Abstract Approximate resolution of linear systems of differential equations with varying coefficients is a recurrent problem, shared by a number of scientific and engineering areas, ranging from Quantum Mechanics to Control Theory. When formulated in operator or matrix form, the Magnus expansion furnishes an elegant setting to build up approximate exponential representations of the solution of the system. It provides a power series expansion for the corresponding exponent and is sometimes referred to as Time-Dependent Exponential Perturbation Theory. Every Magnus approximant corresponds in Perturbation Theory to a partial re-summation of infinite terms with the important additional property of preserving, at any order, certain symmetries of the exact solution. The goal of this review is threefold. First, to collect a number of developments scattered through half a century of scientific literature on Magnus expansion. They concern the methods for the generation of terms in the expansion, estimates of the radius of convergence of the series, generalizations and related non-perturbative expansions. Second, to provide a bridge with its implementation as generator of especial purpose numerical integration methods, a field of intense activity during the last decade. Third, to illustrate with examples the kind of results one can expect from Magnus expansion, in comparison with those from both perturbative schemes and standard numerical integrators. We buttress this issue with a revision of the wide range of physical applications found by Magnus expansion in the literature.
The steep stepwise uptake of water vapor and easy release at low relative pressures and moderate temperatures together with high working capacities make metal–organic frameworks (MOFs) attractive, promising materials for energy efficient applications in adsorption devices for humidity control (evaporation and condensation processes) and heat reallocation (heating and cooling) by utilizing water as benign sorptive and low-grade renewable or waste heat. Emerging MOF-based process applications covered are desiccation, heat pumps/chillers, water harvesting, air conditioning, and desalination. Governing parameters of the intrinsic sorption properties and stability under humid conditions and cyclic operation are identified. Transport of mass and heat in MOF structures, at least as important, is still an underexposed topic. Essential engineering elements of operation and implementation are presented. An update on stability of MOFs in water vapor and liquid systems is provided, and a suite of 18 MOFs are identified for selective use in heat pumps and chillers, while several can be used for air conditioning, water harvesting, and desalination. Most applications with MOFs are still in an exploratory state. An outlook is given for further R&D to realize these applications, providing essential kinetic parameters, performing smart engineering in the design of systems, and conceptual process designs to benchmark them against existing technologies. A concerted effort bridging chemistry, materials science, and engineering is required.
Over the past few years, the application of camera-equipped Unmanned Aerial Vehicles (UAVs) for visually monitoring construction and operation of buildings, bridges, and other types of civil infrastructure systems has exponentially grown. These platforms can frequently survey construction sites, monitor work-in-progress, create documents for safety, and inspect existing structures, particularly for hard-to-reach areas. The purpose of this paper is to provide a concise review of the most recent methods that streamline collection, analysis, visualization, and communication of the visual data captured from these platforms, with and without using Building Information Models (BIM) as a priori information. Specifically, the most relevant works from Civil Engineering, Computer Vision, and Robotics communities are presented and compared in terms of their potential to lead to automatic construction monitoring and civil infrastructure condition assessment.
Bone regenerative engineering provides a great platform for bone tissue regeneration covering cells, growth factors and other dynamic forces for fabricating scaffolds. Diversified biomaterials and their fabrication methods have emerged for fabricating patient specific bioactive scaffolds with controlled microstructures for bridging complex bone defects. The goal of this review is to summarize the points of scaffold design as well as applications for bone regeneration based on both electrospinning and 3D bioprinting. It first briefly introduces biological characteristics of bone regeneration and summarizes the applications of different types of material and the considerations for bone regeneration including polymers, ceramics, metals and composites. We then discuss electrospinning nanofibrous scaffold applied for the bone regenerative engineering with various properties, components and structures. Meanwhile, diverse design in the 3D bioprinting scaffolds for osteogenesis especially in the role of drug and bioactive factors delivery are assembled. Finally, we discuss challenges and future prospects in the development of electrospinning and 3D bioprinting for osteogenesis and prominent strategies and directions in future.
Accelerated industrialization has caused complex mixed toxicant pollution, where synergistic or antagonistic interactions render conventional detection methods inadequate. Herein, we develop an integrated framework by pioneering the integration of microbial electrochemical systems (MECs) with machine learning (ML) for quantifying formaldehyde, tetracycline, Ag<sup>+</sup>, and Cu<sup>2+</sup> in multi-component, multi-ratio, and multi-concentration mixtures. MECs generated dynamic current–time (I–t) signals responsive to toxicant stress, though signal overlap from mixed toxicants hindered direct quantification. Guided by toxicokinetics and electrochemical mechanisms, we developed a novel mechanism-driven feature engineering strategy with exclusively original indicators, which extracted 22 multidimensional features capturing instantaneous characteristics, kinetic patterns, and microbial stress-adaptive responses to resolve signal ambiguity, and provided biologically meaningful, high-information feature inputs that effectively bridge electrochemical response signals and ML modeling. Comparative analysis of four ML models (SVM, KNN, PLS, and RF) showed RF outperformed others, achieving R<sup>2</sup> > 0.9 for all toxicants (formaldehyde: 0.959; tetracycline: 0.934; Ag<sup>+</sup>: 0.936; Cu<sup>2+</sup>: 0.957) with minimized MAE and RMSE. Microbial community analysis identified <i>Geobacter anodireducens</i> (71.5%, electroactive for heavy metals) and <i>Comamonas testosteroni</i> (12.9%, organic degrader) as key functional taxa, supported by KEGG enzyme abundance data. This work overcomes traditional MEC limitations via innovative feature engineering and pioneering ML integration, providing a rapid, low-cost, and high-accuracy tool for environmental mixed toxicant monitoring.
Building Information Modeling (BIM) has changed the landscape of the architectural, engineering, and construction (AEC) industry in recent decades. However, BIM is not well researched in most developing countries; in particular, few studies have addressed its adoption in Malawi. A non-probability, purposive sampling approach was adopted. A total of 143 questionnaires were completed. This research reveals that, while construction experts are aware of BIM, the level of uptake remains quite low. Architects in Malawi are the most knowledgeable, followed by land surveyors and then engineers. This research shows that most experts in Malawi are at level 1 of BIM usage, which is the first stage of BIM adoption and is characterized by the use of 3D models and output representation. Furthermore, the study results have shown that the Malawian AEC sector is currently succeeding at the modelling stage of maturity but is stalled by lack of collaborative frameworks, such as Integrated Project Delivery (IPD). Therefore, unless the industry shifts toward a unified Common Data Environment (CDE), advanced capabilities like clash detection will remain underutilized and disconnected from broader project success metrics. Statistical analysis has shown that the correlation analysis demonstrates a strong link (r = 0.75) between Integrated Project Delivery (IPD) and high BIM maturity, whereas traditional Design-Bid-Build methods show a critical misalignment with digital workflows. The study identifies high software costs and a lack of national standards as the primary barriers to adoption. Therefore, there is a need for robust sensitization to the benefits of BIM and training to improve its uptake in the context of Malawi’s construction industry. In order to advance Malawi’s BIM maturity, the research recommends a strategic shift toward integrated procurement models, the establishment of national BIM mandates, and the modernization of technical education to bridge the existing knowledge gap.
Based on the steel sheet pile cofferdam project for the main bridge piers of a cross-sea bridge, finite element numerical simulations were conducted to analyze the influence of construction sequences in marine environments, as well as the effects of initial water levels and support positions under various construction conditions on the stress and deformation behavior of steel sheet piles. Using a staged construction simulation with a Mohr–Coulomb soil model and stepwise activation of loads/excavation, this study delivers practically relevant trends: staged dewatering halves the sheet pile head displacement (top lateral movement <0.08 m vs. ~0.16 m in the original scheme) and mobilizes the support system earlier, while slightly increasing peak bending demand (~1800 kN·m) at the bracing elevation; the interaction between water head and brace elevation is explored through fitted response curves and summarized in figures/tables, and soil/structural properties are tabulated for reproducibility. The results indicate that a well-designed dewatering process, along with the coordination between water levels and internal support positions, plays a critical role in controlling deformation. The findings offer valuable references for the design and construction of sheet pile cofferdams in marine engineering under varying construction methods and water level conditions.
Ecological-self-compacting concrete (Eco-SCC) pavements offer advantages such as reduced cement consumption, lower carbon emissions, and improved economic performance. However, their durability has not been sufficiently studied. Based on the literature review and fatigue test data, the fatigue parameters of Eco-SCC were determined using the Chaboche damage evolution model. A finite element model of fatigue damage in Eco-SCC pavement structures was established to compare the fatigue damage distribution under different loading positions, identify the unfavorable loading positions, and analyze the influence of slab thickness and modulus on the durability of Eco-SCC pavements. SCC plate thickness and modulus on the durability of Eco-SCC pavement. The results show that fatigue damage under different loading positions is mainly distributed at the bottom of the slab, and controlling the bending and tensile stresses at the slab bottom is key to improving Eco SCC pavement durability. For longitudinal cracking, the most unfavorable loading positions are ranked as slab corner > slab edge > slab center; for transverse cracking, the order is slab edge > slab corner > slab center, which is consistent with the Specifications for Design of Highway Cement Concrete Pavement (JTG D40—2011). Increasing the slab thickness or decreasing the modulus effectively suppresses both transverse and longitudinal cracking of Eco-SCC pavements. To optimize longitudinal cracking control while delaying transverse cracking, it is recommended that, when the modulus is 24 000 MPa, 30 000 MPa, and 40 000 MPa, the slab thicknesses be set at 26 cm, 28 cm, and 30 cm, respectively.
Raghavendra Bakale, Santosh S. Pawar, S.K. Sushant
et al.
This review article provides an overview of the development and applications of biomaterials in the areas of design and functionality of medical devices, dental implants, and prosthetics, highlighting recent advancements, challenges, and future directions.The foundation of this review lies in the examination of the classification, properties, and characteristics of various biomaterials, encompassing metals, ceramics, polymers, composites, natural biomaterials and hybrid biomaterials. Biomaterials have found extensive applications in medical devices, such as cardiovascular stents, pacemakers, implantable sensors, and biosensors. In dental implants, titanium-based and ceramic-based implants have improved osseointegration and aesthetics. Prosthetics have also been benefited from biomaterials, with advancements in limb replacements, orthotics, and tissue engineering scaffolds.The biological interactions between biomaterials and the human body are crucial, with biocompatibility, bioactivity, and biodegradability being key considerations. Recent advancements in biomaterials design, such as nanostructured surfaces, bio-inspired materials, and 3D printing, have enhanced biomaterials performance. However, challenges persist, including toxicity and biocompatibility concernsand mechanical property optimization.Despite these challenges, biomaterials research continues to advance, driven by emerging trends such as personalized medicine, tissue engineering, biohybrid systems, tailored biomaterials for individual patient needs, biomaterials-based scaffolds for tissue regeneration and integrating biomaterials with living tissues hold immense promise.
This review aims to provide researchers, clinicians, and industry professionals with a thorough understanding of biomaterials development and applications, inspiring innovative solutions for improved healthcare outcomes.By exploring the vast potential of biomaterials, this review seeks to bridge the gap between materials science, engineering, and medicine, fostering collaboration and innovation in the pursuit of better patient care.
Abstract: The review of space applications of MEMS sensors as well as the fi rst presentation
of plasma fluid optical gas microspectrometer and ion mass microspectrometer, developed in
Poland for future Venusian, Martian and Lunar missions have been presented. Additionally,
Polish subminiature biomedical lab-on-chip payload and its space tests at LOE has been
showed. Finally CSAC atomic microclock and its applications has been discussed.
Keywords: MEMS; Space; Miniaturization; Spectrometer; Lab-chip; CSAC
Highway engineering. Roads and pavements, Bridge engineering
Post-grouted shafts (PGDS) and stiffened deep cement mixed (SDCM) shafts reinforce the surrounding soils with cement to enhance the bearing capacity of shaft foundations, and their applications are becoming increasingly widespread. Field tests involving two post-grouted shafts and two stiffened deep cement mixing shafts were conducted at the bridge foundations projects, analyzing the vertical bearing performance of the shafts with cement-stabilized soil enhancement. Additionally, numerical simulations were performed to establish calculation models for single shaft and groups of drilled shafts, PGDS, and SDCM shafts, enabling a comparative analysis of their bearing capacity performance within the identical strata. The results indicate that the post-grouted shaft demonstrated significant bearing deformation capacity, as confirmed by field tests. After grouting, the ultimate bearing capacities of DS1 and DS2 improved by 124.5 % and 110.9 %, respectively. In both single and group modeling shaft foundations, the post-grouted shafts demonstrated the highest bearing deformation characteristics, followed by the identical-size stiffened deep cement mixed shaft, while the long-core SDCM shafts and the ungrouted shafts exhibited the weakest performance. Due to interaction effects among group shafts, the total bearing capacity of the group shafts is not simply the sum of the individual shafts. Specifically, the reduction factor for group shaft capacity ranges from 0.68 to 0.79 at the Baoying Large Bridge site, while at the Yangkou Canal Bridge site, it varies from 0.66 to 0.85. The findings of this study provide valuable insights for practical engineering applications.
Materials of engineering and construction. Mechanics of materials
Accurate prediction of concrete compressive strength is essential for ensuring structural safety in civil engineering, particularly in road and bridge construction, where inadequate strength can lead to deformation, cracking, or collapse. Traditional non-destructive testing (NDT) methods, such as the Rebound Hammer Test, estimate strength using regression-based formulas fitted with measurement data; however, these formulas, typically optimized via the least squares method, are highly sensitive to initial parameter settings and exhibit low robustness, especially for nonlinear relationships. Meanwhile, AI-based models, such as neural networks, require extensive datasets for training, which poses a significant challenge in real-world engineering scenarios with limited or unevenly distributed data. To address these issues, this study proposes a gradient-boosting artificial bee colony (GB-ABC) algorithm for robust regression curve fitting. The method integrates two novel mechanisms: gradient descent to accelerate convergence and prevent entrapment in local optima, and a point density-weighted strategy using Gaussian Kernel Density Estimation (GKDE) to assign higher weights to sparse data regions, enhancing adaptability to field data irregularities without necessitating large datasets. Following data preprocessing with Local Outlier Factor (LOF) to remove outliers, validation on 600 real-world samples demonstrates that GB-ABC outperforms conventional methods by minimizing mean relative error rate (RER) and achieving precise rebound-strength correlations. These advancements establish GB-ABC as a practical, data-efficient solution for on-site concrete strength estimation.
The combination system bridges of cable-stayed and shaped arch bridges feature innovative structures and complex force distributions, necessitating intricate construction processes. Monitoring these processes ensures that the bridge's stress state aligns with designed internal forces. Measured stress values on the main girder's edges align with theoretical trends but are slightly lower. Throughout construction, the middle span experiences compression, with maximum stresses of -5.1 MPa on both edges. Full support during construction minimizes the impact of stay cable and derrick tension on main girder stress. After support removal, compressive stress increases on the upper edge and decreases on the lower. The tower’s elevation is slightly above design, aiding in reducing prestress loss and deflection in later stages. At 16.5 m above the bridge girder, the tower’s left side experiences tension and the right compression, with a tensile stress of only 1.0 MPa, indicating sound design and effective construction control. Received: 30.1.2025 Received in revised version: 14.7.2025 Accepted: 30.8.2025
In the past 30 years, the wind resistance of railway bridges has undergone great success with the efforts from the whole research community under the rapid developments of high-speed railways in China. The present paper thus aims to illustrate this success and provide our personal perspectives for future studies. The wind resistance of railway bridges is a new branch of bridge wind engineering. Thus, we first trace the wind-induced collapse of 1940 Tacoma Narrows Bridge in America and the wind resistant design of Maogang Bridge in China. Then, the developments of bridge wind engineering community in China and its in-service, newly constructed, and under construction test facilities are introduced. Referring to the “Alan G. Davenport Wind Loading Chain”, the recent developments are separately demonstrated in the following five aspects: wind properties, wind loads, bridge dynamic characteristics, wind-induced vibrations, and prevention and control technologies. Based on the above research results, the first wind resistance specification for railway bridges has been published and implemented. Finally, a non-comprehensively perspective on the wind resistance of railway bridges is provided with the aim to trigger more advanced improvements in this research area.
Abstract The real juncture between corrugated steel webs (CSWs) and flanges follows a multi-segmented line, distinct from that of flat steel webs. Classic methods may yield significant deviations in predicting the elastic global shear buckling capacity of CSWs of various scales due to their failure to consider real boundary constraints. Therefore, a universally applicable formula for calculating the elastic critical global shear buckling stress of CSWs, which accounts for real boundary conditions, is proposed. This formula is pertinent to both large-scale engineering CSWs and small-scale testing CSWs. This study commenced with a comprehensive reassessment of the elastic global shear buckling calculation method. Subsequently, the influence of geometric parameter ratios on the elastic critical global buckling stress was examined. The primary parameter was identified and employed to improve the global buckling coefficient. The proposed calculation method was validated using different corrugation configurations, including 1000-type, 1200-type, 1600-type, 1800-type, and 2000-type CSWs, as well as other CSWs used in experimental settings. These results were compared with those obtained from other reference methods. Findings indicate that the accuracy of the classic theoretical method is affected by variations in both boundary conditions and geometric dimensions due to the constraint effect of real boundary conditions. Under the real boundary conditions, the elastic critical global shear buckling stress of CSWs with simply supported boundary conditions is close to that of CSWs with consolidated boundary conditions. The ratio of web height to corrugation depth primarily affects the elastic global shear buckling capacity, which decreases as the ratio increases. The Easley formula can be modified based on the web height to corrugation depth ratio. Comparisons of numerous numerical and theoretical results reveal that the proposed calculation method exhibits commendable computational precision. In comparison to alternative formulas, the proposed method demonstrates enhanced consistency for calculating CSWs with varying geometric dimensions and boundary conditions, thereby demonstrating its favorable applicability. These conclusions provide valuable reference for the shear design of CSWs.