Search Results (1,716)

Fiber-reinforced polymer (FRP) composites are increasingly used in civil engineering for strengthening and repairing existing reinforced concrete (RC) members using externally bonded reinforcement (EBR) and near-surface mounted (NSM) methods. However, the fire performance of FRP-strengthened RC members has been an important issue that should be properly considered in the fire safety design process since FRP composites exhibit significant performance degradation at elevated temperatures. This paper aims to review studies on the fire performance of FRP-strengthened RC members based on the existing research results presented in the literature to provide a comprehensive understanding of key factors influencing the structural behavior of FRP-strengthened RC members under fire conditions. It provides an overview of FRP composite material properties, such as their mechanical and thermal behavior and bond characteristics between FRP-to-concrete interfaces at elevated temperatures. Additionally, this paper reviews experimental and numerical research conducted on FRP-strengthened RC members, examining load-carrying capacities and fire endurance ratings. Finally, this review will provide existing fire resistance design methods as well as simple design methods for temperature prediction. Full article

Hydraulic concrete is quite different from normal concrete in the terms of aggregate gradation and construction-induced interfaces. To explore their influences on the dynamic mechanical behaviors of hydraulic concrete, several mesoscale numerical models with different aggregate gradations and interfaces were established and subjected to dynamic compressive or tensile loadings. The results show that aggregate gradation significantly affected hydraulic concrete failure patterns under dynamic loads, but interface effects were less obvious, and stressing uniformity improved with an increasing loading rate. The dynamic compressive and tensile strengths of hydraulic concrete showed a strain rate effect independent of gradation, but decreased with larger coarse aggregates, especially at higher rates. Weak-bonding interfaces significantly reduced strength at low loading rates, with a more pronounced effect on tensile strength than compressive strength. The results of this study provide a theoretical basis for the application of hydraulic concrete containing large-size aggregates in practical engineering. Full article

Wound and injury healing processes are intricate and multifaceted, involving a sequence of events from coagulation to scar tissue formation. Effective wound management is crucial for achieving favorable clinical outcomes. Understanding the cellular and molecular mechanisms underlying wound healing, inflammation, and regeneration is essential for developing innovative therapeutics. This review explored the interplay of cellular and molecular processes contributing to wound healing, focusing on inflammation, innervation, angiogenesis, and the role of cell surface adhesion molecules. Additionally, it delved into the significance of calcium signaling in skeletal muscle regeneration and its implications for regenerative medicine. Furthermore, the therapeutic targeting of cellular senescence for long-term wound healing was discussed. The integration of cutting-edge technologies, such as quantitative imaging and computational modeling, has revolutionized the current approach of wound healing dynamics. The review also highlighted the role of nanotechnology in tissue engineering and regenerative medicine, particularly in the development of nanomaterials and nano–bio tools for promoting wound regeneration. Moreover, emerging nano–bio interfaces facilitate the efficient transport of biomolecules crucial for regeneration. Overall, this review provided insights into the cellular and molecular mechanisms of wound healing and regeneration, emphasizing the significance of interdisciplinary approaches and innovative technologies in advancing regenerative therapies. Through harnessing the potential of nanoparticles, bio-mimetic matrices, and scaffolds, regenerative medicine offers promising avenues for restoring damaged tissues with unparalleled precision and efficacy. This pursuit marks a significant departure from traditional approaches, offering promising avenues for addressing longstanding challenges in cellular and tissue repair, thereby significantly contributing to the advancement of regenerative medicine. Full article

The complex collagen network of the native meniscus and the gradient of the density and alignment of this network through the meniscal enthesis is essential for the proper mechanical function of these tissues. This architecture is difficult to recapitulate in tissue-engineered replacement strategies. Prenatally, the organization of the collagen fiber network is established and aggrecan content is minimal. In vitro, fibrochondrocytes (FCCs) produce proteoglycans and associated glycosaminoglycan (GAG) chains early in culture, which can inhibit collagen fiber formation during the maturation of tissue-engineered menisci. Thus, it would be beneficial to both specifically and temporarily block deposition of proteoglycans early in culture. In this study, we transiently inhibited aggrecan production by meniscal fibrochondrocytes using siRNA in collagen gel-based tissue-engineered constructs. We evaluated the effect of siRNA treatment on the formation of collagen fibrils and bulk and microscale tensile properties. Specific inhibition of aggrecan production by fibrochondrocytes via siRNA was successful both in 2D monolayer cell culture and 3D tissue culture. This inhibition during early maturation of these in vitro constructs increased collagen fibril diameter by more than 2-fold. This increase in fibril diameter allowed these tissues to distribute strains more effectively at the local level, particularly at the interface of the bone and soft tissue. These data show that siRNA can be used to modulate the ECM to improve collagen fiber formation and mechanical properties in tissue-engineered constructs, and that a transient decrease in aggrecan promotes the formation of a more robust fiber network. Full article

This study explores the development and performance of photocatalytic cementitious composites modified with nano-TiO₂ to address urban air quality and sustainability challenges. Nine mortar series were prepared, incorporating binders with varying carbon footprints and mass contents across different series. The interplay between the fundamental (abrasion resistance) and functional (air purification efficiency) properties of the composites’ surfaces and interfaces was investigated. The photocatalytic removal of airborne pollutants, specifically nitrogen oxides (NOx) and ozone (O₃), was evaluated under simulated environmental conditions. The variations in binder composition influenced the composites’ overall initial carbon footprint and air purification efficiency. The assessment revealed a possible net decrease in carbon emissions over the life cycle of the composite due to the removal of ozone (greenhouse gas) and its precursor—NOx, highlighting the potential of photocatalytic cementitious composites for dual environmental benefits in an urban environment, emphasizing the critical role of surface and interface engineering in achieving carbon-negative composites. Full article

The aerodynamic performance of transonic compressors, particularly the stall margin, is significantly influenced by inlet distortion. While time-marching methods accurately simulate such unsteady flows, they can be time-consuming. To enhance the computational efficiency, two Fourier-based methods are proposed in this paper: the time-accurate method with interface filtering and the time–space collocation (TSC) method. The time-accurate method with interface filtering ignores the rotor–stator interaction effects, enabling a larger time step and faster convergence. In contrast, the TSC method accounts for harmonics of conservative variables and transforms the unsteady simulation into multiple steady-state calculations, thereby reducing computational costs. The two Fourier-based methods are validated using NASA Stage 67 and a two-stage transonic fan. Near the peak efficiency point, the results from both methods closely match that of URANS simulation and experimental data. The time-accurate method with interface filtering demonstrates a speed enhancement of 4 to 5 times as a result of a reduction in the iteration steps. In contrast, the TSC method exhibits a speed improvement of at least 20 times in two specific cases, attributable to the significantly smaller mesh size and iteration steps employed in the TSC method compared to the URANS method. Near the stall point, more harmonics for inlet distortion are necessary in TSC simulation to accurately capture flow separation. In the two-stage transonic fan simulations, the strong rotor–stator interaction effects lead to deviations from the URANS simulation; nevertheless, the Fourier-based simulations accurately reflect the trend of the stall margin under total pressure distortion. Overall, the Fourier-based methods show promising potential for engineering applications in estimating the performance degradation of compressors subjected to inlet distortion. Full article

The voltage control of synchronous generators, particularly under varying load conditions, remains a significant and complex challenge in the field of engineering. Although various control methods have been implemented for automatic voltage regulator (AVR) systems to control the terminal voltage of synchronous generators, the PID-based control method continues to be one of the most basic and widely used approaches. Determining the optimal values for the Kp, Ki, and Kd values is essential to ensuring efficient and rapid performance in a PID controller. This study presents PLC-based PID controller tuning using an adaptive artificial bee colony–fuzzy logic (aABC-FL) approach for voltage control in a micro-hydro power plant installed as an experimental setup. The real-time control and monitoring of the system was conducted using an S7-1200 programmable logic controller (PLC) integrated with a totally integrated automation (TIA) portal interface and a SCADA screen. The aABC-Fuzzy design was developed using the MATLAB/Simulink platform, with PLC-MATLAB communication established through OPC UA and the KEPServerEX interface. The results obtained from experiments conducted under different load conditions showed that the proposed aABC-FL PID significantly minimized settling time and overshoot compared to the classical PLC-PID. Additionally, the proposed method not only provided a good dynamic response but also proved to be robust and reliable for real physical AVR systems. Full article

Geographic data are the foundation of geographic model construction, and any stage of their acquisition, processing, and analysis may have an impact on the efficiency and quality of geographic modeling and simulation. With the advent of the era of big data, a large number of data resources are generated in the field of geographic information. However, due to the heterogeneity of geographic data and the security of data usage, massive geographic data resources are difficult to fully explore and utilize, resulting in the formation of data islands. This paper proposes a service-oriented geographic data-sharing and computing framework, which provides users with a complete set of geographic data access and application processes (such as data acquisition, processing, configuration, etc.), so as to reduce the difficulty of using data and improve the efficiency of data sharing. The framework mainly consists of three core components: (1) the “Data service container” can publish data resources as data services to provide a consistent data access interface; (2) the “Workspace” provides a series of methods and tools for users to develop data-computing solutions; and (3) the “Data-computing engine” is responsible for performing computing tasks such as data processing and configuration. Finally, a case of runoff simulation using the SWAT model is designed, in which the whole process of data sharing, acquisition, calculation, and application is realized, so as to verify the validity of the proposed framework. Full article

The human skin is a remarkable organ capable of extensive regeneration, especially after severe injuries such as burns and related wounds. The de-epidermized dermis (DED) model has become a valuable in vitro tool for skin regeneration studies, particularly for testing the mechanism of action and the efficacy of clinical cutaneous cell therapies. To further improve the quality and robustness of these applications, our study focused on optimizing and standardizing DED tissue preparation and storage, enhancing its effectiveness for clinical testing. Therefore, we optimized the air-liquid interfacial culture medium composition by simplifying the historical formulation without compromising keratinocyte (therapeutic cell model) viability or proliferation. Furthermore, we investigated the impacts of adding burn wound exudates in the model by focusing on cell behavior for enhanced translational significance. The results revealed notable differences in keratinocyte adhesion and proliferation between burn wound exudates collected at the early stages and late stages of acute patient treatment, providing new information on a possible therapeutic window to apply cell therapies on burn patients. Generally, this study reported a robust method for the preclinical in vitro assessment of keratinocyte-based cutaneous cell therapies using DED models. Overall, the study underscored the importance of using in vitro models with enhanced translational relevance to better predict the clinical effects of cutaneous cell therapies in burn patient populations. Full article

This research follows closely previous findings in flow characteristics and phenomena that take place in the piston ring and cylinder liner interface during motoring and firing engine operation, and also compares results between different optical engine set-ups. Cavitation visualisation in a simulating lubrication single-ring test rig and oil transport and cavitation visualisation in custom made cylinder assemblies of optical engines are the tools used to quantify the transport process under the piston ring and cylinder liner. Simplification of the interface is an essential technique that enhances the researcher’s confidence in results interpretation. Engine complexity and severe oil starvation are impeding the analysis of the experimental results. Visualisation experiments constitute an effective way to test various lubricant types and assess their overall performance characteristics, including their properties and cavitation behaviour. The repeatability of the visualisation method establishes the parametric study effects and offers valuable experimental results. As a further step towards the lubricant composition effect, a link between the lubricant formulation and the operating conditions could be established as the oil performance is assessed with a view to its transport behaviour. Image processing is used to quantify the impact of cavitation on piston ring lubrication in conjunction with varied operating and lubricant parameters. The characteristics of the lubricant and the working environment have an impact on these types of cavities. Viscosity, cavitation, oil film thickness (OFT), lubricant shear-thinning characteristics and friction are all linked. Full article

Epoxy resins have exhibited exceptional performance in engineering applications, particularly as a replacement for traditional mechanical joints in adhesive bonding. This study evaluates the suitability of two innovative adhesives, SikaPower^®-1511 and SikaPower^®-1548, in various graded configurations. The thermal curing behavior of the adhesives was analyzed using differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). Shear tests and finite element simulations were employed to investigate the strength performance and interfacial stress distribution of four adhesive configurations, including single and graded joints in single lap adhesive joints. The results show that SikaPower^®-1548 reveals a slower heat-curing rate and achieves an average shear limit load of 9 MPa, outperforming the more rigid SikaPower^®-1511, which reaches 4 MPa. Ultimate load predictions indicate that the shear strength of the 1511-1548-1511 graded configuration is slightly lower than that of SikaPower^®-1511, with a decrease of 8.86%. In contrast, the 1548-1511-1548 configuration demonstrates a significant improvement, achieving a 32.20% increase in shear strength, along with a 13.12% reduction in peel stress field intensity at the interface end and a 12.21% reduction in shear stress field intensity. Overall, the experimental and simulation results highlight the significant advantages of graded joints over traditional single joints in alleviating stress concentrations and enhancing joint strength. Additionally, the research confirms the potential of epoxy resins in advanced engineering applications, providing a reliable theoretical foundation and technical guidance for the design of graded adhesives. Full article

Si anode materials are promising candidates for next-generation Li-ion batteries (LIBs) because of their high capacities. However, expansion and low conductivity result in rapid performance degradation. Herein, we present a facile one-pot method for pyrolyzing polystyrene sulfonate (PSS) polymers at low temperatures (≤400 °C) to form a thin carbonaceous layer on the silicon surface. Specifically, micron silicon (mSi) was transformed into porous mSi (por-mSi) by a metal-assisted chemical etching method, and a phenyl-based thin film derived from the thermolysis of PSS formed a strong Si–C/Si–O–C covalent bonding with the Si surface, which helped maintain stable cycle performance by improving the interfacial properties of mSi. Additionally, PSS-grafted por-mSi (por-mSi@PSS) anode was coated with polyaniline (PANI) for endowing additional electrical conductivity. The por-mSi@PSS/PANI anode demonstrated a high reversible capacity of ~1500 mAh g⁻¹ at 0.1 A g⁻¹ after 100 cycles, outperforming or matching the performance reported in recent studies. A thin double layer composed of phenyl moieties and a conductive PANI coating improved the stability of Si-based anodes and provided an effective pathway for Li⁺ ion transport to the Si interface, suggesting that polymer-modified Si anodes hold significant promise for advanced LIB applications. Full article

This study introduces AgroTec 4.0, which is a smart farming system designed to revolutionize strawberry cultivation in greenhouses through the integration of edge computing technology in the Andean region of Ecuador. The primary objective has been to enhance cultivation efficiency by comparing results from strawberry crops with and without the system, under identical greenhouse conditions. Given the low educational and economic status of local farmers, AgroTec 4.0 was engineered to be user-friendly, easy to operate, and cost-effective, empowering producers with data-driven decision-making capabilities. Key findings underscore the potential of AgroTec 4.0 and agricultural data, including a 15% increase in strawberry yield, from 5.0 kg/m² in the control greenhouse to 5.75 kg/m² with AgroTec 4.0, highlighting the system’s ability to maximize productivity. There has also been a significant 20% reduction in water usage, decreasing from 80 L/m² in the control greenhouse to 64 L/m² with the system, showcasing AgroTec 4.0’s efficiency in resource management. Furthermore, there were significant improvements in fruit quality, with an 11.8% increase in the Brix index (from 8.5 to 9.5) and a 16.7% increase in average fruit weight (from 30 to 35 g), demonstrating the system’s capacity to enhance product quality. Finally, there has been an impressive 103.03% return on investment (ROI) with AgroTec 4.0, compared to no change in ROI in the control greenhouse, emphasizing the economic value of implementing this technology. These results underscore the transformative potential of AgroTec 4.0 in precision agriculture, offering a scalable and sustainable approach for small-scale producers in Ecuador. The system’s modularity and real-time data analysis capabilities allow for flexible adaptation to various needs, providing farmers with an intuitive interface for managing crops and optimizing resource use. This study demonstrates the feasibility of leveraging agricultural data and edge computing to improve cultivation practices and enhance productivity, contributing efficiently to the sustainability of agriculture in challenging environments. Full article

Sodium-ion batteries (SIBs) hold significant promise in energy storage devices due to their low cost and abundant resources. Layered transition metal oxide cathodes (Na_xTMO₂, TM = Ni, Mn, Fe, etc.), owing to their high theoretical capacities and straightforward synthesis procedures, are emerging as the most promising cathode materials for SIBs. However, the practical application of the Na_xTMO₂ cathode is hindered by an unstable interface, causing rapid capacity decay. This work reviewed the critical factors affecting the interfacial stability and degradation mechanisms of Na_xTMO₂, including air sensitivity and the migration and dissolution of TM ions, which are compounded by the loss of lattice oxygen. Furthermore, the mainstream interface modification approaches for improving electrochemical performance are summarized, including element doping, surface engineering, electrolyte optimization, and so on. Finally, the future developmental directions of these layered Na_xTMO₂ cathodes are concluded. This review is meant to shed light on the design of superior cathodes for high-performance SIBs. Full article

Antimony selenide (Sb₂Se₃) shows promise for photovoltaics due to its favorable properties and low toxicity. However, current Sb₂Se₃ solar cells exhibit efficiencies significantly below their theoretical limits, primarily due to interface recombination and non-optimal device architectures. This study presents a comprehensive numerical investigation of Sb₂Se₃ thin-film solar cells using SCAPS-1D simulation software, focusing on device architecture optimization and interface engineering. We systematically analyzed device configurations (substrate and superstrate), hole-transport layer (HTL) materials (including NiOx, CZTS, Cu₂O, CuO, CuI, CuSCN, CZ-TA, and Spiro-OMeTAD), layer thicknesses, carrier densities, and resistance effects. The substrate configuration with molybdenum back contact demonstrated superior performance compared with the superstrate design, primarily due to favorable energy band alignment at the Mo/Sb₂Se₃ interface. Among the investigated HTL materials, Cu₂O exhibited optimal performance with minimal valence-band offset, achieving maximum efficiency at 0.06 μm thickness. Device optimization revealed critical parameters: series resistance should be minimized to 0–5 Ω-cm² while maintaining shunt resistance above 2000 Ω-cm². The optimized Mo/Cu₂O(0.06 μm)/Sb₂Se₃/CdS/i-ZnO/ITO/Al structure achieved a remarkable power conversion efficiency (PCE) of 21.68%, representing a significant improvement from 14.23% in conventional cells without HTL. This study provides crucial insights for the practical development of high-efficiency Sb₂Se₃ solar cells, demonstrating the significant impact of device architecture optimization and interface engineering on overall performance. Full article