The thermal deposition of hydroxyapatite (HA) on titanium alloy substrate (Ti-6A1-4V) leads to a structure that has very good osseointegration properties. However, clinical failures have been occasionally reported at the interface between substrate and coating. Lifetime is the main parameter in such prostheses; therefore, in order to improve their quality, it is necessary to evaluate the level of stresses near the interface. The high-energy synchrotron radiation combines the advantages of a bulk analysis and reduced volume of the gauge. The objective of our study was to calculate the residual stress using a nonlinear finite-element model and to measure residual stress level near the interface, in the hydroxyapatite coating and in titanium alloy substrate with a nondestructive and high-resolution experiment. The high-energy synchrotron radiation of the BM16 beam-line at ESRF (Grenoble-France) was used with a resolution of down to 10 micrometers. The experimental measurements validate the results found by means of nonlinear finite-element analysis of the plasma spraying induced stress.
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http://dx.doi.org/10.1109/TBME.2005.847526 | DOI Listing |
3D Print Addit Manuf
December 2024
School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, P.R. China.
Thermal cracking is one of the serious issues that deteriorates the processibility of laser powder bed fusion (LPBF) high-strength aluminum components. To date, the effects of processing parameters on crack formation are still not well understood. The purpose of this study is to understand the correlation between the thermal cycle and the hot cracking during LPBF of Al-Cu-Mg-Mn alloys.
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December 2024
School of Mechanical Engineering, Pusan National University, Busan, Korea.
Heat accumulation due to repetitive simple laser processing paths during building up a three-dimensional structure is a well-known issue that needs to be settled to reduce the excessively high residual stress and thermal deformation in a powder bed fusion (PBF) additive manufacturing process. Because of the dependency of laser path on the thermal dispersion, it is essential to analyze the heat accumulation phenomenon during laser processing. A computational fluid dynamics (CFD) analysis based on the volume of fraction method is used to optimize the laser path for minimizing the local heating up in the PBF process.
View Article and Find Full Text PDFAm J Ophthalmol
December 2024
Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China; School of Medicine, Nankai University, Tianjin, China; Tianjin Eye Hospital, Tianjin Key Laboratory of Ophthalmology and Visual Science, Tianjin Eye Institute, Nankai University Affiliated Ophthalmology Hospital, Tianjin, China; Nankai Eye Institute, Nankai University, Tianjin, China. Electronic address:
Purpose: To analyze the effect of individual parameters on the postoperative refractive outcomes of small incision lenticule extraction in myopic eyes using machine learning methods.
Design: Retrospective Clinical Cohort Study METHODS: We included 477 patients (922 eyes) of small incision lenticule extraction at Tianjin Ophthalmology Hospital and divided the patients into two groups to analyzed the factors affecting postoperative refractive outcomes based on the label of postoperative spherical equivalent (SE) ≤ -0.50D.
Korean Circ J
November 2024
Department of Cardiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
Background And Objectives: Traditional manual percutaneous coronary intervention (PCI) exposes operators to significant radiation and physical stress. The recently developed Advanced Vascular Intervention Assist Robot (AVIAR) 2.0 system in South Korea aimed to overcome these issues by evaluating its safety and feasibility in a clinical setting.
View Article and Find Full Text PDFFatigue cracking of rib-to-deck conventional single-sided welded joints is a prevalent issue in orthotropic steel decks (OSDs), significantly impacting their structural integrity and durability. Rib-to-deck innovative double-sided welded joints have the potential to enhance the fatigue resistance of OSD. However, Welding Residual Stresses (WRS) significantly influence the fatigue life of these joints, mandating its consideration in fatigue assessments.
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