The additive manufacturing of thin-walled components is key to producing complex, high-value hollow designs, particularly in the aerospace industry. To master the fabrication of such parts and limit defects that compromise quality, in situ process monitoring is essential. This work implements an off-axis infrared camera to track thermal behavior during LP-DED manufacturing of 316L single-bead walls. The solidification parameters such as the cooling rate, thermal gradient, and solidification rate were extracted from the thermal images and correlated with the microstructural observations. Although trends were identified between process parameters (laser power and scanning speed) and thermal or microstructural characteristics, some of these relationships diverged from expectations in the literature. Geometrical defects, including stacking irregularities and surface roughness, were found to disrupt heat flow, leading to heterogeneous grain morphologies and local alterations in thermal measurements. These findings emphasize the need to account for geometrical defects to ensure reliable thermal monitoring and effective process control. In addition to highlighting the strong influence of geometrical defects, this study demonstrates the potential of in situ IR-based monitoring to predict the microstructure in LP-DED through a comprehensive experimental methodology.
We report an autopsy case in which broncholithiasis mimicked retained ballistic projectiles in a putrefied body. A medico-legal autopsy was performed on a 76-year-old male found in an advanced state of putrefaction. Macroscopic examination during autopsy revealed small, stony intrapulmonary nodules raising suspicion of retained pellets. Whole-body post-mortem computed tomography (PMCT) allowed us to further characterize these elements. The structures were subsequently analyzed using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS) to determine their elemental composition. PMCT demonstrated multiple hyperdense micronodules within the right upper lobe, arranged in a linear endobronchial pattern without metallic artifacts, strongly suggesting a calcified biological origin. SEM-EDS analysis revealed a predominance of calcium and phosphorus, with no evidence of metallic elements typically associated with ballistic materials. These findings and histopathological examination confirmed the diagnosis of broncholithiasis. Broncholithiasis may closely mimic retained ballistic fragments at the macroscopic level in decomposed bodies, representing a significant forensic diagnostic pitfall. While PMCT is key to orienting the diagnosis, this work highlights the value of a multimodal approach combining post-mortem imaging, histopathology, and elemental microanalysis to provide definitive chemical confirmation and prevent misinterpretation of the cause and manner of death.
Differentiating bladed weapons in sharp force trauma remains a critical forensic challenge. While macroscopic examination offers preliminary clues, it often lacks the precision to identify the specific weapon used. Yet, correctly attributing a wound to a particular blade type can be decisive in legal investigations. This study explores the combined use of morphological analysis using Scanning Electron Microscopy (SEM) with elemental analysis via SEM-coupled Energy-Dispersive X-ray Spectroscopy (EDX), to detect unique signatures left by different bladed weapons.We conducted a prospective experimental study using three smooth-bladed knives: a hunting knife, a ceramic knife, and a common utility knife (Opinel type 8). A custom-built machine created standardized stab wounds on ex vivo specimens with consistent pressure. A total of 30 wounds (10 per knife type) were analyzed.Wounds were first examined using SEM to identify specific morphological criteria like groove depth and width. Simultaneously, EDX was used to identify and quantify trace particles from the blades. Analysis was performed on both bone and soft tissue samples to represent conditions of maximal and more realistic deposition. The elemental composition of each blade was determined as a reference, and negative controls ensured sample integrity.While morphological differences exist between wounds produced by each of the weapons, their distinction remains a challenge. Scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX) provides complementary data. A detailed statistical comparison of particle density and nature was performed. Thus, distinct morphological features and characteristic elemental signatures were observed in the wounds. These results demonstrate that a combined morphological and compositional analysis provides an effective method for differentiating sharp force injuries.This research establishes a comprehensive protocol for characterizing sharp force injuries. The findings will enhance forensic investigations by providing a precise, objective method to identify the type of weapon used, thereby making a valuable contribution to forensic pathology.
Surrogate models are of high interest for many engineering applications, serving as cheap-to-evaluate time-efficient approximations of black-box functions to help engineers and practitioners make decisions and understand complex systems. As such, the need for explainability methods is rising and many studies have been performed to facilitate knowledge discovery from surrogate models. To respond to these enquiries, this paper introduces SMT-EX, an enhancement of the open-source Python Surrogate Modeling Toolbox (SMT) that integrates explainability techniques into a state-of-the-art surrogate modelling framework. More precisely, SMT-EX includes three key explainability methods: Shapley Additive Explanations, Partial Dependence Plot, and Individual Conditional Expectations. A peculiar explainability dependency of SMT has been developed for such purpose that can be easily activated once the surrogate model is built, offering a user-friendly and efficient tool for swift insight extraction. The effectiveness of SMT-EX is showcased through two test cases. The first case is a 10-variable wing weight problem with purely continuous variables and the second one is a 3-variable mixed-categorical cantilever beam bending problem. Relying on SMT-EX analyses for these problems, we demonstrate its versatility in addressing a diverse range of problem characteristics. SMT-Explainability is freely available on Github: https://github.com/SMTorg/smt-explainability .
The ABD-900AM is a newly developed nickel-based alloy specifically designed for additive manufacturing, and it can be printed using a wide range of process parameters. This alloy, combined with the L-PBF process, allows for the production of dense parts with reference microstructures that are multi-scale, and facilitates the study of the links between these microstructures and their tribological behaviors. To study the relationships between microstructures and tribological behaviors, the parts are built vertically without interlayer rotation. The plane studied are obtained with three scanning directions : 0 degrees, 45 degrees and 90 degrees. These angles allow to generate different microstructures on the planes on which are conducted the microstructural characterizations and tribological tests, for which the sliding direction is always parallel to the building direction. This choice of parameter enables access to different crystallographic textures (200) and (111), and cellular structures with varying morphologies and homogeneity within the melt pools. Tribological tests were performed on these microstructures in a ball-on-flat configuration with alternating motion, without lubrication, and at room temperature. For the three laser angles (0 degrees, 45 degrees, and 90 degrees), the wear volumes are 0.60 +/- 0.12 mm3, 0.81 +/- 0.15 mm3, and 1.00 +/- 0.09 mm3, respectively. The wear resistance is primarily related to the amount of oxide layers formed on the wear track of the samples.
