Guidance For Design Research Articles

Azulene-Containing Bis(squaraine) Dyes: Design, Synthesis and Aggregation Behaviors.

The relationship among chemical structure, physicochemical property and aggregation behavior of organic functional material is an important research topic. Here, we designed and synthesized three bis(squaraine) dyes BSQ1, BSQ2 and BSQ3 through the combination of two kinds of unsymmetrical azulenyl squaraine monomers. Their physicochemical properties were investigated in both molecular and aggregate states. Generally, BSQ1 displayed different assembly behaviors from BSQ2 and BSQ3. Upon fabrication into nanoparticles, BSQ1 tend to form J-aggregates while BSQ2 and BSQ3 tend to form H-aggregates in aqueous medium. When in the form of thin films, three bis(squaraine) dyes all adopted J-aggregation packing modes while only BSQ1 presented the most significant rearrangement of aggregate structures as well as the improvement in the carrier mobilities upon thermal annealing. Our research highlights the discrepancy of aggregation behaviors originating from the molecular structure and surrounding circumstances, providing guidance for the molecular design and functional applications of squaraines.

Multiple Leap Maneuver Trajectory Design and Tracking Method Based on Prescribed Performance Control during the Gliding Phase of Vehicles

A novel standard trajectory design and tracking guidance used in the multiple active leap maneuver mode for hypersonic glide vehicles (HGVs) is proposed in this paper. First, the dynamic equation and multiconstraint model are first established in the flight path coordinate system. Second, the reference drag acceleration-normalized energy (D-e) profile of the multiple active leap maneuver mode is quickly determined by the Newton iterative algorithm with a single design parameter. The range to go error is corrected by the drag acceleration profile update algorithm, and the drag acceleration error of the gliding terminal is corrected by the aerodynamic parameter estimation algorithm. Then, the reference drag acceleration tracking guidance law is designed based on the prescribed performance control method. Finally, the CAV-L vehicle model is used for numerical simulation. The results show that the proposed method can satisfy the design requirements of drag acceleration under multiple active leap maneuver modes, and the reference drag acceleration can be tracked precisely. The adaptability and robustness of the proposed method are verified by the Monte Carlo simulations under various combined deviation conditions.

Analysis of shear shock waves in soft materials: From periodic elastic laminates and fibre-reinforced composites to molecular chain networks

We investigate the effect of microstructure and molecular length-scale structures on the formation of shear shock waves in soft materials. We consider (i) soft materials with layered microstructures, (ii) transversely isotropic fibre-reinforced composites (FC), as well as (iii) molecular chain networks, using homogenised energy density functions at the continuum scale. Critical conditions for the formation of shear shocks are found analytically for laminates and FCs, and are shown to depend only on the angle between the initial orientation direction and the applied load. We elucidate the effects of the microstructural material parameters on the shock formation distance. Our results show that increased stiffness ratio and volume fraction of fibres decreases the shock formation distance. The analysis of molecular chain networks indicates that an increase in the entanglement increases the critical shock formation distance. We also highlight that by an appropriate choice of loading and material parameters, shock formation can be avoided, providing guidance for design of protective materials and structures.

Rational Design of an In-Situ Polymer-Inorganic Hybrid Solid Electrolyte Interphase for Realising Stable Zn Metal Anode under Harsh Conditions.

The in-depth understanding of the composition-property-performance relationship of solid electrolyte interphase (SEI) is the basis of developing a reliable SEI to stablize the Zn anode-electrolyte interface, but it remains unclear in rechargeable aqueous zinc ion batteries. Herein, a well-designed electrolyte based on 2 M Zn(CF3SO3)2-0.2 M acrylamide-0.2 M ZnSO4 is proposed. A robust polymer (polyacrylamide)-inorganic (Zn4SO4(OH)6.xH2O) hybrid SEI is in situ constructed on Zn anodes through controllable polymerization of acrylamide and coprecipitation of SO4 2- with Zn2+ and OH-. For the first time, the underlying SEI composition-property-performance relationship is systematically investigated and correlated. The results showed that the polymer-inorganic hybrid SEI, which integrates the high modulus of the inorganic component with the high toughness of the polymer ingredient, can realize high reversibility and long-term interfacial stability, even under ultrahigh areal current density and capacity (30 mA cm-2~30 mAh cm-2). The resultant Zn||NH4V4O10 cell also exhibits excellent cycling stability. This work will provide a guidance for the rational design of SEI layers in rechargeable aqueous zinc ion batteries.

Numerical simulation of gradient catalyst layer design in proton exchange membrane water electrolyzer with enhanced performance

The catalyst loading, ionomer content and agglomerate radius in the catalyst layer (CL) of proton exchange membrane water electrolyzer (PEMWE) plays critical role on its electrochemical performance. Conventionally, the CL in PEMWE is modeled with uniform composition and homogeneous domain. In this study, a two-dimensional PEMWE model considering linear gradient distribution of catalyst, ionomer and agglomerate radius in CL was developed and their effect on the electrolyzer performance were systematically investigated. The results show that, when the total catalyst, ionomer loading and the average agglomerate radius in CL are kept constant, the optimum PEMWE performance was achieved with low catalyst loading, high ionomer content, and small agglomerates radius distribution at the CL-PEM interface. Compared with the uniform CL, this optimized gradient CL design results into a 7.01% improvement in the PEMWE current density. Meanwhile, under the gradient CL design, increased maximum temperature and oxygen concentration with lower liquid water saturation is found inside PEMWE, which might affect the temperature distribution uniformity within the PEMWE. The results of this work provide insightful guidance for the CL optimization design of PEMWE.

Imaging the Iodine Sorption-Induced Synchronous Skeleton-Pore Interactions of Single Covalent Organic Framework Particles.

Covalent organic frameworks (COFs) are promising iodine adsorbents. For improved performances, it is critical and essential to fundamentally understand the underlying mechanism. Here, using the operando dark-field optical microscopy (DFM) imaging technique, the observation of an extraordinary structure shrinkage of 2D triphenylbenzene (TPB)-dimethoxyterephthaldehyde (DMTP)-COF upon the adsorption of I2 vapor at the single-particle resolution is reported. Combining single-particle DFM imaging with other experimental and theoretical methods, it is revealed that the shrinkage mechanism of the TPB-DMTP-COF is attributed to the I2 sorption-induced synchronous skeleton-pore interactions. The redox reaction of I2 and TPB-DMTP-COF yields some cationic skeletons and I3 - species, which triggers the multi-directional halogen-bonding interactions of I2 and I3 - as well as strong cation-π interactions between neutral and cationic skeletons, accompanying the synchronous in-plane skeleton shrinking in the xy plane and compact out-of-plane layer packing in the z-direction. This understanding of the synchronous action between the skeleton and pore breaks the perspective on the structure robustness of 2D COFs with excellent stability during the I2 uptake, which offers pivotal guidance for the rational design and creation of advanced microporous adsorbents.

Bridging Atom Engineering for Low-Temperature Oxygen Activation in a Robust Metal-Organic Framework.

Achieving active site engineering at the atomic level poses a significant challenge in the design and optimization of catalysts for energy-efficient catalytic processes, especially for a reaction with two reactants competitively absorbed on catalytic active sites. Herein we show an example that tailoring the local environment of cobalt sites in a robust metal-organic framework through substituting the bridging atom from -Cl to -OH group leads to a highly active catalyst for oxygen activation in an oxidation reaction. Comprehensive characterizations reveal that this variation imparts drastic changes on the electronic structure of metal centers, the competitive reactant adsorption behavior, and the intermediate formation. As a result, exceptional low-temperature CO oxidation performance was achieved with T25(Temperature for 25% conversion) = 35°C and T100 (Temperature for 100% conversion) = 150°C, which stands out from existing MOF-based catalysts and even rivals many noble metal catalysts. This work provides a guidance for the rational design of catalysts for efficient oxygen activation for an oxidation reaction.

Bridging Atom Engineering for Low‐Temperature Oxygen Activation in a Robust Metal‐Organic Framework

Achieving active site engineering at the atomic level poses a significant challenge in the design and optimization of catalysts for energy‐efficient catalytic processes, especially for a reaction with two reactants competitively absorbed on catalytic active sites. Herein we show an example that tailoring the local environment of cobalt sites in a robust metal‐organic framework through substituting the bridging atom from ‐Cl to ‐OH group leads to a highly active catalyst for oxygen activation in an oxidation reaction. Comprehensive characterizations reveal that this variation imparts drastic changes on the electronic structure of metal centers, the competitive reactant adsorption behavior, and the intermediate formation. As a result, exceptional low‐temperature CO oxidation performance was achieved with T25(Temperature for 25% conversion) = 35°C and T100 (Temperature for 100% conversion) = 150°C, which stands out from existing MOF‐based catalysts and even rivals many noble metal catalysts. This work provides a guidance for the rational design of catalysts for efficient oxygen activation for an oxidation reaction.

Neural Network Approximation for Pessimistic Offline Reinforcement Learning

Deep reinforcement learning (RL) has shown remarkable success in specific offline decision-making scenarios, yet its theoretical guarantees are still under development. Existing works on offline RL theory primarily emphasize a few trivial settings, such as linear MDP or general function approximation with strong assumptions and independent data, which lack guidance for practical use. The coupling of deep learning and Bellman residuals makes this problem challenging, in addition to the difficulty of data dependence. In this paper, we establish a non-asymptotic estimation error of pessimistic offline RL using general neural network approximation with C-mixing data regarding the structure of networks, the dimension of datasets, and the concentrability of data coverage, under mild assumptions. Our result shows that the estimation error consists of two parts: the first converges to zero at a desired rate on the sample size with partially controllable concentrability, and the second becomes negligible if the residual constraint is tight. This result demonstrates the explicit efficiency of deep adversarial offline RL frameworks. We utilize the empirical process tool for C-mixing sequences and the neural network approximation theory for the Holder class to achieve this. We also develop methods to bound the Bellman estimation error caused by function approximation with empirical Bellman constraint perturbations. Additionally, we present a result that lessens the curse of dimensionality using data with low intrinsic dimensionality and function classes with low complexity. Our estimation provides valuable insights into the development of deep offline RL and guidance for algorithm model design.

UniADS: Universal Architecture-Distiller Search for Distillation Gap

In this paper, we present UniADS, the first Universal Architecture-Distiller Search framework for co-optimizing student architecture and distillation policies. Teacher-student distillation gap limits the distillation gains. Previous approaches seek to discover the ideal student architecture while ignoring distillation settings. In UniADS, we construct a comprehensive search space encompassing an architectural search for student models, knowledge transformations in distillation strategies, distance functions, loss weights, and other vital settings. To efficiently explore the search space, we utilize the NSGA-II genetic algorithm for better crossover and mutation configurations and employ the Successive Halving algorithm for search space pruning, resulting in improved search efficiency and promising results. Extensive experiments are performed on different teacher-student pairs using CIFAR-100 and ImageNet datasets. The experimental results consistently demonstrate the superiority of our method over existing approaches. Furthermore, we provide a detailed analysis of the search results, examining the impact of each variable and extracting valuable insights and practical guidance for distillation design and implementation.

Effects of Shear Characteristics of Anchoring Interface on Bearing Performance of Fully Grouted Bolts Based on Variable Controlling Method

The shear strength parameter of an anchoring interface is one of the key parameters affecting the design of bolt support. To better realize the design of bolt support, the pullout model of fully grouted bolts was established by FLAC3D numerical software. The commonly used tri-linear bond-slip model of the anchoring interface was selected. The variable controlling method was used to investigate the effects of the shear strength parameters of the anchoring interface on the bearing performance of fully grouted bolts. The results show that, with the increase in the displacement at the peak shear stress, the bearing capacity and the energy absorption of fully grouted bolts decrease and the ability of the fully grouted anchoring system to resist external loads weakens. Meanwhile, the deformation capacity of fully grouted bolts increases, and the durability of the fully grouted anchoring system is enhanced. With the increase in the residual shear stress and the displacement at the residual shear stress, the bearing capacity and deformation capacity of fully grouted bolts both increase, and the energy absorption also increases. Increasing the post-peak bearing properties of the anchoring interface can help improve the bearing performance of fully grouted bolts and enhance the ability of the fully grouted bolts to resist failure. The results may provide guidance for support design and performance enhancement of fully grouted bolts.

Sucrose ester embedded lipid carrier for DNA delivery

Sucrose esters (SEs) have great potential in the field of nucleic acid delivery due to their unique physical and chemical properties and good biosafety. However, the mechanism of the effect of SEs structure on delivery efficiency has not been studied. The liposomes containing peptide lipids and SEs were constructed, and the effects of SEs on the interaction between the liposomes and DNA were studied. The addition of SEs affects the binding rate of liposomes to DNA, and the binding rate gradually decreases with the increase of SEs’ carbon chain length. SEs also affect the binding site and affinity of liposomes to DNA, promoting the aggregation of lipids to form liposomes, where DNA wraps around or compresses inside the liposomes, allowing it to compress DNA without damaging the DNA structure. COL-6, which is composed of sucrose laurate, exhibits the optimal affinity for DNA, and SE promotes the formation of ordered membrane structure and enhances membrane stability, so that COL-6 exhibits a balance between rigidity and flexibility, and thus exhibits the highest delivery efficiency of DNA among these formulations. This work provides theoretical foundations for the application of SE in gene delivery and guides for the rational design of delivery systems.

Effects of embedded walls on tunnelling-induced sandy ground displacements: a numerical investigation

Urban tunnelling projects pose significant risks to the integrity of nearby structures due to ground movements induced by the excavation process. Embedded walls are commonly employed as a protective measure to mitigate these adverse effects. This paper presents a comprehensive numerical investigation into the effects of embedded walls on tunnelling-induced ground displacements, aiming to provide insights and recommendations for optimal embedded wall design. The study assesses the impact of varying embedded wall length and horizontal distance from the tunnel on soil settlement and horizontal displacements. Results demonstrate the complex interplay between embedded wall length, horizontal distance, and ground movement patterns, and the highly non-linear influence of key parameters on embedded wall efficiency (i.e. its ability to reduce settlements). A preliminary design chart is proposed to guide engineers in determining the appropriate horizontal location and depth of embedded walls to effectively reduce tunnelling-induced ground displacements. The findings contribute to a better understanding of embedded wall performance in the context of tunnelling and provide valuable guidance for the practical design and implementation of protective measures in urban areas.

A Review of Durability of New and Old Concrete Joints

The purpose of this study is to explore the durability of the new and old concrete joints, including chloride ion erosion, freeze-thaw phenomena, and the influence of aggregates. Firstly, taking into account the difference in material properties between the old and new concrete, this study analyzes the chloride ion transport characteristics of the joints in detail, focusing on the key areas of the joints, that is, the areas where the old concrete may have been eroded by chloride ions. Secondly, this study explores the change in the properties of the joints under freeze-thaw conditions, and the influence of different interface treatment methods on the properties of the joints. Finally, this study examines the influence of the type and content of aggregates on the durability of the joints. Through the above research, this paper aims to provide some useful guidance and suggestions for the durability design of the old and new concrete structures.

Numerical analysis on the seismic performance of subway station reinforced by ECC-BFRP

In areas with high seismic activity, enhancing the seismic performance of subway station structures is of paramount importance. This paper presents a novel approach involving the application of an ECC-BFRP (Engineered Cementitious Composite with Basalt Fiber Reinforced Polymer) composite layer to reinforce central columns of subway stations situated in loess site. To evaluate the effectiveness of this reinforcement method, a three-dimensional finite element model of subway station structure, accounting for soil-structure interaction (SSI) effects, was meticulously developed using the finite element software Abaqus. The seismic responses of the subway stations with various reinforcement scenarios such as reinforced by the cement mortar, ECC, Mortar-BFRP and ECC-BFRP layer were respectively analyzed in comparison to the unreinforced station. Both the structural displacement response and the changing pattern of damage development for the overall and local structural members were obtained. The results indicated that the ECC-BFRP composite layer could effectively improve the stiffness of the central column and reduce the seismic response of the station. Meanwhile, the seismic damage of the central column was significantly reduced, and the seismic damage distribution of other structural members was uniformly distributed. Consequently, the seismic performance of the station was effectively improved. The research results provided valuable guidance for the seismic design of underground structures.

Concrete Pavement Design Analysis Using AASHTOWare Pavement Mechanistic-Empirical Design Software

Local calibration of pavement performance models embedded in the AASHTOWare Pavement Mechanistic-Empirical Design (PMED) software may be needed to implement this design methodology. A recent survey showed that, despite local calibration, several state highway agencies in the U.S. are using the American Association of State Highway Transportation Officials (AASHTO) Guide for Design of Pavement Structures (1993 version) and the PMED software for comparative design of jointed plain concrete pavement (JPCP). This paper describes the recalibration process of the JPCP distress models in the PMED software and comparative designs obtained by the PMED software and 1993 AASHTO design guide. The results show that the calibration/recalibration process depends on the availability of measured performance data. Not all global coefficients must be changed in the calibration/recalibration process. The 1993 AASHTO design guide yielded higher JPCP slab thickness for projects with high truck traffic than the PMED software when no friction is assumed between the slab and a cementitious base. An assumption of full friction will have a discernible effect on the slab thickness obtained from PMED.

Advances in the Stability of Catalysts for Electroreduction of CO2 to Formic Acid.

The electroreduction of CO2 to high-value products is a promising approach for achieving carbon neutrality. Among these products, formic acid stands out as having the most potential for industrialization due to its optimal economic value in terms of consumption and output. In recent years, the Faraday efficiency of formic acid from CO2 electroreduction has reached 90~100 %. However, this high selectivity cannot be maintained for extended periods under high currents to meet industrial requirements. This paper reviews excellent work from the perspective of catalyst stability, summarizing and discussing the performance of typical catalysts. Strategies for preparing stable and highly active catalysts are also briefly described. This review may offer a useful data reference and valuable guidance for the future design of long-stability catalysts.

Estimating internal moisture generation rates in recently constructed, occupied homes in the southeastern United States

Internal moisture generation (IMG), or moisture generated by building occupants via activities such as respiration, cooking, bathing, and cleaning, is a critical input required for design, analysis, and simulation of building enclosure and HVAC systems. Based on previously published values, ASHRAE Standard 160-2021 provides guidance for estimating IMG rates for moisture control design analysis, which is based on occupied home datasets collected in the 1980s and 1990s. Residential energy use simulation software also utilizes estimates for IMG for energy rating, energy analysis, and code compliance calculations, as specified in ANSI/RESNET/ICC Standard 301. Data quantifying IMG rates in newer homes are useful in determining the continued relevance of current design and simulation guidance, and whether the guidance represents conditions found in new housing stock. ASHRAE Research Project 1844, conducted by the Florida Solar Energy Center (FSEC), a research institute of the University of Central Florida, estimated IMG rates in newer occupied homes built since 2013 in the southeastern United States using a moisture balance model approach. The project obtained occupied home data in cooperation with a U.S. Department of Energy Building America research project to characterize indoor air quality (IAQ) in newer U.S. homes, along with presence, functionality, and occupant use of control measures. Full-scale laboratory homes operating with known IMG rates were used to validate a moisture balance model and quantify the accuracy of estimates obtained when the model is applied to data from occupied homes with unknown IMG rates.

Effect of interphase layer on matrix cracking in fiber reinforced ceramic matrix composites

The onset of matrix steady-state cracking stands as a pivotal mechanical characteristic in fiber reinforced ceramic matrix composites (FRCMCs), garnering substantial attention and investigations. Experimentally, it has been demonstrated that increasing interphase layer thickness may cause non-monotonic changes in matrix cracking stress. However, the existing models can hardly elucidate this phenomenon thoroughly due to the neglect of interphase thickness. This paper presents a comprehensive analytical model for the matrix cracking incorporating interphase, the Poisson effect, Coulomb friction, fiber asperities, residual thermal stress (RTS), and their coupling effects, along with a modified criterion for interfacial debonding that accounts for the presence of the axial RTS. Based on the proposed model, three distinct cracking domains, i.e., perfectly bonded, debonding with and without interfacial separation, have been identified with the critical conditions deduced analytically. Thereby the mechanism of the non-monotonic influence of interphase thickness is thoroughly revealed as the transition of cracking modes. Meanwhile, the role of interphase on the matrix cracking is systematically studied, and the results indicate that interphase has a notable effect through relieving axial RTS, adjusting interfacial friction, altering interfacial shear modulus, and influencing debonding toughness. The outcomes of this study offer valuable guidance for the interphase design of FRCMCs.

Modelling and onsite testing on dynamic thermal responses of built environment in passive solar rooms on Tibetan plateau

It of great importance in assessing built thermal environment level and evaluating corresponding indoor air conditioning demand for energy conservation in construction sectors. Nevertheless, because of the unique meteorological features in plateau area, classical building performance simulation approach contributes to thermal performance evaluation errors since most design codes or standards relies on low attitude regions. In this paper, a modified and improved dynamic thermal design model is put forward for built environment and energy consumption estimation for passive buildings for plateau buildings. Moreover, the simplified experiment is set up to monitor dynamic thermal responses for modelling building. The testing validation illustrate that the onsite measurement accuracy level is quite acceptable for engineering applications with less than 30% relative change range coefficient. Besides, the experiment data demonstrates that window-to-wall ratios, architectural orientation, thermal insulation coefficients, have substantial impacts for solar heat gains in plateau buildings. The study renders building design guidance for energy conservation in high altitude plateau areas.