Fundamental Design Research Articles

Recent Progress on Multifunctional Electrolyte Additives for High‐Energy‐Density Li Batteries – A Review

AbstractThe improvement of the safety, specific energy, cycle life and the cost reduction of Li‐ion batteries are hot research topics. Now, in the pursuit of high energy density, the employed high‐energy‐density cathode/anode materials and the increased operation voltage challenge the prevalent electrolyte formula, like the existing ester and ether electrolytes cannot withstand the high‐voltage operation and high‐capacity anode such as lithium (Li), silicon (Si) and silicon‐graphite (Si−C) composite anode. It is recognized that stable electrolyte‐electrode interfaces can avoid the electrolytes side reactions and protect the electrode materials. Up to now, various additives have been developed to modify the electrode‐electrolyte interfaces, such as famous 4‐fluoroethylene carbonate, vinylene carbonate and lithium nitrate, and the LIBs and lithium metal batteries (LMBs) performances have been improved greatly. However, the lifespan of the higher‐energy‐density batteries with Li/Si/Si−C anode and high‐nickel layer oxides cathode materials cannot meet the request due to the lack of ideal electrolyte formula. In this review, we present a comprehensive and in‐depth overview on the electrolyte additives, especially focused on multifunctional additives, the reaction mechanisms of various additives and fundamental design. Finally, novel insights, promising directions and potential solutions for the multifunctional electrolyte additives are proposed to motivate high‐energy‐density Li battery chemistries.

Principles and Design of Biphasic Self‐Stratifying Batteries Toward Next‐Generation Energy Storage

AbstractLarge‐scale energy storage devices play pivotal roles in effectively harvesting and utilizing green renewable energies (such as solar and wind energy) with capricious nature. Biphasic self‐stratifying batteries (BSBs) have emerged as a promising alternative for grid energy storage owing to their membraneless architecture and innovative battery design philosophy, which holds promise for enhancing the overall performance of the energy storage system and reducing operation and maintenance costs. This minireview aims to provide a timely review of such emerging energy storage technology, including its fundamental design principles, existing categories, and prototype architectures. The challenges and opportunities of this undergoing research topic will also be systematically highlighted and discussed to provide guidance for the subsequent R&D of superior BSBs while conducive to bridging the gap for their future practical application.

Principles and Design of Biphasic Self-Stratifying Batteries Toward Next-Generation Energy Storage.

Large-scale energy storage devices play pivotal roles in effectively harvesting and utilizing green renewable energies (such as solar and wind energy) with capricious nature. Biphasic self-stratifying batteries (BSBs) have emerged as a promising alternative for grid energy storage owing to their membraneless architecture and innovative battery design philosophy, which holds promise for enhancing the overall performance of the energy storage system and reducing operation and maintenance costs. This minireview aims to provide a timely review of such emerging energy storage technology, including its fundamental design principles, existing categories, and prototype architectures. The challenges and opportunities of this undergoing research topic will also be systematically highlighted and discussed to provide guidance for the subsequent R&D of superior BSBs while conducive to bridging the gap for their future practical application.

Machine learning-based modelling, feature importance and Shapley additive explanations analysis of variable-stiffness composite beam structures

In the current work, the displacement and inner stress state of orthotropic, composite, variable-stiffness beam structures is investigated, combining the extended Kantorovich method (EKM) with machine learning (ML) modeling and explainable artificial intelligence (AI) techniques. The complete displacement and inner stress fields of variable stiffness (VS) composite beams with a through-thickness variation of their material properties are computed for different orthotropy, material gradation and slenderness attributes. Both deep learning and tree-based machine learning architectures are considered, identifying high accuracy and low computational cost modeling architectures. Thereupon, the significance of underlying fundamental design features is assessed, classifying their importance for the first time. In particular, material orthotropy, stiffness gradation and slenderness are analyzed for different boundary conditions, elucidating their interdependence and relative significance. It is shown that reduced end kinematic constraints overall favor the importance of stiffness gradation. Differences in the importance of each design feature for the transverse displacement and inner normal and shear stress fields are identified and quantified using Shapley additive explanations (SHAP) analysis. It is found that material orthotropy is more important than stiffness gradation for the transverse displacement rather than for the normal or shear stress fields developed, for which their relative importance is inverted. What is more, evidence is provided that increased gradation and orthotropy values have opposite signed contributions to the stress fields developed at critical positions of the VS composite, while they uniquely yield equal-signed contributions to the transverse displacement field.

A methodological framework for rigorous systematic reviews: Tailoring comprehensive analyses to clinicians and healthcare professionals

Systematic reviews represent a fundamental study design, providing the highest level of evidence across diverse research inquiries, encompassing both public health and clinical research and practice. However, for healthcare professionals, the process of selecting, synthesizing, and interpreting evidence can be challenging, and requires specialized skills. Therefore, it is imperative to explore innovative solutions aimed at simplifying and making the traditional systematic review process more accessible while ensuring the validity and reliability of results.In this perspective, our research objective is to develop a systematic review framework that, while maintaining a rigorous methodological approach, streamlines the process for healthcare professionals. This study describes such approach in every phase, from the collection of evidence to the writing of the text, creating a guide for the healthcare professional who approaches this type of research. The qualitative and organizational analysis tools are also described, providing useful information for the use of non-paid programs.This systematic review aims to develop a framework with a rigorous methodological approach that allows simplify the process for clinicians and healthcare professionals. The implementation of this methodology in clinical practice offers new perspectives to ensure a thoughtful consideration and application of scientific evidence and opens the way to innovative and easily accessible solutions to facilitate the conduct of systematic reviews in the clinical care setting.

MorphGI: A Self-Propelling Soft Robotic Endoscope Through Morphing Shape.

Colonoscopy is currently the best method for detecting bowel cancer, but fundamental design and construction have not changed significantly in decades. Conventional colonoscope (CC) is difficult to maneuver and can lead to pain with a risk of damaging the bowel due to its rigidity. We present the MorphGI, a robotic endoscope system that is self-propelling and made of soft material, thus easy to operate and inherently safe to patient. After verifying kinematic control of the distal bending segment, the system was evaluated in: a benchtop colon simulator, using multiple colon configurations; a colon simulator with force sensors; and surgically removed pig colon tissue. In the colon simulator, the MorphGI completed a colonoscopy in an average of 10.84 min. The MorphGI showed an average of 77% and 62% reduction in peak forces compared to a CC in high- and low-stiffness modes, respectively. Self-propulsion was demonstrated in the excised tissue test but not in the live pig test, due to anatomical differences between pig and human colons. This work demonstrates the core features of MorphGI.

Design and analysis of hetero-dielectric Junctionless-TFET(JL-TFET) with N+ pocket as label free biosensors

This paper includes sensitivity assessment of label-free biosensors using hetero dielectric Junctionless-TFET (HD-JL-TFET) thorough TCAD simulator. The fundamental structure, operation and design of a Junctionless-TFET (HD-JL-TFET) as biosensor are investigated in this paper. For the purpose of detecting the biomolecule, a nano-gap is added close to the source end between the gate and channel. To test the sensing potential, we adjusted the charge density and material dielectric constant (K) by comprehensive calibrated device simulation. For several biomolecules, the device’s sensitivity was examined as surface potential, electron tunnelling rate, and conduction-valence band edge fluctuation. Additionally, the Id versus VGS features, the sensitivity to the drain current, and the ION/IOFF fluctuation are also examined. By contrasting neutral or charged biomolecules using various dielectric constants, the sensitivity characteristics of positive, negative, and neutral biomolecules are examined. The development of biosensors, which enable the rapid and precise detection of multiple biomolecules, has revolutionized the field of bioanalysis.

Limousine: Blending Learned and Classical Indexes to Self-Design Larger-than-Memory Cloud Storage Engines

We present Limousine, a self-designing key-value storage engine, that can automatically morph to the near-optimal storage engine architecture shape given a workload, a cloud budget, and target performance. At its core, Limousine identifies the fundamental design principles of storage engines as combinations of learned and classical data structures that collaborate through algorithms for data storage and access. By unifying these principles over diverse hardware and three major cloud providers (AWS, GCP, and Azure), Limousine creates a massive design space of quindecillion (1048) storage engine designs the vast majority of which do not exist in literature or industry. Limousine contains a distribution-aware IO model to accurately evaluate any candidate design. Using these models, Limousine searches within the exhaustive design space to construct a navigable continuum of designs connected along a Pareto frontier of cloud cost and performance. If storage engines contain learned components, Limousine also introduces efficient lazy write algorithms to optimize the holistic read-write performance. Once the near-optimal design is decided for the given context, Limousine automatically materializes the corresponding design in Rust code. Using the YCSB benchmark, we demonstrate that storage engines automatically designed and generated by Limousine scale better by up to 3 orders of magnitude when compared with state-of-the-art industry-leading engines such as RocksDB, WiredTiger, FASTER, and Cosine, over diverse workloads, data sets, and cloud budgets.

Lightweight verifiable blockchain top-[formula omitted] queries

Blockchain has been exploited in many applications as a fundamental technology to construct trust and share data among multiple participants. A user with limited resources who runs a light node fetches data records stored on the blockchain by requesting a full node that maintains the complete blockchain data. As a type of broadly used query, top-k queries which ask for data records with the highest k values in a certain region can be useful in many blockchain scenarios. However, untrusted full nodes may return incorrect top-k results. In this paper, we take the first step toward addressing the problem of verifiable blockchain top-k queries without the help of a trusted third-party. First, we design a novel Sorted Merkle tree-based authenticated data structure and based on it we propose a new index named inverted SMT index that supports verifiable top-k query with specific keyword conditions. Second, we propose a fundamental strawman design to support verifiable blockchain top-k queries with arbitrary query regions. We further introduce two improved schemes, named segmentation design and sliding-window design, that overcome the efficiency obstacle of the strawman design. Finally, we confirm the efficiency of our solutions through an extensive experimental evaluation.

“The Beauty of Homes Beautiful Collectively”: The Olmsted Firm and the View from the Suburban House

Abstract The landscape architects Frederick Law Olmsted and his sons John Charles and Frederick Jr. changed the prevailing understanding of the view from the suburban home. Historically, such vistas reflected a sense of isolation in nature, an experience that the early suburban communities of the nineteenth century attempted to replicate. In contrast, the elder Olmsted, in his first suburban design, posited the need for the neighborhood to be visible and distinguishable from the houses; it would form the foreground of views into more distant landscapes. This article examines the lineage of this vista and how Frederick Law Olmsted’s sons, through their firm Olmsted Brothers, later came to replicate it systematically in their suburban projects. A comparison with possible antecedents of this particular view shows that the Olmsteds not only made it a fundamental design factor but also endowed it with ethical and aesthetic qualities.

Investigation on the Compressive Characteristics and Optimization of Design Parameters of a Novel Functionally Graded Cell Structure

Novel structural conceptualizations frequently incorporate inventive ideas, materials, or construction techniques. This study presents a unique design inspired by the traditional practice of sikku rangoli, a cultural tradition prevalent in the southern region of India, particularly in Tamil Nadu. Because it was novel, it was necessary to optimize the fundamental design for maximal outputs. In contrast to honeycomb structures, intercellular interactions are believed to contribute to the overall strengthening of the structure. By eliminating sharp corners from the structure, stress accumulation is prevented, resulting in improved stress distribution. Therefore, the design aspects that were deemed significant were taken into consideration and through the implementation of experimental design, an optimum design was determined. Utilizing the optimal base design as a foundation, the structure underwent several printing processes using diverse materials and incorporated multiple fillers. Furthermore, the structure was subjected to modifications employing the functional grading design concept. The study employed the functional grading design concept to examine the variations in load bearing capability, load distribution, and failure mode. The findings indicate that the compression strength of the composite structure was mostly influenced by the wall thickness. The combination of a carbon fiber reinforced base material with silicone rubber as filler, together with a functional graded cell structure featuring top and bottom densification, exhibited the highest compression strength compared to all other combinations. In order to investigate the accurate impact of the FG structures, every cell design was printed using PLA-CF, subjected to testing devoid of any additives, and the output parameters were computed. The results indicated that the center densified cell design exhibited significant values for specific energy absorption, relative density, and compressive strength (52.63 MPa, 0.652, and 2.95 kJ kg−1, respectively). The design of the base cell exhibited the greatest crushing force efficacy of 0.982.

Effects of curved vanes on aerodynamic performance and flow structures in highly loaded tandem cascades

Combining tandem cascades and curved vanes can mitigate the separation in highly loaded compressor cascades. Flow loss mechanisms in curved tandem cascades are crucial for fundamental design and optimization. This study investigates the flow losses and vortex structures in curved tandem cascades with different curved angles and an original straight tandem cascade. Numerical simulations are conducted at variable incidence angles. The results indicate no consistent effect of curved angles on the aerodynamic performance of curved tandem cascades. The tandem cascade with a curved angle of 5° effectively reduces losses at all incidence angles, while the tandem cascade with a curved angle of 15° extends the critical incidence angle to 3°. The comparative analyses reveal that curved vanes increase spanwise pressure gradients, causing low-energy fluid near endwalls to move toward the midspan. The weighting coefficient of losses quantitatively describes that curved vanes weaken the trailing edge shedding vortices of both vanes and passage vortex while enhancing the end wall spanwise vortex of the front vane, thus affecting the loss distribution. Finally, this study innovatively applies topological analysis methods to curved tandem cascades, establishing the relationship between topological structures and vortex structures in corner regions of tandem cascades, which provides a valid research approach to reveal the vortex dynamics mechanisms of the loss distribution in tandem cascades influenced by curved vanes.

Pressure-induced metallization and enhanced photoelectric activity in layered tin disulfide

Two-dimensional layered metal dichalcogenides have given rise to considerable interest in electronics and optoelectronics fields because of their excellent physical and chemical properties and promising applications. Tin disulfide (SnS2) is an important member of them due to its environment-friendly and resource-rich characteristics. Here, a series of in situ electrical transport experiments and photocurrent measurements under high pressure have been performed to investigate the electrical and opto-electrical properties of 4H-SnS2. With increasing pressure, the electrical resistivity of 4H-SnS2 decrease significantly, leading to a transition from semiconducting to metallic state above 58.6 GPa. The increase in pressure results in a substantial enhancement in photoelectric activity, indicating the extensive potential of utilizing pressure as a trigger for in situ optoelectronic applications. Combined with our previous results of x-ray diffraction and optical absorption at high pressure, pressure-induced structural distortion, bandgap narrowing, metallization, and enhancement of photoelectric activity of 4H-SnS2 are tunable and reversible, which are of great significance for both fundamental research and device design.

Experimental investigation of varying design parameters on the production rate and temperature polarisation of a DCMD system

Much of the research in the analysis of Temperature polarisation (TP) and the productivity of a membrane distillation (MD) system tends to concentrate on operational conditions. However, substantial enhancements in permeate flux can be realised through the incorporation of fundamental design modifications. This research showed that TP can be successfully mitigated almost to a level of non-existence, by manipulating the module orientation and flow channel height of an in-house designed direct contact membrane distillation (DCMD) system. Notably, at higher flow channel heights, changing the module orientation from the default horizontal position with the feed side on top (FST) to a sideway orientation led to a remarkable 90% increase in the permeate flux of the DCMD module. Permeate side on top (PST) and sideways orientations performed significantly better than FST for larger channel heights, while at low channel heights, the improvement was slight. Temperature measurements proved that thermal convective currents and secondary flows played a vital role in assisting or opposing TP and cannot be disregarded when investigating the hydrodynamics of a DCMD system. The impact of flow directions was insignificant with different channel heights, while the proximity of the flow inlets played a pivotal role in shaping the temperature profiles along the membrane.

High-Capacity, Cooperative CO2 Capture in a Diamine-Appended Metal-Organic Framework through a Combined Chemisorptive and Physisorptive Mechanism.

Diamine-appended Mg2(dobpdc) (dobpdc4- = 4,4'-dioxidobiphenyl-3,3'-dicarboxylate) metal-organic frameworks are promising candidates for carbon capture that exhibit exceptional selectivities and high capacities for CO2. To date, CO2 uptake in these materials has been shown to occur predominantly via a chemisorption mechanism involving CO2 insertion at the amine-appended metal sites, a mechanism that limits the capacity of the material to ∼1 equiv of CO2 per diamine. Herein, we report a new framework, pip2-Mg2(dobpdc) (pip2 = 1-(2-aminoethyl)piperidine), that exhibits two-step CO2 uptake and achieves an unusually high CO2 capacity approaching 1.5 CO2 per diamine at saturation. Analysis of variable-pressure CO2 uptake in the material using solid-state nuclear magnetic resonance (NMR) spectroscopy and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) reveals that pip2-Mg2(dobpdc) captures CO2 via an unprecedented mechanism involving the initial insertion of CO2 to form ammonium carbamate chains at half of the sites in the material, followed by tandem cooperative chemisorption and physisorption. Powder X-ray diffraction analysis, supported by van der Waals-corrected density functional theory, reveals that physisorbed CO2 occupies a pocket formed by adjacent ammonium carbamate chains and the linker. Based on breakthrough and extended cycling experiments, pip2-Mg2(dobpdc) exhibits exceptional performance for CO2 capture under conditions relevant to the separation of CO2 from landfill gas. More broadly, these results highlight new opportunities for the fundamental design of diamine-Mg2(dobpdc) materials with even higher capacities than those predicted based on CO2 chemisorption alone.

The “I” in ICAPs: examining treatment intensity under the microscope

ABSTRACT Background Intensive Comprehensive Aphasia Programs (ICAPs) provide high doses of treatment over short periods. Treatment intensity in post-stroke aphasia rehabilitation and research is not well understood and is typically underspecified, including within ICAPs and modified Intensive Comprehensive Aphasia Programs (mICAPs), in which intensity is a fundamental design component. One recently developed model of treatment conceptualisation, the Multidimensional Dose Articulation Framework (MDAF), may offer a systematic, comprehensive, and granular method of characterising treatment intensity, though this framework has not yet been used to capture elements of intensity and dose during an ICAP or mICAP. Aims The purpose of this paper is to examine and describe increasingly specific details of treatment intensity for both an ICAP and mICAP delivered at the University of Montana (UMT). Methods & Procedures Fourteen participants with aphasia attended an 84-hour ICAP (n = 8) or a 24-hour mICAP (n = 6) delivered by graduate student clinicians at UMT. Ethics approval was obtained from the UMT IRB (#13-23). We examined intensity and dose using components of the MDAF including broad temporal parameters, and episode-specific length and intensity. Descriptive statistics were used to report group-level, participant-level, and treatment-level parameters. Outcomes & Results In this descriptive manuscript, we use a series of vignettes to report temporal parameters from the MDAF including treatment duration, days, sessions, and session density, and episode-level characteristics including episode length and episode intensity. Vignette one examines ICAP and mICAP planned versus actual temporal parameters. Vignette two describes episode-level detail across two evidence-based treatments administered during the ICAP. Vignette three details differences in delivery of a single treatment approach between two participants. In each vignette, we discuss the benefits and challenges of tracking treatment intensity with fine detail. Conclusions Comprehensive specification of dose and intensity parameters is essential to compare efficacious treatment programs and to understand variability in treatment response across individuals with aphasia. The MDAF is a promising tool, though detailed treatment intensity remains a challenging construct to measure, particularly at the level of the episode. Clinical researchers interested in dose and intensity and authors of evidence-based therapy approaches must continue to work to define and describe active ingredients within therapy approaches.

The performance of general practice in the English NHS: An analysis using Starfield’s framework for primary care

Abstract General practice in the English NHS is in crisis. In response, politicians are proposing fundamental reform to the way general practice is organized. But ideas for reform are contested, and there are conflicting interpretations of the problems to be addressed. We use Barbara Starfield’s ‘4Cs’ framework for high performing primary care to provide an overall assessment of the current role and performance of general practice in England. We first assess theoretical alignment between Starfield’s framework and the role of general practice in England. We then assess actual performance using publicly available national data and targeted literature searches. We find close theoretical alignment between Starfield’s framework and the model of NHS general practice in England. But in practice, its model of universal comprehensive care risks being undermined by worsening and inequitable access, while continuity of care is declining. Underlying causes of current challenges in general practice in England appear more closely linked to under-resourcing than the fundamental design of the system. General practice in England must evolve, but wholesale re-organization is likely to damage and distract. Instead, policymakers should focus on adequately resourcing general practice while supporting general practice teams to improve the quality and coordination of local services.

Perturbative diffraction methods resolve a conformational switch that facilitates a two-step enzymatic mechanism

Enzymes catalyze biochemical reactions through precise positioning of substrates, cofactors, and amino acids to modulate the transition-state free energy. However, the role of conformational dynamics remains poorly understood due to poor experimental access. This shortcoming is evident with Escherichia coli dihydrofolate reductase (DHFR), a model system for the role of protein dynamics in catalysis, for which it is unknown how the enzyme regulates the different active site environments required to facilitate proton and hydride transfer. Here, we describe ligand-, temperature-, and electric-field-based perturbations during X-ray diffraction experiments to map the conformational dynamics of the Michaelis complex of DHFR. We resolve coupled global and local motions and find that these motions are engaged by the protonated substrate to promote efficient catalysis. This result suggests a fundamental design principle for multistep enzymes in which pre-existing dynamics enable intermediates to drive rapid electrostatic reorganization to facilitate subsequent chemical steps.

Highly-sensitive wafer-scale transfer-free graphene MEMS condenser microphones

Since the performance of micro-electro-mechanical system (MEMS)-based microphones is approaching fundamental physical, design, and material limits, it has become challenging to improve them. Several works have demonstrated graphene’s suitability as a microphone diaphragm. The potential for achieving smaller, more sensitive, and scalable on-chip MEMS microphones is yet to be determined. To address large graphene sizes, graphene-polymer heterostructures have been proposed, but they compromise performance due to added polymer mass and stiffness. This work demonstrates the first wafer-scale integrated MEMS condenser microphones with diameters of 2R = 220–320 μm, thickness of 7 nm multi-layer graphene, that is suspended over a back-plate with a residual gap of 5 μm. The microphones are manufactured with MEMS compatible wafer-scale technologies without any transfer steps or polymer layers that are more prone to contaminate and wrinkle the graphene. Different designs, all electrically integrated are fabricated and characterized allowing us to study the effects of the introduction of a back-plate for capacitive read-out. The devices show high mechanical compliances Cm = 0.081–1.07 μmPa−1 (10–100 × higher than the silicon reported in the state-of-the-art diaphragms) and pull-in voltages in the range of 2–9.5 V. In addition, to validate the proof of concept, we have electrically characterized the graphene microphone when subjected to sound actuation. An estimated sensitivity of S1kHz = 24.3–321 mV Pa−1 for a Vbias = 1.5 V was determined, which is 1.9–25.5 × higher than of state-of-the-art microphone devices while having a ~9 × smaller area.

Consuming responsibly: Prioritising responsible consumption behaviours in Australia

Human behaviour is at the centre of unsustainable consumption and production. Responsible consumption behaviours must therefore be at the centre of the solution. However, because it is inefficient for policymakers and practitioners, and ineffective for users, to attempt to target all responsible consumption behaviours simultaneously in a given initiative, some form of prioritisation is necessary. Through a combination of collaborative workshops and surveys with key stakeholders, this study applied established methods of prioritisation to identify a ‘long list’ of 84 responsible consumption behaviours across three material streams – fashion, electronics and furniture. The ‘long list’ was then taken to a prioritisation summit with government, academic, business, and community stakeholders. The behaviours were rated against explicit prioritisation criteria related to likelihood of adoption, timing, impact and potential system reach. This yielded a final ‘short list’ of seven prioritised behaviours, including a mixture of achievable consumer behaviours that can be realised in the short-term, as well as larger-scale and longer-term manufacturer- and government-related behaviours supporting fundamental design and policy shifts. By drawing on the collective knowledge and expertise of academic and non-academic experts, the study identified and prioritised behaviours to reduce material resource consumption in Australia that are impactful and transformative, while also being practical and realistic to implement.