometer concept based on ultrathin all-dielectric metamaterial with azimuth-incidence-angle tuned perfect optical absorption: Design and analysis

Novel concepts for efficient compact spectroscopy are extensively researched due to their fundamental applications in prominent fields such as chemistry, biology, and physics. Here, with an unprecedented spectral-azimuthal resolution, such a concept is introduced and exemplified in the mid-infrared, in which its advantages are paramount and have yet to be established industrially. The concept is based on the design and instrumentation of optical absorption spectral tuning (or sensitivity) to the relative azimuthal component of light impinging on specifically designed metamaterials (MMs). The inversely-designed MMs offer perfect photo-absorption inside λ0/200 ultra-thin layer of lead telluride. Two small-footprint system designs are proposed to instrument the spectral-azimuth-angle tuning for spectrometry. The first is based on a single or few spinning MM layout elements, and the second, to avoid spinning, utilizes a fixed focal-plane-array approach. The latter exploits the inherent variations in the local azimuthal-incidence angle. While low absorption is the Achilles heel of conventional mid-infrared photodetector spectrometers, the optimized MMs, besides their unique spectral-azimuth-angle tuning functionality, provide giant absorption enhancement, facilitating higher resolution and even smaller in-plane form factor. The highlighted concept opens an additional dimension to encode-decode spectral information, yielding profound advantages over conventional designs, such as those based on diffraction gratings.

Distributed beamforming design for UAV‐based integrated communication and jamming systems

AbstractThe integrated communication and jamming system is proposed by exploiting the diversity gain and flexible deployment of unmanned aerial vehicle (UAV)‐based distributed multiple input multiple output technology, which is expected to gain higher spectral efficiency and system scalability. This paper designs transmit beamforming of multiple UAVs so that they can simultaneously impose jamming signal to jamming targets and communication signal to communication users at the same frequency. The aim is to maximize the total jamming effect of all jamming targets while achieving a certain communication rate of communication users by optimizing the transmit beamforming matrices. Two cases are considered in which the UAV swarm works in clock synchronization and clock asynchronization. Specifically, the problem is formulated into a non‐convex optimization in the synchronous case. A near optimal solution is derived by decoupling the beamforming matrix into multi‐user interference suppression matrix and single‐user beamforming matrix. In the asynchronous case, the transmitter–receiver matching relation needs to consider and multiple optimization variables are highly coupled, penalty factors and intermediate variables to convert the optimization problem to convex programming are introduced. The simulation results show that the proposed beamforming design algorithm coordinates the communication and jamming signal rationally and outperforms the conventional beamforming design algorithms.

Optimizing photovoltaic thermal systems with wavy collector Tube: A response Surface-Based design study with desirability analysis

A comprehensive simulation model and predictive analysis are employed to investigate the performance of a photovoltaic thermal (PVT) system with a wavy collector tube. Response surface methodology and desirability analysis are utilized to develop a robust model that considers five critical design variables: collector wavelength, amplitude, diameter, panel width, and fluid inlet velocity. The complex interactions between these variables and their impact on the system’s energy and exergy outputs are thoroughly examined. Single and multi-objective optimization techniques are strategically applied to maximize the PVT system’s performance under various operating conditions. The results reveal that the wavy tube configuration achieves superior electrical and thermal energy efficiency compared to the conventional straight-tube design. The system’s performance is significantly enhanced by optimizing the collector amplitude, inlet velocity, diameter, wavelength, and panel width. The optimized wavy-tube PVT system demonstrates remarkable overall energy and exergy efficiencies of 85% and 14.67%, respectively, outperforming the baseline straight-tube system’s efficiencies of 72.41% and 12.72%. This research provides valuable insights into the optimal design of PVT systems and contributes to the advancement of PVT technology. The findings highlight the potential for widespread implementation of highly efficient and sustainable PVT systems in the renewable energy sector.

Full-scale evaluation of FFU configurations in an optical cleanroom injection molding for improving thermal performance and contaminant removal

Cleanrooms are critical in the semiconductor industry, particularly for optical fabrication, where even minor contamination can compromise product quality. Effective airflow and uniform airflow distribution help to prevent contaminant accumulation, mitigate temperature variations, and avoid cross-contamination, which is crucial for achieving high-quality results and compliance with industry standards. This study introduces a novel approach to optimizing Fan Filter Unit (FFU) configurations to enhance thermal performance and contaminant removal in cleanroom settings. Integrating field measurements with advanced Computational Fluid Dynamics (CFD) simulations to comprehensively evaluate four distinct FFU designs, from dispersed to centralized configurations, focused on their impact on airflow dynamics, temperature uniformity, and particle concentration. The study identifies a significant advancement in FFU configuration by demonstrating that centralized arrangements (Designs 2 and 4) substantially improve cleanroom performance. Design 4 emerged as the most effective, showcasing a marked improvement in airflow circulation, a 12 % reduction in temperature variation, and a 15 % decrease in particle concentration compared to conventional designs. This achievement underscores the novel contribution of this study in optimizing FFU configurations to enhance both thermal performance and contaminant control. These findings not only advance the theoretical understanding of FFU design but also provide practical insights for improving cleanroom environments. The study offers a significant step forward in developing efficient cleanroom designs, contributing valuable guidelines for achieving good environmental control in sensitive manufacturing processes.

Development of an innovative patch antenna design and implementation using ENG materials for health care systems and 5G networks

The object of this study is a new design of an overhead microstrip antenna, including Epsilon Negative (ENG) metamaterials and L-shaped parasitic overlays aimed at achieving dual-band operation and improving the performance of modern wireless communication systems. The research is aimed at solving the problem of limited bandwidth and dual-band functionality in conventional antenna designs. This study solves the problem of limited bandwidth and dual-band functionality in conventional microstrip patch antenna designs, which are crucial for modern wireless communication systems. The inclusion of L-shaped parasitic overlays effectively expands the bandwidth in each frequency range. The results indicate significant improvements: at the upper resonant frequency, a 10 dB return loss bandwidth of 27.84 % (2.88–3.81 GHz) and a 3 dB axial ratio bandwidth of 5.05 % (2.90–3.05 GHz) are achieved, while at the lower resonant frequency, a return loss bandwidth is 10 dB, which is 6.11 % (2.22–2.36 GHz). These improvements indicate a significant increase in antenna performance compared to conventional designs, which is confirmed by comparing the simulation results with the measurement results. Distinctive features contributing to these results include the use of ENG metamaterials, which improve electromagnetic properties and signal propagation; vertical transitions, which provide efficient dual-band operation; and L-shaped parasitic overlays, which significantly expand bandwidth. These characteristics combine to eliminate the limitations of traditional designs, which makes the proposed antenna suitable for use in a wide frequency range in modern wireless communication systems.

Precise AIE-Based Ternary Co-Assembly for Saccharide Recognition and Classification.

Saccharides are involved in nearly all life processes. However, due to the complexity and diversity of saccharide structures, their selective recognition is one of the most challenging tasks. Distinct from conventional receptor designs that rely on delicate and complicated molecular structures, here a novel and precise ternary co-assembled strategy is reported for achieving saccharide recognition, which originates from a halogen ions-driven aggregation-induced emission module called p-Toluidine, N, N'-1-propen-1-yl-3-ylidene hydrochloride (PN-Tol). It exhibits ultra-strong self-assembly capability and specifically binds to 4-mercaptophenylboronic acid (MPBA), forming highly ordered co-assemblies. Subsequent binding of various saccharides results in heterogeneous ternary assembly behaviors, generating cluster-like, spherical, and rod-like microstructures with well-defined crystalline patterns, accompanied by significant enhancement of fluorescence. Owing to the excellent expandability of the PN module, an array sensor is constructed that enables easy classification of diverse saccharides, including epimer and optical isomers. This strategy demonstrates wide applicability and paves a new avenue for saccharide recognition, analysis, and sequencing.

Three-dimensional thermal-electrochemical-hydrodynamic numerical study of vanadium redox flow battery with different flow fields and non-homogeneously compressed electrode

This paper presents a concise 3D numerical study of Vanadium Redox Flow Batteries (VRFBs) with different flow field designs and non-homogeneously compressed electrodes. The model integrates mass, momentum, charge, and energy transport equations, including reaction kinetics for vanadium species. Four flow field designs (conventional, parallel, serpentine, and interdigitated) are evaluated for heat distribution uniformity. The model accounts for non-uniform electrode properties due to compression. Numerical results are validated against experimental data, exploring the impact of operating parameters such as current density, flow rate, and temperature on thermal behavior. The study also compares heat generated by electrochemical reactions, ohmic losses, and chemical activation across different flow fields. The findings revealed the highest temperature gradient and non-uniformity (in terms of temperature) with conventional designs followed by interdigitated, parallel and serpentine. Importantly, the study consistently highlights elevated temperatures in the discharge condition across all configurations. This emphasizes the need for precise temperature control to prevent VO₂+ precipitation. These insights from VRFB optimization efforts are thoroughly presented in this paper.

Augmenting thermal performance in tubular solar stills: A multifaceted strategy with wick cords, integrated baffles, reflectors, and nano-PCM

This study investigates the enhancement of freshwater production using a modified cords wick tubular solar still (CWTSS) compared to a traditional tubular solar still (TSS). The CWTSS design increased freshwater yield by 102 % over the baseline TSS. Also, the impact of using baffles (CWTSS-B) was tested. Incorporating reflectors into the CWTSS (CWTSS-B-R) further improved performance, achieving a 201 % increase in production with reflectors and 160 % without reflectors, highlighting the significant role of reflectors in solar energy capture and distillation efficiency. Various wick cord numbers (12, 22, 32, and 42) were tested to identify the optimal configuration. The use of nanoparticle-enhanced Phase Change Material (PCM) in the CWTSS (CWTSS-PCM) resulted in a 240 % production increase compared to the TSS, demonstrating the effectiveness of PCM in thermal energy storage and management. The most significant improvement was observed in the CWTSS-fan configuration, which employed a fan and an external condenser, leading to a 256 % increase in water production, reaching 15,300 mL/m2 compared to 4300 mL/m2 for the TSS. The modified design's freshwater production cost was $0.01/L, a 50 % reduction from the conventional design's cost of $0.02/L.

Modelling climate change-induced nonstationarity in rainfall extremes: A comprehensive approach for hydrological analysis

Climate change and global warming have induced a dynamic shift in extreme rainfall patterns, leading to nonstationary behaviour. This alteration in behaviour challenges conventional hydrologic design, which assumes stationarity and can yield misleading outcomes. This study aims to address nonstationarity by modelling distribution parameters with covariates. Utilizing a 70-year (1951–2020) high-resolution India Meteorological Department (IMD) gridded dataset, extreme annual rainfall across diverse Indian cities was extracted and modelled. Previous research and goodness-of-fit tests favour the Generalized Extreme Value (GEV) distribution for modelling extremes. This study incorporates indices like Nino3.4, dipole mode index, global and local temperature, CO2, and time to characterize nonstationarity in extreme annual rainfall, leveraging climate cycles and global warming. Performance assessment employs the Akaike information criterion, Bayesian information criterion and Likelihood ratio test, while quantile reliability is evaluated through confidence intervals (CIs). Findings reveal widespread nonstationary trends in most grid points, translating to wider CIs in estimated quantiles for chosen non-exceedance probability and covariates in fitted models. Generally, nonstationary conditions are associated with broader confidence bands in return levels, highlighting nonstationary model weaknesses compared to stationary models. However, the results showed that the rainfall extremes follow a nonstationary pattern. Hence, there is a strong need to develop nonstationary models of low uncertainty.

The First Optimisation of a 16 kV 4H-SiC N-Type IGCT

A challenge in the development of Silicon carbide (SiC) gate turn-off thyristors lie in an uneven transient behaviour, necessitating expensive snubbers. To address these limitations and simplify circuit topology we present an optimized 16 kV n-type SiC integrated gate commutated thyristor (IGCT) design, which utilises a novel highly doped base strip (HDBS). A particular focus is on optimizing the gate commutation of the GCT during switching, and the trade-offs in the HDBS base design were investigated. The findings reveal that compared with conventional GCT design, the HDBS design under high current conditions recorded a 11.8% reduction in turn-off power losses. When simulating the device in a high-voltage scenario, the HDBS IGCT demonstrated a 3.9% reduction in turn-off power losses and an improved turn-on power loss performance. This resulted in a reduction of power losses by 12.1% and 2.3% in high current and high voltage conditions, respectively. In summary, the novel SiC HDBS IGCT design paves the way towards a secure, high current density, and low loss switching SiC thyristor device.

GA optimized novel design and analysis of graphene-based antennas for THz spectroscopic security applications

The proposed research paper introduces a novel design of THz graphene-based antennas capable of countering terrorism by detecting explosive materials and drugs. The research work is subdivided into three distinct sections; the initial research entails conducting a comparative analysis of conventional and genetic algorithm-based optimised designs of terahertz antennas utilising graphene material. Subsequently, three supplementary designs are evaluated in comparison to the optimum design: one integrating a copper ground with a graphene patch, another integrating a copper patch with a graphene ground, and a third incorporating both a copper patch and ground. All four optimised designs, each resonating at a frequency of 5.6 THz, are used to detect explosive compounds like Trinitrotoluene (TNT). The optimised graphene-based antenna outshines the rest of the designs in terms of radiation efficiency, with a value of 90.03 %. It also exhibits superior performance regarding S11 parameters, with a value of −53.38 dB, and VSWR, with a value of 1.004, at the resonant frequency. The optimised antenna demonstrates superior performance concerning gain (dB) and directivity (dBi), measuring 6.56 dB and 7.02 dBi, respectively. During the final phase of the proposed research, a graphene antenna was modified to function as a tri-band antenna by incorporating a 180° mirrored f-shaped slot within the antenna’s patch. The tri-band antenna functions at resonant frequencies of 3.37 THz, 4 THz, and 5.2 THz. These frequencies detect explosives and narcotics, notably l-histidine, ammonium nitrate (NH4NO3), and PETN in PE. These resonant frequencies hold the potential to be utilised in future applications of 6G technology worldwide.

A versatile electrochemical cell for in-situ GI-XRD measurements on lab-scale XRD devices

In-situ X-ray diffraction (XRD) cells for electrochemical experiments suffer from strong attenuation of primary and diffracted beams within the electrolyte solution. To reduce the intensity loss of the X-rays, the use of a thin layer of electrolyte solution is an essential element of the conventional cell design. On the other hand, the thin layer electrolyte geometry is a considerable limitation for electrochemical measurements. To overcome these drawbacks a versatile electrochemical cell for in-situ GI-XRD measurements was constructed and used for the electrodeposition of Cu2O thin films on a copper substrate.In this design, a thin copper metal film working electrode is applied on a polyimide foil and then backside-illuminated in GI-XRD geometry. In this way, the XRD pattern is measured from the electrolyte/electrode interface of the working electrode. The X-rays only have to penetrate the polymer foil and the sputtered metal layer, resulting in high-intensity signals.In this work, we demonstrate the abilities of the in-situ cell with quantitative measurements of cathodic deposition of Cu2O thin layers. The results show a good agreement between the diffracted X-ray peak intensities and the calculated and measured thicknesses of the oxide layers. The cell design allows the structural characterization of electrode surfaces during electrochemical measurements without the disadvantages of thin layer cells and therefore does not require high intensity synchrotron radiation to perform X-ray diffraction during electrochemical investigations.

Analysis of the behavior of piled foundations in unconventional soil

Building foundations using pile groups generally assume that the piles absorb the entire load of the structure. However, it is known that pile caps rest not only on the piles but also on the surrounding soil. These foundations involve great complexity in the phenomenon of load sharing, especially when they are situated on unconventional soils, such as tropical climate soils. To study this behavior, static load tests were conducted on real foundations. These tests were also used to calibrate a three-dimensional finite element numerical model (FEA-3D) using Rocscience's RS3 software. The results showed that the settlement corresponding to the allowable load of the pile groups was significantly lower, ranging from 22 % to 73 %, compared to pile caps that exert contact pressure on the soil. For pile groups, the efficiency ranged between 92 % and 109 %, while for pile caps with contact, it ranged from 132 % to 178 %. In this sense, it becomes evident that estimating the settlement of the pile group based on the conventional design, which does not consider the contact between the cap and the soil, can significantly underestimate the settlement, and provide an overly optimistic analysis of the soil-structure interaction.