General Design Research Articles

A general design framework of flexible thermoelectric devices bridging power requirements for wearable electronics

Wearable thermoelectric generators (WTEGs) promise sustainable power for wearable electronics with various strategies proposed for on-body applications. However, there is still a lack of power-demand-oriented system design that directly provides WTEG configurations tailored to targeted end electronics, resulting in sufficient power only under extreme ambience. To address this, we propose a straightforward, power-demand-oriented design framework for WTEGs that bridges the power requirements of end electronics. As we input the properties of thermoelectric materials, specific operational conditions (temperature and heat transfer coefficient), expected power output and required flexibility, the design framework can directly determine the geometric features of thermoelectric pillars and fill factor. The effectiveness has been widely verified using data from the literature, showing a mean absolute deviation of 7.1 %. This framework shows high working efficiency and significantly shortens the design process, which is the very first ever-reported design tool for WTEGs. As a case, we use the framework and design a skin-conformable thermoelectric textile (TET) with optimal structure configurations and enhanced heat transfer capabilities, achieving a high normalized power density of 4.48 μW cm−2 K−2. As expected, the TET, with a maximum power density of 231 μW cm−2 successfully powered a series of on-body electronics when attached to the forearm at a breezy ambient temperature of ∼283 K. On the other hand, the TET exhibits a cooling effect of 5.73 K. Our work provides a thermal design guide for WTEGs, shedding light on the direct connection between WTEG configurations and end electronics.

Self-Healing Materials for Bioelectronic Devices.

Though the history of self-healing materials stretches far back to the mid-20th century, it is only in recent years where such unique classes of materials have begun to find use in bioelectronics-itself a burgeoning area of research. Inspired by the natural ability of biological tissue to self-repair, self-healing materials play a multifaceted role in the context of soft, wireless bioelectronic systems, in that they can not only serve as a protective outer shell or substrate for the internal electronic circuitry-analogous to the mechanical barrier that skin provides for the human body-but also, and most importantly, act as an active sensing safeguard against mechanical damage to preserve device functionality and enhance overall durability. This perspective presents the historical overview, general design principles, recent developments, and future outlook of self-healing materials for bioelectronic devices, which integrates topics in many research disciplines-from materials science and chemistry to electronics and bioengineering-together.

Interpretable AI and Machine Learning Classification for Identifying High-Efficiency Donor-Acceptor Pairs in Organic Solar Cells.

To enhance the efficiency of organic solar cells, accurately predicting the efficiency of new pairs of donor and acceptor materials is crucial. Presently, most machine learning studies rely on regression models, which often struggle to establish clear rules for distinguishing between high- and low-performing donor-acceptor pairs. This study proposes a novel approach by integrating interpretable AI, specifically using Shapely values, with four supervised machine learning classification models, namely, support vector machines, decision trees, random forest, and gradient boosting. These models aim to identify high-efficiency donor-acceptor pairs based solely on chemical structures and to extract important features that establish general design principles for distinguishing between high- and low-efficiency pairs. For validation purposes, an unsupervised machine learning algorithm utilizing loading vectors obtained from the principal component analysis is employed to identify crucial features associated with high-efficiency donor-acceptor pairs. Interestingly, the features identified by the supervised machine learning approach were found to be a subset of those identified by the unsupervised method. Noteworthy features include the van der Waals surface area, partial equalization of orbital electronegativity, Moreau-Broto autocorrelation, and molecular substructures. Leveraging these features, a backward-working model can be developed, facilitating exploration across a wide array of materials used in organic solar cells. This innovative approach will help navigate the vast chemical compound space of donor and acceptor materials essential in creating high-efficiency organic solar cells.

Enlargement of the localized resonant band gap by using multi-layer structures

Multi-layer structures possess highly geometrically tunable optical resonances to change the surface plasmon frequencies in the wide range. A simple analytic model is presented to describe the plasmon hybridization of multi-layer metamaterial structures with multipole resonances. We theoretically demonstrate that the number of plasmon modes increases with the number of layers, which results in the enlargement of the localized resonant optical band gap. To explore the interaction between incident fields and multi-layer structures, we derive the closed-form perturbed field in terms of a generalized polarization matrix, whose dimension matches the number of layers. This enables us to obtain the eigenmode frequencies and their corresponding eigenfunctions for three-dimensional multi-layer concentric spheres and two-dimensional multi-layer concentric cylinders in a vacuum setting. These findings offer nanoscientists a general design principle that can be applied to facilitate the proper selection of the metamaterial parameters, thereby inducing the desired resonance and enabling customized applications to be realized.

A Research on Evaluating General Design of Ultra-long Tunnel Based on Pareto-optimal Weight

In tunnel engineering, the choice of general design scheme critically impacts safety, economy, and sustainability. To optimize this for ultra-long tunnels, a Pareto optimal weight-based evaluation system was developed. It encompasses design elements, construction conditions, operation risks, and economic impacts. A multi-expert decision matrix using binary language structure was built, and a three-objective Pareto model determined optimal weights. Evaluation cloud maps were generated to compare schemes, revealing the K scheme as optimal for the Tianshan Shengli Tunnel. This system offers a scientific method for tunnel design decisions, improving decision-making efficiency and quality, with significance for complex engineering problems. The application of this system helps to improve the efficiency and quality of engineering decision-making and promotes the development and innovation of tunnel engineering technology.

Generalized Interphase Design for Stabilized Li/Inorganic Electrolyte Interfaces

AbstractAll‐solid‐state Li metal batteries (ASSLMBs) using inorganic solid‐state electrolytes (ISEs) are considered promising energy storage technologies owing to their intrinsic safety and high energy density. Nevertheless, one critical challenge confronting ASSLMBs is the inability of the ISEs to prevent Li dendrite growth, which has not yet been fully addressed. Herein, general design principles of artificial solid electrolyte interphases (ASEI) for suppressing Li dendrites in ASSLMBs are proposed by systematically exploring the formation mechanism of Li dendrites. Subsequently, a tailored LiF‐Li3N ASEI is constructed to inspect the Li‐dendrite‐free design principles. The LiF‐Li3N modified Li (LFN‐Li) can effectively inhibit the side reactions and suppress the growth of Li dendrites, thus boosting the critical current densities of Li10GeP2S12 (LGPS) to a record‐high value of 3.4 mA cm−2. Furthermore, the LFN‐Li/LGPS/LFN‐Li can cycle stably for over 5000 h at 0.2 mA cm−2. Crucially, the versatility of the designed ASEI is highlighted as it ensures outstanding long‐term stability in symmetric cells featuring oxide Li1.3Al0.3Ti1.7(PO)3 or halide Li2ZrCl6 ISEs. As a result, the ASEI enables LiNi0.8Mn0.1Co0.1O2/LGPS/LFN‐Li and FeS2/LGPS/LFN‐Li cells to achieve high discharge‐specific capacities and desirable cyclic stability at room temperature. The generalized ASEI design principles rationalize the development of high‐energy ASSLBMs.

Layered double hydroxides and metal-organic frameworks for electrocatalytic CO2 reduction: A comprehensive review

Electrocatalytic carbon dioxide (CO2) reduction has emerged as a promising approach for converting CO2 into value-added products and mitigating greenhouse gas emissions. Layered double hydroxides (LDHs) and metal-organic frameworks (MOFs) have attracted significant attention as potential electrocatalysts for CO2 reduction due to their unique structural properties and tunable chemical compositions. In this review, we provide a comprehensive overview of recent advances in the utilization of LDHs and MOFs as electrocatalysts for CO2 reduction. Scrutiny on various catalysts, along with their general design ways for CO2 reduction is presented. This review will provide insight into the up-to-date research progress in MOF-based materials for CO2 conversion. Furthermore, we highlight opportunities in this field and propose future research directions aimed at optimizing the performance of LDHs and MOFs for CO2 reduction applications.

'What Happened?': Perceptions of Patients with Hypertension of Conflicting Results between Self-Reported Medication Adherence and Chemical Adherence Testing: A Qualitative Study.

To explore the perceptions of outpatients with hypertension regarding the conflicting results between their self-reported medication adherence and chemical adherence testing. An exploratory generic qualitative study design with semi-structured interviews was conducted. Thirteen adult patients being treated with antihypertensives were interviewed. Patients had a negative chemical adherence test for at least one prescribed antihypertensive, while they reported to adhere to their medication. Audio-recorded interviews were thematically analyzed. Six themes emerged: (1) becoming frustrated with medication intake, (2) being uncomfortable with addressing medication nonadherence, (3) feeling ashamed and angry about their nonadherence, (4) feeling falsely accused of nonadherence, (5) experiencing results as a wakeup call and (6) wanting to be heard and listened to. Participants reacted differently to the adherence test results. Two distinct groups were identified among the participants: the first group felt shameful, disappointed, and angry at themselves for being nonadherent; the second group felt falsely accused and rejected the adherence test results. No differences between both groups were found in their reasons for becoming frustrated with medication intake and their behavior after the adherence test results. Patients felt that communication with clinicians is key in the treatment support of patients with hypertension. Clinicians need to consider the reasons for nonadherence and the different responses of patients to the chemical adherence test results in their support to optimize treatment for patients with hypertension.

Enhancing shift current response via virtual multiband transitions

Materials exhibiting a significant shift current response could potentially outperform conventional solar cell materials. The myriad of factors governing shift-current response, however, poses significant challenges in finding such strong shift-current materials. Here we propose a general design principle that exploits inter-orbital mixing to excite virtual multiband transitions in materials with multiple flat bands to achieve an enhanced shift current response. We further relate this design principle to maximizing Wannier function spread as expressed through the formalism of quantum geometry. We demonstrate the viability of our design using a 1D stacked Rice-Mele model. Furthermore, we consider a concrete material realization - alternating angle twisted multilayer graphene (TMG) - a natural platform to experimentally realize such an effect. We identify a set of twist angles at which the shift current response is maximized via virtual transitions for each multilayer graphene and highlight the importance of TMG as a promising material to achieve an enhanced shift current response at terahertz frequencies. Our proposed mechanism also applies to other 2D systems and can serve as a guiding principle for designing multiband systems that exhibit an enhanced shift current response.

Predicting Heteropolymer Interactions: Demixing and Hypermixing of Disordered Protein Sequences

Cells contain multiple condensates which spontaneously form due to the heterotypic interactions between their components. Although the proteins and disordered region sequences that are responsible for condensate formation have been extensively studied, the rule of interactions between the components that allow demixing, i.e., the coexistence of multiple condensates, is yet to be elucidated. Here, we construct an effective theory of the interaction between heteropolymers by fitting it to the molecular dynamics simulation results obtained for more than 200 sequences sampled from the disordered regions of human proteins. We find that the sum of amino acid pair interactions across two heteropolymers predicts the Boyle temperature qualitatively well, which can be quantitatively improved by the dimer pair approximation, where we incorporate the effect of neighboring amino acids in the sequences. The improved theory, combined with the finding of a metric that captures the effective interaction strength between distinct sequences, allowed the selection of up to three disordered region sequences that demix with each other in multicomponent simulations, as well as the generation of artificial sequences that demix with a given sequence. The theory points to a generic sequence design strategy to demix or hypermix thanks to the low-dimensional nature of the space of the interactions that we identify. As a consequence of the geometric arguments in the space of interactions, we find that the number of distinct sequences that can demix with each other is strongly constrained, irrespective of the choice of the coarse-grained model. Altogether, we construct a theoretical basis for methods to estimate the effective interaction between heteropolymers, which can be utilized in predicting phase separation properties as well as rules of assignment in the localization and functions of disordered proteins. Published by the American Physical Society 2024

Symmetric optical multipass matrix systems and the general rapid design methodology

We proposed an original type of multipass cell named symmetric optical multipass matrix system (SMMS), in which the same matrix patterns of various sizes can be formed on both sides. According to its special symmetric configurations, the SMMS design problem is modeled as a variant of the classical traveling salesman problem, which can be rapidly solved by evolutionary optimization algorithms. Two sets of 3-mirror SMMSs are designed, analyzed and built, which show superior characteristics of high stability, desirable beam quality and adjustable optical path lengths. Additionally, they can support simultaneous detection of multiple species with multi-laser channels. The proposed method is further extended to design a 4-mirror SMMS, which verifies the universality and robustness of the design methodology. The experimental observations are in consistent with the theoretical calculations. The newly proposed SMMSs have a broad application prospect in trace gas measurement.

Skin-inspired interlocked microstructures with soft-hard synergistic effect for high-sensitivity and wide-linear-range pressure sensing

Flexible pressure sensors have shown great application potential in intelligent robotics, healthcare monitoring, and human–machine interfaces. However, critical challenge exists in reconciling the trade-off between high sensitivity and wide linear sensing range. Here, inspired by the delicate microstructures of human skin, a piezoresistive pressure sensor with soft-hard synergistic interlocked (SHSI) microstructures is proposed to enhance the sensitivity while maintaining broad linear sensing range. The proposed SHSI sensor is face-to-face assembled by a soft sensing layer with spinosum microstructures and a hard interdigital electrode layer with dome microstructures. The design of SHSI microstructures enables efficient mechanical stimulus amplification and consistent compressibility of the sensor under pressure. Consequently, the as-prepared SHSI sensor simultaneously exhibits a maximum sensitivity as high as 67.1 kPa−1 and a wide linear working range up to 650 kPa. Meanwhile, low limit of detection (7 Pa), fast response (40 ms) and recovery (37 ms), as well as prominent stability and durability over 10,000 cycles of the sensor are realized. Owing to these outstanding sensing performances, the successful applications of the SHSI sensor in physiological signal monitoring and wearable human–machine interfaces are demonstrated. This work offers a general design approach to achieve coordination of high sensitivity and broad linear range of flexible pressure sensors.

General Adaptable Design and Evaluation Using Markov Processes

Abstract Facing the challenges posed by increasingly complex, dynamic, and unforeseen requirements, the design process is grappling with the critical issue of ensuring sustained product satisfaction amid changing demands. This paper introduces an approach for evaluating design adaptability, considering potential future requirements. Entropy serves as a crucial indicator to quantify design effort and the Markov process is employed to simulate potential requirement changes. The information contents of design requirements and design solutions are defined based on information entropy theory, and the design adaptability of a design candidate is evaluated by calculating the extra design effort for satisfying the design requirements, which is the difference in information content between the design candidate and design requirements. Moreover, a simulation method for requirement evolution is proposed, which integrates information entropy theory and the Markov process to accommodate potential future requirements. The general design adaptability of design solutions is then calculated based on conditional entropy, taking into account the evolving design requirements. Finally, the effectiveness of the proposed approach is validated through a case study involving the design and evaluation of a hybrid additive manufacturing device.

Lifting relations for a generalized total-energy double-distribution-function kinetic model and their impact on compressible turbulence simulation

Recently, Qi et al. (2022) and Guo et al. (2023) proposed two alternative designs of an efficient mesoscopic method using the total-energy double-distribution-function (DDF) formulation, hereafter referred to as the Qi model and the Guo model. The two models share the same advantage of using only 40 discrete particle velocities to fully reproduce the Navier–Stokes-Fourier (NSF) system. However, the Guo model is based on a more rigorous kinetic consideration, while the Qi model relies on a more general design of the source term to allow for adjustable bulk-to-shear viscosity ratio. In this paper, we derive lifting relations for the Qi model based on two alternative approaches, namely, the Hermite expansion and the Chapman–Enskog expansion, which can be used to construct the boundary and initial conditions for the mesoscopic method. For three-dimensional compressible turbulence simulations, including compressible decaying homogeneous isotropic turbulence and Taylor–Green vortex flows, the derived two sets of lifting relations are applied to the initialization distribution function to study their impacts. Interestingly, for the Qi model, the two sets of lifting relations yield the same results without numerical artifacts, whereas for the Guo model, an appropriate lifting relation must be specified to avoid numerical artifacts resulting from the flow initialization (Qi et al., 2023).

End-rotation-driven kinetic elastica structures: Concept and morphology design

Euler’s elastica, a family of planar curves describing the equilibrium shapes of a thin elastic beam subjected to end forces and moments, demonstrates both geometric versatility and mechanical functionality, leading to its diverse applications across multiple disciplines. Despite its roots in ancient structural engineering practices, the kinetic potential of Euler’s elastica remains largely unexplored in this domain. To address this gap, this paper proposes the concept of end-rotation-driven kinetic elastica (ERKE) structures. This novel kinetic form consists of a sequence of discrete elastica arches transformed from initially straight members by elastic bending. The kinetic behavior arises from manipulating the end rotations of each elastica arch, prompting a continuous flow of motions resulting from adaptations in the arch shape. This adaptive quality opens up limitless possibilities for creating visually captivating dynamic patterns in the overall structure by coordinating the motions of individual arches. As the inaugural exploration of ERKE structures, this paper centers around their conceptualization, with an emphasis on morphology design, which refers to the creation of desirable dynamic patterns. To this end, the paper provides an exposition of the general design procedure and criteria, along with demonstrative examples. The paper also envisions potential application scenarios and identifies research needs, paving the way for future investigations.

Accessibility, Usability, and Universal Design for Learning: Discussion of Three Key LX/UX Elements for Inclusive Learning Design

In this paper, we aim to provide readers with three critical concepts that can maximize inclusivity of learner experience (LX) and user experience (UX) design: accessibility, usability, and universal design for learning (UDL). Although recent K-12 and postsecondary education have experienced rapid change in its student population with the growing awareness of the equal opportunities for all, general design methods of addressing such diversity across formal and informal learning contexts are still prone to retrofitted changes to predefined instructions in favor of standardization. This is due in part to the limited interpretation of accessibility as the concept for the medical model of disabilities where learners with disabilities are not regarded as users or consumers, but as clients or patients. Moreover, LX and UX have been widely designed with the usability of dominant group in mind while trading off exclusion of those who cannot fit themselves into it. However, accessibility and usability are not mutually exclusive; rather, a truly inclusive learning design (i.e. UDL) comes from the interplay between them. Through the paper, we provide definition and description of each concept and provide practical examples of how UDL principles can be applied to inclusive learning design.

Flexible generation of structured terahertz fields via programmable exchange-biased spintronic emitters

Structured light, particularly in the terahertz frequency range, holds considerable potential for a diverse range of applications. However, the generation and control of structured terahertz radiation pose major challenges. In this work, we demonstrate a novel programmable spintronic emitter that can flexibly generate a variety of structured terahertz waves. This is achieved through the precise and high-resolution programming of the magnetization pattern on the emitter’s surface, utilizing laser-assisted local field cooling of an exchange-biased ferromagnetic heterostructure. Moreover, we outline a generic design strategy for realizing specific complex structured terahertz fields in the far field. Our device successfully demonstrates the generation of terahertz waves with diverse structured polarization states, including spatially separated circular polarizations, azimuthal or radial polarization states, and a full Poincaré beam. This innovation opens a new avenue for designing and generating structured terahertz radiations, with potential applications in terahertz microscopy, communication, quantum information, and light-matter interactions.

Numerical study of low‐rise composite steel frame responses to blast loading using direct simulation method

AbstractThis paper investigated the blast behavior of a low‐rise composite steel structure of three stories subjected to internal and external explosions for the same explosive charge of 250 kg TNT. A comparison of three various blast scenarios is aimed at better understanding how blast waves propagate in confined risk zones and their damage effects on far and exposed elements to an explosive charge. Evaluation of the damage level and the overall response of the proposed numerical model is done by estimating the adequacy of structural members subjected to blast loading using general limits in attempting to check the structure's strength and regularity. The analysis was based on load combinations and damage criteria according to the Unified Facilities Criteria which are general design approaches suitable for civil design applications in forecasting blast loads and structural system responses. The overall behavior of this structure was simulated based on a dynamic analysis by the direct simulation approach, which was chosen for modeling blast loads using the Friedlander blast load equation, and the simpler, less expensive, more accurate, and realistic A.T.‐BLAST model to deduce the simplified blast‐wave overpressure profile. The material nonlinearity at a high strain rate using the Johnson‐Cook strength and concrete plasticity damage model is studied dynamically using ABAQUS finite element code to simulate the explicit dynamic nonlinear analysis. The overall response of the proposed numerical model was evaluated by estimating the adequacy of structural members, considering the blast load as the initial cause of failure, such as axial plastic strain, internal forces limits, maximum deformation, support rotation, demand‐capacity‐ratio (DCRshear/moment), drift index and material damage model. The position of the explosive charge played an important role in determining the rate at which the structural element begins to plastic strains, displacements, moments, or rotations beyond the limits, and then key elements should be considered in structural design against progressive collapse. Results showed that steel members exhibit early indicators of failure, such as buckling necking, shear tearing, or plastic hinges, whereas concrete slabs break up immediately due to brittleness. DCRmoment values successfully showed the columns in which the first plastic joint can occur, whereas DCRshear values signaled the onset of shear failure at connections. Besides, plastic hinges played an important role in dissipating energy and preventing total structural collapse via the Strong Column‐Weak Beam design concept, which appears repeatedly in this study. The structure is a well‐designed and ductile building capable of supporting higher loads and is considered to be repairable and intact.

Influence of the Bis-Carbene Ligand on Manganese Catalysts for CO2 Electroreduction.

First row transition metal complexes have attracted attention as abundant and affordable electrocatalysts for CO2 reduction. Manganese complexes bearing bis-N-heterocyclic carbene ligands defining 6-membered ring metallacycles have proven to reduce CO2 to CO selectively at very high rates. Herein, we report the synthesis of manganese carbonyl complexes supported by a rigid ortho-phenylene bridged bis-N-heterocyclic carbene ligand (ortho-phenylene-bis(N-methylimidazol-2-ylidene), Ph-bis-mim), which defines a 7-membered ring metallacycle. We performed a comparative study with the analogues complexes bearing an ethylene-bis(N-methylimidazol-2-ylidene) ligand (C2H4-bis-mim) and a methylene-bis(N-methylimidazol-2-ylidene) ligand (CH2-bis-mim), and found that catalysts comprising a seven-membered metallacycle retain similar selectivity and activity as those with six-membered metallacycles, while reducing the overpotential by 120-190 mV. Our findings reveal general design principles for manganese bis-N-heterocyclic carbene electrocatalysts, which can guide further designs of affordable, fast and low overpotential catalysts for CO2 electroreduction.

Mechanical response of 3D printed irregular sutural tessellations with Voronoi tile patterns under tension

The mechanical response of bio-inspired irregular sutural tessellations with Voronoi tile patterns are designed and fabricated via multi-material 3D printing. The effective mechanical properties of the designs were characterized via uni-axial tension mechanical experiments on the 3D printed specimens. Systematic nonlinear finite element simulations are conducted to explore the damage initiation and evolution of the designs. The influences of important design parameters, including tile length aspect ratio R, tile size irregularity Cstd, suture amplitude irregularity Astd, and stiffness ratio between the soft and hard phases, were evaluated. The effective stiffness, Poisson’s ratio, strength, toughness, and failure mechanisms are systematically quantified. The results demonstrate that an optimized level of suture irregularity exists for maximizing the modulus of toughness. The results provide a general design guideline for designing functionally graded two-phase tessellations with high mechanical performance.