Search Results (106)

Background: Medial-compartment knee osteoarthritis (KOA) carries substantial disability and long-term cost. High tibial osteotomy (HTO) and unicompartmental knee arthroplasty (UKA) are key joint-preserving or joint-replacing options for selected patients, but their comparative economic ranking remains uncertain. Methods: This critical narrative review synthesized comparative economic evidence on HTO versus UKA for isolated medial-compartment KOA. PubMed and Web of Science were searched as primary sources for English-language studies published from 1 January 2000 to 15 January 2026, while Google Scholar and citation tracking were used supplementarily to identify potentially missed records. Eligible studies were direct economic evaluations or comparative cost/resource studies with clear decision relevance to the HTO–UKA choice. Burden and cost-of-illness studies were used for contextual framing only and were not included in the core comparative synthesis. Results: The direct evidence base was small and methodologically heterogeneous and was dominated by decision-analytic models that differed in perspective, time horizon, utility metric, and assumptions regarding reoperation, revision, and conversion to total knee arthroplasty (TKA). These structural differences largely explain why a U.S. lifetime societal model favored HTO, a UK age-stratified 10-year model produced age-dependent findings, and a recent Canadian public-payer model favored UKA. Observational studies suggest that UKA episode costs can fall substantially in outpatient or ambulatory pathways, whereas HTO costs may rise when reoperations and technique-specific resource use are explicitly captured. Conclusions: Current evidence does not support a context-free economic ranking of HTO and UKA. Because the available studies are heterogeneous and incremental utility differences are often small, the findings should be interpreted cautiously and as scenario-dependent rather than definitive. Future comparative analyses should use contemporary pathway data, transparent and standardized costing, and explicit downstream event definitions for both procedures. Full article

On 6 February 2023, Türkiye was struck by two devastating earthquakes with moment magnitudes of 7.8 and 7.6, causing severe damage to numerous tall reinforced concrete buildings and emphasizing the need for improved seismic design strategies. This study investigates the seismic response of a representative high-rise reinforced concrete building by systematically varying the shear wall area-to-floor area ratio, a key parameter directly influencing lateral stiffness and overall stability. Utilizing a solid modeling approach and incorporating three-directional seismic records, this research provides detailed insights into displacement behavior beyond conventional frame-based analyses. Focusing on Adana, a major urban center with a significant concentration of tall buildings and notable seismic risk, three design scenarios with shear wall ratios of 1.14%, 1.54%, and 2.1% were examined. The results demonstrate that increasing the shear wall cross-sectional area compared to the building plan area significantly reduces lateral and vertical displacements, with the most pronounced improvement observed when moving from 1.14% to 1.54%. Further increase to 2.1% provides additional enhancement in seismic performance. This study suggests that adopting a minimum shear wall area-to-floor area ratio of at least 2% along each principal direction (resulting in a total combined ratio of approximately 4% for the building) can substantially improve seismic resilience and mitigate collapse risk in tall structures. Importantly, the shear wall ratios were considered separately for each principal direction, with the total combined ratio doubling, highlighting the need for balanced wall distribution in both directions. Full article

The study presented a newly proposed mega-sub controlled structure system (MSCSS), connected to the design and building of high-rise structures, as enhanced durability and efficiency of mega-structural frames attracted the attention of researchers. In this article, a more reasonable and advanced mega-sub controlled structure model is designed and investigated under wind load. The complex model analysis theory is used to generate the equations of motion, the response spectrum (RS) expression, and the mean square response (MSR). The dynamic features that influence the control response of MSCSS, such as relative stiffness ratio (RD) and relative mass ratio (MR) between the mega-frame and substructure, are defined and investigated. The result showed that the displacement effectiveness is highly effective at low stiffness ratios, with a sharp decrease in maximum displacement observed when RD is less than 0.17 (RD < 0.17). Optimal response control effectiveness was identified within the RD range of 0.17 to 0.6. Also, the result indicates better acceleration control effectiveness when RD is between 0.3 and 0.5; however, this control decreases significantly when RD > 0.6. Furthermore, the study reveals that increasing the relative mass ratio obviously improves both displacement and acceleration control effectiveness at fixed RD = 0.3. Full article

This study presents a probabilistic assessment of seismic loss and recovery for residential buildings in Bucharest, Romania, using the FEMA P-58 framework implemented in SP3. A typology set is developed to represent the building stock, accounting for structural system, construction period, and height. The analysis evaluates scenario-based losses, functional recovery times, and expected annual loss (EAL) across seismic hazard levels representative of Vrancea earthquakes. Results show that frame-based systems are highly sensitive to building height, with the highest losses and longest recovery times in older mid- and high-rise buildings. For pre-1990 construction, masonry-infilled reinforced concrete frames are more representative than bare frames and drive the vulnerability of the older building stock. Reinforced concrete shear wall systems perform better, with lower losses and faster recovery across all categories. Nonstructural damage, especially drift-sensitive components, is a contributor to both repair cost and downtime. The results are interpreted comparatively, highlighting the role of structural system, code era, and height. While absolute values depend on modeling assumptions, the study provides a consistent basis for identifying vulnerable typologies and supporting risk mitigation and resilience planning. Full article

Long-period ground motions (LPGMs), rich in low-frequency content, can resonate with long-period structures like high-rise buildings, leading to severe damage. As seismic design shifts from safety toward resilience, limited attention to LPGMs makes it difficult to ensure the seismic resilience of long-period structures. This study used Perform-3D software to model three high-rise reinforced concrete (RC) frame–shear wall structures with varying periods and one with infill walls for resilience assessment. The resilience indicators and seismic resilience grades under LPGMs and ordinary ground motions (OGMs) were compared using the Standard for Seismic Resilience Assessment of Buildings (GB/T38591-2020) and the Guideline for Evaluation of Seismic Resilience Assessment of Urban Engineering Systems (RISN-TG041-2022), which are national standards in China. The results show that the structural response under LPGMs is significantly different from that under OGMs. In particular, the influence of LPGMs on displacement-sensitive non-structural components is much greater than OGMs. Resilience indicators were higher under LPGMs. The presence of infill walls notably reduced resilience indicators, with a stronger effect under OGMs. Based on GB/T38591-2020, the seismic resilience of each structure generally decreases by 1–2 grades under LPGMs, while evaluations based on RISN-TG041-2022 show similar ratings under both LPGMs and OGMs. Full article

Low-voltage ride-through (LVRT) capability is essential for grid-connected photovoltaic (PV) systems, especially as rising renewable integration challenges grid stability during voltage disturbances. Existing LVRT methods often target isolated control functions, leading to limited system resilience. This paper presents a unified control strategy integrating DC-link voltage regulation, reactive power injection, and overvoltage mitigation using a coordinated fuzzy logic framework. The proposed architecture employs a cascaded control structure comprising an outer voltage loop and an inner current loop with feed-forward decoupling, synchronized via a Synchronous Reference Frame Phase-Locked Loop (SRF-PLL). At its core is a dual-input, single-output Fuzzy Logic Controller (FLC), featuring optimized membership functions and dynamic rule-based logic to manage multiple control objectives during grid faults. The proposed FLC-based unified LVRT controller for grid-tied PV system was implemented and validated for both symmetrical and asymmetrical fault conditions in MATLAB/Simulink 2023b platform. The proposed FLC-based LVRT controller achieves voltage sag compensation of 97.02% and 98.4% for symmetrical and asymmetrical faults, respectively, outperforming conventional PI control, which achieves 94.02% and 96.5%. The system maintains a stable DC-link voltage of 800 V and delivers up to 78% reactive power support during faults. Fault detection and recovery are completed within 200 ms, complying with Bangladesh grid code requirements. This integrated fuzzy logic approach offers a significant advancement for enhancing grid stability in high-renewable environments and supports reliable renewable utilization, and more sustainable grid operation in developing regions. Full article

The truss transfer story serves as a critical structural zone connecting different structural systems in high-rise buildings. This component incorporates numerous inclined-web trusses, which are prone to cracking and failure under seismic events. To enhance the seismic performance of long-span transfer structures and address the tensile cracking vulnerability of inclined-web trusses in conventional truss transfer stories, this study investigates the seismic behavior of a novel composite system: a prestressed CFRP tendon–steel-reinforced concrete transfer story structure with inclined-web trusses and two specimens of inclined-web truss transfer story frames—with and without prestressed CFRP tendons—were designed and fabricated. These specimens were subjected to horizontal low-cycle reversed loading to examine seismic performance indicators, including crack propagation patterns, failure modes, hysteretic curves, skeleton curves, stiffness degradation, ductility, and energy dissipation capacity. The results demonstrate that incorporating prestressed CFRP tendons into the inclined-web trusses did not alter the failure mode of the steel-reinforced concrete transfer story structure. The primary failure morphology consistently manifested as flexural-shear failure in the bottom chord columns. During the loading process, tensile cracking failure manifested in the inclined-web members of both specimens, with and without prestressing. Crack distribution remained uniform in all cases. The inclined-web trusses incorporating prestressed strands exhibited an 80% increase in cracking load compared to the non-prestressed specimen. Furthermore, the prestressed specimen demonstrated superior resistance to performance degradation and enhanced energy dissipation capacity. Both configurations exhibited significant deformation capacity and satisfactory seismic performance. The prestressed CFRP tendons enhance the crack resistance and deformation capacity of a transfer story structure with inclined-web trusses, providing novel insights for seismic design of truss transfer story structures. Full article

Steel frame structures have been increasingly widely used in high-rise and multi-story building design. However, traditional rigid welded beam–column joints exhibit poor ductility and high residual stress, which are key reasons for their susceptibility to brittle failure under strong earthquake actions. This study proposes a new type of beam–column joint for steel frames: the corrugated web beam–column joint. In this new joint, the web of the I-beam near the beam flange is partially replaced with a corrugated web that exhibits a folding effect—this modification weakens the plastic bending capacity of the I-beam and promotes the outward movement of plastic hinges. Low-cycle reciprocating loading tests were conducted to verify the performance of two specimens, namely one with the traditional beam–column joint and the other with the corrugated web beam–column joint. Through experimental comparison, it was found that plastic hinges in the new corrugated web joint are generated at the corrugated web, while no damage occurs at the beam-end welds. This indicates that the corrugated web beam–column joint can stably achieve the outward movement of plastic hinges and avoid the location of the beam-end welds, thereby providing theoretical and experimental foundations for the structural design of new ductile steel frames. Full article

Modern weeding technologies include chemical weeding, non-contact methods such as laser weeding, and conventional mechanical inter-row cultivation characterized by soil loosening and weed uprooting. For maize, mechanical inter-row cultivation is key to cutting herbicide use and enhancing the soil–crop environment. This study developed a vision-guided intelligent inter-row cultivator with electric lateral shifting—its frame fabricated from Q235 low-carbon structural steel and assembled mainly via bolted and pinned joints—that computes real-time lateral deviation between the implement and crop rows through maize plant recognition and crop row fitting and uses delay compensation to command a servo-electric cylinder for precise ±15 cm inter-row adjustments corresponding to 30% of the 50 cm row spacing. To test the system’s dynamic response, 1–15 cm-commanded lateral displacements were evaluated at 0.31, 0.42, and 0.51 m/s to characterize the time-displacement response of the servo-electric shift mechanism; field tests were conducted at 0.51 m/s with three 30 m passes per maize growth stage to collect row-guidance error and root-injury data. Field results show that at an initial offset of 5 cm, the mean absolute error is 0.76–1.03 cm, and at 15 cm, the 95th percentile error is 7.5 cm. A root damage quantification method based on geometric overlap arc length was established, with rates rising with crop growth: 0.12% at the V2 to V3 stage, 1.46% at the V4 to V5 stage, and 9.61% at the V6 to V8 stage, making the V4 to V5 stage the optimal operating window. Compared with chemical weeding, the system requires no herbicide application, avoiding issues related to residues, drift, and resistance management. Compared with laser weeding, which requires high tool power density and has limited effective width, the tractor–implement system enables full-width weeding and shallow inter-row tillage in one pass, facilitating integration with existing mechanized operations. These results, obtained at a single forward speed of 0.51 m/s in one field and implement configuration, still require validation under higher speeds and broader field conditions; within this scope they support improving the precision of maize mechanical inter-row cultivation. Full article

Gulf Cooperation Council (GCC) economies are investing heavily in digital infrastructure to diversify beyond hydrocarbons, yet the productivity returns from these investments remain uncertain. This study examines whether digital adoption enhances labor productivity in GCC economies (2000–2023). We construct a Composite Digital Index (CDI) from broadband subscriptions, internet use, and mobile penetration. Interpreting the Gulf economies as socio-technical systems, we frame digital adoption, productivity, and investment (measured by GCF) as a reinforcing loop, with government effectiveness amplifying the cycle and oil rents dampening it. Using panel data methods, including fixed-effects and long-run estimators, we find that digital adoption yields persistent productivity gains. In the long run, a one-point increase in CDI is associated with a 12.6 percentage point rise in labor productivity growth (p < 0.05). This effect triples—to approximately 38.5 percentage points—when moderated by strong government effectiveness (CDI × Governance interaction: +26.3; p < 0.01). Conversely, the productivity payoff declines significantly with oil-rent dependence: for every 10 percentage-point rise in oil rents, the marginal effect of digital adoption drops by 3.4 points. These gains are significantly larger where government effectiveness is stronger, while oil dependence weakens them. The findings imply that infrastructure adoption alone is insufficient: institutions and fiscal structures condition whether digital adoption translate into sustained productivity growth. Policy priorities should focus on institutional reform, fiscal diversification, and enabling firm-level digital absorption—particularly in high-rent economies—so that adoption translates into broad-based productivity dividends. Full article

This study presents a comprehensive seismic performance assessment and performance-based seismic design (PBSD) optimization for a 21-story Science and Innovation Building with three basement levels, characterized by pronounced plan and vertical irregularities. An engineering-oriented PBSD framework was established, integrating irregularity identification, nonlinear time-history analysis, performance target definition, and energy dissipation evaluation. Comparative analyses between the actual and modified structural models indicate that skip-floor columns have negligible effects on the global stiffness, vibration periods, and interstory drift ratios, suggesting that they should not be classified as independent irregularities. Nonlinear time-history analyses under rare earthquakes confirm that the tower maintains overall stability, with maximum interstory drift ratios of 1/149 and 1/150 in the X and Y directions, respectively. The core tube acts as the primary energy-dissipation component, while the outer frame remains mostly elastic, forming a dual defense system of “core-tube dissipation and frame protection.” Buckling and PBSD verifications demonstrate that skip-floor columns remain elastic under rare earthquakes, satisfying both strength and deformation limits. For the podium, elastic and elastoplastic analyses using multiple software platforms show consistent responses, revealing that more than 80% of the input seismic energy is dissipated through material hysteresis. In addition, a practical construction sequence based on the recommended design is proposed to facilitate implementation and enhance engineering applicability. The proposed PBSD modeling and optimization framework provides a practical and replicable methodology for evaluating and enhancing the seismic performance of irregular high-rise buildings with discontinuous vertical systems. Full article

Seven groups of near-field pulse-like ground motions and three groups of ordinary ground motions were bidirectionally inputted into a symmetrical high-rise structure to comparatively study the deformation and energy dissipation characteristics of the structure. The results reveal that compared to ordinary ground motions, under near-field pulse-like ground motions, the inter-story drift angles of the structure significantly exceed the code limit, accompanied by a downward shift of the floors with the maximum drift angles. Moreover, the input energy is substantially higher and the hysteresis energy dissipation supersedes damping energy dissipation as the dominant mode. During an 8-degree frequent earthquake, coupling beams are the main energy-dissipating members, the floors below 2/3 of structural height mainly dissipate hysteresis energy by coupling beams, while the floors above 2/3 of structural height mainly dissipate hysteresis energy by frame beams. During 8-degree design earthquakes and rare earthquakes, frame beams are the main energy-dissipating members, the hysteresis energy ratio of coupling beams is significantly reduced, and the hysteresis energy ratio of shear walls gradually increases. During 8-degree design earthquakes, the 1st floor mainly dissipates hysteresis energy by shear walls, the 2nd to 6th floors mainly dissipate hysteresis energy by coupling beams, and the 7th to 36th floors mainly dissipate hysteresis energy by frame beams. During 8-degree rare earthquakes, the hysteresis energy on the 1st to 2nd floors is mainly dissipated by shear walls, while it is mainly borne by frame beams on other floors. Full article

Macro-scale modeling is a fundamental approach for assessing structural damage and occupant comfort in urban high-rises during earthquakes or typhoons. The key to its effectiveness is accurately reproducing dynamic responses and extracting modal characteristics. The critical issue is whether the macro-scale model can effectively capture Flexure-Shear Coupled (FSC) dynamic behavior. This paper proposes a macro-scale modeling method for high-rise structures with FSC dynamic behavior using deep learning (DL). FSC dynamic behavior is quantified by establishing Displacement Interaction Coefficients (DInC) under each mode shape. To account for the flexural resistance of horizontal members and the anti-overturning contribution of vertical members in high-rise structures, equivalent stiffness parameters representing horizontal and vertical members are introduced into the Lumped Parameter Model (LPM), enhancing the flexibility of the macro-scale model in expressing FSC dynamic behavior. The DInCs are used as input features to identify the LPM’s stiffness parameters, enabling efficient macro-scale modeling. The method was validated on a frame and a frame-core tube structure by comparing dynamic characteristics with their detailed finite element models. This method holds engineering application potential in areas requiring highly accurate and rapid structural characteristic or response calculations, such as seismic response analysis and design optimization of high-rise structures. Full article

An efficient cooling configuration is critical for ensuring the safe operation of electrical machines and is key for optimizing the iterative design of motors. To improve the heat dissipation performance of high-power, explosion-proof, integrated variable-frequency permanent magnet motors used in mining and reduce the risk of permanent magnet demagnetization, this study considers a 1600 kW mining explosion-proof variable-frequency permanent magnet motor as its research object. Based on the zigzag-type water channel structure of the frame, a novel rotor-cooling scheme integrating axial–radial ventilation structures and axial flow fans was proposed. The temperature field of the motor was simulated and analyzed using a fluid–thermal coupling method. Under rated operating conditions, the flow characteristics of the frame water channel and the temperature distribution law inside the motor were compared when the water supply flow rates were 5.4, 4.8, 4.2, 3.6, 3, 2.4, and 1.8 m³/h, respectively, and the relationship between the motor temperature rise and the variation in water flow rate was revealed. A production prototype was developed, and temperature rise tests were conducted for verification. The test results were in good agreement with the simulation calculation results, thereby confirming the accuracy of the simulation calculation method. The results provide an important reference for enterprises in the design optimization and upgrading of high-power explosion-proof integrated variable-frequency permanent-magnet motors. Full article

Seven groups of long-period ground motions (LPGMs) and three groups of ordinary ground motions (OGMs) were selected and bidirectionally input into a high-rise structure; the energy distribution and dissipation characteristics of the structure were studied comparatively. The results show that at the same seismic level, the input energy of the structure under LPGMs is significantly greater than that under OGMs. Under OGMs, the structure mainly dissipates energy through damping energy, while under LPGMs, hysteretic energy becomes the main way of energy dissipation. During an 8-degree frequent earthquake, coupling beams are the main energy dissipation members, the floors below 2/3 of the structural height mainly dissipate hysteresis energy by coupling beams, with the hysteretic energy ratio ranging from 61% to 99.9%, and the floors above 2/3 of the structural height mainly dissipate hysteretic energy by frame beams. During 8-degree design and rare earthquakes, the hysteretic energy ratio of coupling beams significantly decreases, and frame beams are the main energy-dissipating members; the hysteresis energy on the first to second floors is mainly dissipated by shear walls, while on floors above the third floor, the hysteresis energy is mainly borne by frame beams, the hysteretic energy ratio from the fifth to the twelfth accounts for 56% to 89%, and above the twelfth floor accounts for more than 85% to 90% on that floor. Full article