Search Results (463)

This paper introduces an innovative automatic trajectory generation method for the robotic deburring of molded parts, effectively addressing challenges posed by burr defects and workpiece deformation common in casting and injection molding processes. Existing offline trajectory planning methods often struggle with substantial burr sizes and complex surface deformations, resulting in compromised machining quality due to over-adaptation. To overcome these issues, the proposed approach utilizes 3D vision techniques to achieve precise burr localization. A novel burr point cloud segmentation method based on feature analysis, combined with a tolerance-constrained non-rigid registration algorithm, accurately identifies burr regions and optimizes trajectory positioning within defined manufacturing tolerances. Furthermore, the method employs quantitative burr height distribution analysis to dynamically adjust robotic feed rates, significantly enhancing processing efficiency. Experimental validations demonstrated that the proposed method reduces the deburring time by up to 68% compared to conventional techniques, achieving an average trajectory deviation of only 0.79 mm. This study provides a robust, efficient, and precise solution for automating deburring operations in complex molded components, highlighting its substantial potential for industrial applications. Full article

Aiming at the stochasticity, uncertainty, and strong perturbation of the linear Fresnel solar thermal power collection subsystem, this study establishes a multivariate prediction model for the linear Fresnel collector subsystem based on complex environmental characteristics and designs a PID controller and MPC controller for the tracking and control of the outlet temperature. By analyzing the heat transfer process of the collector, constructing a model in Multiphysics for three-dimensional modeling of the collector, extracting data through simulation, fuzzy clustering the data and using different clustering centers for parameter identification in order to obtain the multi-model. By using the field data from the site of Dunhuang Dacheng Linear Fresnel Molten Salt Collector Field, considering the inlet temperature, normal direct irradiance and wind speed are used as the perturbation quantities, and the flow rate of molten salt is used as the control quantity. Considering three representative weather conditions, the switching criterion of minimizing the real-time point error is adopted for switching the outlet temperature of the collector. Simulation analysis results show that under the same conditions, the tracking error of the single model is relatively large, with the output temperature error fluctuating between −100 °C and 100 °C and containing many burrs. In contrast, the output temperature error of the multi-model switching control is controlled within 50 °C, which features a smaller tracking error and a faster tracking speed compared with the single-model control. When faced with large disturbances, the multi-model MPC switching control achieves better tracking performance than the multi-model PID switching control. It tracks temperatures closer to the set value, with a faster tracking speed and more excellent anti-interference performance. Full article

Chronic subdural hematoma (cSDH) is a common neurosurgical condition in the elderly, often resulting from minor head trauma. Traditional surgical treatments such as burr-hole drainage carry recurrence rates of 10–20% and significant risks in older patients, especially those on anticoagulation therapy. Middle meningeal artery (MMA) embolization has emerged as a minimally invasive alternative, aiming to reduce blood flow to the dura and thereby promote hematoma resolution and lower recurrence. We conducted a bibliometric analysis of publications on MMA embolization for cSDH up to December 2023. The analysis shows a sharp increase in research activity over the past decade. North America, Japan, and Europe are leading contributors, with collaborative networks forming among major institutions. Key journals in neurosurgery and neurointervention have published much of this research, and author collaborations are extensive. Frequently used keywords such as “recurrence” and “treatment outcome” reflect an emphasis on reducing rebleeding and improving patient outcomes. In conclusion, MMA embolization is rapidly gaining attention as a promising treatment for cSDH. While early results are favorable and multi-center efforts are expanding the evidence base, further research is needed to establish long-term efficacy, optimize patient selection, and standardize techniques. Full article

Background: In healthy adults, probiotic supplementation alone does not increase Urolithin A (UroA) and rarely increases butyrate, both microbiome-derived metabolites that influence key biological functions involved in regulating gastrointestinal symptoms. Accordingly, this clinical trial evaluated key biological functions of a multi-species synbiotic with 24 probiotic strains and a polyphenol-based prebiotic using capsule-in-capsule delivery technology. Methods: We conducted a randomized, placebo-controlled trial among healthy participants (n = 32). Participants were administered a daily synbiotic (53.6 billion AFU multi-species probiotic and 400 mg Indian pomegranate extract; DS-01) or matching placebo for 91 days. Samples were obtained at baseline Day 0, and Days 7, 14, 49, and 91. Endpoints included changes in fecal microbiome composition, urinary UroA, fecal butyrate, serum CRP, and safety. Results: The synbiotic significantly increased alpha-diversity of Bifidobacterium and Lactobacillus spp. at all timepoints, including at end-of-study (Day 91, p < 0.0001) and increased native beneficial microbes. UroA production was significantly increased in the synbiotic arm at short-term (Day 7, 12-fold, p < 0.02) and long-term (Day 91, 49-fold, p < 0.001) timepoints. A higher proportion of synbiotic participants were capable of converting polyphenols into UroA (Day 91, 100% vs. 44.4%; p < 0.01). Mechanistically, synbiotic participants showed an increased abundance of Lactobacillus species involved in UroA precursor metabolism and UroA-producing Gordonibacter species. The synbiotic also significantly increased fecal butyrate levels (p < 0.03), and butyrate-producing species, in low-baseline butyrate producers, through Day 91, and was associated with reduced systemic inflammation. Conclusions: This multi-species synbiotic significantly increases diversity and abundance of key beneficial bacteria, enhances UroA production and butyrate levels, and is associated with lowered systemic inflammation. This is the first synbiotic to increase both UroA and butyrate. Full article

Technological advancements for the miniaturization of electronic components highlight a critical role of thin and durable stencils in advanced surface mount technology. Here, we report a transparent and fine film stencil consisting of a clear polyimide film and a functional diamond-like carbon coating layer for the fine-pitch surface mount technology process. High-quality and burr-free apertures in the thin film result from the thermally stable laser-cut process using a repetitive and low-power irradiation of nanosecond pulse laser, enhancing the printing accuracy of solder paste with fewer solder joint defects. The carbon coating layer with an electrostatic discharge composition facilitates smooth and robust surfaces and sidewalls of the apertures for the high solder paste release and high mechanical durability of the fine film stencil. The low-cost and easy fabrication of the fine film stencil accelerates the potential industrial replacement of the conventional metal stencils at a reduced thickness and further open a new opportunity for the mass production of the fine-pitch surface mount technology process. Full article

This paper introduces a new unit-Burr distortion function constructed via a transformation of the Burr random variable. The distortion can be applied to existing base copulas to create new copula families. The relationships of tail dependence coefficients and tail orders between the base bivariate copula and the unit-Burr distorted copula are derived. The unit-Burr distortion-induced family of copulas includes well-known copula classes, such as the BB1, BB2, and BB4 copulas, as special cases. The unit-Burr distortion of existing bivariate copulas may result in a family of copulas with both lower and upper tail coefficients ranging from 0 to 1. An empirical application to the rates of return for Microsoft and Google stocks is presented. Full article

This paper explores statistical inferences for the maximum ranked set sampling with unequal samples (MaxRSSU) from the Burr Type-III distribution. Under the assumption that the differences between different multiple MaxRSSU cycles are non-ignorable, classical likelihood and Bayesian approaches are employed for estimation of the model parameters and reliability indices. By taking into account the multiple-cycle effect, the maximum likelihood estimators for the parameters of the Burr Type-III distribution are established, along with an analysis of their existence and uniqueness. Furthermore, approximate confidence intervals are constructed based on asymptotic theory. In addition, a hierarchical Bayesian framework is conducted for analysis, and a Monte Carlo sampling method is proposed for complex posterior computation. Extensive simulation studies are carried out for evaluating the performance of the proposed methods, and a further two real-data examples are also provided for illustration. The numerical results indicate that the proposed methods work satisfactorily and the hierarchical Bayesian approach appears more appealing when the uncertainty cycle effect is involved. Full article

Helical milling presents a promising alternative to conventional drilling for hole production, offering superior surface quality and improved production efficiency. While this technique has been extensively applied in the aerospace industry, its potential for machining common engineering materials, such as AISI 1045 steel, remains underexplored in the literature. This study addresses this gap by systematically evaluating the influence of key process parameters—cutting speed (V_c), axial depth of cut (a_p), and tool diameter (D_t)—on hole quality attributes, including surface roughness, burr formation, and nominal diameter accuracy. A full factorial experimental design (2³) was employed, coupled with analysis of variance (ANOVA), to quantify the effects and interactions of these parameters. The results reveal that, with a higher V_c, it is possible to reduce surface roughness (R_a) by 30% to 40%, while an increased a_p leads to a 50% increase in R_a. Additionally, D_t emerged as the most critical factor for nominal diameter accuracy, reducing geometrical errors by 1% with a larger D_t. Burr formation was predominantly observed at the lower end of the hole, highlighting challenges specific to this technique. These findings provide valuable insights into optimizing helical milling for low-carbon steels, offering a foundation for broader industrial adoption and further research. Full article

To address the issues of burr formation, structural deformation, and tearing in the conventional machining of Nomex honeycomb composites, this study aims to clarify the mechanisms by which ultrasonic vibration-assisted cutting enhances machining quality. A multi-scale analysis framework is developed to examine the effects of ultrasonic vibration on fiber distribution, cell-level shear response, and the overall cutting mechanics. At the microscale, analyses show that ultrasonic vibration mitigates stress concentrations, thereby shortening fiber length. At the mesoscale, elastic buckling and plastic yielding models show that ultrasonic vibration lowers shear strength and modifies the deformation. A macro-scale comparison of cutting behavior with and without ultrasonic vibration was conducted. The results indicate that the intermittent contact effect induced by vibration significantly reduces cutting force. Specifically, at an amplitude of 40 μm, the cutting force decreased by approximately 29.7% compared to the condition without ultrasonic vibration, with an average prediction error below 8.6%. Compared to conventional machining, which causes the honeycomb angle to deform to approximately 130°, ultrasonic vibration preserves the original 120° geometry and reduces burr length by 36%. These results demonstrate that ultrasonic vibration effectively reduces damage through multi-scale interactions, offering theoretical guidance for high-precision machining of fiber-reinforced composites. Full article

Background: Foreign bodies (FBs) within the masticatory space are a rare but significant complication of oral and maxillofacial procedures. Despite advancements in orthognathic surgery, instrument breakage and accidental loss can lead to challenging secondary procedures. Clinical experience with retained foreign bodies in the masticatory space following orthognathic surgery and related dental procedures is summarized. Methods: A retrospective search was conducted in the surgical and radiological database of a tertiary referral center for maxillofacial surgery, covering procedures from January 2017 to December 2024. Patients were included if they had undergone orthognathic surgery and presented with a retained FB in the masticatory space confirmed through imaging. Clinical records, operative notes, imaging studies, and follow-up data were reviewed. Results: Out of 2092 procedures, four patients (0.19%) were identified. Two FBs were related to broken surgical instruments during orthognathic surgery (a suture needle and a burr fragment), while two were fractured local anesthesia needles during third molar extraction under local anesthesia. All FBs were located in deep compartments of the masticatory space (paramandibular or pterygopalatine region). Surgical retrieval via transoral approach under general anesthesia was successful in all cases. One patient experienced transient facial nerve dyskinesia; no long-term complications or recurrences were noted. Conclusions: Retained foreign bodies in the masticatory space are infrequent yet warrant prompt recognition and surgical management to mitigate the risk of infection, nerve damage, and repeated procedures. Thorough instrument checks, proper technique, and advanced imaging modalities are crucial for minimizing these complications in orthognathic surgery. Full article

In airport operations management, accurately estimating the service durations of ground support equipment such as Potable Water Trucks (PWTs) is essential for improving resource allocation efficiency and ensuring timely aircraft turnaround. Traditional estimation methods often use fixed averages or assume normal distributions, failing to capture real-world variability and extreme scenarios effectively. To address these limitations, this study performs a comprehensive statistical analysis of PWT service durations using operational data from Beijing Daxing International Airport (ZBAD) and Shanghai Pudong International Airport (ZSPD). Employing chi-square goodness-of-fit tests, twenty probability distributions—including several heavy-tailed candidates—were rigorously evaluated under segmented scenarios, such as peak versus non-peak periods, varying temperature conditions, and different aircraft sizes. Results reveal that heavy-tailed distributions offer context-dependent advantages: the stable distribution exhibits superior modeling performance during peak operational periods, whereas the Burr distribution excels under non-peak conditions. Interestingly, contrary to existing operational assumptions, service durations at extremely high and low temperatures showed no significant statistical differences, prompting a reconsideration of temperature-dependent planning practices. Additionally, analysis by aircraft category showed that the Burr distribution best described service durations for large aircraft, while stable and log-logistic distributions were optimal for medium-sized aircraft. Numerical simulations confirmed these findings, demonstrating that the proposed heavy-tailed probabilistic models significantly improved resource prediction accuracy, reducing estimation errors by 13% to 25% compared to conventional methods. This research uniquely demonstrates the practical effectiveness of employing context-sensitive heavy-tailed distributions, substantially enhancing resource efficiency and operational reliability in airport ground handling management. Full article

Introduction: The important factor in applying substances for inner ear therapy is the atraumatic execution, as well as effective concentration uniformly distributed in all regions of the cochlea within a reasonable time frame. This study investigates whether an additional cochlear opening (“second-hole technique”) can improve fluid distribution and reduce intracochlear pressure during dye delivery into the cochlear models and human petrous bone. Material and Methods: Three experimental setups were used: an uncoiled scala tympani model, a full-scale 3D-printed cochlear model, and a human petrous bone. In all cases, 1% methylene blue-stained saline was infused using a cochlear catheter (MED-EL, Innsbruck, Austria) through the round window. Intracochlear pressure was measured via fiberoptic pressure sensors inserted through a burr hole (artificial cochlear models) or at the lateral semicircular canal (human petrous bone). A second hole was made on the helicotrema in the inner ear models or at the oval window of the human petrous bone to examine the effect of a second hole on intracochlear pressure and fluid distribution. Dye distribution and intracochlear pressure were measured in 3D artificial models at two flow rates (0.2 and 0.4 mL/h). The intracochlear pressure were measured in the human petrous bone at a fixed rate (0.4 mL/h). Results: The use of a second hole significantly improved dye distribution in 3D models at both flow rates (p < 0.05) and led to earlier saturation-level distribution. Intracochlear pressure remained significantly lower and more stable in models with a second hole (p < 0.05). In human petrous bones, pressure fluctuation was reduced by the second hole, though pressure still increased over time. Conclusions: Using a second-hole technique leads to a faster, uniform level of dye distribution throughout the cochlear models, as well as a lower intracochlear pressure, which can be assumed to be an essential factor for hearing preservation during dye application. Full article

As one component of a study to improve Medicago spp. germplasm in eastern Australia, fifteen phenotypic and agronomic attributes were recorded for 4715 plants grown from the seed of 90 accessions of the widely naturalized pasture legume Medicago polymorpha from 90 sites in eight regions of inland New South Wales. The species expressed wide polymorphism. However, many leaflet attributes were associated with specific climate and soil characteristics, which varied from east to west across the collection zone. Discriminant analysis showed that accessions from the four most northern (summer dominant rainfall) and western (arid–semiarid) regions (Group A) differed from accessions from the most southern, temperate (winter dominant rainfall) and eastern (higher rainfall) regions (Group B). Group A flowered earlier and had shorter pod spines. Group B had lower plant vigor. Regions from which Group A accessions were collected had higher soil pH, lower winter rainfall, and higher minimum winter temperature than Group B regions. The diversity in the population, particularly the difference in flowering times among accessions collected from drier, warmer regions and those from more mesic, cooler regions, and the wide variation in flowering time measured among plants grown from accessions within all collection regions, is likely to ensure the long-term persistence of M. polymorpha in a changing climate. Elite lines were subsequently identified and lodged in National and International Genebanks for future research. Full article

Innovative approaches in hot forging, such as the use of floating dies, which aim to minimise burr formation by controlling material flow, require precise management of die geometry distortions. These distortions, primarily caused by thermal gradients, must be tightly controlled to prevent malfunctions during production. This study introduces a comprehensive thermal analysis framework that captures the complete forging cycle—from billet transfer and die closure to forging, spray-cooling, and lubrication. Two advanced heat transfer models were developed: a pressure- and lubrication-dependent contact heat transfer model and a spray-cooling model that simulates fluid dispersion over die surfaces. These models were implemented within the finite element software FORGE-NxT to evaluate the thermal behaviour of dies under realistic operating conditions. These two new models, contact and spray-cooling, implemented within a full-cycle thermal simulation and validated with industrial thermal imaging data, represent a novel contribution. The simulation results showed an average temperature deviation of just 5.8%, demonstrating the predictive reliability of this approach. This validated framework enables accurate estimation of thermal fields in the dies, and offers a practical tool for optimising process parameters, reducing burr formation, and extending die life. Moreover, its structure and methodology can be adapted to various hot forging applications where thermal control is critical to ensuring part quality and process efficiency. Full article

The ‘ring by spring’ (RBS) phenomenon entails pressures for college seniors on Christian campuses to become engaged by the spring semester of their senior year. These marital pressures often run counter to national trends in the USA as the median age at first marriage continues to climb. The social clock theory suggests that society places a normative timetable on major events such as marriage. But the social clock may not happen the same way for all people, and influences on Christian campus may represent deviations from most normative social clocks. This study investigated RBS awareness, experiences, pressures, and perceptions, along with assessing for differences in gender and religiosity across multiple universities, both Christian and not, across two different states. Results show wide awareness and experience with RBS at many universities along with some notable differences by gender and religiosity. Implications are provided for researchers and practitioners based on study findings. Full article