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Keywords = resonance energies

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19 pages, 1159 KiB  
Article
Determining the Effect of Different Concentrations of Spent Coffee Grounds on the Metabolomic Profile of Swiss Chard
by Thabiso Motseo and Lufuno Ethel Nemadodzi
Int. J. Plant Biol. 2025, 16(3), 88; https://doi.org/10.3390/ijpb16030088 (registering DOI) - 7 Aug 2025
Abstract
In the coming decades, the agricultural system will predictably rely on organic material to produce crops and maintain food security. Currently, the use of inorganic fertilizers to grow crops and vegetables, such as Swiss chard, spinach, and lettuce, is on the rise and [...] Read more.
In the coming decades, the agricultural system will predictably rely on organic material to produce crops and maintain food security. Currently, the use of inorganic fertilizers to grow crops and vegetables, such as Swiss chard, spinach, and lettuce, is on the rise and has been proven to be detrimental to the soil in the long run. Hence, there is a growing need to use organic waste material, such as spent coffee grounds (SCGs), to grow crops. Spent coffee grounds are made of depleted coffee beans that contain important soluble compounds. This study aimed to determine the influence of different levels (0.32 g, 0.63 g, 0.92 g, and 1.20 g) of spent coffee grounds on the metabolomic profile of Swiss chard. The 1H-nuclear magnetic resonance (NMR) results showed that Swiss chard grown with different levels of SCGs contains a total of 10 metabolites, which included growth-promoting metabolites (trehalose; betaine), defense mechanism metabolites (alanine; cartinine), energy-reserve metabolites (sucrose; 1,6 Anhydro-β-D-glucose), root metabolites (thymine), stress-related metabolites (2-deoxyadenosine), caffeine metabo-lites (1,3 Dimethylurate), and body-odor metabolites (trimethylamine). Interestingly, caprate, with the abovementioned metabolites, was detected in Swiss chard grown without the application of SCGs. The findings of the current study suggest that SCGs are an ideal organic material for growing Swiss chard for its healthy metabolites. Full article
23 pages, 4361 KiB  
Article
Novel Visible Light-Driven Ho2InSbO7/Ag3PO4 Photocatalyst for Efficient Oxytetracycline Contaminant Degradation
by Jingfei Luan and Tiannan Zhao
Molecules 2025, 30(15), 3289; https://doi.org/10.3390/molecules30153289 - 6 Aug 2025
Abstract
In this study, a Z-scheme Ho2InSbO7/Ag3PO4 (HAO) heterojunction photocatalyst was successfully fabricated for the first time by ultrasound-assisted solvothermal method. The structural features, compositional components and morphological characteristics of the synthesized materials were thoroughly characterized by [...] Read more.
In this study, a Z-scheme Ho2InSbO7/Ag3PO4 (HAO) heterojunction photocatalyst was successfully fabricated for the first time by ultrasound-assisted solvothermal method. The structural features, compositional components and morphological characteristics of the synthesized materials were thoroughly characterized by a series of techniques, including X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectrum, X-ray photoelectron spectroscopy, transmission electron microscopy, scanning electron microscopy and energy-dispersive X-ray spectroscopy. A comprehensive array of analytical techniques, including ultraviolet-visible diffuse reflectance absorption spectra, photoluminescence spectroscopy, time-resolved photoluminescence spectroscopy, photocurrent testing, electrochemical impedance spectroscopy, electron paramagnetic resonance, and ultraviolet photoelectron spectroscopy, was employed to systematically investigate the optical, chemical, and photoelectronic properties of the materials. Using oxytetracycline (OTC), a representative tetracycline antibiotic, as the target substrate, the photocatalytic activity of the HAO composite was assessed under visible light irradiation. Comparative analyses demonstrated that the photocatalytic degradation capability of the HAO composite surpassed those of its individual components. Notably, during the degradation process, the application of the HAO composite resulted in an impressive removal efficiency of 99.89% for OTC within a span of 95 min, along with a total organic carbon mineralization rate of 98.35%. This outstanding photocatalytic performance could be ascribed to the efficient Z-scheme electron-hole separation system occurring between Ho2InSbO7 and Ag3PO4. Moreover, the adaptability and stability of the HAO heterojunction were thoroughly validated. Through experiments involving the capture of reactive species and electron paramagnetic resonance analysis, the active species generated by HAO were identified as hydroxyl radicals (•OH), superoxide anions (•O2), and holes (h+). This identification provides valuable insights into the mechanisms and pathways associated with the photodegradation of OTC. In conclusion, this research not only elucidates the potential of HAO as an efficient Z-scheme heterojunction photocatalyst but also marks a significant contribution to the advancement of sustainable remediation strategies for OTC contamination. Full article
(This article belongs to the Special Issue Nanomaterials in Photochemical Devices: Advances and Applications)
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21 pages, 2240 KiB  
Review
A Review of Fluorescent pH Probes: Ratiometric Strategies, Extreme pH Sensing, and Multifunctional Utility
by Weiqiao Xu, Zhenting Ma, Qixin Tian, Yuanqing Chen, Qiumei Jiang and Liang Fan
Chemosensors 2025, 13(8), 280; https://doi.org/10.3390/chemosensors13080280 - 2 Aug 2025
Viewed by 233
Abstract
pH is a critical parameter requiring precise monitoring across scientific, industrial, and biological domains. Fluorescent pH probes offer a powerful alternative to traditional methods (e.g., electrodes, indicators), overcoming limitations in miniaturization, long-term stability, and electromagnetic interference. By utilizing photophysical mechanisms—including intramolecular charge transfer [...] Read more.
pH is a critical parameter requiring precise monitoring across scientific, industrial, and biological domains. Fluorescent pH probes offer a powerful alternative to traditional methods (e.g., electrodes, indicators), overcoming limitations in miniaturization, long-term stability, and electromagnetic interference. By utilizing photophysical mechanisms—including intramolecular charge transfer (ICT), photoinduced electron transfer (PET), and fluorescence resonance energy transfer (FRET)—these probes enable high-sensitivity, reusable, and biocompatible sensing. This review systematically details recent advances, categorizing probes by operational pH range: strongly acidic (0–3), weakly acidic (3–7), strongly alkaline (>12), weakly alkaline (7–11), near-neutral (6–8), and wide-dynamic range. Innovations such as ratiometric detection, organelle-specific targeting (lysosomes, mitochondria), smartphone colorimetry, and dual-analyte response (e.g., pH + Al3+/CN) are highlighted. Applications span real-time cellular imaging (HeLa cells, zebrafish, mice), food quality assessment, environmental monitoring, and industrial diagnostics (e.g., concrete pH). Persistent challenges include extreme-pH sensing (notably alkalinity), photobleaching, dye leakage, and environmental resilience. Future research should prioritize broadening functional pH ranges, enhancing probe stability, and developing wide-range sensing strategies to advance deployment in commercial and industrial online monitoring platforms. Full article
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25 pages, 7503 KiB  
Article
A Diagnostic Framework for Decoupling Multi-Source Vibrations in Complex Machinery: An Improved OTPA Application on a Combine Harvester Chassis
by Haiyang Wang, Zhong Tang, Liyun Lao, Honglei Zhang, Jiabao Gu and Qi He
Appl. Sci. 2025, 15(15), 8581; https://doi.org/10.3390/app15158581 - 1 Aug 2025
Viewed by 222
Abstract
Complex mechanical systems, such as agricultural combine harvesters, are subjected to dynamic excitations from multiple coupled sources, compromising structural integrity and operational reliability. Disentangling these vibrations to identify dominant sources and quantify their transmission paths remains a significant engineering challenge. This study proposes [...] Read more.
Complex mechanical systems, such as agricultural combine harvesters, are subjected to dynamic excitations from multiple coupled sources, compromising structural integrity and operational reliability. Disentangling these vibrations to identify dominant sources and quantify their transmission paths remains a significant engineering challenge. This study proposes a robust diagnostic framework to address this issue. We employed a multi-condition vibration test with sequential source activation and an improved Operational Transfer Path Analysis (OTPA) method. Applied to a harvester chassis, the results revealed that vibration energy is predominantly concentrated in the 0–200 Hz frequency band. Path contribution analysis quantified that the “cutting header → conveyor trough → hydraulic cylinder → chassis frame” path is the most critical contributor to vertical vibration, with a vibration acceleration level of 117.6 dB. Further analysis identified the engine (29.3 Hz) as the primary source for vertical vibration, while lateral vibration was mainly attributed to a coupled resonance between the threshing cylinder (58 Hz) and the engine’s second-order harmonic. This study’s theoretical contribution lies in validating a powerful methodology for vibration source apportionment in complex systems. Practically, the findings provide direct, actionable insights for targeted structural optimization and vibration suppression. Full article
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14 pages, 4979 KiB  
Article
Oxygen Vacancy-Engineered Ni:Co3O4/Attapulgite Photothermal Catalyst from Recycled Spent Lithium-Ion Batteries for Efficient CO2 Reduction
by Jian Shi, Yao Xiao, Menghan Yu and Xiazhang Li
Catalysts 2025, 15(8), 732; https://doi.org/10.3390/catal15080732 - 1 Aug 2025
Viewed by 276
Abstract
Accelerated industrialization and surging energy demands have led to continuously rising atmospheric CO2 concentrations. Developing sustainable methods to reduce atmospheric CO2 levels is crucial for achieving carbon neutrality. Concurrently, the rapid development of new energy vehicles has driven a significant increase [...] Read more.
Accelerated industrialization and surging energy demands have led to continuously rising atmospheric CO2 concentrations. Developing sustainable methods to reduce atmospheric CO2 levels is crucial for achieving carbon neutrality. Concurrently, the rapid development of new energy vehicles has driven a significant increase in demand for lithium-ion batteries (LIBs), which are now approaching an end-of-life peak. Efficient recycling of valuable metals from spent LIBs represents a critical challenge. This study employs conventional hydrometallurgical processing to recover valuable metals from spent LIBs. Subsequently, Ni-doped Co3O4 (Ni:Co3O4) supported on the natural mineral attapulgite (ATP) was synthesized via a sol–gel method. The incorporation of a small amount of Ni into the Co3O4 lattice generates oxygen vacancies, inducing a localized surface plasmon resonance (LSPR) effect, which significantly enhances charge carrier transport and separation efficiency. During the photocatalytic reduction of CO2, the primary product CO generated by the Ni:Co3O4/ATP composite achieved a high production rate of 30.1 μmol·g−1·h−1. Furthermore, the composite maintains robust catalytic activity even after five consecutive reaction cycles. Full article
(This article belongs to the Special Issue Heterogeneous Catalysis in Air Pollution Control)
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18 pages, 2280 KiB  
Article
Theoretical Modeling of a Bionic Arm with Elastomer Fiber as Artificial Muscle Controlled by Periodic Illumination
by Changshen Du, Shuhong Dai and Qinglin Sun
Polymers 2025, 17(15), 2122; https://doi.org/10.3390/polym17152122 - 31 Jul 2025
Viewed by 262
Abstract
Liquid crystal elastomers (LCEs) have shown great potential in the field of soft robotics due to their unique actuation capabilities. Despite the growing number of experimental studies in the soft robotics field, theoretical research remains limited. In this paper, a dynamic model of [...] Read more.
Liquid crystal elastomers (LCEs) have shown great potential in the field of soft robotics due to their unique actuation capabilities. Despite the growing number of experimental studies in the soft robotics field, theoretical research remains limited. In this paper, a dynamic model of a bionic arm using an LCE fiber as artificial muscle is established, which exhibits periodic oscillation controlled by periodic illumination. Based on the assumption of linear damping and angular momentum theorem, the dynamics equation of the model oscillation is derived. Then, based on the assumption of linear elasticity model, the periodic spring force of the fiber is given. Subsequently, the evolution equations for the cis number fraction within the fiber are developed, and consequently, the analytical solution for the light-excited strain is derived. Following that, the dynamics equation is numerically solved, and the mechanism of the controllable oscillation is elucidated. Numerical calculations show that the stable oscillation period of the bionic arm depends on the illumination period. When the illumination period aligns with the natural period of the bionic arm, the resonance is formed and the amplitude is the largest. Additionally, the effects of various parameters on forced oscillation are analyzed. The results of numerical studies on the bionic arm can provide theoretical support for the design of micro-machines, bionic devices, soft robots, biomedical devices, and energy harvesters. Full article
(This article belongs to the Section Polymer Physics and Theory)
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13 pages, 1573 KiB  
Review
Recent Progress of Carbon Dots in Fluorescence Sensing
by Xiao-Tian Lou, Lei Zhan and Bin-Bin Chen
Inorganics 2025, 13(8), 256; https://doi.org/10.3390/inorganics13080256 - 31 Jul 2025
Viewed by 228
Abstract
Carbon dots (CDs) have attracted much attention as new types of luminescent carbon nanomaterials in recent years because of their tunable fluorescence, good biocompatibility, high stability, and low cost. In this review, the classification of CDs is overviewed based on their differences in [...] Read more.
Carbon dots (CDs) have attracted much attention as new types of luminescent carbon nanomaterials in recent years because of their tunable fluorescence, good biocompatibility, high stability, and low cost. In this review, the classification of CDs is overviewed based on their differences in structure. Subsequently, the latest research progress of CDs in fluorescence sensing is systematically summarized and various sensing principles are elucidated in detail, including fluorescence resonance energy transfer, aggregation-induced emission, aggregation-caused quenching, electron transfer, and the inner filter effect. Finally, the challenges and future direction of CD fluorescent probes are discussed in detail. The purpose of this review is to stimulate the design of advanced CD fluorescent probes and achieve the accurate and reliable measurement of analytes in complex samples. Full article
(This article belongs to the Special Issue Synthesis and Application of Luminescent Materials, 2nd Edition)
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25 pages, 7320 KiB  
Article
A Comprehensive Evaluation of a Chalcone Derivative: Structural, Spectroscopic, Computational, Electrochemical, and Pharmacological Perspectives
by Rekha K. Hebasur, Varsha V. Koppal, Deepak A. Yaraguppi, Neelamma B. Gummagol, Raviraj Kusanur and Ninganagouda R. Patil
Photochem 2025, 5(3), 20; https://doi.org/10.3390/photochem5030020 - 30 Jul 2025
Viewed by 210
Abstract
This study details how 3-(naphthalen-2-yl)-1-phenylprop-2-en-1-one (3NPEO) behaves in terms of photophysics when exposed to different solvents. The solvatochromic effect study reveals significant polarity shifts in the excited states of the 3NPEO compound, likely due to an intramolecular proton transfer mechanism. Measurements of dipole [...] Read more.
This study details how 3-(naphthalen-2-yl)-1-phenylprop-2-en-1-one (3NPEO) behaves in terms of photophysics when exposed to different solvents. The solvatochromic effect study reveals significant polarity shifts in the excited states of the 3NPEO compound, likely due to an intramolecular proton transfer mechanism. Measurements of dipole moments provide insight into their resonance structures in both ground and excited states. Electrochemical analysis revealed a reversible redox process, indicating a favorable charge transport potential. HOMO and LUMO energies of the compound were computed via oxidation and reduction potential standards. 3NPEO exhibits optimal one-photon and two-photon absorption characteristics, validating its suitability for visible wavelength laser applications in photonic devices. Furthermore, molecular docking and dynamics simulations demonstrated strong interactions between 3NPEO and the progesterone receptor enzyme, supported by structure–activity relationship (SAR) analyses. In vitro cytotoxicity assays on the MDAMB-231 breast cancer cell line showed moderate tumor cell inhibitory activity. Apoptosis studies confirmed the induction of both early and late apoptosis. These findings suggest that 3NPEO holds promise as a potential anticancer agent targeting the progesterone receptor in breast cancer cells. Overall, the findings highlight the substantial influence of solvent polarity on the photophysical properties and the design of more effective and stable therapeutic agents. Full article
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17 pages, 3206 KiB  
Article
Inverse Punicines: Isomers of Punicine and Their Application in LiAlO2, Melilite and CaSiO3 Separation
by Maximilian H. Fischer, Ali Zgheib, Iliass El Hraoui, Alena Schnickmann, Thomas Schirmer, Gunnar Jeschke and Andreas Schmidt
Separations 2025, 12(8), 202; https://doi.org/10.3390/separations12080202 - 30 Jul 2025
Viewed by 159
Abstract
The transition to sustainable energy systems demands efficient recycling methods for critical raw materials like lithium. In this study, we present a new class of pH- and light-switchable flotation collectors based on isomeric derivatives of the natural product Punicine, termed inverse Punicines. [...] Read more.
The transition to sustainable energy systems demands efficient recycling methods for critical raw materials like lithium. In this study, we present a new class of pH- and light-switchable flotation collectors based on isomeric derivatives of the natural product Punicine, termed inverse Punicines. These amphoteric molecules were synthesized via a straightforward four-step route and structurally tuned for hydrophobization by alkylation. Their performance as collectors was evaluated in microflotation experiments of lithium aluminate (LiAlO2) and silicate matrix minerals such as melilite and calcium silicate. Characterization techniques including ultraviolet-visible (UV-Vis), nuclear magnetic resonance (NMR) and electron spin resonance (ESR) spectroscopy as well as contact angle, zeta potential (ζ potential) and microflotation experiments revealed strong pH- and structure-dependent interactions with mineral surfaces. Notably, N-alkylated inverse Punicine derivatives showed high flotation yields for LiAlO2 at pH of 11, with a derivative possessing a dodecyl group attached to the nitrogen as collector achieving up to 86% recovery (collector conc. 0.06 mmol/L). Preliminary separation tests showed Li upgrading from 5.27% to 6.95%. Radical formation and light-response behavior were confirmed by ESR and flotation tests under different illumination conditions. These results demonstrate the potential of inverse Punicines as tunable, sustainable flotation reagents for advanced lithium recycling from complex slag systems. Full article
(This article belongs to the Special Issue Application of Green Flotation Technology in Mineral Processing)
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17 pages, 4598 KiB  
Article
Efficient Tetracycline Hydrochloride Degradation by Urchin-Like Structured MoS2@CoFe2O4 Derived from Steel Pickling Sludge via Peroxymonosulfate Activation
by Jin Qi, Kai Zhu, Ming Li, Yucan Liu, Pingzhou Duan and Lihua Huang
Molecules 2025, 30(15), 3194; https://doi.org/10.3390/molecules30153194 - 30 Jul 2025
Viewed by 179
Abstract
Steel pickling sludge serves as a valuable iron source for synthesizing Fe-based catalysts in heterogeneous advanced oxidation processes (AOPs). Here, MoS2@CoFe2O4 catalyst derived from steel pickling sludge was prepared via a facile solvothermal approach and utilized to activate [...] Read more.
Steel pickling sludge serves as a valuable iron source for synthesizing Fe-based catalysts in heterogeneous advanced oxidation processes (AOPs). Here, MoS2@CoFe2O4 catalyst derived from steel pickling sludge was prepared via a facile solvothermal approach and utilized to activate peroxymonosulfate (PMS) for tetracycline hydrochloride (TCH) degradation. Comprehensive characterization using scanning electron microscopy (SEM)-energy dispersive spectrometer (EDS), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) confirmed the supported microstructure, composition, and crystalline structure of the catalyst. Key operational parameters—including catalyst dosage, PMS concentration, and initial solution pH—were systematically optimized, achieving 81% degradation efficiency within 30 min. Quenching experiments and electron paramagnetic resonance (EPR) analysis revealed SO4∙− as the primary oxidative species, while the catalyst maintained high stability and reusability across cycles. TCH degradation primarily occurs through hydroxylation, decarbonylation, ring-opening, and oxidation reactions. This study presents a cost-effective strategy for transforming steel pickling sludge into a high-performance Fe-based catalyst, demonstrating its potential for practical AOP applications. Full article
(This article belongs to the Section Nanochemistry)
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18 pages, 4279 KiB  
Article
Chemophotothermal Combined Therapy with 5-Fluorouracil and Branched Gold Nanoshell Hyperthermia Induced a Reduction in Tumor Size in a Xenograft Colon Cancer Model
by Sarah Eliuth Ochoa-Hugo, Karla Valdivia-Aviña, Yanet Karina Gutiérrez-Mercado, Alejandro Arturo Canales-Aguirre, Verónica Chaparro-Huerta, Adriana Aguilar-Lemarroy, Luis Felipe Jave-Suárez, Mario Eduardo Cano-González, Antonio Topete, Andrea Molina-Pineda and Rodolfo Hernández-Gutiérrez
Pharmaceutics 2025, 17(8), 988; https://doi.org/10.3390/pharmaceutics17080988 - 30 Jul 2025
Viewed by 337
Abstract
Background/Objectives: The heterogeneity of cancer disease and the frequent ineffectiveness and resistance observed with currently available treatments highlight the importance of developing new antitumor therapies. The properties of gold nanoparticles, such as their photon-energy heating, are attractive for oncology therapy; this can [...] Read more.
Background/Objectives: The heterogeneity of cancer disease and the frequent ineffectiveness and resistance observed with currently available treatments highlight the importance of developing new antitumor therapies. The properties of gold nanoparticles, such as their photon-energy heating, are attractive for oncology therapy; this can be effective and localized. The combination of chemotherapy and hyperthermia is promising. Our aim was to evaluate the combination therapy of photon hyperthermia with 5-fluorouracil (5-FU) both in vitro and in vivo. Methods: This study evaluated the antitumor efficacy of a combined chemo-photothermal therapy using 5-fluorouracil (5-FU) and branched gold nanoshells (BGNSs) in a colorectal cancer model. BGNSs were synthesized via a seed-mediated method and characterized by electron microscopy and UV–vis spectroscopy, revealing an average diameter of 126.3 nm and a plasmon resonance peak at 800 nm, suitable for near-infrared (NIR) photothermal applications. In vitro assays using SW620-GFP colon cancer cells demonstrated a ≥90% reduction in cell viability after 24 h of combined treatment with 5-FU and BGNS under NIR irradiation. In vivo, xenograft-bearing nude mice received weekly intratumoral administrations of the combined therapy for four weeks. The group treated with 5-FU + BGNS + NIR exhibited a final tumor volume of 0.4 mm3 on day 28, compared to 1010 mm3 in the control group, corresponding to a tumor growth inhibition (TGI) of 100.74% (p < 0.001), which indicates not only complete inhibition of tumor growth but also regression below the initial tumor volume. Thermographic imaging confirmed that localized hyperthermia reached 45 ± 0.5 °C at the tumor site. Results: These findings suggest that the combination of 5-FU and BGNS-mediated hyperthermia may offer a promising strategy for enhancing therapeutic outcomes in patients with colorectal cancer while potentially minimizing systemic toxicity. Conclusions: This study highlights the potential of integrating nanotechnology with conventional chemotherapy for more effective and targeted cancer treatment. Full article
(This article belongs to the Special Issue Advanced Nanotechnology for Combination Therapy and Diagnosis)
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12 pages, 5121 KiB  
Article
Design of an Energy Selective Surface Employing Dual-Resonant Circuit Topology
by Honglin Zhang, Jihong Zhang, Song Zha, Huan Jiang, Tao Zhou, Chenxi Liu and Peiguo Liu
Electronics 2025, 14(15), 3029; https://doi.org/10.3390/electronics14153029 - 30 Jul 2025
Viewed by 164
Abstract
A dual-polarization energy selective surface (ESS) with low insertion loss (IL) and high shielding effectiveness (SE) based on a dual-resonant equivalent circuit topology was proposed for high-intensity radiation field (HIRF) protection in this paper. The design principle was elucidated through an equivalent circuit [...] Read more.
A dual-polarization energy selective surface (ESS) with low insertion loss (IL) and high shielding effectiveness (SE) based on a dual-resonant equivalent circuit topology was proposed for high-intensity radiation field (HIRF) protection in this paper. The design principle was elucidated through an equivalent circuit model and translated into a physical ESS implementation. It consists of two resonant rings, vertically arranged and loaded with diodes, along with two lumped capacitors. Simulation and measurement results demonstrate that the IL is less than 3 dB when in the OFF state in a working frequency band, and the SE exceeds 20 dB when in the ON state. Moreover, the ESS’s dual-polarization, low cost, and easy-to-design characteristics hold great promise for broad applications in protecting communication and radar systems in complex electromagnetic environments. Full article
(This article belongs to the Section Microelectronics)
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23 pages, 4301 KiB  
Article
Multiscale Modeling and Optimization of Aluminum Foam Material Properties Under Dynamic Load
by Andrei-Nicolae Bădăluţă, Sergiu-Valentin Galaţanu, Jaroslav Kováčik and Liviu Marşavina
Appl. Sci. 2025, 15(15), 8433; https://doi.org/10.3390/app15158433 - 29 Jul 2025
Viewed by 162
Abstract
Aluminum foam materials have gained significant attention over the past decade, particularly in the automotive industry, due to their excellent stiffness-to-weight ratio and superior energy absorption capabilities. In this study, a multiscale numerical material model was developed to accurately and efficiently simulate the [...] Read more.
Aluminum foam materials have gained significant attention over the past decade, particularly in the automotive industry, due to their excellent stiffness-to-weight ratio and superior energy absorption capabilities. In this study, a multiscale numerical material model was developed to accurately and efficiently simulate the vibrational behavior of aluminum foams. The foam specimens were categorized into four density classes based on their measured mass and calculated volume. Two specimens were selected to conduct CT (computerized tomography) scans and quantify the volume of air in their density class. Based on the CT measurements, a representative volume element (RVE) was built using ANSYS Material Designer (MD). The newly obtained material was employed in conducting normal mode numerical simulations. The resonance frequencies and response amplitudes were compared with physical experiments and showed correlation within 3%. These findings underscore the efficacy of using CT scans in foam to develop material models and accurately predict structural behavior. By conducting comprehensive investigations and numerical simulations, we established a correlation between physical tests and simulation results, highlighting the reliability of the developed models. Full article
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19 pages, 5970 KiB  
Article
Interface Material Modification to Enhance the Performance of a Thin-Film Piezoelectric-on-Silicon (TPoS) MEMS Resonator by Localized Annealing Through Joule Heating
by Adnan Zaman, Ugur Guneroglu, Abdulrahman Alsolami, Liguan Li and Jing Wang
Micromachines 2025, 16(8), 885; https://doi.org/10.3390/mi16080885 - 29 Jul 2025
Viewed by 278
Abstract
This paper presents a novel approach employing localized annealing through Joule heating to enhance the performance of Thin-Film Piezoelectric-on-Silicon (TPoS) MEMS resonators that are crucial for applications in sensing, energy harvesting, frequency filtering, and timing control. Despite recent advancements, piezoelectric MEMS resonators still [...] Read more.
This paper presents a novel approach employing localized annealing through Joule heating to enhance the performance of Thin-Film Piezoelectric-on-Silicon (TPoS) MEMS resonators that are crucial for applications in sensing, energy harvesting, frequency filtering, and timing control. Despite recent advancements, piezoelectric MEMS resonators still suffer from anchor-related energy losses and limited quality factors (Qs), posing significant challenges for high-performance applications. This study investigates interface modification to boost the quality factor (Q) and reduce the motional resistance, thus improving the electromechanical coupling coefficient and reducing insertion loss. To balance the trade-off between device miniaturization and performance, this work uniquely applies DC current-induced localized annealing to TPoS MEMS resonators, facilitating metal diffusion at the interface. This process results in the formation of platinum silicide, modifying the resonator’s stiffness and density, consequently enhancing the acoustic velocity and mitigating the side-supporting anchor-related energy dissipations. Experimental results demonstrate a Q-factor enhancement of over 300% (from 916 to 3632) and a reduction in insertion loss by more than 14 dB, underscoring the efficacy of this method for reducing anchor-related dissipations due to the highest annealing temperature at the anchors. The findings not only confirm the feasibility of Joule heating for interface modifications in MEMS resonators but also set a foundation for advancements of this post-fabrication thermal treatment technology. Full article
(This article belongs to the Special Issue MEMS Nano/Micro Fabrication, 2nd Edition)
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22 pages, 11766 KiB  
Article
Seismic Performance of Tall-Pier Girder Bridge with Novel Transverse Steel Dampers Under Near-Fault Ground Motions
by Ziang Pan, Qiming Qi, Ruifeng Yu, Huaping Yang, Changjiang Shao and Haomeng Cui
Buildings 2025, 15(15), 2666; https://doi.org/10.3390/buildings15152666 - 28 Jul 2025
Viewed by 163
Abstract
This study develops a novel transverse steel damper (TSD) to enhance the seismic performance of tall-pier girder bridges, featuring superior lateral strength and energy dissipation capacity. The TSD’s design and arrangement are presented, with its hysteretic behavior simulated in ABAQUS. Key parameters (yield [...] Read more.
This study develops a novel transverse steel damper (TSD) to enhance the seismic performance of tall-pier girder bridges, featuring superior lateral strength and energy dissipation capacity. The TSD’s design and arrangement are presented, with its hysteretic behavior simulated in ABAQUS. Key parameters (yield strength: 3000 kN; initial gap: 100 mm; post-yield stiffness ratio: 15%) are optimized through seismic analysis under near-fault ground motions, incorporating pulse characteristic investigations. The optimized TSD effectively reduces bearing displacements and results in smaller pier top displacements and internal forces compared to the bridge with fixed bearings. Due to the higher-order mode effects, there is no direct correlation between top displacements and bottom internal forces. As pier height decreases, the S-shaped shear force and bending moment envelopes gradually become linear, reflecting the reduced influence of these modes. Medium- to long-period pulse-like motions amplify seismic responses due to resonance (pulse period ≈ fundamental period) or susceptibility to large low-frequency spectral values. Higher-order mode effects on bending moments and shear forces intensify under prominent high-frequency components. However, the main velocity pulse typically masks the influence of high-order modes by the overwhelming seismic responses due to large spectral values at medium to long periods. Full article
(This article belongs to the Special Issue Seismic Analysis and Design of Building Structures)
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