Search Results (443)

The bridge deck is more vulnerable to deterioration than other structural components. This is due to its direct exposure to environmental factors such as vehicular loads, chloride ingress, and freeze–thaw cycles. The resulting accelerated degradation often results in a serviceability life that is shorter than the intended design life. However, the absence of standardized condition assessment methods coupled with clear definitions of remaining service life has limited the establishment of rational guidelines for repair and strengthening. In a bid to address this lack, this study focuses on PSC-I type bridges in South Korea, utilizing long-term field inspection data to analyze environmental, structural, and material factors—including reinforcement corrosion, chloride diffusion, and freeze–thaw actions. Environmental zoning was applied based on regional conditions, while structural zoning was performed according to load characteristics, thereby allowing the classification of deck regions into moment zones and cantilever sections. Machine learning models were employed to identify dominant deterioration mechanisms, with the validity of the zoning classification being evaluated via model accuracy and SHAP value analysis. Additionally, a regression-based approach was proposed to estimate the remaining service life of the bridge deck for each corrosion phase, thereby providing a quantitative framework for durability assessment and maintenance planning. Full article

Public transport companies are aware that the success of their operations largely depends on the proper sizing and optimization of their processes. Among the key activities are the maintenance and repair of the vehicle fleet. This paper presents the application of mathematical optimization methods from the field of operations research to improve the efficiency of service workshops for bus maintenance and repair. Based on an analysis of collected data using queueing theory, the authors assessed the current system performance and found that the queueing system still has spare capacity and could be downsized, which aligns with the company’s management goals. Specifically, the company plans to reduce the number of bus repair service stations (servers in a queueing system). The main question is whether the system will continue to function effectively after this reduction. Three specific downsizing solutions were proposed and evaluated using queueing theory methods: extending the daily operating hours of the workshops, reducing the number of arriving buses, and increasing the productivity of a service station (server). The results show that, under high system load, only those solutions that increase the productivity of individual service stations (servers) in the queueing system provide optimal outcomes. Other solutions merely result in longer queues and associated losses due to buses waiting for service, preventing them from performing their intended function and causing financial loss to the company. Full article

Carbon flow tracking and spatial pattern optimization at the scale of urban functional zones are key scientific challenges in achieving carbon neutrality. However, due to the complexity of carbon metabolism processes within urban functional zones, related studies remain limited. To address these scientific challenges, this study, based on the “source–sink–flow” ecosystem services framework, develops an integrated analytical approach at the scale of urban functional zones. The carbon balance is quantified using the CASA model in combination with multi-source data. A network model is employed to trace carbon flow pathways, identify critical nodes and interruption points, and optimize the urban spatial pattern through a low-carbon land use structure model. The research results indicate that the overall carbon balance in Hangzhou exhibits a spatial pattern of “deficit in the center and surplus in the periphery.” The main urban area shows a significant carbon deficit and relatively poor connectivity in the carbon flow network. Carbon sequestration services primarily flow from peripheral areas (such as Fuyang and Yuhang) with green spaces and agricultural functional zones toward high-emission residential–commercial and commercial–public functional zones in the central area. However, due to the interruption of multiple carbon flow paths, the overall carbon flow transmission capacity is significantly constrained. Through spatial optimization, some carbon deficit nodes were successfully converted into carbon surplus nodes, and disrupted carbon flow edges were repaired, particularly in the main urban area, where 369 carbon flow edges were restored, resulting in a significant improvement in the overall transmission efficiency of the carbon flow network. The carbon flow visualization and spatial optimization methods proposed in this paper provide a new perspective for urban carbon metabolism analysis and offer theoretical support for low-carbon city planning practices. Full article

Introduction: Haglund’s deformity, characterized by bony enlargement at the back of the heel, often coincides with Achilles tendon pathology due to impingement on the retrocalcaneal bursa and tendon insertion. Surgical management of Haglund’s deformity with a preexisting Achilles tendon rupture is complex, and understanding the outcomes of this subset of patients is essential for optimizing treatment strategies. Methods: This retrospective study reviewed patients undergoing open surgical management for Haglund’s syndrome between January 2015 and December 2023. Patients with chronic degenerative changes secondary to Haglund’s deformity and a preoperative Achilles tendon rupture were compared to those without. Data on demographics, surgical techniques, weightbearing protocols, and complications were collected. Univariate analysis was performed using χ² or Fisher’s exact test for categorical variables, and the T-test or Wilcoxon rank-sum test for continuous and ordinal variables, with normality assessed via the Shapiro–Wilk test. Results: Four hundred and three patients were included, with 13 having a preoperative Achilles tendon rupture. There was a higher incidence of preoperative ruptures among males. Surgical repair techniques and postoperative weightbearing protocols varied, though were not randomized. Complications included persistent pain, wound breakdown, infection, plantar flexion weakness, and revision surgery. While patients with Haglund’s deformity and a preoperative Achilles tendon rupture demonstrated a trend toward higher complication rates, including postoperative rupture and wound breakdown, these differences were not statistically significant in our analysis. Conclusions: A cautious approach is warranted in managing these patients, with careful consideration of surgical planning and postoperative rehabilitation. While our findings provide valuable insights into managing patients with Haglund’s deformity and preoperative Achilles tendon rupture, the retrospective design, limited sample size of the rupture group, and short duration of follow-up restrict generalizability and the strength of the conclusions by limiting the power of the analysis and underestimating the incidence of long-term complications. Therefore, the results of this study should be interpreted with caution. Further studies with larger patient cohorts, validated functional outcome measures, and comparable follow-up durations between groups are needed to confirm these results and optimize treatment approaches. Full article

The article presents a new AM (Additive Manufacturing) process development, necessary to repair parts made from Aluminum 6061 material, with T6 treatment. The laser Directed Energy Deposition (DED) and Extreme High-Speed Directed Energy Deposition (EHLA) capabilities are evaluated for repairing Al large components. To optimize the process parameters, single-track depositions were analyzed for both laser-powder DED (feed rate of 2 m/min) and EHLA (feed rate 20 m/min) for AlSi10Mg and Al6061 powders. The cross-sections of single tracks revealed the bonding characteristics and provided laser-powder DED, a suitable parameter selection for the repair. Three damage types were identified on the Al component to define the specification of the repair process and to highlight the capabilities of laser-powder DED and EHLA in repairing intricate surface scratches and dents. Our research is based on variation of the powder mass flow and beam power, studying the influence of these parameters on the weld bead geometry and bonding quality. The evaluation criteria include bonding defects, crack formation, porosity, and dilution zone depth. The bidirectional path planning strategy was applied with a fly-in and fly-out path for the hatching adjustment and acceleration distance. Samples were etched for a qualitative microstructure analysis, and the HV hardness was tested. The novelty of the paper is the new process parameters for laser-powder DED and EHLA deposition strategies to repair large Al components (6061 T6), using AlSi10Mg and Al6061 powder. Our experimental research tested the defect-free deposition and the compatibility of AlSi10Mg on the Al6061 substrate. The readers could replicate the method presented in this article to repair by laser-powder DED/EHLA large Al parts and avoid the replacement of Al components with new ones. Full article

Abdominal arteriovenous fistula [AVF] is a rare but serious complication of penetrating trauma, often associated with high morbidity and mortality. This report presents the case of a 24-year-old male who sustained multiple gunshot wounds, leading to the formation of an ilio-iliac AVF and a pseudoaneurysm. The patient arrived at the emergency department hemodynamically unstable, with bullet wounds to the forearm, thigh, and lumbosacral region. Initial non-arterial phase CT revealed a pseudoaneurysm anterior to the right external iliac vessels and a surrounding hematoma, raising suspicion for AVF. A second biphasic CTA confirmed an AVF connection between the right external iliac artery and external iliac vein, as well as the arterialization of the vein. Additionally, fat stranding and bowel wall thickening suggested potential hollow viscus injury. Due to the patient’s unstable condition and possible intra-abdominal injuries, an open laparotomy was performed. A stent was placed in the right external iliac artery, the vein was primarily repaired, and serosal injuries to the duodenum and cecum were surgically addressed. The patient recovered gradually, although a persistent serous discharge was noted and managed in follow-up. This case highlights the importance of considering AVF in penetrating abdominal trauma and the critical role of biphasic CTA in diagnosis and surgical planning. Full article

Background/Objectives: Nerve injuries cause functional loss and psychosocial issues due to prolonged rehabilitation. Recently, 3D-modeled nerve conduits have been used to aid in surgical planning. This study investigated the impact of 3D-bioprinted PLA, chitosan, alginate, and collagen conduits on nerve regeneration in a rat sciatic nerve crush injury model. Methods: This study, conducted at Kütahya University of Health Sciences, involves 50 rats were divided into four groups: (1) sham-operated controls, (2) sciatic nerve injury without treatment, (3) injury treated with a PLA conduit, and (4) injury treated with 3D-printed tubes composed of chitosan and alginate. The procedures were performed, blood was collected, and the rats were sacrificed after two months. Weekly checks for infection, scar healing, and motor responses were performed. Results: Rats with nerve conduits showed less macroscopic scarring. Weekly assessments of motor nerve recovery showed no movement restrictions in limbs treated with PLA conduits, graft conduits, or conduits bridging retracted nerve stumps, based on responses to stimulus checks. An infection developed in the sciatic nerve and surrounding muscle tissue of one rat with a bio-graft conduit, prompting histopathological examination to investigate its cause. Conclusions: This proof-of-principle study demonstrates the feasibility of using 3D-printed biocompatible nerve conduits for peripheral nerve repair, providing a basis for future, more comprehensive investigations. Full article

Earthen flood protection structures are planned and constructed with an expected service life of several decades while being exposed to environmental impacts that may lead to structural or hydraulic failure. Current maintenance procedures involve only repairing external damage, leaving internal processes contributing to structural damage often undetected. Through structural health monitoring (SHM), structural deficits can be detected before visible damage occurs. To improve maintenance workflows and support predictive maintenance of dikes, this paper reports on the integration of digital twin concepts with SHM strategies, referred to as “digital-twin-based SHM”. A digital twin concept, including a standard-compliant building information model, is proposed and implemented in terms of a digital twin environment. For integrating monitoring and sensor data into the digital twin environment, a customized webform is designed. A communication protocol links preprocessed sensor data stored on a server with the digital twin environment, enabling model-based visualization and contextualization of the sensor data. As will be shown in this paper, a digital twin environment is set up and managed in the context of SHM in compliance with technical standards and using well-established software tools. In conclusion, digital-twin-based SHM, as proposed in this paper, has proven to advance predictive maintenance of dikes, contributing to the resilience of critical infrastructure against environmental impacts. Full article

Mitral regurgitation (MR) is a common valvular heart disease associated with significant morbidity and mortality. For patients at high or prohibitive surgical risk, mitral transcatheter edge-to-edge repair (M-TEER) offers a less invasive alternative to surgery. This review outlines key aspects of patient selection and procedural planning for M-TEER, with a focus on clinical and echocardiographic criteria essential for success. Comprehensive imaging—especially 2D and 3D transesophageal echocardiography—is critical to assess leaflet anatomy, coaptation geometry, and mitral valve area. Selection criteria differ between primary and secondary MR and are guided by trials such as COAPT and MITRA-FR. Optimal outcomes rely on careful screening, anatomical suitability, and multidisciplinary evaluation. With growing experience and advancing technology, M-TEER has become a transformative option for treating severe MR in non-surgical candidates. Full article

Bioactive materials have recently shown potential in nerve repair and regeneration by promoting the growth of new cells, tissue repair, and restoring nerve function. These natural, synthetic, and hybrid materials offer a biomimetic structure, enhance cell attachment, and release bioactive molecules that promote the axonal extension of severed nerves. Scaffold-based preclinical studies have shown promising results on enhancing nerve repair; however, they are limited by the immune response and fabrication, scalability, and cost. Nevertheless, advances in manufacturing, including 3D bioprinting, and other strategies, such as gene editing by CRISPR, will overcome these shortcomings. The opportunity for the development of individualized approaches and specific treatment plans for each patient will also increase the effectiveness of bioactive materials for the treatment of nerve injuries. Combining bioactive materials with the neural interface can develop new reliable therapeutic solutions, particularly for neuroprosthetics. Finally, it is essential to stress a multidisciplinary focus, and future studies are needed to enhance the potential of bioactive materials for patients with nerve injuries and the field of regenerative medicine. Full article

Background/Objectives: Achilles tendon pathologies, such as Achilles tendinitis, tendinosis, ruptures, and equinus contracture, cause pain and functional impairment. While surgical intervention is indicated in some cases, many patients are successfully managed with nonoperative treatment. The goal of this review was to evaluate the current evidence-based treatments for the nonoperative management of Achilles tendon disorders, focusing on indications and clinical outcomes. Methods: A scoping review of the literature was conducted from 2015 to 2025 from the PubMed database. Research published in the last ten years was included if it addressed nonoperative treatments for Achilles tendinopathy, acute ruptures, and/or equinus contracture. The outcome measures of interest included functional outcomes, re-rupture rates, and overall patient satisfaction. Results: Nonoperative management results in favorable outcomes for a wide range of Achilles tendon pathologies. Eccentric loading is supported for chronic tendinopathy, and functional rehabilitation programs with early mobilization have shown comparable outcomes to surgical repair for acute tendon ruptures. Combination therapy for the nonoperative management of equinus is favored. These therapies include stretching protocols, casting, and the botulinum toxin. Conclusions: The literature supports the notion that nonoperative management strategies for Achilles tendon pathologies provide symptom relief and functional improvement in patients. However, these treatment plans should be individualized and tailored to patient-specific goals. Full article

This study aimed to evaluate the effectiveness of different rehabilitation protocols following osteochondral autograft transplantation (OAT) in patients with focal osteochondral defects of the femoral condyle, using the MOCART 2.0 knee score as a primary imaging outcome. Twenty-nine patients were divided into three groups: Group 1 (n = 9) received OAT with bone marrow aspirate concentrate (BMAC) and a 12-week two-phase rehabilitation program; Group 2 (n = 11) received OAT with a 12-week program without BMAC; and Group 3 (n = 9) received OAT with a shortened 6-week program. At the 12-month follow-up, Group 1 demonstrated a superior cartilage repair quality, with the highest mean MOCART 2.0 score (96.1), compared to Group 2 (80.2) and Group 3 (71.7). Notably, complete defect filling was observed in five patients in Group 1 versus four in Group 2 and only one in Group 3. The integration and surface integrity were also better preserved in Group 1. The addition of BMAC and an extended, progressive rehabilitation protocol significantly enhanced the morphological cartilage repair parameters. These results suggest that a biologically enhanced and prolonged recovery plan may offer a greater structural restoration of cartilage after OAT than conventional or accelerated protocols. Full article

Polyurea failures in reinforced concrete tanks, such as swimming pools and sewage treatment plants, require a thorough analysis of the causes of failures during renovation. Urban agglomerations are increasingly relying on these facilities for maintaining city functioning, and the increasing concentration of pollutants in these facilities necessitates urgent repairs due to frequent failures. More thorough analysis should be given to repeated failures on the same object or “twin” objects within a short period, causing high renovation costs and long shutdowns. The causes of failures can be found not only as a result of insufficient knowledge but also in a limited analysis of the entire project from the assumption phase to completion. The article analyzed water and sewage tanks on which failures of applied polyurea coatings occurred many times. The posteriori uses of the risk management analysis with the assessment of the impact and probability of occurrence of the planned activities that failed allows it to be applied a priori and treated as a necessary analysis. For this purpose, in selected repairs, those activities that had the greatest impact on failure and a relatively high probability of occurrence during implementation were distinguished from the entire project. Based on the risk management analysis, it was shown that the basic cause of the failure was the poor knowledge and insufficient experience of the entities performing the repairs, and the errors that occurred could be minimized by conducting good diagnostics of the facility, selecting professional designers and contractors, and constant monitoring of each important activity. Full article

Within computer-aided geometric design (CAGD), Said–Ball curves are primarily adopted in domains such as 3D object skeleton modeling, vascular structure repair, and path planning, owing to their flexible geometric properties. Techniques for curve degree reduction seek to reduce computational and storage demands while striving to maintain the essential geometric attributes of the original curve. This study presents a novel degree reduction model leveraging Euclidean distance and curvature data, markedly improving the preservation of geometric features throughout the reduction process. To enhance performance further, we propose a multi-strategy enhanced coati optimization algorithm (MSECOA). This algorithm utilizes a good point set combined with opposition-based learning to refine the initial population distribution, employs a fitness–distance equilibrium approach alongside a dynamic spiral search strategy to harmonize global exploration with local exploitation, and integrates an adaptive differential evolution mechanism to boost convergence rates and robustness. Experimental results demonstrate that the MSECOA outperforms nine highly cited agorithms in terms of convergence performance, solution accuracy, and stability. The algorithm exhibits superior behavior on the IEEE CEC2017 and CEC2022 benchmark functions and demonstrates strong practical utility across four engineering optimization problems with constraints. When applied to multi-degree reduction approximation of Said–Ball curves, the algorithm’s effectiveness is substantiated through four reduction cases, highlighting its superior precision and computational efficiency, thus providing a highly effective and accurate solution for complex curve degree reduction tasks. Full article

This study presents a comprehensive material characterization, including physical, hygric, and mechanical properties, of historical ceramic bricks to enhance the understanding of heritage masonry structures and support the effective planning of conservation interventions. The primary objective is to systematize the knowledge of constituent materials in brick walls from different historical periods and to evaluate the compatibility of modern repair materials with the original fabric. To this end, a comprehensive experimental protocol was employed, which included the determination of fundamental physical properties such as density, water absorption, and sorptivity. Additionally, chemical and thermogravimetric analyses were performed, followed by freeze–thaw resistance testing and compressive strength measurements. Microstructural analysis was conducted using mercury intrusion porosimetry. The results identified the pore size ranges most susceptible to frost-induced degradation and revealed correlations between the physical, hygric, and mechanical properties of the tested ceramic materials. These findings provide essential data on the physico-mechanical characteristics of historical bricks, establishing a basis for the informed selection of compatible materials in conservation practice. Full article