Search Results (1,184)

Additive manufacturing (AM) enables the consolidation of components and the integration of new functionalities in metallic parts, but layered fabrication often results in poor surface quality and geometric deviations. Among various surface treatment techniques, machining is often favoured for its capability to enhance not only surface finish but also critical geometric tolerances such as flatness and circularity, in addition to dimensional accuracy. However, machining AM components, particularly thin-walled structures, poses challenges related to unconventional material properties, complex fixturing, and heightened susceptibility to chatter. This study investigates the vibrational behaviour of thin-walled Ti6Al4V components produced via laser powder bed fusion, using a jet-engine compressor blade demonstrator. Four stock envelope designs were evaluated: constant, tapered, and two topologically optimised variants. After fabrication by Laser Powder Bed Fusion, the blades underwent tap testing and subsequent machining to assess changes in modal characteristics. The results show that optimised geometries can enhance modal performance without increasing the volume of the stock material. However, these designs exhibit more pronounced in situ modal changes during machining, due to greater variability in material removal and chip load, which amplifies vibration sensitivity compared to constant or tapered stock designs. Full article

The effects of extreme heat events on Surface Urban Heat Island Intensity (SUHII) were investigated in Lecce (southern Italy) during the summer months (June–August) from 2018 to 2025. The analysis began with the identification of heatwave frequency, duration, and intensity using the Warm Spell Duration Index (WSDI), based on a homogenized long-term temperature record, which indicated a progressive increase in persistent extreme events in recent years. High-resolution ECOSTRESS land surface temperature (LST) data were then processed and combined with CORINE Land Cover (CLC) information to examine the thermal response of different urban fabrics, compact residential areas, continuous/discontinuous urban fabric, and industrial–commercial zones. SUHII was derived from each ECOSTRESS acquisition and evaluated across multiple diurnal intervals to assess temporal variability under both normal and WSDI conditions. The results show a consistent diurnal asymmetry: daytime SUHII becomes more negative during WSDI periods, reflecting enhanced rural warming under dry and highly irradiated conditions, despite overall higher absolute LST during heatwaves, whereas nighttime SUHII intensifies, particularly in dense urban areas where higher thermal inertia promotes persistent heat retention. Statistical analyses confirm significant differences between normal and extreme conditions across all classes and time intervals. These findings demonstrate that extreme heat events alter the urban–rural thermal contrast by amplifying nighttime heat accumulation and reinforcing daytime negative SUHII values. The integration of WSDI-derived heatwave characterization with multi-year ECOSTRESS observations highlights the increasing thermal vulnerability of compact urban environments under intensifying summer extremes. Full article

This work investigates the optimization of Laser Powder Bed Fusion (LPBF) parameters for the C71500 copper-nickel alloy using mechanically produced, non-thermally generated powder. Utilization of this powder presents a more sustainable powder generation method through significant reduction in energy usage and CO₂ emissions and a large array of alloys to be utilized within LPBF. A comprehensive design of experiments (DOE), with varying laser power and scan speed, was employed to construct a process performance map, which was subsequently refined using machine learning algorithms. Specimens fabricated under optimized conditions exhibited high dimensional fidelity, low surface roughness and porosity, and achieved relatively dense specimens. Mechanical testing confirmed that the optimized parameter sets exceeded standard wrought alloy values for ultimate tensile strength and yield strength, with almost meeting standard cast alloy values demonstrating feasibility of implementing common bar stock alloys in LPBF applications. The observed variability in tensile properties was attributed to inefficient laser parameters requiring further optimization. Future efforts will focus on repeating the optimization using quality powder controls and further refining tensile performance within the high-density region of the parameter space. Full article

Additive manufacturing, or 3D printing, is a method for creating three-dimensional objects layer-by-layer based on a digital model. This article presents the results of research on selective laser melting (SLM) of 316L stainless steel powder. Its aim is to investigate the relation between the mechanical properties of SLM-fabricated 316L steel samples obtained from uniaxial tensile tests and the SLM process parameters including the build-up strategy. Four different configurations of 3D printing orientation relative to the build platform were considered. The variable parameters of the SLM process were laser power and laser scanning speed. The morphology of the external surfaces and the microstructure of the SLM-processed samples were examined. The results show that samples printed in the longitudinal and transverse configurations had the highest tensile strength. Samples printed in the vertical and diagonal configurations had the greatest dispersion of values of mechanical parameters. The main difference in mechanical properties after doubling the SLM process parameters was a decrease in elongation for samples printed in the longitudinal configuration and an increase in this value for samples printed in the transverse configuration. The use of higher laser powers and laser scanning speeds guarantees a more compact, non-porous microstructure of SLM-processed samples. Full article

This study investigates the materials and fabrication selection criteria for 3D-printed aluminosilicate components aimed for passive cooling and CO₂ adsorption in indoor conditions, considering their manufacturing environmental impact. The dual-function components were fabricated using Liquid Deposition Modelling (LDM), an Additive Manufacturing (AM) technique utilising customised slurry-based feedstock materials. To assess the environmental implications of the production process, the study employs the Life Cycle Assessment (LCA) methodology, a standardised framework used to quantify potential environmental impacts across the product’s life cycle. The study outlines a systematic approach to materials and fabrication processes selection, focusing on the functional properties required, the importance of locally sourced materials, and the constraints imposed by the fabrication techniques. The fabrication methodology was analysed for material/energy efficiency and waste generation. Post-processing stages were evaluated to identify opportunities for energy savings, particularly by exploring Low-Temperature Firing (LTF). The selected criteria proved efficient in enhancing shaping control and minimising shrinkage variability, with a recorded weight loss of 3.04% via LTF. The LCA results indicated that the 23% reduction in climate change impact was primarily driven by the lower electricity demand of the LTF Protocol, demonstrating that energy-efficient post-processing is a critical lever for sustainable ceramic fabrication. Full article

The proliferation of free-form architecture necessitates efficient detailing methods for complex spatially bending-torsion steel members. Current approaches suffer from low modeling efficiency, inaccurate surface fitting, and limited capabilities for variable-section generation and plate unfolding. This study presents a comprehensive parametric detailing module developed within the Grasshopper (GH) platform to overcome these challenges. The core innovations include (1) a data structure that integrally describes member axes, cross-sections, and unfolding information; (2) an algorithm that automatically generates interpolation points based on curvature variation to ensure axis smoothness; (3) the use of architectural surface normals as member torsion vectors, eliminating manual control point placement; and (4) integrated alignment and unfolding functions for fabrication-ready outputs. In an engineering case study, the module reduced modeling time by approximately 70% compared to conventional methods while achieving a root-mean-square deviation of less than 2 mm between the fitted and target surfaces. The system enables rapid generation of 3D models and 2D fabrication drawings for complex bending-torsion members, significantly enhancing detailing efficiency and precision. Full article

Auxetic textiles, characterized by a negative Poisson’s ratio, offer considerable promise for innovative applications across multiple fields. In our earlier work, Miura-ori-inspired auxetic fabrics with three different initial dihedral fold angles—30°, 45°, and 60°—were successfully fabricated via jacquard weaving. Their fundamental auxetic behaviors were evaluated, showing deformation characteristics consistent with those in their geometric models. This study further investigates the mechanical properties of Miura-ori-based auxetic woven fabrics. Tensile testing, air permeability measurement, compression performance assessment, and repeated-loading cyclic rope-stretching tests were performed on the three fabric variants. The results show that the fabrics exhibit excellent air permeability, which increases with the proportion of the folded areas; the highest air permeability was observed at Miura-30°. Moreover, Miura-60° exhibited superior compression resistance. The fabrics also demonstrated outstanding structural stability under cyclic tensile loading, exhibiting optimal elastic recovery at the 30° configuration. Collectively, these findings provide a solid theoretical basis for future applications of Miura-ori auxetic woven fabrics. Full article

The development of implantable neural interfaces is essential for enabling bidirectional communication between the nervous system and prosthetic devices, yet their evaluation still relies primarily on in vivo models which are costly, variable, and ethically constrained. Here, we report a bio-inspired artificial nerve simulator engineered as a reproducible ex vivo platform for pre-implantation testing of plug-type electrodes. The simulator is fabricated from a conductive hydrogel composite based on reduced graphene oxide (rGO), polyaniline (PANI), agarose, sucrose, and sodium chloride, with embedded conductive channels that replicate the fascicular organization and conductivity of peripheral nerves. The resulting construct exhibits impedance values of ~2.4–2.9 kΩ between electrode needles at 1 kHz, closely matching in vivo measurements (~2 kΩ) obtained in Sus scrofa domesticus nerve tissue. Its structural and electrical fidelity enables systematic evaluation of electrode–nerve contact properties, signal transmission, and insertion behavior under controlled conditions, while reducing reliance on animal experiments. This bio-inspired simulator offers a scalable and physiologically relevant testbed that bridges materials engineering and translational neuroprosthetics, accelerating the development of next-generation implantable neural interfaces. Full article

Background/Objectives: Pathological tooth loss resulting from poor oral hygiene or systemic diseases can lead to partial edentulism, affecting patients both psychologically and physically. These consequences include facial height reduction, temporomandibular dysfunction, and impaired phonetics and mastication. Immediate complete dentures are often an effective provisional solution during the transition to full edentulism; however, establishing the occlusal plane can be challenging when remaining teeth prevent a conventional wax try-in. This clinical case aims to present a qualitative clinical case study of a single patient, illustrating the use of the Broadrick Occlusal Plane Analyzer (BOPA) for the establishment of an occlusal plane in harmony with the anterior and condylar guidance. Methods: A 51-year-old male patient presented to the Department of Prosthodontics at the School of Dentistry, Autonomous University of Guadalajara, with partial edentulism, periodontal disease, and generalized Grade III tooth mobility. Immediate maxillary and mandibular complete dentures were selected as the treatment of choice. Due to the presence of remaining teeth that hindered clinical determination of the occlusal plane, the BOPA was used during the denture design process. Results: Anatomical landmarks were combined with BOPA tracing to establish an occlusal plane harmonious with anterior and condylar guidance. The center of the curve was modified to accommodate anatomic variability in anteroposterior reference points. Conclusions: The use of the Broadrick Occlusal Plane Analyzer facilitated the accurate determination of the occlusal plane for the fabrication of immediate complete dentures in a patient where clinical assessment was limited. This modification allowed the establishment of a bilateral balanced occlusal scheme, contributing to functional and acceptable provisional oral rehabilitation during postoperative alveolar healing. Full article

The characterization of carbonate subsurface reservoirs, which host significant natural resources such as water and hydrocarbon, is crucial for earth scientists and engineers. Key characterization methods include seismic and downhole sonic techniques. This study explores the relative influence of mineralogy versus pore geometry on acoustic velocity and velocity–porosity relationships in carbonate rocks, which is important for seismic and sonic interpretation in reservoir characterization. A global dataset from ten localities encompassing different carbonate lithologies—including limestones, fabric-preserving (FP) and non-fabric-preserving (NFP) dolostones, and siliceous carbonates—was analyzed using laboratory measurements and Differential Effective Medium (DEM) modeling. Results show that the mineralogy influence decreases with porosity, so it is limited only to tight rocks where dolostones show higher velocity than limestones while siliceous carbonates show the least velocity. As porosity increases, FP dolostones retain higher velocities, whereas NFP dolostones have comparable or lower velocities than limestones, contrary to expectations from mineral elastic properties. This behavior is mainly governed by pore geometry, as supported by petrographic analysis and DEM modeling. Siliceous carbonates display notably lower velocities, which is entirely attributed to smaller pore aspect ratios (about 50% less than in limestones) rather than mineralogical effects. Overall, this study highlights that pore geometry dominates over mineralogy in determining acoustic velocity within porous carbonates, providing a valuable framework for improving seismic and sonic-based porosity estimation across variable carbonate lithologies. Full article

Fused deposition modeling (FDM) is one of the most widely adopted additive manufacturing (AM) technologies due to its accessibility and versatility; however, ensuring process reliability and product quality remains a significant challenge. This work introduces a novel methodology to evaluate the fidelity of programmed extruder head trajectories and speeds against those executed during the printing process. The approach integrates infrared thermography and image processing. A type-V ASTM D638-14 polylactic acid (PLA) specimen was fabricated using 16 layers, and its G-code data were systematically compared with kinematic variables extracted from long-wave infrared (LWIR) thermal images. The results demonstrate that the approach enables the detection of deviations in nozzle movement, providing valuable insights into layer deposition accuracy and serving as an early indicator for potential defect formation. This thermal image–based monitoring can serve as a non-invasive tool for in situ quality control (QC) in FDM, supporting process optimization and improved reliability of AM polymer components. These findings contribute to the advancement of smart sensing strategies for integration into industrial additive manufacturing workflows. Full article

In manufacturing processes, both material processing methods and the resulting microstructure play a fundamental role in determining material behavior during component fabrication and subsequent service conditions. Materials produced by additive manufacturing exhibit a unique microstructure due to the rapid heating and solidification cycles inherent to the process, distinguishing them from conventionally cast counterparts and leading to differences in mechanical and functional properties. This article presents problems related to the longitudinal turning of Ti6Al4V titanium alloy elements produced by the casting and powder laser sintering (DMLS) methods. The authors made an attempt to establish a procedure for determining the optimal parameters of finishing cutting while minimizing the specific cutting force, taking into account the criterion of machined surface quality. In the course of the experiments, the influence of the cutting data on the cutting force values, surface roughness parameters, and chip shape was examined. The material hardening state during machining and the variability of the specific cutting force as a function of the cross-sectional shape of the cutting layer were also tested. The authors presented a practical application of the proposed optimization algorithm. It was found that by changing the shape of the cross-section of the cutting layer, it was possible to carry out the turning process with significantly reduced specific cutting force (from 2300 N/mm² to 1950 N/mm²) without deteriorating the surface roughness. Full article

The widespread adoption of high-strength steel reinforcement in China has driven a growing demand for 600 MPa grade and higher-strength stirrups in engineering applications. This study experimentally investigates the seismic performance of concrete columns reinforced with 630 MPa high-strength steel stirrups. Six concrete columns were designed and fabricated, incorporating key variables including concrete strength, stirrup strength, and stirrup spacing ratio. Low-cycle reversed loading tests were subsequently conducted on these specimens, enabling a thorough evaluation of their seismic characteristics. Additionally, the study examines the cumulative damage effects and confining influence of 630 MPa high-strength stirrups on the core concrete. The findings reveal that concrete columns with a low ratio of 630 MPa high-strength stirrups exhibit enhanced seismic performance when the concrete strength is relatively low. However, with increasing concrete strength, the confinement efficiency of 630 MPa ultra-high-strength stirrups diminishes, leading to accelerated damage progression and reduced ductility. Both low- and high-strength concrete columns benefit from a high stirrup ratio, which provides effective confinement. Furthermore, 630 MPa high-strength stirrups help mitigate damage accumulation while enhancing yield displacement, peak displacement, ultimate displacement, ductility, and energy dissipation capacity. The use of 630 MPa high-strength stirrups not only ensures superior seismic performance but also reduces reinforcement requirements and improves construction efficiency. Full article

In this study, TiB₂/AlSi10Mg, 2 wt.% SiC + TiB₂/AlSi10Mg, and 5 wt.% SiC + TiB₂/AlSi10Mg composite powders were prepared via high-energy ball milling. For the first time, TiB₂ and SiC hybrid particle-reinforced aluminum matrix composites (AMCs) were fabricated using the Laser-Directed Energy Deposition (LDED) technique. The effects of processing parameters on the microstructure evolution and mechanical properties were systematically investigated. Using areal energy density as the main variable, the experiments combined microstructural characterization and mechanical testing to elucidate the underlying strengthening and failure mechanisms. The results indicate that both 2 wt.% and 5 wt.% SiC + TiB₂/AlSi10Mg composites exhibit excellent formability, achieving a relative density of 98.9%. However, the addition of 5 wt.% SiC leads to the formation of brittle Al₄C₃ and TiC phases within the matrix. Compared with the LDED-fabricated AlSi10Mg alloy, the tensile strength of the TiB₂/AlSi10Mg composite increased by 21.4%. In contrast, the tensile strengths of the 2 wt.% and 5 wt.% SiC + TiB₂/AlSi10Mg composites decreased by 3.7% and 2.6%, respectively, mainly due to SiC particle agglomeration and the consumption of TiB₂ particles caused by TiC formation. Nevertheless, their elastic moduli were enhanced by 9% and 16.3%, respectively. Fracture analysis revealed that the composites predominantly exhibited ductile fracture characteristics. However, pores larger than 10 μm and SiC/TiB₂ clusters acted as crack initiation sites, inducing stress concentration and promoting the propagation of secondary cracks. Full article

Recent global efforts to produce lightweight electrified vehicles have motivated the push toward advanced lightweight materials which led to the creation of novel alloys optimized for use in high-pressure die casting (HPDC). HPDC enables the fabrication of near-net-shape automotive parts, significantly reducing or eliminating additional machining steps. A key feature of HPDC is the extremely fast cooling that forces the alloy to solidify within only a few seconds. Because of these rapid cooling conditions, it becomes essential to accurately evaluate the thermophysical behavior of newly designed lightweight alloys during severe quenching. Precisely quantifying these material properties is crucial for properly controlling HPDC operations and for building reliable numerical models that simulate filling and solidification. The thermophysical characteristics of such alloys vary markedly with temperature, especially when the material undergoes the fast solidification typical of HPDC. Therefore, understanding how these properties change with temperature during intense cooling becomes a critical requirement in alloy development. To address this need, a dedicated experimental system was designed to solidify molten metal samples under controlled and variable cooling conditions by applying multiple impinging water jets. An inverse heat-transfer algorithm was formulated to extract temperature-dependent thermal conductivity and diffusivity of the alloy as it solidifies under rapid cooling. To verify the reliability of both the inverse model and the measurements, experiments were performed using pure Tin, a reference material with well-documented thermophysical properties. The computed thermophysical properties of Tin were benchmarked against values reported in the literature and demonstrated reasonable consistency, with a maximum deviation of 13.6%. Full article