Search Results (2,624)

This paper introduces a novel design for a liquid-deployed Piezoelectric Micromachined Ultrasonic Transducer (PMUT). This design was specifically developed to resonate at a lower ultrasonic frequency than a PMUT with a circular, fully clamped diaphragm with the same diameter. Furthermore, the novel design was also optimised to enhance its ultrasonic radiation reception capabilities. These parametric enhancements were necessary to develop a PMUT device that could form part of an eventual microscale sensory device used for the Structural Health Monitoring (SHM) of reinforced concrete (RC) structures. Through these two enhancements, an eventual microscale sensor can be made smaller, thus taking up a smaller die footprint and also be able to be deployed further apart from each other. Eventually, this would reduce the developed distributed sensor system’s cost. The innovative design employed a configuration where the diaphragm was only pinned at particular points along its circumference. This paper presents results from Finite Element Modelling (FEM), as well as experimental work that was conducted to develop and test this novel PMUT. The experimental work presented involved both laser vibrometry and ultrasonic radiation lab work. The results show that when compared to a clamped diaphragm design, the novel device managed to achieve the required reduction in resonant frequency and presented an enhanced sensitivity to incoming ultrasonic radiation. Full article

To improve the out-of-plane stability of partially encased composite (PEC) beam webs and enhance the synergy between concrete and section steel, a new type of wavy web PEC beam was designed and fabricated. In this study, the flange thickness and shear–span ratio were varied as key parameters. Low-cycle reversed loading tests were conducted to investigate the effects of these variables on the load-bearing capacity, failure patterns, deformation capacity, hysteretic energy dissipation capacity, and stiffness degradation of the wavy web PEC beams. Numerical simulations were performed using ABAQUS CAE2023, a finite element analysis (FEA) software, under low-cycle reversed loading conditions. The applicability of the ABAQUS software CAE2023 for the corrugated web PEC beam model was validated by comparing test results with finite element analysis results. A detailed parametric analysis was then carried out using the finite element model to further investigate the mechanical properties of the wavy web PEC beams. The research findings are as follows: the wavy web PEC beams exhibited good ductility; a larger shear–span ratio led to a transition in the failure pattern from shear failure to flexural failure; varying the flange thickness significantly affected the failure location and characteristics; and reducing the flange thickness could limit the propagation of concrete cracks, thereby improving toughness and energy dissipation capacity. Full article

Equivalent circuit models represent one of the most efficient virtual representations of battery systems, with numerous applications supporting the design of electric vehicles, such as powertrain evaluation, power electronics development, and model-based state estimation. Due to their popularity, their parameter extraction and model parametrization procedures present high interest within the research community, with novel approaches at an elementary level still being identified. This article introduces and compares in detail two novel parameter extraction methods based on the distinct application of least squares linear regression in relation to the autoregressive exogenous as well as the state-space equations of the double polarization equivalent circuit model in an iterative optimization-type manner. Following their application using experimental data obtained from an NCA Sony VTC6 cell, the results are benchmarked against a method employing differential evolution. The results indicate the least squares linear regression applied to the state-space format of the model as the best overall solution, providing excellent accuracy similar to the results of differential evolution, but averaging only 1.32% of the computational cost. In contrast, the same linear solver applied to the autoregressive exogenous format proves complementary characteristics by being the fastest process but presenting a penalty over the accuracy of the results. Full article

The depletion of global resources has intensified efforts to address energy scarcity. One promising area is the use of solar photovoltaic (PV) roofs for energy savings. This study conducts a comprehensive bibliometric analysis of 333 articles published between 1993 and 2023 in the Web of Science (WOS) core database to provide a global overview of research on solar photovoltaic (PV) roofs, with a particular emphasis on their energy-saving benefits. The analysis identifies current trends and future development trajectories in this field. Over the past three decades, research on solar PV roofs has shown steady growth, progressing from initial exploration to stable development. Key research themes include integrating renewable energy with building efficiency, the synergistic benefits of green roofs and PV systems, the design and practical application of PV-integrated roofs, and optimization techniques for parametric models. Future research will likely prioritize the efficient integration of PV components with roof maintenance structures, shifting from solely assessing PV component performance to evaluating the holistic performance of roofs and their broader impact on the built environment. This shift underscores the importance of improving the overall sustainability of the building. By aligning research efforts with these emerging trends, stakeholders can contribute to developing more effective and sustainable energy solutions for the future. Full article

With the rapid development of the information age, the need for high-resolution reconnaissance and surveillance is becoming more and more urgent. It is necessary to develop photoelectric pods with a high-precision stabilization function, which isolate the influence of external disturbance and realize the tracking of maneuvering targets. In this paper, the internal frame stabilization loop control technique is studied. Firstly, the mathematical models of the current loop are established. Secondly, the friction model, parametric model, and mechanical resonance model of the system are identified. Finally, a fourth-order tracking differentiator and a fifth-order extended state observer are designed. Through simulation verification, the stability performance of HO-ADRC, increasing by 145.17%, is better than that of PID. In terms of disturbance suppression and noise removal ability, HO-ADRC is also better than PID. Full article

Artificial intelligence (AI) requires the provision of learnable data to successfully deliver requisite prediction power. In this article, it is demonstrable that standard physico-chemical parameters, while useful, are insufficient for the development of powerful antimicrobial prediction algorithms. Initial models that focussed solely on the values extractable from the knowledge on electrotopological, structural and constitutional descriptors did not meet the acceptance criteria for classifying antimicrobial activity. In contrast, efforts to conceptually define the diametric opposite of an antimicrobial compound helped to advance the predicted category as a learnable trait. Remarkably, the inclusion of ligand–receptor interactions using the ability of the molecules to stimulate transmembrane TAS2Rs receptor helped to increase the ability to distinguish the antimicrobial molecules from the inactive ones, confirming the hypothesis of a predictor–predicted synergy behind bitterness psychophysics and antimicrobial activity. Therefore, in a single bio–endogenic psychophysical vector representation, this manuscript helps demonstrate the contribution to parametrization and the identification of relevant chemical manifolds for molecular design and (re-)engineering. This novel approach to the development of AI models accelerated molecular design and facilitated the selection of newer, more powerful antimicrobial agents. This is especially valuable in an age where antimicrobial resistance could be ruinous to modern health systems. Full article

With the implementation of the rural revitalization strategy, rural residences have become an essential component of China’s building energy conservation efforts. However, most existing research has focused more on urban buildings, with less attention given to rural residences. This study, taking rural residential buildings (RRBs) in the hot summer and cold winter zones in China as an example, proposes a more precise, two-stage optimization design framework using Rhino-Grasshopper for the overall optimization of RRBs. First, field surveys and numerical analysis of collected rural residential design drawings were conducted to clarify spatial characteristics and air conditioning usage. The parametric optimization design of RRBs was then conducted in two steps. The first step involves room function positioning, where spatial geometric models are established. Annual dynamic simulation analyses of AC (air conditioning) and AL (artificial lighting) energy consumption are performed to obtain energy intensity distribution maps. Based on the principle that “space with higher energy consumption is set in the location with lower energy consumption intensity” and the habit of functional space distribution, room function positioning, and adjustments are made. In the second step, the SPEA-2 genetic algorithm was applied for multi-objective optimization of room width, depth, WWR (window-to-wall ratio), SHGC (solar heat gain coefficient), and VLT (visible light transmittance), all based on the logical relationships of the building structure. The final Pareto front solution sets were obtained by multi-objective optimization simulation (MOO). A typical three-bay RRB was selected for application in this study, and the optimized design led to a total energy savings rate of 11% in annual AC and AL energy consumption. Full article

Background/Objective: Caregivers from the Millennial generation are an emerging and understudied group of unpaid care providers in America who may benefit from digitally delivered support. To inform the design/tailoring of interventions for this group, we aimed to understand how Millennials may differ from other generations of caregivers regarding digital health-related technology use. Methods: Using the Health Information National Trends Survey (HINTS), Version 6, we conducted a cross-sectional study comparing health technology access and use across four generations of unpaid caregivers (n = 545; Millennials, Gen X, Baby Boomers, and Silent Generation) of adults with chronic conditions using chi-square and Kruskal–Wallis non-parametric tests. Results: Compared to Baby Boomer and Silent Generation caregivers, Millennial caregivers more frequently reported having a cellular internet connection, using a wearable activity device, a health/wellness mobile application, choosing telehealth appointments for convenience, and most frequently used social media in general and to view health-related videos (ps < 0.005). Additionally, Millennials were more likely to report possessing a smartphone (compared to Gen X and Silent Generation) and more frequently used social media for peer interaction about health (compared to all older generations; ps < 0.005). Conclusion: Millennials differ from older generations of caregivers regarding health-related technology access and use, which may have implications for intervention design and tailoring. Full article

This paper investigates the seismic performance of thin-walled stiffened steel square box columns, modeling bridge piers subjected to unidirectional cyclic lateral loading with a constant axial load, focusing on local, global, and local-global interactive buckling phenomena. Initially, the finite element model was validated against existing experimental results. The study further explored the degradation in strength and ductility of both thin-walled and compact columns under cyclic loading. Thin-walled, stiffened steel square box columns exhibited buckling near the base, forming a half-sine wave shape. The research also addresses discrepancies from different material models used to analyze steel tubular bridge piers. Analysis using a modified two-surface plasticity model (2SM) yielded results closer to experimental data than a multi-linear kinematic hardening model, particularly for compact sections. The 2SM, which accounts for cycling within the yield plateau and strain hardening regime, demonstrated enhanced accuracy over the multi-linear kinematic hardening model. Additionally, a parametric study was conducted to assess the impact of key design parameters—such as width-to-thickness ratio (R_f), column slenderness ratio (λ), and magnitude of axial load (P/P_y)—on the performance of thin-walled stiffened steel square box columns. Design equations were then developed to predict the strength and ductility of bridge piers. These equations closely matched experimental results, achieving an accuracy of 95% for ultimate strength and 97% for ductility. Full article

Background: This study aimed to evaluate post-operative lower limb function following second-generation mechanically aligned medial pivot (MP) TKA implantation. Standard gait analysis was performed to collect kinematic and kinetic data, which were then compared with physiological data from the literature obtained using the same evaluation methodology as the present study. The hypothesis was that this TKA would not fully restore normal knee and adjacent joint motion during walking. Methods: Our cohort comprised 15 patients consecutively enrolled from September 2019 to December 2022 who underwent primary TKA with the second-generation MP Evolution Knee System (MicroPort Orthopaedics Inc., Arlington, TN, USA). Pre-operatively and 6 months post-surgery, gait analysis during level walking was performed on all patients, as well as clinical evaluations using the Knee Society Score (KSS), the Knee Injury and Osteoarthritis Outcome Score (KOOS), and the Visual Analogue Scale (VAS). Results: The clinical scores improved significantly (p < 0.001) after surgery (pre-/post-operative KSS functional, KSS clinical, VAS, and KOOS: 51.7 ± 17.3/84 ± 18.4, 45.3 ± 16.2/74.1 ± 12.6, 6.9 ± 1.8/2.0 ± 1.9, and 33.9 ± 11.8/69.1 ± 16.5, respectively). The statistical parametric mapping (SPM) analysis between the post-operative and reference control data revealed significant differences in the initial and final 20% of the gait cycle for the rotation of the knee in the frontal and transverse planes and for the rotation of the ankle in the sagittal plane. Conclusions: This study shows that new-generation MP TKA with mechanical alignment does not fully restore normal gait biomechanics, particularly in knee rotational movements, indicating a need for improved surgical techniques and prosthetic designs. Full article

To study the performance of lightweight foamed concrete (LWFC) in widened embankments of high-speed railways, this study first conducted numerous strength, permeability, and water immersion tests to investigate the mechanical properties and water resistance of LWFC with designed dry densities of 550, 600, and 650 kg/m³. Secondly, a field test was performed to analyze the behavior of the deformation and the internal pressure within the LWFC-filled portions. Furthermore, a parametric study via numerical modeling was performed to investigate the effects of four key factors on the performance of the LWFC-filled, widened embankments. Results showed that LWFC possesses adequate bearing capacity and impermeability to meet high-speed railway embankment widening requirements. However, water seepage reduces LWFC strength. The additional pressure from LWFC filling increases initially but then decreases once dehydration occurs. The settlement induced by LWFC accounted for 71% of the total filling height, which is only 37.5% of the total settlement after construction. The parametric study results show that the maximum settlement of widened and existing portions induced by LWFC was 46.3–49.6% and 48.3–53.2% of those induced by traditional fillers due to the LWFC’s lower density as well as their better self-supporting ability. Making an appropriate reduction in the thickness of the retain wall installed against the LWFC-filled widened embankment of the high-speed railway generates a few variations in the lateral deformation of the wall. Furthermore, the effects of the pile offset on the deformation of the LWFC-filled embankment were more sensitive compared to the diameter of the piles. Full article

Based on a systematic literature review, no design guidelines addressing practical issues related to steel circular hollow section (CHS) members under hydrostatic pressure have been documented thus far, except for the design recommendations proposed by the European standard EN 1993-1-6 concerning the strength and stability of shell structures. Considering that the existing codes are often outdated and subject to improvement, there is a growing demand for modern solutions that can accurately replicate the stability loss response of equipment subject to external pressure. The development of a more direct and simple method, augmented by reliable computational techniques, is advisable to avoid the numerous challenges associated with manual calculations. This approach will streamline the design process and mitigate the complexity of current practical or technical approaches. Thus, this research has formulated a method to predict design strength through the direct application of the critical elastic buckling stress, determined from Generalised Beam Theory (GBT) analyses, induced by hydrostatic pressure in custom-crafted equations, finely tuned for this specific objective. The authors present a formulation of GBT to analyze the elastic buckling behavior of CHS subject to both combined axial compression and external pressure. This work provides an extensive study of the behavior of circular cylindrical shells under external loading conditions. It first introduces the analyses of GBT and the theoretical and empirical formulas applicable to this objective. It then describes the steps involved in the development and validation of a numerical model that simulates the response of circular cylindrical shells under hydrostatic pressure, conducting an extensive parametric study using finite element analyses (FEAs). The results from available tests validate the finite element (FE) model. Upon achieving adequate agreement between the generated numerical and experimental results, new resistance reduction curves for cylindrical shell members are developed based on the results of the parametric study. Additionally, the study compares the existing provisions of EN 1993-1-6 for the design of cylindrical shells under hydrostatic pressure. Finally, a statistical approach is adopted to compare the responses of cylindrical shells calculated according to the EN 1993-1-6 code recommendations with those obtained through the newly proposed method. Full article

This study builds a refined finite element (FE) model to research the flexural behavior of a reinforced beam with prestressed CFRP tendons. The precision of the FE model is validated through a comparison with the experimental outcomes. The numerical findings align well with the experimental outcomes, encompassing the failure mode, load-deflection curve, load-strain curves of concrete, steel reinforcements and CFRP tendons. The variances between predicted values and experimental results are within 10%. Leveraging the verified FE model, an extensive parametric study has been carried out to examine the effects of various parameters, including the CFRP tendon prestress, the CFRP tendon diameter, the deviator layout, the anchorage height and the prestressing strand prestress. Leveraging the findings from the parametric study, some refined design recommendations are proposed for practical reinforcement applications: Increasing the CFRP tendon prestress in practical reinforcement designs is recommended; CFRP tendons with larger diameters are recommended for use in practical reinforcement designs; Employing a linear CFRP tendon profile for reinforcement is not considered optimal in practical applications; The prestress loss in the prestressing strands of PC beams should be considered in practice. Full article

Artificial reefs featuring different shapes and functions have been deployed around the world, causing impacts on marine ecosystems. However, the approaches typically used to deliver topological complexity, flexibility and expanding requirements to prospective structures during the initial design stages are not well established. The aim of this study was to highlight the advantages and provide evidence on how modularity and parametric design can holistically leverage the performance of multifunctional artificial reefs (MFARs). In particular, the goal was to develop a parametric design for MFAR and establish a direct relationship between specific design parameters and the MFAR target functions or design requirements. The idea of implementing the parametric design for generating the initial biomimetic geometry of the individual modular unit was explored. Furthermore, possible ways of manipulating the geometric parameters of the individual module and the whole assembly were proposed. The findings suggest that, by adopting the developed procedure and the examples studied, several functions may be reached within a single assembly: the promotion of marine biodiversity restoration, the support of scientific platforms with various sensors, as well as the development of recreational diving and of touristic attraction areas. Acquired knowledge suggests that the concept of a nature-like design approach was developed for artificial reefs with varying scales, complexity and functions, which widens the range of possibilities of how smart design of human-made underwater structures may contribute to benefiting the near shore ecosystems. Full article

The purpose of this study is to develop a new architectural model that responds to environmental pollution. The subject of this study is infrastructure buildings related to automobiles, which cause environmental pollution. Parking facilities accommodate several vehicles, necessitating the design of large-scale parking infrastructure. In this study, the parametric design of an energy-independent building was developed targeting the facade of a large-scale parking facility. As basic research for the development of the parametric design, a parking building was planned toward the optimization of parking space. Based on this basic research, a kinetic photovoltaic facade was developed to achieve optimal renewable energy generation from the perspective of eco-friendly architectural design. Energy simulation using building information modeling (BIM) on the kinetic photovoltaic system developed in this study over a period of one year resulted in the generation of a total of 692,386 kWh·year⁻¹. The novelty of this study is the development of a kinetic photovoltaic facade that is oriented according to the optimal tilt angle every month, focusing on the infrastructure. The significance of the kinetic photovoltaic system lies in the fact that it not only maximizes the efficiency of renewable energy generation but also presents a new architectural design model. Full article