Energy storage is an essential stage in energy production and usage. The advantages of supercapacitors, including their extended lifespan, high power density, wide operating temperature ranges, and quick charge-discharge periods, set them apart from other energy storage technologies. The supercapacitor (SC) design’s electrochemical performance was examined in this work using WS-active carbon material derived from walnut shell waste as the electrode material. Thus, this study aims to utilize waste material that has no economic value for energy storage. In this way, a dual-purpose study was carried out, serving the environmental field by disposing of a waste material and the energy storage field by producing a new supercapacitor electrode material. Electrochemical tests were performed to assess the energy storage activity of the WS-electrode. In this context, Cyclic Voltammetry/CV, Electrochemical Impedance Spectroscopy/EIS, Galvanostatic Charge-Discharge/GCD and stability cycling analysis were performed. The WS-active material used as electrode material was prepared by carbonizing walnut shell supplemented with 30% Cu with HCl+distilled water for 60 minutes at 800 ℃. As a result of the measurements of the two-electrode cell system in the presence of 6M KOH electrolyte solution using WS-active material as the electrode, capacitance values were obtained as 78.90, 50.57, 39.24 and 29.69 F g-1 at current densities of 0.5, 0.75, 1 and 1.50 A g-1, respectively.
Water losses increase operational costs for utilities and lead to significant revenue reductions; therefore, effective control and sustainable management of apparent losses are critical for utilities. This study proposes a methodological framework for the efficient management and prioritization of apparent loss components using multi‐criteria decision‐making (MCDM) methods, including the Analytical Hierarchy Process (AHP), Analytic Network Process (ANP), and the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS). A total of 72 components were identified under six main headings for apparent loss management (ALM), and 10 evaluation criteria were defined to assess these components. The weights of the criteria were calculated with AHP and ANP, while TOPSIS was applied to prioritize the ALM components based on these weights. The results indicate that the ANP method, which accounts for complex interdependencies among criteria, provides more stable and reliable weighting results. According to the TOPSIS analysis, 14 components showed similar priority rankings. Overall, the findings offer a valuable contribution to decision‐making processes in the planning and strategy development stages of apparent loss management.
The tunnels, in some cases, are excavated in sequential sections to prevent sudden stress release and to manage stress distributions in a controlled manner. Although each country employed different methods, referred to as country-specific methods, they can be discussed in general terms. Since the excavation sequences in tunnels are fixed with the project, it is not possible to examine this effect with field measurements. Therefore, these effects have been investigated using numerical modelling methods. In this study, eight different excavation scenarios were created using sequential tunneling methods throughout the history of tunneling. These excavation scenarios were modelled for the modified horseshoe-shaped tunnels excavated in six different weak rock masses and four different depths. In addition to the unsupported excavation models examined according to different excavation scenarios, the supported excavations were also modelled using the empirical support suggestion of a rock mass classification system. The stresses affecting the support elements were analyzed on supported excavation models. The study emphasizes that the excavation slice and sequence should be taken into consideration when designing tunnels.
Subterranean environments such as caves, tunnels, and underground urban structures present significant challenges for search and rescue operations due to hazards like unstable terrain, limited visibility, and the absence of GPS signals. To address these challenges, autonomous mobile robots have emerged as a viable solution. This paper presents a modular autonomy stack for autonomous underground exploration, object detection and localization in simulated hazardous subterranean environments. The system integrates three core modules: LIO-SAM for lidar-IMU odometry, GBPlanner2 as the exploration planner with a pure-pursuit tracker for path following, and YOLOv3 for real-time artifact detection with depth-based localization. We evaluate the integrated stack in multiple virtual circuits (cave, tunnel, and urban) and report circuit-wise performance, including odometry drift, exploration coverage, and detection errors. The system performs best in the urban circuit, where it localizes multiple artifacts with low horizontal drift. Performance degrades in steep or cluttered terrain, where limited observability and collision-checking errors reduce coverage and increase failure rates.
Spider robots are widely preferred due to their superior mobility enabled by multi-legged structures and articulated joints, which allow effective locomotion on uneven terrain and obstacle negotiation. However, the mechanical complexity of legged systems may lead to limited payload capacity, a high number of moving parts, and increased sensitivity to impacts, while balance control becomes more challenging due to variations in the center of gravity. This study aims to mitigate these drawbacks by proposing the mechanical design and prototype implementation of a six-legged spider robot, supported by material selection and an embedded electronic setup for actuation and sensing. Forward and inverse kinematic models of a 3-DOF leg are derived using the Denavit–Hartenberg convention to enable consistent foot placement and trajectory generation. In addition, predefined gait patterns are implemented and evaluated on the prototype to assess feasible locomotion behavior, and a structural deformation analysis of critical leg segments is performed to investigate mechanical robustness under loading. The presented platform provides a practical basis for further developments in hexapod locomotion for field-oriented applications such as search and rescue, reconnaissance, and hazardous environment exploration.
