Structural Control Research Articles

Single photon scattering with the giant and small atom interplay in a one-dimensional coupled resonator waveguide

We study single photon scattering in a one-dimensional coupled resonator waveguide, which is dressed by a small and a giant artificial atom simultaneously. Here, we have set the small atom to be a neighbor to one leg of the giant atom, and the giant atom couples to the waveguide via two distant sites. When the small and giant atoms are both resonant with the bare resonator in the waveguide, we observe the perfect reflection of the resonant incident photon. On the other hand, when the small atom is detuned from the giant atom, the single photon reflection is characterized by a wide window and Fano line shape. We hope our work will pave the way for the potential application of small and giant atom hybrid systems in the study of photonic control in the low-dimensional waveguide structure.

Structural and hydrodynamic controls on fluid travel time distributions across fracture networks

Fracture networks are preferential flow paths playing a critical role in a wide range of environmental and industrial problems. Their complex multiscale structure leads to broad distributions of fluid travel times, affecting many biogeochemical processes. Yet, the relationship between the fracture network structures, their hydrodynamic properties, and the resulting anomalous transport dynamics remains unclear. We use a large database of fracture network models to investigate the factors controlling fluid velocity and travel-time distributions across a wide range of networks, from synthetic to field-calibrated models, with aperture variability at both fracture and network scales. Analysis reveals that transport statistics have generic properties across investigated networks, including notably heavy-tailed travel time distributions. Networks of increasing complexity and heterogeneity lead to broader velocity distributions and more channeled velocity fields, where flow concentrates in a narrow channel web in the three-dimensional (3D) fracture structure. While heterogeneity in point-velocity statistics increases travel-time variability, channeling tends to reduce it. This counterintuitive phenomenon challenges current theories, which assume that long travel time power law exponents are determined solely by point-velocity statistics. By analyzing velocity and travel time statistics for different flow structures, we develop a coupled Continuous Time Random Walk framework capturing the unexpected control of the velocity field's spatial structure on anomalous transport in fracture networks. This leads to a unique class of random walk models capturing the respective roles of velocity heterogeneity and spatial structure on transport in networks. These findings open a prospective for characterizing, modeling, and predicting transport dynamics in complex networks, with potential applications to geological, biological, and engineered networks.

The rise and contestation of platform capitalism: Evidence from two food delivery blackouts in Malaysia

The vulnerability and inequality of on-demand gig workers around the world are epitomised by the insecure rights that arise from the legal implications of their status. They are the biggest victims of capital accumulation under platform capitalism, which has skilfully exploited this worker–employer relationship. The resistance of gig workers is essential to counter the powerful structural control structures of platform capitalism. However, theoretical developments in the ideology and resistance of the industrial relations processes that overshadow platform capitalism and empirical studies of them in non-Western contexts are underdeveloped. This study develops an analytical framework in the process of platform capitalism versus gig worker resistance and examines longitudinal resistance and changes and challenges to platform capitalism. A longitudinal analysis of food delivery boycotts for Malaysian p-hailing gig workers in 2022 and 2024 produced different results and complexities in terms of the robustness and continuity of this resistance. The study finds theoretical fluidity in the robustness of workers’ commodification processes under platform capitalism, the focus on organising motives and demands of resistance, and two routes of resistance to the powerful platform balance of power.

Coordinated Optimization and Management of Oxygen Content and Cathode Pressure for PEMFC based on Hybrid Nonlinear Robust Control

Cathode inlet and exhaust management remains a significant challenge in proton exchange fuel cell (PEMFC). Achieving optimal oxygen content in real-time through precise control of the inlet gas is crucial for maintaining optimal output. Additionally, coordinating the air inlet and exhaust to ensure consistent cathode and anode pressures is essential for balancing the internal stack pressure and preventing nitrogen penetration, thereby enhancing PEMFC’s stability and lifespan. This paper addresses these challenges by introducing a mixed control strategy based on a fifth-order nonlinear mathematical model of the PEMFC stack cathode. Two non-singular fast terminal sliding mode structure controllers are combined as control system to optimize oxygen content and pressure control under dynamic loading conditions. The non-singular terminal sliding mode structure ensures finite-time convergence while mitigating potential singularity issues associated with traditional terminal sliding modes. The results showcase the robustness and effectiveness of the proposed control method in managing load variations, external disturbances, and PEMFC uncertainties.

Nanofiltration Membrane with Enhanced Ion Selectivity Based on a Precision-Engineered Ultrathin Polyethylene Supporting Layer.

Nanofiltration (NF) technology is increasingly used in the water treatment and separation fields. However, most research has focused on refining the selective layer while overlooking the potential role of the supporting layer. With expertise in ultrathin polymer films, particularly in the production of polyethylene (PE) membranes, we explore the possibility of improving NF membrane performance by precisely controlling the structure and surface properties of the ultrathin supporting layer in this work. Here, we introduced an innovative NF membrane that used a submicrometer ultrathin PE membrane produced through a biaxial stretching process, which is significantly thinner than commercial PE membranes available on the market. The core innovations are as follows: first, we focused on precise control of the supporting layer rather than just the selective layer, achieving significant enhancements in overall NF membrane performance; second, the ultrathin PE supporting layer served as a tunable interface for interfacial polymerization, offering possibilities for structural control of the selective layer and advancing membrane performance innovations. The resulting NF membrane boasts an overall thickness of ∼630 nm, which represents the thinnest NF membrane documented to date. This ultrathin NF membrane showed an ultrahigh Cl-/SO42- selectivity of 338.03, placing it at the forefront of existing literature. This study sheds light on the important role of the supporting layer in the preparation of selective layers. We believe that this approach has the potential to contribute to the development of ultrathin, high-performance NF membranes.

Electromechanical modelling and vibration control analysis of cyclic symmetric structures with a piezoelectric vibration absorber

This study explored the application of piezoelectric vibration absorbers (PVAs) equipped with synthetic circuits for the vibration control of cyclic symmetric structures. A cyclic symmetric electromechanical model (CSEM) integrated with PVAs was introduced to facilitate the design and optimization of the PVAs. This model was formulated analytically based on the circulant matrix theory, and the dynamic response was computed using the complex mode superposition method with explicit consideration of the intrinsic resistance within the PVA. A case study involving a simplified blisk model and an experimental test rig was conducted to validate the proposed CSEM. The validity of the model was confirmed through a comparative analysis of both the natural and dynamic characteristics obtained using the finite element model and experimental results. Furthermore, the impact of synthetic circuit parameters (inductance and negative capacitance values) and the placement of piezoelectric patches on the vibration control performance of PVA were investigated. The results suggested that the optimal inductance coincide with the analytical value, whereas the optimal negative capacitance of the series was slightly greater than the intrinsic capacitance of the patch. Additionally, mounting the piezoelectric patch on the blade root improved the vibration control.

Metal-Organic-Framework-Derived CuO-ZnO@CN Hollow Nanoreactors: Precise Structural Control and Efficient Catalytic Performance.

Hollow carbon-nitrogen nanoreactors constitute a class of porous materials that have widespread application owing to their large inner cavities, low densities, core-shell interfaces, and enrichment effects. Direct carbonization of precursors is the simplest and most economical method to prepare porous carbon-nitrogen materials; however, this method requires high temperatures, thus yielding nonoxide structures. In this study, CuO-ZnO@CN (CN: carbon-nitrogen layers) is prepared using the two-step heating of zeolitic imidazolium skeleton-8 (ZIF-8) coated with CuO-ZnO precursors. During carbonization, the ZIF-8 nanoparticles are converted into carbon-nitrogen layers at high temperatures. Next, a heating process based on the autocatalytic effect of Cu can be used to etch the hollow structure prepared by the carbon-nitrogen layers. The CuO-ZnO@CN hollow composites fabricated using this method exhibit excellent catalytic properties for the ethynylation of formaldehyde. The proposed strategy can be used to develop techniques for syntheses of readily reducible carbon oxide claddings and their composites.

A statistical mechanics investigation of unfolded protein response across organisms.

Living systems rely on coordinated molecular interactions, especially those related to gene expression and protein activity. The Unfolded Protein Response is a crucial mechanism in eukaryotic cells, activated when unfolded proteins exceed a critical threshold. It maintains cell homeostasis by enhancing protein folding, initiating quality control, and activating degradation pathways when damage is irreversible. This response functions as a dynamic signaling network, with proteins as nodes and their interactions as edges. We analyze these protein-protein networks across different organisms to understand their intricate intra-cellular interactions and behaviors. In this work, analyzing twelve organisms, we assess how fundamental measures in network theory can individuate seed proteins and specific pathways across organisms. We employ network robustness to evaluate and compare the strength of the investigated protein-protein interaction networks, and the structural controllability of complex networks to find and compare the sets of driver nodes necessary to control the overall networks. We find that network measures are related to phylogenetics, and advanced network methods can identify main pathways of significance in the complete Unfolded Protein Response mechanism.

Enhancing the Energy Release Performance of Al/CuO Nanothermites through Hierarchical Structure

ABSTRACT The objective of this study is to enhance the mixing uniformity and contact efficiency between nano-Al and oxidizers through structural control, while suppressing the “pre – ignition fusion” effect of nanothermites. We employed biotemplate approach, utilizing Lycopodium japonicum Thunb. spores (LP) and Papilio maackii wings (PW) as sacrificial templates, to successfully fabricate hierarchically structured Al/PW-CuO and Al/LP-CuO nanothermites. At a stoichiometric ratio of Ф = 1.5, Al/PW-CuO exhibited the highest heat release of 2278.00 J/g, whereas Al/LP-CuO also achieved a substantial heat release of 1969.08 J/g. These outstanding performances are attributed to the unique structures of PW-CuO and LP-CuO, especially the spine-like plate structure of PW-CuO, which provides more reaction sites, thereby enhancing spatial utilization and heat release efficiency. This study provides new insights for the design and application of highly active nanoenergetic materials.

Dynamic Analysis and Vibration Control of Additively Manufactured Thin-Walled Polylactic Acid Polymer (PLAP) and PLAP Composite Beam Structures: Numerical Investigation and Experimental Validation

This study primarily presents a numerical investigation of the dynamic behavior and vibration control in thin-walled, additively manufactured (AM) beam structures, validated through experimental results. Vibration control in thin-walled structures has gained significant attention recently because vibrations can severely affect structural integrity. Therefore, it is necessary to minimize these vibrations or keep them within acceptable limits to ensure the structure’s integrity. In this study, the AM beam structures were made of polylactic acid polymer (PLAP), short carbon fiber reinforced in PLAP (SCFR|PLAP), and continuous carbon fiber reinforced in PLAP (CCFR|PLAP), with 0°|0° layer orientations. The finite element modeling (FEM) of the AM beam structures integrated with macro fiber composite (MFC) was carried out in Abaqus. The initial four modal frequencies of bending modes (BMs) and their respective modal shapes were acquired through numerical simulation. It is crucial to highlight the numerical findings that reveal discrepancies in the 1st modal frequencies of the beams, ranging up to 1.5% compared to their respective experimental values. For the 2nd, 3rd, and 4th modal frequencies, the discrepancies are within 10%. Subsequently, frequency response analysis (FRA) was carried out to observe the frequency-dependent vibration amplitude spectrum at the initial four BM frequencies. Despite discrepancy in the amplitude values between the numerical and experimental datasets, there was consistency in the overall amplitude behavior as frequency varied. THz spectroscopy was performed to identify voids or misalignment errors in the actual beam models. Finally, vibration amplitude control using MFC (M8507-P2) was examined in each kinematically excited numerical beam structure. After applying a counterforce with the MFC, the controlled vibration amplitudes for the PLAP, SCFR|PLAP, and CCFR|PLAP configurations were approximately ±19 µm, ±16 µm, and ±13 µm, respectively. The trend in the controlled amplitudes observed in the numerical findings was consistent with the experimental results. The numerical findings of the study reveal valuable insights for estimating trends related to vibration control in AM beam structures.

Optimization of Vibration Control of Adjacent Buildings Structures by a New Inertial Amplified Mass-Tuned Damper

Optimization of Vibration Control of Adjacent Buildings Structures by a New Inertial Amplified Mass-Tuned Damper

Precise Synthesis of Single‐Atom Catalysts for Boosting Next‐Generation Advanced Oxidation and Reduction Processes in Sustainable Energy Applications

AbstractSingle‐atom catalysts (SACs) demonstrate high selectivity, maximal atom utilization, and unique active site configurations, establishing them as a rapidly expanding research field. Understanding the intrinsic relationship between structure and catalytic performance is crucial for the effective use of SACs in catalysis. However, providing a clear explanation of the coordination environment and intrinsic structural regulation of SACs remains a significant challenge for next‐generation renewable energy materials, especially in advanced oxidation and reduction processes critical for sustainable energy applications. This comprehensive review offers an in‐depth overview of the current progress and design of SACs, with a specific focus on precise synthesis, structural control, and the relationship between structure and performance. Furthermore, we elucidate the reaction mechanisms of various catalytic systems and the selective methods used to precisely synthesize and enhance catalytic reactions in the sustainable energy sector. Finally, this review explores the complex challenges in investigating and developing SACs and offers a perspective on solutions in advanced oxidation and reduction technologies for future research to overcome these challenges and achieve practical applications.

Rapid, Controlled Branching Polymerization of Cyanoacrylate via Pathway-Enabled, Site-Specific Branching Initiation.

Controlled branched structures remain a key synthetic limitation for monomeric tissue adhesives because their on-site polymerization that enables adhesion formation requires rapid kinetics, high conversion, and straightforward setup. In this context, site-specific branching initiation by using evolmers is potentially effective for structural control; however, the efficiency and kinetics in current reaction setups persists to be a major challenge. In this paper, an evolmer induces a controlled branching polymerization of cyanoacrylate amid the high monomer reactivity useful in rapid adhesion. The contrasting reactivities between the vinyl and the initiating groups in the evolmer molecule generate a kinetic pathway that favors a control-enabling branching mechanism. Through density functional theory calculations, the reaction pathway toward branching is shown to kinetically favor site-specific initiation by six orders of magnitude than the route toward non-specificity. Reaction monitoring confirms the branching polymerization after the polymerization with the evolmer forms a more compact structure than the linear counterpart. Control of branching density is demonstrated in rapid polymerizations within minutes and in polymerizations completed in an instant. These results provide a template for achieving site-specific branching initiation during adhesion formation and, broadly, where conditions for kinetic control are necessary.

Planar Chiral Charge-Transfer Cyclophanes: Convenient Synthesis, Circularly Polarized Light-Responsive Photothermal Conversion and Supramolecular Chiral Assembly.

We report herein a series of macrocycles in which the densely π-stacked charge-transfer (CT) donor/acceptor with naphthalenediimides (NDIs) or perylene diimide (PDI) as acceptor moiety pairing various donor moieties are locked by covalent bond. The X-ray crystallography of C8BDT-NDI reveals a short intramolecular π-stacking distance around 3.4 Å and the existence of intermolecular donor/acceptor π-stacking (3.7 Å). The intramolecular CT is highly dependent on the electron-donating ability of donor moiety and replacing carbazole (C8KZ) with benzo[1,2-b:4,5-b']dithiophene (C8BDT) or dihydroindolo[3,2-b]indole (C8DN) redshift CT absorption into NIR region. Notably, both C8BDT-NDI and C8DN-NDI demonstrate excellent photothermal performance, which is a result of the active non-radiative pathways. Interestingly, the different molecular symmetry between donor and acceptor moiety in cyclophanes endow C8BDT-NDI and C8DN-NDI with intrinsic planar chirality. The enantiomeric C8BDT-NDI shows chiral selectivity for incident light, i.e., when irradiated by left-circularly polarized light, (R)-C8BDT-NDI is more sensitive and a higher maximum stable temperature is achieved. While, enantiomeric C8DN-NDI pack with different orientations forming M- and P-handedness helix, respectively, demonstrating molecular planar chirality being transferred and amplified through molecular assembly. These results provide insight into the intramolecular charge transfer in enforced D/A π-stacks in which CT interactions and planar chirality would be engineered through structural control.

Effect of efficient structural tuning on the microstructure, corrosion resistance, and wear performance of AlCoCrFeNi/AT13 composite coatings

This study developed a rapid structure control technique for AlCoCrFeNi/AT13 (Al₂O₃–13 % TiO₂) composite coatings using plasma spraying and dual powder feeding. Four coatings were fabricated: pure HEA, HEA-D (dispersed), HEA-S1 (multilayer with outer HEA), and HEA-S2 (multilayer with outer AT13). The introduction of AT13 altered the internal stress distribution and enhanced corrosion resistance by lowering the electrochemical reaction rate. In layered coatings (HEA-S1, HEA-S2), the AT13 interlayer barrier reduced corrosion tendency. Additionally, pure HEA coatings exhibited adhesive wear. While HEA-D coatings experienced abrasive wear as AT13 particles improved plastic deformation and interface shearing. HEA-S1 reduced strain and wear via an internal AT13 layer. HEA-S2 achieved superior abrasion resistance through an outer AT13 layer, exhibiting typical abrasive wear mechanisms.

Correction to: Structural controls on cobalt mineralisation during regional metamorphism: an example from the Rajapalot area, Finland

Correction to: Structural controls on cobalt mineralisation during regional metamorphism: an example from the Rajapalot area, Finland

Improving the Dynamics of an Electrical Drive Using a Modified Controller Structure Accompanied by Delayed Inputs

This paper presents the operation of a modified speed controller with a standard PI/PID structure that includes the preprocessing of the controller’s input signal, focusing on the past behavior of control errors. The modification involves adding a delay line, with the outputs of the individual line segments summed with a weighting method, as detailed in the paper. One of the significant advantages of this method is its use of a standard industrial controller structure, which makes it highly practical and easily implementable in existing systems. By relying on well-established control frameworks, this approach reduces the need for specialized hardware or complex modifications, allowing for smoother integration and lower implementation costs. The delay-based signal shaping shows excellent properties for the electric drive system powered by a hard-switching PWM converter. The set of weighted delays acts as a filter whose parameters are chosen using the quality function to test different configurations for optimal performance. When tested in a speed control system for a Permanent Magnet Synchronous Motor, the modifications improved the control quality index, indicating better performance and efficiency. Importantly, the system allows for reducing or eliminating the gain in the differentiating part of the controller, which decreases motor current chattering and noise. This paper includes an experimental verification of the proposed solution in a laboratory setting under semi-industrial conditions.

Seismic response control of RC structure using U- shape damper as isolator

Seismic response control of RC structure using U- shape damper as isolator

Research on Digital Construction Technology for Special-Shaped Shell Pipe Structures

The aesthetic appeal of special-shaped shell pipe structures makes them highly favored by architects and holds promising prospects for various applications. In the detailed design stage, NURBS curves should be divided into multiple continuous arcs due to the limitations of current steel structure fabrication equipment, which can only accommodate pipes with equal-curvature bends. However, the traditional manual fitting methods suffer from several issues including low efficiency, undercutting at the interface, poor smoothness of curves, and lack of control over tolerances. Furthermore, the weaker out-of-plane stiffness and utilization of bending arc pipe sections pose significant challenges in terms of spatial positioning and installation accuracy that need to be addressed. The study focuses on addressing these challenges by investigating digital construction technology for special-shaped shell pipe structures and developing a parametric algorithm that enables automatic fitting of spatial NURBS curves into multiple arcs, thereby achieving seamless curve fitting. A post-processing program was developed to enable the parametric generation of fabrication and installation information for structural members, which can be seamlessly integrated into the BIM database. Finally, structural position control technology is proposed to improve assembly efficiency and ensure consistency between the completed construction state and the design shape. The above digital construction technology has been applied in projects such as the Haihua Island International Conference Center. It can provide complete technical solutions for modeling of special-shaped shell pipe structures, including establishment of a member information database, fabrication at the workshop and installation on site, construction organization management, as well as installation accuracy control.

Research on Voltage Prediction Using LSTM Neural Networks and Dynamic Voltage Restorers Based on Novel Sliding Mode Variable Structure Control

To address the issue of uncertainty in the occurrence time of voltage sags in power grids, which affects power quality, a voltage state prediction method based on LSTM neural networks is proposed for predicting voltage states. For the problem of quickly and accurately compensating for voltage sags, a DVR system based on a new approach law of sliding mode variable structure control is proposed, which significantly reduces chattering, improves response speed, and enhances the robustness of the system. The stability of the system is proven based on Lyapunov stability theory. Simulation experiments are conducted to analyze the voltage state prediction effect based on the LSTM neural network and the compensation effect of the novel reaching law of sliding mode variable structure control under different levels of voltage sag, validating the effectiveness and correctness of the proposed solution.