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Rotor assembly is a core tache in the whole process of aero-engine manufacturing. It is critical to ensure the excellent concentric performance of the overall assembly to satisfy the requirements of vibration-free and noise-free. However, assembly deviation is unavoidable due to the parts’ geometrical error, and it is difficult to meet the target requirement by manual adjustments in practical production. Three-dimensional deviation modeling is a feasible means to analyze assembly precision and optimize assembly process. Existing methods can construct the position and pose of geometric deviations in space but unable to handle the problem of surface morphology expression. This will cause a great loss of physical constraints and deviation information to the reliability of the analysis results. This article focuses on two points: one is the deviation expression for morphology error, and the other is the deviation propagation for multistage rotational optimization. Firstly, vectorization method of non-line contour was introduced to characterize the morphology feature of mounting edge, the core idea of which was that multiple vectors were used to approximate the contour curve; secondly, the similarity of each group of corresponding vectors in source features and target features was calculated and evaluated, to realize morphology evaluation and matching; next, combining the multistage revolving characteristics of rotors, the deviation propagation model was established for optimum mounting angle searching. Finally, this contour vectorization-based assembly technique was demonstrated by an example application of four-stage rotors assembly. Experimental results show that compared with traditional deviation modeling method, the overall concentric performance has improved 26.6% by using the suggested method, and the optimal installation angles (2π/3 rad, πrad, and π/3 rad) can be easily solved. It proves that contour vectorization-based assembly technique is feasible and of high practicability. It can be integrated with computer systems to propose assistance for operators in assembling stage.

This research introduces the Urban Traffic Mobility Optimization Model (UTMOM), a data-driven methodology for analyzing two distinctive urban traffic datasets through the integration of data mining and mathematical modeling. Designed to decode the complexities of urban mobility patterns, UTMOM meticulously evaluates daily traffic dynamics with a focus on reducing discrepancies and underscoring variations in traffic intensity, particularly during peak times. Our findings unveil pivotal insights into the differences across datasets, providing a substantial contribution to the realms of traffic management and urban planning. UTMOM delves into the intricacies of traffic flow variations, emphasizing the critical importance of comprehending fluctuations in traffic volume across diverse times and locations. By incorporating detailed graphical representations and statistical validations, including ANOVA analysis, our study delivers a comprehensive evaluation of UTMOM’s precision in reflecting real-world traffic scenarios. These insights affirm the value of data-informed strategies in optimizing traffic flow and alleviating congestion. Positioned as a valuable asset for traffic engineers, data scientists, and urban planners, UTMOM advocates for advanced modeling techniques to improve urban mobility. Beyond enriching academic discourse on traffic analysis, UTMOM offers actionable intelligence for enhancing the efficiency and sustainability of urban transportation systems. Through this in-depth investigation, our aim is to catalyze the development of innovative solutions to traffic challenges, steering towards smoother and more sustainable urban environments.

This study aimed to evaluate the effect of resin type and printing design on the dimensional accuracy of three dimensional (3D) printed orthodontic models, considering their clinical relevance for applications such as in-house aligner fabrication. Since low-cost Liquid Crystal Display (LCD) printers have been increasingly adopted in practice but data on their trueness and precision with different resins and print designs were limited, the study sought to provide evidence-based insights into their reliability. A mandibular model was designed using Blenderfordental (B4D, version 1.1.2024; Dubai, United Arab Emirates) software and fabricated with the Anycubic Photon Mono 7 Pro 14K (Anycubic, Shenzhen, China) LCD printer. The model was printed in vertical orientation using three different print designs at two layer thicknesses (50 µm and 100 µm). Four resins (Elegoo, Anycubic, eSUN, and Phrozen) were used, and each resin was printed with all three designs, yielding 126 models per resin and a total of 504 printed models. Dimensional deviations between the printed and reference models were assessed using root mean square (RMS) values and color-coded deviation maps. Significant differences in trueness were found among resins and print designs at both layer thicknesses (p < 0.001). At a layer thickness of 50 µm, eSUN and Anycubic showed superior trueness, whereas Phrozen exhibited the highest deviations. At a layer thickness of 100 µm, Anycubic, eSUN, and Phrozen generally performed better than Elegoo. Overall, printing at 100 µm yielded better performance than at 50 µm. Precision analysis revealed resin-dependent differences, with eSUN showing significantly higher precision than Elegoo at both layer thicknesses (p = 0.006 at 100 µm, p < 0.001 at 50 µm) and superior precision compared to Phrozen at 50 µm (p = 0.019). Both resin selection and print design significantly affect the dimensional accuracy of 3D-printed dental models.

Thermoelectric generators (TEGs) have the potential to convert waste heat into electrical energy, making them attractive for energy harvesting applications. However, accurately estimating TEG parameters from industrial systems is a complex problem due to the mathematical complex non-linearities and numerous variables involved in the TEG modeling. This paper addresses this research gap by presenting a comparative evaluation of three optimization methods, Particle Swarm Optimization (PSO), Salps Search Algorithm (SSA), and Vortex Search Algorithm (VSA), for TEG parameter estimation. The proposed integrated approach is significant as it overcomes the limitations of existing methods and provides a more accurate and rapid estimation of TEG parameters. The performance of each optimization method is evaluated in terms of root mean square error (RMSE), standard deviation, and processing time. The results indicate that all three methods perform similarly, with average RMSE errors ranging from 0.0019 W to 0.0021 W, and minimum RMSE errors ranging from 0.0017 W to 0.0018 W. However, PSO has a higher standard deviation of the RMSE errors compared to the other two methods. In addition, we present the optimized parameters achieved through the proposed optimization methods, which serve as a reference for future research and enable the comparison of various optimization strategies. The disparities observed in the optimized outcomes underscore the intricacy of the issue and underscore the importance of the integrated approach suggested for precise TEG parameter estimation.

Giant cantilevered tree-shaped steel structures are highly susceptible to cumulative deformation and geometric deviation during staged construction due to their complex spatial configuration, long cantilever characteristics, and nonlinear load transfer mechanisms. To address these challenges, this study investigates deformation monitoring and control of such structures based on 3D laser scanning, taking the “Tree of Life” project as a representative case. A high-precision full-field monitoring system is established to acquire multi-stage point cloud data throughout the construction process. The collected data are registered with the BIM model to quantify spatial deviations and track the deformation evolution of key structural components. Meanwhile, a staged preloading–unloading strategy is implemented to simulate operational loads, reconstruct load transfer paths, and regulate structural deformation during construction. Based on continuous field measurements, the deformation characteristics of different structural regions, including ring beams, rotating platforms, and trunk–branch systems, are systematically analyzed. The results indicate that the structure exhibits a pronounced global torsional deformation pattern. The displacement of ring beams ranges from 40.35 mm to 80.15 mm, while the maximum local displacement reaches 131.37 mm in geometrically complex regions, primarily attributed to the coupling effects of complex geometry, long cantilever action, stiffness discontinuity, and load concentration. Furthermore, deformation exhibits a progressive and stage-dependent accumulation pattern under sequential loading–unloading processes. The proposed monitoring and control approach achieves millimeter-level accuracy and enables effective feedback for construction adjustment and deviation mitigation. The integration of 3D laser scanning with staged load regulation provides a reliable technical framework for deformation monitoring and control of complex cantilevered steel structures. While the findings are based on a single complex project, further validation on additional cases is required to fully establish the general applicability of the proposed framework, although its integration of 3D monitoring, BIM registration, and staged load regulation suggests potential transferability to other large-scale cantilevered steel structures with similar geometric complexity.

Severe pelvic fractures often prove difficult for surgeons as they require patient-specific surgical treatment plans and customized equipment. Developing virtual patient-specific 3D pelvis models would ease the surgical planning process and enable development of custom fixation plates. This paper aims to examine pelvic symmetry to conclude whether the contralateral side may be used as a reference model for the fractured side of the pelvis. Fourteen subjects with intact pelvises were involved in this study. CT scans of the pelvises were converted to 3D models and the right sides of the pelvises were reflected and aligned with the left sides. A deviation analysis was then performed for each set of models and results showed that the average root mean square (RMS) of values was 1.14 ± 0.26 mm and the average percentage of points below a deviation threshold of ± 2 mm was 91.9 ± 5.55%. The deviation color maps (DCMs) showed that the largest deviations were on the non-articular surfaces. The volume and surface area of each model were also examined and showed no significant differences between left and right sides. These results indicate that the pelvis displays bilateral symmetry and this concept can be used to develop fully intact patient-specific 3D pelvis models for fracture reconstruction using the unfractured contralateral side.

One of the most common procedures implemented in the diagnosis of cancer and tumour is percutaneous biopsy under Computed Tomography (CT) image guidance. A 9-DOF hybrid redundant fully actuated robotic manipulator with a novel arc and train design is developed the retrieval of suspected tissue for biopsy procedure under CT guidance. The mathematical model of the robotic manipulator is formulated using standard DH convention. Inverse kinematics of the novel arc and train structure for CT bed mountability is also derived in this research. 3D-CAD model of the robot is developed and compared with the CT machine and a human model in SolidWorks 201 simulation is performed using MATLAB. A dual camera system and the actuator's internal position sensors are used to obtain and plot the robot's deviation analysis from the goal during experimentation. Actuator sensor data is plotted against the required profile in order to determine the causes of the deviation and assess the positional trajectory and velocity trajectory profile. The deviations in position in the range of 3 to 3.5 mm in each of X, Y, or Z axes and the variance in the angle is between 0.4 and 0.55 degrees. It performed amicably under simulated laboratory conditions.

Background As digital methods are widely used in clinical dentistry, the accuracy of dental prostheses remains critical. However, how each step in both conventional and digital methods affects the accuracy of the overall area and each area of the tissue surface remains unclear. This study aims to evaluate the effects of three-dimensional (3D) printing and injection molding processes on the trueness of mandibular complete denture bases. Methods Ten physical impressions were made using a standard edentulous lower jaw plaster model. In accordance with the scan data from these impressions, the denture bases were designed and fabricated using 3D printing. Additionally, conventional polymethyl methacrylate (PMMA) denture bases were made from the same impressions via the injection molding method. The tissue surfaces were scanned and divided into four regions. Deviation analyses were performed using the root mean square (RMS) method. Two-way ANOVA was employed for statistical analyses. Results A significant difference in trueness was found between the two methods ( p  < 0.05). In the injection molding process, the largest deviation originated primarily from the plaster filling process (222.35 ± 11.77 μm), followed by wax-up fabrication (211.10 ± 55.25 μm) and resin injection (161.87 ± 59.95 μm). The deviation of the border seal area was the greatest among the regions. In the 3D printing process, the CAD design showed the greatest deviation (179.22 ± 55.13 μm). The maximum deviation was 219.83 ± 45.37 μm in the border seal area. The printing process was associated with a deviation of 138.10 ± 24.42 μm, with the maximum deviation in the retromolar pad area reaching 193.92 ± 28.13 μm. Conclusions Both methods demonstrated clinically acceptable tissue surface adaptation. The 3D-printed base better adapted to the integrated tissue surface, especially in the border seal area. However, owing to the significant differences observed in this study, further clinical validation is needed.

Understanding bilateral pelvic symmetry can be useful for analyzing complex pelvis anatomy and simplifying difficult procedures for pelvic fractures. This paper aims to quantify the degree of regional pelvic symmetry using computer-based methods. CT scans of 30 intact pelvises were digitized into 3D models and regions were defined: the ilium, acetabulum, pubis, and ischium. The right hemipelvis was aligned with the left, and deviations between the two models were quantified using method 1 (global registration) and method 2 (local registration). Symmetry was evaluated using the root mean square (RMS) of the deviations and the percentage of points within preset thresholds of ± 2 mm and ± 1 mm. The results showed that > 86% of points are within the ± 2 mm deviation threshold and average RMS are < 1.33 mm. For all regions, method 2 showed lower deviations than method 1. The pubis and ischium regions showed a large difference in symmetry between the two methods indicating high local symmetry, but a degree of global asymmetry. Conversely, the acetabular and iliac regions showed similar levels of symmetry with the two methods. When evaluated locally, the pelvic regions can be considered highly symmetric; the acetabulum is highly symmetric globally as well. These findings can be used in future studies to assess the feasibility of patient-specific implants using the mirrored contralateral hemipelvis as a template for unilateral pelvic fracture fixation.