Search Results (136)

Knee rotational stability is crucial for anterior cruciate ligament (ACL) procedures, yet, current clinical assessments are subjective and lack precision. This study evaluates the accuracy and repeatability of the GATOR system, developed by PreciX Pte Ltd. and integrating ultrasound with inertial measurement units (IMUs), against a reference IMU (Xsens DOTS) for measuring knee flexion and rotation in six cadaveric specimens secured in an Oxford Knee Jig. Two experiments were conducted: (A) knee flexion from 0° to 120°, and (B) internal/external rotation at 0°, 30°, 60°, 90°, and 120° flexion. Analysis using Bland–Altman plots, root mean square error (RMSE: 3.93° for internal rotation, 6.90° for external rotation), mean biases, and paired t-tests (Bonferroni corrected) revealed that GATOR recorded lower peak flexion angles (91.49–114.65°) compared to the reference (110.31–118.49°). For rotation, internal rotation showed narrower limits of agreement than external rotation (biases: 1.91–6.88°). Over 60% of trials had errors < 5°, and 80% < 10°, indicating good agreement. Despite no isolated comparison of GATOR’s ultrasound component, findings suggest reduced soft tissue artifact due to bone-referenced sensor alignment. With optimal placement (10–15 cm from the knee center), GATOR shows promise in ACL assessment and remote rehabilitation. Full article

This study presents a sustainable and adaptive approach to mineral processing. A hybrid intelligent control system was developed to beneficiate fine chromite ore in a jigging machine. The objective is to enhance separation efficiency and reduce chromium losses through real-time optimization of process parameters under variable feed conditions. The method addresses ore composition fluctuations by integrating three components: Physical modeling of particle motion, regression analysis, and neural network-based prediction. The jig bed level and pulsation frequency are used as control variables, while the Cr₂O₃ content in the feed ($C_r$) is treated as a disturbance. A neural network predicts the Cr₂O₃ content in the concentrate ($C_c$) and in the tailings ($C_t$), representing chromite-rich and gangue fractions, respectively. The optimization is performed using a constrained Interior-Point algorithm. The model demonstrates high predictive accuracy, with a mean squared error (MSE) below 0.01. The proposed control algorithm reduces chromium losses in tailings from 7.5% to 5.5%, while improving concentrate quality by 3–6%. A real-time human–machine interface (HMI) was developed in SIMATIC WinCC for process visualization and control. The hybrid framework can be adapted to other mineral processing systems by adjusting the model structure and retraining the neural network on new ore datasets. Full article

We propose a method to reconstruct a 3D coordinate system and a vascular map for the operation of magnetic medical robots (MMRs) controlled by a magnetic navigation system (MNS) using two 2D X-ray images and four corners of an MNS. Utilizing the proposed method, we calculated the relative rotation angle of a C-arm considering its rotational precision error. We derived the position information and 3D coordinate system of an MNS workspace in which the magnetic fields are generated and controlled by an MNS. The proposed method can also be utilized to reconstruct vascular maps. Reconstructed vascular maps are in the 3D coordinate system of the C-arm and can be transformed into the 3D coordinate system of an MNS workspace to generate the magnetic flux density with the desired direction and magnitude at the position of the MMR. The proposed method allows us to remotely and precisely control the MMR inserted into the vessel by controlling the external magnetic field. The proposed method was validated through in vitro experiments with an MNS mock-up and a vascular jig. Finally, the proposed method was applied to in vivo experiments where the MMR was inserted into the superficial femoral artery of a mini pig to remotely control the motion of the MMR. This research will enable precise and effective control of MMRs in various medical procedures utilizing an MNS. Full article

Vibration test jigs are essential components for evaluating the dynamic performance and durability of automotive parts, such as lamps. This study aimed to derive optimal jig configurations that simultaneously maximize natural frequency and minimize structural weight through topology optimization. A fixed-grid finite-element model was constructed by incorporating realistic lamp mass and boundary conditions at the mounting interfaces to simulate actual testing scenarios. Four optimization formalizations were investigated: (1) compliance minimization, (2) compliance minimization with natural-frequency constraints, (3) natural-frequency maximization, and (4) natural-frequency maximization with compliance constraints. Both full-domain and reduced-domain designs were analyzed to assess the influence of domain scope. The results indicate that formulations that use only natural-frequency objectives often result in shape divergence and convergence instability. In contrast, strategies incorporating frequency as a constraint—particularly compliance minimization with a natural-frequency constraint—exhibited superior performance by achieving a balance between stiffness and weight. Furthermore, the reduced-domain configuration enhanced the natural frequency owing to the greater design freedom, although this resulted in a trade-off of increased weight. These findings underscore the importance of selecting appropriate formalization strategies and domain settings to secure reliable vibration performance and support the necessity of multi-objective optimization frameworks for the practical design of vibration-sensitive structures. Full article

Objective: This study compared the tooth movement patterns of a power arm and a lever jig during mandibular canine retraction into a premolar extraction space using skeletal anchorage. Methods: A finite element model was developed based on anatomical structures. A mini-implant was placed between the mandibular second premolar and first molar, and canine retraction was simulated using a power arm and a lever jig. The lever jig’s vertical arm lengths were 6 mm, 8 mm, and 10 mm, corresponding to force application distances of 4.5 mm, 6.4 mm, and 8.2 mm from the archwire, matching the power arm. Finite element analysis was performed using linear mechanical properties and an explicit method. Results: With the power arm, increasing vertical length led to greater extrusion, while the posterior force remained unchanged. The lever jig also showed increased extrusion with length but to a lesser extent. Posterior force increased proportionally with the lever jig length. Initial displacement analysis showed greater extrusion and distal tipping with the power arm, while the lever jig suppressed extrusion and facilitated controlled tipping. Stress analysis revealed a more uniform periodontal ligament stress distribution with the lever jig. Conclusion: The lever jig minimizes extrusion and enhances force concentration posteriorly, promoting efficient distal movement. Full article

Background/Objectives: Mandibular advancing devices (MADs) are removable intraoral apparatuses to use during sleep that modify the spatial position of the mandible, increasing airway patency and improving respiratory function at night in patients with obstructive sleep apnea syndrome (OSAS). Methods: In this work, a new mandibular advancement device useful for mild-to-moderate OSAS patients is presented. It is developed through a CAD–CAM process and involves a passive propulsion of the mandible thanks to the attraction of rare-earth magnets positioned in the thickness of two thermally molded PET-G devices. The use of a PET-G device compared to traditional resin ones offers several clinical advantages related to the innovative characteristics of this polymer, which allows the fabrication of thinner devices, with high resistance to fluid corrosion, resulting in less bulk inside the oral cavity. Results: The innovative feature of the device proposed by the authors is that mandibular propulsion induced by the attraction of the magnetic jigs is not affected by a patient’s mandibular posture during sleep. Conclusions: The original apparatus proposed by the authors determines a mesializing movement of the jaw through a different mechanism to traditional MADs and presents the great advantage of a digital and CAD–CAD workflow that can be developed directly by the clinicians in the practice. Full article

Layout design is the process in which industrial robots and other manufacturing components are positioned within a manufacturing system so that the intended operations can be handled appropriately. The traditional layout design process presents several challenges. It involves numerous iterations of testing different manually generated manufacturing layouts, requiring extensive trial and error to achieve an optimal solution. This process is highly time-consuming and demands significant expertise and cognitive effort from the designer. Within this publication, a flexible, scalable, and efficient function-block-based solution is presented for the optimization of manufacturing system layouts, especially in the field of multi-robot cells in two different use cases: one in additive manufacturing and one in jig-less welding. The findings showcase that the methodology followed enabled the efficient allocation of industrial robots in a workspace, minimizing the cognitive effort required in comparison to the traditional manual trial-and-error layout design procedure. Full article

Sea anchors are crucial for stabilizing fishing vessels and improving operations, specifically for jigging vessels. Their effective performance depends on design and material choice, with the canopy material playing a key role. We compared the drainage and drying rates of sea anchor canopies made from polyamide (PA) fabric, polyester (PES) fabric, and canopies designed with alternating strips of PA and PES (PA-PES) fabric to improve sea anchor performance, work efficiency, safety, and the stability of fishing operations. PA fabric had a fast initial draining rate due to high seawater absorption but a slow drying rate, resulting in a heavy canopy. PES fabric showed optimal draining due to low seawater absorption and fast drying. PA-PES fabric showed intermediate performance. Statistical analyses revealed that Sample B performed significantly better than PA fabric and PA-PES fabric, which showed no significant differences in performance. The low absorption and fast drying properties of PES fabric enhance the handling and efficiency of sea anchors, reducing worker fatigue and improving safety. These characteristics make it an exceptional alternative to PA fabric for sea anchor canopies. Future studies should examine the roles of sea anchor canopy material and structure in fishing operation safety and efficiency. Full article

Due to changes in the German government’s energy concept, the amount of gypsum produced in flue gas desulfurisation plants (FGD gypsum) will fall from 5 million tons per year to 1 million tons or less by 2038 at the latest. As of 2016, FGD gypsum accounts for 55% of German gypsum mix. The resulting raw material gap must be closed through innovative recycling concepts, such as the processing of existing mine dumps. The process development aims to achieve a calcium sulfate dihydrate content of 85% and a reduction in the stockpile volume by 50%. The main components of the stockpiles are calcium sulfate in the form of gypsum stone as well as clay minerals and organic matter. Successful laboratory tests were transferred to a pilot scale jigging machine with dewatering screening. The process water is circulated throughout the entire process. The gypsum content in the heavy fraction is 76% when measured with ICP OES and 87% when measured via thermogravimetric methods. Furthermore, pilot-scale dry screening on the stockpile took place, and up to 1500 tons of material could be processed. Due to fluctuating weather conditions, the screening quality was subject to significant variations. Under optimal conditions, up to 60% of the feed could be recovered as gypsum stone; however, the screening process was nearly impossible during rain; therefore, a process combination of screening and a downstream jigging machine is recommended. Full article

Vibration testing is crucial for understanding structural dynamics, yet conventional modeling of bolt connections often leads to significant inaccuracies. This study systematically compares six bolt connection methods—bonded, adaptive bonded, joint, beam, screw, and fixed bolt—using a finite element analysis of a headlamp vibration test jig. The six bolt connection methods were selected based on approaches adopted in previous studies. The experimental results identified the joint connection method as the most accurate, minimizing deviations in natural frequency to 7.6 Hz compared to experimental tests at 493.2 Hz, while bonded methods overestimated the frequency at 544.1 Hz due to excessive stiffness assumptions. Efficiency analyses highlighted bonded methods as the most computationally streamlined, offering preprocessing times as short as 30 s and shorter overall analysis times. These findings emphasize the importance of selecting appropriate bolt connection methods in the early design phase to ensure accurate natural frequency predictions and mode shape representations. Although this study does not consider bolt preload forces, the work shows the possibility of offering practical guidelines for improving the reliability and efficiency of vibration test jig designs by bridging the gap between analysis and experimental results. Full article

This study examines the challenges associated with processing hard coal, with a specific focus on gravitational enrichment methods and the utilization of jigs for coal separation. The research involves the simulation and modeling of physical property distributions and the analysis of both the feed density distribution and the characteristics of the enrichment products. Findings indicate that the resultant density distributions are influenced not only by the gravitational enrichment process but also by the preceding procedures and the inherent properties of the coal, such as particle size, sulfur content, and ash content, all of which significantly affect the quality of the outcomes. In modeling and optimization efforts, the study emphasizes approximating grain density using selected statistical distributions—specifically, the Weibull, logistic, and Gaudin–Schuhmann–Andreyev (GSA) distributions—before and after the enrichment process. Statistical analyses demonstrate that the GSA distribution most accurately fits the grain density distribution in the feed, while the Weibull distribution provides the best approximation for the separation products. The quality of these approximations was assessed using the coefficient of determination (R²) and the Mean Squared Error (MSE). The best quality of approximation for feed was obtained by means of the GSA distribution function, and the MSE was approximately 3.1 for two analyzed values of feed flow rates. In the case of concentrates and tailings, the results are not unequivocal. Full article

Drones utilize rechargeable batteries as a power source. Operating a drone requires human interaction with the exchange or recharge process of these batteries. This can provide limits for drones, which is why some use cases for drones could benefit from automated battery exchange. The purpose of this work was to research how a robotic arm could be used to automatically exchange flight batteries in flying drones without interference from operators and create a proof-of-concept system for evaluation. The devised method was based around a separate jig, which would hold the drone in place during the exchange operation, where battery exchange itself was handled by the use of a robotic arm. The constructed prototype could exchange flight batteries in drones in under two minutes with reasonable perpetuity and reliability. Full article

A small induction furnace (SIF), which has the important components of copper coils, a ceramic jig, and a graphite crucible, employed for a glass souvenir production process, has been developed as a form of clean technology for multiphysics, consisting of electromagnetics analysis (EA) and thermal analysis (TA). First, two experiments were established to measure parameters for multiphysics results validation and boundary condition settings. Then, the parameters were applied to multiphysics, in which the EA revealed magnetic flux density (B) and ohmic losses, and the TA reported a temperature consistent with the experimental results, confirming the multiphysics credibility. Next, a ferrite flux concentrator was added to the SIF during development. Multiphysics revealed that PC40 ferrite, as a flux concentrator with a suitable design, could increase B by about 159% compared to the conventional SIF at the power of 1000 W. As expected, the B increases alongside the increase in power applied to the coils, and is more densely concentrated in the flux concentrator than in other regions, enhancing the production process efficacy. Lastly, the developed SIF was employed in the actual process and received good feedback from users. The novel research findings are the developed SIF and methodology, exclusively designed for this research and practically employed for a glass souvenir production process. Full article

This paper reviews the process of research, development and production of a system for the active orientation of small screws. The parts feature two different shapes on each side, which is suitable for machine vision inspection and not for classical vibratory bowl traps. When a part enters the jig, it is rotated at an angle of 90° for inspection. Based on the orientation, it may stay in this position or be rotated at 180°. This allows for active orientation; regardless of how the screw is presented to the camera, it is always positioned in the correct orientation by a servo mechanism. The main challenges are related to the small dimensions of the part. First of all, it has a diameter of only 3 mm and a length of 7 mm. A vibratory bowl feeder is used only for feeding and there is no orientation functionality in it. Afterwards, a vibratory linear feeder is placed so the ready parts are stacked and, thus, some buffer is created. This is important because vibratory bowl feeders are known for having unequal productivity in time and this could be solved by the linear feeder. Another key difficulty is the quality of the source parts. They are produced by several suppliers and sometimes there are chips and other remnants alongside the packages with screws. This imposes the need for a cleaning system as part of the servo actuator’s mechanism. Cleaning does not occur on every cycle; it is based on a timer that is predefined. Full article

This paper describes commonly used processes to produce aviation fuel and alternative routes with potential production yields for sustainable aviation fuels (SAF) like HEFA and ATJ. It also presents the possible sources (crude oil, refinery processes), causes (filter clogging, engine failure), and forms of contamination in both conventional and alternatively produced aviation fuels. Special attention is focused on the threats of fuel contamination with solid particles/trace elements, water, microorganisms, and fatty acid methyl esters (FAME). This review also presents the standard and novel advanced methods (ICP-MS, MALDI, ViPA) for identifying contaminations in aviation fuel. It also identifies possible ways to control and eliminate the risk of contamination, such as the fallowing coherent JIG system to ensure the quality of aviation fuel. Another approach that is very interesting and worth considering for future development is the idea of predictive maintenance and machine learning in monitoring and detecting contamination. Full article