This study evaluated the influence of vacuum carburizing parameters on the microstructure, microhardness profile, and case hardening depth (CHD550) of TL 4227 and TL 4521 steels used in highly loaded gear components. Experiments were performed on industrial gear components using an ALD ModulTherm system at 960, 980, and 1,000 °C, followed by gas quenching and tempering. The work focused on industrial validation of VW TL gear steels and shortened carburizing cycles based on previous temperature-focused results. Metallographic examination and microhardness profiling were performed to establish correlations between process parameters and case properties. CHD550 increased from approximately 0.65 mm to 0.9 mm with increasing carburizing temperature, while surface hardness remained around 740 HV1. A reduction of the total carburizing cycle time by approximately 15–20
Mining critical minerals in the Democratic Republic of Congo comes with tough governance hurdles, environmental damage, and deep socioeconomic strains. This study’s approach blends SWOT with PESTLE analysis, drawing on the insight of experts from 32 organizations in 11 countries, including Canada, France, Germany, India, Norway, Pakistan, Poland, Portugal, Romania, Spain, and the United States. This two‑pronged approach makes it easier to fully examine the structural, political, and socio‑environmental sides of the cobalt industry in the Democratic Republic of the Congo. The PESTLE analysis paints the DRC’s political climate as unstable and steeped in corruption, with social governance in deep crisis and environmental oversight falling far short. In the SWOT analysis, strengths at 14.49 and opportunities at 12.54 edge ahead of weaknesses at 12.95 and threats at 11.27 on average. This forms the foundation for the study’s conclusion: greater transparency in institutions, fairer labour market governance, and stronger environmental laws could help curb the extractive injustices tied to cobalt mining in the DRC.
This paper presents an integrated system for autonomous lane following with obstacle avoidance in unmanned tracked vehicles (UTVs), combining monocular vision and Active Disturbance Rejection Control (ADRC). A vision-based guidance system is developed using deep learning models: YOLOPv2 for lane segmentation and YOLOv8 for obstacle detection within a dynamic region of interest. Novel lane processing algorithms address partial detections and generate aligned lane boundaries, while a computationally efficient virtual lane generation mechanism enables path planning around obstacles without requiring dedicated depth sensors. To follow the path defined by this guidance system, an ADRC controller is designed for the UTV’s lateral control channel based on a kinematic model, incorporating disturbance estimation via an extended state observer, ensuring robust regulation of lateral path error. The system’s effectiveness is demonstrated through comprehensive experimental validation on a physical UTV platform in two distinct environments: an indoor track with static obstacles and an outdoor setting with both static and dynamic obstacles. Outdoor trials confirm the system’s robustness against real-world challenges, including sloped terrain, varying natural lighting, and multi-colored lane markings. Furthermore, the system successfully navigated around obstacles and critically validated its fail-safe stop logic when the path was fully blocked. Comparative tests against a conventional PID controller quantitatively demonstrate the ADRC’s superior tracking accuracy and disturbance rejection capabilities, highlighting its enhanced robustness in both controlled indoor and unstructured outdoor environments. These results confirm the feasibility of achieving robust lane following and effective obstacle avoidance in UTVs using cost-efficient monocular vision. Supplementary material: https://youtu.be/9aKGugeYmfw?si=qiBCTzi7hYUvwUW6
This research investigates the challenges and potential of Cold Metal Transfer (CMT) for Wire-Arc Additive Manufacturing (WAAM, also known as WADED – Wire-Arc Directed Energy Deposition) of AZ61 magnesium alloys. Despite the excellent properties of magnesium alloys, their processing is challenging due to high vapour pressure, low boiling point, flammability, and difficulties in maintaining a stable welding process. This study examines the effects of key CMT parameters, including boost phase current and duration, burn phase current, electrode speed, and short-circuit (SC) phase current. The results demonstrate that boost phase current, cycle time, droplet surface tension, and material consumption significantly influence deposition size and shape. By optimising these parameters, a stable and efficient welding process was achieved, improving contact angle and ensuring sufficient penetration. The optimised conditions enabled the fabrication of a 50-layer thin-walled component, highlighting the study’s contribution to advancing CMT applications in WADED processes.
Introduction:Radial nerve palsy, with wrist drop and loss of finger and thumb extension, severely impairs grasp and release. In proximal or extensive defects, direct repair or grafting may fail, making distal nerve transfer a preferred alternative. Research question:Can distal median-to-radial nerve transfers restore hand extension and improve quality of life in patients with radial nerve injury? Material and methods:This prospective study included nine patients with radial nerve injuries treated using distal nerve transfer. Surgical reconstruction consisted of transfer of the median nerve branch to the flexor digitorum superficialis to the radial nerve branch for the extensor carpi radialis brevis, combined with transfer of the median nerve branch to the flexor carpi radialis to the posterior interosseous nerve. In addition, a pronator teres to extensor carpi radialis brevis tendon transfer was performed to facilitate wrist extension in long-standing lesions. Functional recovery of wrist, finger (II-V), and thumb extension was assessed 24 months postoperatively using a modified British Medical Research Council scale, and quality of life was evaluated preoperatively and at final follow-up using the PNSQoL questionnaire. Results:All patients achieved satisfactory recovery (BMRC M3-M5) of wrist, finger, and thumb extension, with M4-M5 outcomes predominating, especially for wrist extension. Median PNSQoL improved from 49 to 78, with 88.9% reporting excellent quality of life. Discussion and conclusion:Distal median-to-radial nerve transfer reliably restores hand extension and improves patient-reported outcomes in proximal radial nerve injuries, though larger multicenter studies are needed for confirmation.
