Papers by Keyword: Multifunctionality

Abstract: Heusler alloys are intermetallic compounds formed in two combinations: Full-Heusler (X₂YZ) and Half-Heusler (XYZ). X and Y can be any transition element, and Z belongs to the main group. This shows that there can be a huge variation in the combinations, leading to various properties and applications. We aimed at predicting the combination leading to shape memory properties using machine learning tools and then synthesizing the same. The predictions are done by training the tool with input data. We employed the lattice strain, valence electron concentration ratio, mechanical stress, difference in entropy, and saturation magnetization as input features. The correlation between the martensitic and austenitic temperature was evaluated in terms of regression metrics. The random forest and decision tree modeling were executed. Test scores were obtained using frequency ordering, PCA, linear regression, and correlation matrix to forecast magnetically controlled shape memory effect. The silhouette score matched the transition temperature at which the material showed shape memory behavior. Additionally, from 70% of the training data, a combination of Iron (Fe), Nickel (Ni), and Aluminum (Al) as Full Heusler alloys stimulated the algorithms in gaining the accuracy of predictive modeling by minimizing the error. Through DFT-based bandgap and density of states calculations, the Fe₂NiAl Heusler compound is hypothesized to behave as a half-metallic ferromagnet by considering the atomic number, the number of valence electrons, and the local magnetic moment. The experimental validation will be done along with magnetization studies, magneto-transport, and magneto-caloric measurements.

Abstract: This contribution gathers various examples illustrating the fact that nanocrystalline apatites represent a genuine multi-functionalizable platform for a wide range of biomedical applications. It is indeed possible to convey additional functionalities to the already appealing properties of biomimetic apatites, via appropriate ionic substitutions and/or through controlled molecular adsorptions. In link with bone regeneration, we depict here examples of enhanced osteoconduction/induction and of the addition of antibacterial features to bone implants. But we also point out the promise of apatite-based colloidal nanoparticles in other domains not related to bone, such as nanomedicine (cell diagnosis/therapy), which we address by conferring luminescence properties and by adding cell recognition abilities.

Abstract: This paper focuses on the design and development of a low-cost multifunctional composite component integrated into a shoe hill that generates power in the order of milliwats (mW) through piezoceramic (PZT) stacks and stores this harvested energy in a capacitor integrated into the composite. The use of a thin-film lithium battery integrated into the composite is also explored as a means of permanent power storage. PZT bimorph elements are stacked in a cantilever manner. The space in-between and around the elements is being filled with foam, which provides structural support as well as walking comfort. An insole composite with a PZT layer is also developed that is capable of producing 2.2mW of power to give a total power output of 12.2mW for the in-heel insole combination. The experimental results revealed that the use of PZT bimorph elements (d33=110) instead of polyvinylidene difluoride PVDF sheets (d33=20) increased the power generation potential over five folds, which is further compounded by stacking the PZT elements.