Invited Speakers

Dr. Osman Adiguzel

Dr. Osman Adiguzel

Department of Physics, Firat University, Turkey
Speech Title: Thermomechanical Processes and Reactions in Thermal and Mechanical Memory in Shape Memory Alloys

Abstract: A series of alloy systems called shape memory alloys exhibit a peculiar property called shape memory effect. This phenomenon is initiated by thermomechanical processes on cooling and deformation and performed on heating and cooling. Therefore, this behavior can be called thermal memory or thermoelasticity. Strain energy is stored in the materials due to the plastic deformation and released on heating by recovering the original shape. These alloys exhibit another property, superelasticity, which is performed mechanically by stressing and releasing the material at a constant temperature at the parent phase region, and this behavior can be called mechanical memory. Superelasticity exhibits ordinary elastic material behavior, but it is performed in non-linear way; loading and unloading paths are different at the stress-strain diagram, and hysteresis loop reveals energy dissipation Thermoelasticity is governed by the thermal and stress induced martensitic transformations, and reverse austenitic transformation. Thermal induced martensitic transformation occurs on cooling with cooperative movement of atoms along with lattice twinning in <110 > -type directions on the {110}-type plane of austenite matrix, by means of lattice invariant shear, and ordered parent phase structures turn into twinned martensite structures. The twinned structures turn into detwinned martensite structure with deformation, by means of stress induced martensitic transformation. Detwinned structures also turn into ordered parent phase structure on heating, by means of reverse austenitic transformation. Superelasticity is governed by stress induced martensitic transformations by stressing and releasing materials and ordered parent phase structures turn into detwinned martensitic structure with stressing.

Copper based alloys exhibit this property in metastable beta-phase region, which has bcc-based structures at high temperature parent phase field. Lattice invariant shear and lattice twinning is not uniform in these alloys and cause the formation of complex layered structures, depending on the stacking sequences on the close-packed planes of the ordered lattice.

In the present contribution, x-ray and electron diffraction studies were carried out on two solution treated copper based CuZnAl and CuAlMn alloys. Electron and x-ray diffraction exhibit super lattice reflections. Specimens of these alloys were aged at room temperature, at which both alloys are in martensitic state. A series of x-ray diffractions were taken at different stages of aging in a long-term interval, and reached results are interpreted.

Keywords: Shape memory effect, Martensitic transformation, Thermal memory, Mechanical memory, Twinning and detwinning



Dr. Aurelian Marcu

Dr. Aurelian Marcu

Head of PW-Laser Laboratory, Center for Advanced Laser Technology (CETAL),
National Institute for Laser Plasma and Radiation Physics (NILPRP), Romania
Speech Title: Nanowire Morphology Control: Sensors Applications

Abstract: Present technologies development is directly relaying on the various sensors development and gas sensing is one domain with application from medicine to industry and security. Depending on the ambiental pressure, composition, temperature and other ambiental parameters there are various techniques and materials to be used, but there is a comon trend of miniaturisation, presently supported by nanotechnologies and nanoscience. Basic approach in building miniaturised sensors and nano-sensors are relaying on elementary structures as nanowires and nanoparticles as building blocks, while the present approach of fabricated them is through the “Bottom-UP” techniques.

This paper is presenting fabrication of zinc oxide nanowire fabrication on a surface acoustic wave (SAW) sensor active area, using Vapour-Liquid-Solid growing technique and Pulsed Laser Ablation as particle source. ZnO material has been choosen for the material versatility and bio-compatibility on one hand, and, on the other hand, for its absorption capabilities of various gases, including hydrogen isotopes. Not only the high surface-to-volume ration is important in sensor sensibility and functionality, but also nanostructure morphology and nanostructure covered area geometry. Thus, we are presenting here some catalyst and diffusion based techniques for controlling nanowire morphology, as well as associeted sensor responses for the obtained morphologies.

Correlation between nanowire parameters and sensor response is exemplified here for SAW sensor detection of hidrogen isotopes and some theoretical interpretation and modelling is also included.

Keywords: VLS grow, ZnO nanowires, SAW sensors



Dr. Anca Mazare

Dr. Anca Mazare

Department of Materials Science – WW4-LKO,
Friedrich-Alexander University of Erlangen Nurnberg, Germany
Speech Title: TiO2 Nanostructures by Electrochemical Anodization – Morphology and Biomedical Applications

Abstract: Nanostructuring of titanium is a well-established surface modification approach, resulting in ideal implant biomaterials, as it improves biocompatibility and corrosion resistance. Of the various surface modification techniques, electrochemical anodization is one of the most widely used, leading to self-organized TiO2 nanostructures (nanotubes, nanopores, mesoporous, etc.) [1-3]. The nanotopography of the nanotubular surface clearly influences their use e.g., in osseointegration, antibacterial activity, drug delivery, mitigation of the inflammatory response, etc. [2-6]. Cells react to such nanoscale dimensions and can be synergistically influenced by the nanostructures morphology (e.g. nanotube diameter) and/or by addition of growth factors [4-6]. We will further discuss the key parameters resulting into different nanotubular morphologies, and their effect on the resulting top surface morphology (initiation layer, open-top, nanograss, etc.). Next crucial aspects of anodic nanostructuring, tailored for biomedical applications will be shown. Finally, a synthetic overview of biomedical applications using such nanostructures [4-6] and their future prospects will be shown and discussed.

Keywords: Electrochemical anodization, TiO2 nanotubes, Biomedical applications

References
1. K. Lee; A. Mazare; P. Schmuki Chem. Rev. 2014, 114, 9385.
2. J. Park, A. Cimpean, A. B. Tesler, A. Mazare, Nanomaterials 2021, 11, 2359.
3. A. Mazare, ACS Appl. Mater. Interfaces 2022, 14, 13, 14837.
4. R. Ion, M.G. Necula, A. Mazare, V. Mitran, P. Neacsu, P. Schmuki, A. Cimpean, Current Medicinal Chemistry 2020, 20, 1.
5. A. Mazare, J. Park, S. Simons, S. Mohajernia, I. Hwang, J.E. Yoo, H. Schneider, M.J. Fischer, P. Schmuki, Acta Biomaterialia, 2019, 97, 681.
6. M.G. Necula, A. Mazare, A.M. Negrescu, V. Mitran, S. Ozkan, R. Trusca, J. Park, P. Schmuki, A. Cimpean, Int. J. Mol. Sci. 2022, 23, 3558.



Dr. Ricardo Castedo

Dr. Ricardo Castedo

Geological and Mining Department,
Universidad Politécnica de Madrid, Spain
Speech Title: Numerical Study and Experimental Tests on Full-scale RC Slabs under Close-in Explosions

Abstract: To be update.



More details will come soon…