Ανακοινώσεις

Αποτελέσματα χορήγησης Υποτροφίας Κληροδοτήματος «Μαρίας Μανασσάκη»

16 Σεπτεμβρίου 2026

Ανακοινώνεται ότι, κατόπιν της 184ης/10.09.2026 τακτικής συνεδρίασης της Συνέλευσης του Τμήματος Επιστήμης και Μηχανικής Υλικών του Πανεπιστημίου Κρήτης, εγκρίθηκε ομόφωνα το από 25.08.2026 πρακτικό της Συντονιστικής Επιτροπής Μεταπτυχιακών Σπουδών σχετικά με την αξιολόγηση των υποψηφιοτήτων για την υποτροφία του κληροδοτήματος «Μαρίας Μανασσάκη».

Η υποτροφία απονέμεται στον/στην αιτούντα/ουσα με Αριθμό Πρωτοκόλλου Αίτησης: 15481/25.06.2026 ο/η οποίος/α επελέγη μετά από ενδελεχή αξιολόγηση της ακαδημαϊκής του/ης αριστείας και της προφορικής του/ης παρουσίασης, μεταξύ των τεσσάρων επικρατέστερων υποψηφιοτήτων που προκρίθηκαν στη δεύτερη φάση της διαδικασίας.

Θερμά συγχαρητήρια στον/ην υπότροφο για την εξαιρετική επιστημονική του/ης πορεία. Ευχαριστούμε θερμά το σύνολο των οκτώ φοιτητών (έξι υποψήφιοι διδάκτορες και δύο μεταπτυχιακοί φοιτητές) που κατέθεσαν τις αξιόλογες προτάσεις τους και συμμετείχαν στη διαδικασία επιλογής.

Παρουσίαση Μεταπτυχιακής Διπλωματικής Εργασίας της κ. Περσεφόνης Μαρκάκη

08 Σεπτεμβρίου 2026

ΠΑΝΕΠΙΣΤΗΜΙΟ ΚΡΗΤΗΣ

ΤΜΗΜΑ ΕΠΙΣΤΗΜΗΣ ΚΑΙ ΜΗΧΑΝΙΚΗΣ ΥΛΙΚΩΝ

ΠΑΡΟΥΣΙΑΣΗ ΜΕΤΑΠΤΥΧΙΑΚΗΣ ΔΙΠΛΩΜΑΤΙΚΗΣ ΕΡΓΑΣΙΑΣ

Τίτλος

«Atomistic Modeling for the Shape and Properties of Metal Nanoparticles»  

της Περσεφόνης Μαρκάκη

μεταπτυχιακής φοιτήτριας του Τμήματος Επιστήμης και Μηχανικής Υλικών του Πανεπιστημίου Κρήτης

Επιβλέπων Καθηγητής: Ιωάννης Ρεμεδιάκης

Δευτέρα 14 Σεπτεμβρίου 2026, Ώρα 13:00

H παρουσίαση θα πραγματοποιηθεί στην αίθουσα Τηλε-εκπαίδευσης (Ε130), στο κτήριο του Τμήματος Μαθηματικών και Εφαρμοσμένων Μαθηματικών

Abstract

The shape and size of nanoparticles play a crucial role in determining the properties of materials, particularly in applications where atomic-scale interactions are significant. One of the most widely used methods for predicting equilibrium crystal shapes is the Wulff construction, which is based on the surface energies of crystallographic facets. The Wulff construction method calls for accurate calculation for the energies of the various surfaces of the material. Typically, these energies are obtained by simulating slabs of the material. Recently, an analytical model was proposed by P. Rosakis that yields surface energies from the parameters of the interatomic interactions, eliminating the need for direct simulation. The results reveal excellent agreement between the two approaches, while the analytical model exhibits lower computational cost, suggesting that it constitutes an attractive alternative for surface-energy calculations. Using this idea, computational framework is developed to correlate surface energies with the underlying atomic interactions of metallic nanoparticles, aiming at the reliable prediction of nanoparticle shapes. As a primary application, equilibrium Wulff shapes are generated for face-centered cubic (fcc) metallic nanoparticles, including Au, Al, Ag, Ni, Cu, Pd, Pt, and Pb. For each metal, Wulff constructions are obtained using different parameterizations of the Embedded Atom Method (EAM). The obtained results are compared with available experimental data, as well as with calculations based on Density Functional Theory (DFT) and the Modified Embedded Atom Method (MEAM). The comparison indicates that the EAM framework provides a favorable balance between computational efficiency and predictive accuracy, making it an attractive approach for modeling metallic nanoparticles. Finally, the dataset generated from the crystal geometries is utilized in a supervised machine learning study to develop a model capable of identifying the interatomic potential that most accurately describes the crystal under investigation based on its principal geometrical and energetic characteristics.

Registration for postgraduate students

04 Σεπτεμβρίου 2026

To enroll at the MSc in “Materials Science and Engineering” for the 2026-2027 fall semester candidate graduate students must have fulfilled their degree requirements by the end of the registration period (see below). Students who were provisionally accepted under the requirement of completing their undergraduate studies must also submit a certificate of completion.

Course registration period for the fall semester 2026-2027 of the MSc in “Materials Science and Engineering” is from 21/9/2026 to 2/10/2026.

Courses will start on Monday 21st September 2026.

Πρόσκληση Υποβολής Αιτήσεων για την Εκπόνηση Διδακτορικής Διατριβής στην Ελλάδα

24 Αυγούστου 2026

Πρόσκληση στην Τελετή Αποφοίτησης του Τμήματος Επιστήμης και Μηχανικής Υλικών (22.07.2026)

15 Ιουλίου 2026

Ο Πρόεδρος του Τμήματος Επιστήμης και Μηχανικής Υλικών της Σχολής Θετικών και Τεχνολογικών Επιστημών του Πανεπιστημίου Κρήτης, Αναπληρωτής Καθηγητής κ. Δημήτριος Παπάζογλου, έχει την ιδιαίτερη χαρά να σας προσκαλέσει στην Τελετή Αποφοίτησης του Τμήματος.

Η εκδήλωση θα πραγματοποιηθεί την Τετάρτη, 22.07.2026 και ώρα 11:00, στο αμφιθέατρο «Πετρίδη», το οποίο βρίσκεται στο Κτήριο του Τμήματος Μαθηματικών και Εφαρμοσμένων Μαθηματικών.

Στο επισυναπτόμενο αρχείο θα βρείτε την επίσημη πρόσκληση, καθώς και το αναλυτικό πρόγραμμα της τελετής.

Θερμά συγχαρητήρια σε όλες τις απόφοιτες και όλους τους αποφοίτους μας!

Από τη γραμματεία,

Τμήματος Επιστήμης και Μηχανικής Υλικών 

Πανεπιστήμιο Κρήτης

Δείτε την Πρόσκληση Αποφοίτησης

Παρουσίαση Μεταπτυχιακής Διπλωματικής Εργασίας κ. Γεώργιου Βουρβαχάκη

13 Ιουλίου 2026

ΠΑΝΕΠΙΣΤΗΜΙΟ ΚΡΗΤΗΣ

ΤΜΗΜΑ ΕΠΙΣΤΗΜΗΣ ΚΑΙ ΜΗΧΑΝΙΚΗΣ ΥΛΙΚΩΝ

ΠΑΡΟΥΣΙΑΣΗ ΜΕΤΑΠΤΥΧΙΑΚΗΣ ΔΙΠΛΩΜΑΤΙΚΗΣ ΕΡΓΑΣΙΑΣ

Τίτλος

«Neural Operator Learning for Ultrashort Laser-Matter Interactions of Metals under Non-equilibrium Conditions»  

του Γεώργιου Βουρβαχάκη

μεταπτυχιακού φοιτητή του Τμήματος Επιστήμης και Μηχανικής Υλικών του Πανεπιστημίου Κρήτης

Επιβλέπων: Ιωάννης Πανταζής

Τρίτη 14 Ιουλίου 2026

Ώρα 13:00

H παρουσίαση θα πραγματοποιηθεί στην αίθουσα Τηλε-εκπαίδευσης (Ε130), στο κτήριο του Τμήματος Μαθηματικών και Εφαρμοσμένων Μαθηματικών

Abstract

This thesis studies damage-threshold estimation in ultrashort laser interactions with metallic thin films. The damage threshold is the incident laser fluence at which the film reaches melting onset. Estimating this threshold can be computationally expensive, because each evaluation requires two-temperature-model simulations and repeated threshold searches. This motivates surrogate models for faster threshold prediction.

The physical model is the axisymmetric parabolic two-temperature model (pTTM), which describes nonequilibrium energy exchange between laser-excited electrons and the lattice after femtosecond laser deposition. The work develops optical, thermophysical, and numerical components for threshold calculations, including temperature-dependent material response, ballistic and finite-thickness source corrections, implicit and IMEX time-integration schemes, and bracketing with bisection for threshold search. The numerical schemes are supported by empirical convergence and stability analyses.

The study uses one- and two-dimensional pTTM simulations to generate synthetic data for supervised regression. The surrogate target is the maximum lattice temperature, and threshold fluences are recovered by inverting the predicted temperature-fluence response. The surrogate analysis includes a two-dimensional linear pTTM dataset and a nonlinear two-dimensional extension with temperature-dependent optical properties, electron heat capacity, and electron-phonon coupling. LightGBM and multilayer perceptron models are evaluated on synthetic test sets and material-specific fluence cases.

The results show that the trained surrogates reproduce pTTM temperature targets within the sampled ranges and provide computationally efficient threshold estimates. For Ni and Ti, the nonlinear surrogate reduces the discrepancy between surrogate predictions and pTTM fluence-dependent calculations. Threshold estimates for Ag, Ni, and Ti are compared with reference values from the RIANA/PLAN-hub thermal-response calculator.

Πρόσκληση σε Δημόσια Παρουσίαση της Διδακτορικής Διατριβής της κ. Χριστίνας Σιαϊτανίδου

18 Ιουνίου 2026

Πρόσκληση σε Δημόσια Παρουσίαση της Διδακτορικής Διατριβής της κ. Χριστίνας Σιαϊτανίδου

Επιβλέπων Καθηγητής: Νικόλαος Πελεκάνος

(Σύμφωνα με το άρθρο 95, παρ. 3 του Ν. 4957/2022, ΦΕΚ 141 τ. Α΄/21.7.2022)

Την Παρασκευή 26 Ιουνίου 2026 και ώρα 11:00 στην Κ206 του Τμήματος Επιστήμης Υπολογιστών του Πανεπιστημίου Κρήτης, θα γίνει η δημόσια παρουσίαση και υποστήριξη της Διδακτορικής Διατριβής της υποψήφιας διδάκτορος του Τμήματος Επιστήμης και Μηχανικής Υλικών κ. Χριστίνας Σιαϊτανίδου, με θέμα:

«MAPbCl₃: a case study of a solution processed semiconductor for efficient ultraviolet optoelectronics»

Περίληψη

In recent years, an extensive research effort has been devoted to hybrid organic-inorganic lead halide perovskites due to their remarkable optoelectronic properties and their potential for a wide range of applications, particularly in photovoltaic devices. Among the members of MAPbX3 family of perovskites, methylammonium lead chloride (MAPbCl₃), the Ultra-Violet (UV) representative, remains relatively unexplored compared to its iodide and bromide counterparts, despite its unique optical characteristics and its potential for optoelectronic applications in the UV. As a result, many of its fundamental optical and electronic properties remain insufficiently understood. The present dissertation focuses on MAPbCl₃ single-crystalline thin films and aspires to contribute to a deeper understanding of the optoelectronic properties of lead-halide perovskites.

To this end, we investigated MAPbCl₃ thin single-crystalline films embedded in a vertical cavity configuration. We observed for the first time dual wavelength lasing at 78K under high power densities, occurring at 414nm and 391nm with distinct lasing thresholds. Within the scope of this observation, thin films were scrutinized under μ-Photoluminescence and μ-Reflectivity measurements in order to understand this unusual behavior. Micro-reflectivity measurements revealed, besides the standard exciton feature at the ∼385nm orthorhombic bandgap, an additional previously unreported excitonic peak at ∼412 nm. This second exciton feature aligns with the second lasing line, strongly suggesting the co-existence of a “second phase” within the primary orthorhombic lattice. We show that this second phase persists up to 300K and is likely associated with the quantum dot-like nanostructures detected on the surface of the MAPbCl₃ crystals. The second phase depends on the growth method and crystal size but is likely traceable in all MAPbCl₃ systems. These insights offer enhanced understanding of the MAPbCl₃ system and open new pathways for blue-UV photonic devices.

In addition, we present a normal-incidence optical method to accurately extract the refractive index dispersion of high-quality MAPbCl₃ single crystals with lateral dimensions of several hundred micrometers. The approach relies on analyzing the spectral positions of Fabry-Pérot modes observed in small-angle micro-reflectivity spectra. Its key enabling feature is the use of angle-resolved micro-reflectivity to directly determine the refractive index at a given wavelength, without prior knowledge of the sample thickness or Fabry-Pérot mode order. The extracted refractive index values are ∼10% higher than previously reported, establishing a new benchmark for MAPbCl₃, which we attribute to the superior crystalline quality of our samples. Upon cooling, the refractive index systematically increases across all crystallographic phases, consistent with a negative thermo-optic effect, except at the tetragonal-to-orthorhombic phase transition at 171K, where it exhibits a discontinuous decrease. The proposed methodology is particularly well suited for micron-sized single crystals in cryogenic environments and can be readily extended to other perovskites and emerging material systems.

As prospective work in this thesis, the formation of ferroelastic domains in the orthorhombic phase of MAPbCl₃ single-crystalline thin films was investigated using polarization-dependent optical measurements. Ferroelastic domains were found to be particularly pronounced in samples grown by the space-confined crystallization method. Upon cooling into the orthorhombic phase, reflectivity measurements revealed a characteristic beating pattern which is absent in the tetragonal phase. This behavior is attributed to the interference of two optical paths arising from the birefringence of the orthorhombic crystal structure. A qualitative estimate yielded a birefringence of Δn≈0.08. Nevertheless, a comprehensive polarization-dependent analysis of the reflectivity spectra is required to quantitatively determine the refractive indices along the principal optical axes and to provide further insight into the coupling between structural symmetry breaking and the optical response of halide perovskites.

In parallel, the ultrafast carrier dynamics of MAPbCl₃ were investigated by time-resolved photoluminescence measurements using a streak-camera. The measurements revealed decay times of several tens of picoseconds, highlighting the strong excitonic character of the material. Furthermore, the main band-edge emission peak exhibited a non-exponential decay curve independent of excitation power, which is accompanied by a redshift, suggesting the presence of a dynamic carrier localization process. Temperature-dependent measurements further showed that the radiative lifetime increases with temperature, as expected for bulk excitonic recombination. At the same time, rapid non-radiative recombination channels were observed. However, the validity of these results should be interpreted with caution, as possible degradation of the perovskite samples during the measurements may have affected the extracted non-radiative lifetimes, requiring further investigation before the optoelectronic potential of MAPbCl₃ can be fully assessed.

Εξέταση του μαθήματος “ΜΕΤΥ-446 Ηλεκτρονική Μικροσκοπία Διέλευσης”

08 Ιουνίου 2026

Υποτροφίες του Κληροδοτήματος “Μαρίας Μιχαήλ Μανασσάκη” για το ακαδημαϊκό έτος 2024-25

15 Μαΐου 2026

Επισυνάπτεται προκήρυξη των υποτροφιών του Κληροδοτήματος "Μαρίας Μιχαήλ Μανασσάκη" για το ακαδημαϊκό έτος 2024-25,  η αίτηση των υποψηφίων, υπεύθυνη δήλωση με το προβλεπόμενο κείμενο καθώς και δήλωση προστασίας προσωπικών δεδομένων. Παρακαλώ όπως τα αναρτήσετε στην ιστοσελίδα του Τμήματός σας και στον πίνακα ανακοινώσεων. Καταληκτική ημερομηνία κατάθεσης των δικαιολογητικών η 29η Ιουνίου 2026.

Τα ανωτέρω έχουν αναρτηθεί στην ιστοσελίδα του Πανεπιστημίου στις ανακοινώσεις. Επίσης, περίληψη της προκήρυξης δημοσιεύθηκε σήμερα στην  Εφημερίδα "Εφημερίδα των Συντακτών".

Οι αιτήσεις θα παραλαμβάνονται  ηλεκτρονικά (σκαναρισμένα αρχεία σε μορφή pdf) στο email που θα υποδείξει η  γραμματεία κάθε Τμήματος. Υπενθυμίζεται ότι οι αιτήσεις  θα πρέπει να λαμβάνουν αριθμό πρωτοκόλλου προκειμένου να βεβαιώνεται ότι υποβλήθηκαν εμπρόθεσμα. Επίσης για όλες τις αιτήσεις θα πρέπει να ζητήσετε απόσπασμα ποινικού μητρώου.

Πρόσκληση σε Δημόσια Παρουσίαση της Διδακτορικής Διατριβής της κ. Αικατερίνης Ζωής Πεπονάκη

27 Απριλίου 2026

Επιβλέπων Καθηγητής: Δημήτριος Βλασσόπουλος

(Σύμφωνα με το άρθρο 95, παρ. 3 του Ν. 4957/2022, ΦΕΚ 141 τ. Α΄/21.7.2022)

Την Πέμπτη 30 Απριλίου 2026 και ώρα 12:00 στην αίθουσα Τηλεκπαίδευσης Ε130 του Τμήματος Μαθηματικών και Εφαρμοσμένων Μαθηματικών του Πανεπιστημίου Κρήτης, θα γίνει η δημόσια παρουσίαση και υποστήριξη της Διδακτορικής Διατριβής της υποψήφιας διδάκτορος του Τμήματος Επιστήμης και Μηχανικής Υλικών κ. Αικατερίνης Ζωής Πεπονάκη, με θέμα:

«Visocelasticity and Nonlinear Rheology of Cyclic Macromolecules and Their Mixtures»

Περίληψη

Understanding and controlling macromolecular motion is one of the central challenges in polymer science, because polymer dynamics determine viscoelasticity, processability, and ultimately material performance. While the rheology of linear and branched polymers is described to a large extent by established molecular theories based on the motion of chain ends, ring polymers remain a major unresolved problem. Their closed-loop topology and lack of free ends fundamentally modify their relaxation mechanisms, diffusion, and flow behavior, placing them outside the classical theoretical framework developed for conventional polymer architectures. As a result, ring polymers have emerged as an important model system for probing the role of topology in polymer physics, while also offering opportunities for the design of materials with tailored properties. However, the state of the art in ring polymer rheology is still characterized by major challenges, including conflicting experimental observations, strong sensitivity to linear-chain contamination, incomplete understanding of threading phenomena, and a lack of constitutive descriptions. These difficulties are compounded by the demanding nature of rheological measurements themselves, especially in the melt state, where experiments often approach the technical and instrumental limits of the method. In addition, the synthesis and purification of ring polymers remain particularly challenging, leading to limited sample quantities and making the extraction of reliable rheological data even more demanding.

The goal of this thesis was therefore to advance the understanding of the rheological behavior of synthetic ring polymers and ring-based blends by combining carefully designed experiments with theoretical analysis, and by exploring these systems in both the linear and nonlinear rheological regimes. Particular emphasis was placed on obtaining robust information from difficult, limited-quantity samples and on testing experimental findings against available theoretical descriptions in order to assess their validity and limitations. The thesis is organized progressively: it first addresses the challenges associated with rheology as a technique and the difficulties in obtaining reliable melt-state data for these systems; it then focuses on pure ring architectures, followed by symmetric and asymmetric ring-linear blends, blends of rings with matrices of different molecular architecture, and finally an exploratory, non-systematic investigation of crystallization-related phenomena.

The results show that ring polymers display a rheological response fundamentally distinct from that of their linear analogues, consistent with the absence of free ends and with the weaker dependence of viscosity on molecular weight. Through comparison with theory, the experimental findings help clarify the extent to which existing models can capture the dynamics of ring systems, while also highlighting the regimes in which additional mechanisms must be considered. In pure ring systems, the work contributes to the understanding of their characteristic linear and nonlinear response under melt conditions. In ring-linear blends, the results reveal viscosity enhancement, broadened stress relaxation, and non-monotonic composition dependence, providing strong support for the central role of threading and constraint-release mechanisms. By extending the study to symmetric and asymmetric blends, as well as to blends with branched matrices such as star and H-shaped polymers, this thesis further demonstrates that the rheological impact of rings depends strongly on matrix architecture, molecular-weight asymmetry, polymer flexibility, and especially on the number of available free ends. The contrasting behavior observed in branched matrices indicates that threading is not universal, but is highly sensitive to molecular topology and conformational entropy. Overall, this thesis helps clarify long-standing controversies in ring polymer rheology, expands the experimentally accessible window of melt rheology for topologically complex polymers, and provides new structure-property insights supported by theory toward a more complete molecular understanding of ring polymers and their blends.