A hybrid finite element analysis and evolutionary computation method for the design of lightweight lattice components with optimized strut diameter

Components incorporating lattice structures have become very popular lately due to their lightweight nature and the flexibility that additive manufacturing offers with respect to their fabrication. However, design optimization of lattice components has been addressed so far either with empirical approaches or with the use of topology optimization methodologies. An optimization approach utilizing multi-purpose optimization algorithms has not been proposed yet. This paper presents a novel user-friendly method for the design optimization of lattice components towards weight minimization, which combines finite element analysis and evolutionary computation. The proposed method utilizes the cell homogenization technique in order to reduce the computational cost of the finite element analysis and a genetic algorithm in order to search for the most lightweight lattice configuration. A bracket consisting of both solid and lattice regions is used as a case study in order to demonstrate the validity and effectiveness of the method, with the results showing that its weight is reduced by 13.5 % when using lattice structures. A discussion about the efficiency and the implications of the proposed approach is presented

ΗΦΑΙΣΤΕΙΟΛΟΓΙΚΑ ΧΑΡΑΚΤΗΡΙΣΤΙΚΑ ΣΤΗ ΝΗΣΟ ΜΗΛΟ

Στο πλαίσιο της διπλωματικής μου εργσίας με θέμα “Ηφαιστειολογικά Χαρακτηριστικά στη νήσο Μήλο”, μελετώνται τα ηφαιστειολογικά και γεωλογικά χαρακτηριστικά της νήσου τα οποία έλαβαν χώρα στο παρελθόν. Η μελέτη τέτοιου είδους ηφαιστειολογικών θεμάτων σε έναν χώρο κλειδί όπως αυτός του κεντρικού-νοτίου Αιγαίου πιστεύω ότι θα συμβάλλει τα μέγιστα για την κατανόηση και επίλυση των πολυσύνθετων προβλημάτων που εντοπίζονται στην περιοχή της ανατολικής Μεσογείου. Η Μήλος αποτελεί μέρος του σημερινού ενεργού ηφαιστειακού τόξου του νοτίου Αιγαίου το οποίο αποτελείται από τα ηφαιστειακά κέντρα του Σουσακίου, των Μεθάνων, του Πόρου, της Αίγινας, της Μήλου, της Σαντορίνης, της Νισύρου και της Κω. Η περιοχή μελέτης περιλαμβάνει ολόκληρο το νησί της Μήλου. Μελετώνται τα ηφαιστειακά αέρια που εντοπίζονται σε διάφορα σημεία της νήσου όπως η περιοχή του Καλάμου (φουμαρόλες) , στο Παλαιοχώρι, τα Θειοχώματα και στον Αδάμαντα. Η δειγματοληψία πραγματοποιήθηκε τόσο σε εναέριο όσο και θαλάσσιο περιβάλλον. Επίσης, ιδιαίτερη μελέτη έγινε για τις αέριες φάσεις που διαφεύγουν από το έδαφος γύρω από τις φουμαρόλες και περιοχές με έντονη γεωθερμική ανωμαλία.In my dissertation "Volcanological characteristics of Milos island", both the volcanological and geological characteristics that occured in the past, are being investigated. In my opinion, study of such volcanological issues which take place in the south-central Aegean region, could improve our knowledge about the whole eastern Mediterranean. Milos island is part of the south Aegean active volcanic arc which include the volcanic centers of Sousaki, Methana, Poros, Aegina, Milos, Santorini, Nisyros and Kos. The study area is the whole island of Milos. Volcanic gases of Kalamos (fumaroles), Palaiochori, Thiochoma and Adamas are being studied. Sampes have been collected from the atmospheric air, the sea, regions where fumaroles are being released and from areas which are characterized by significant geothermal anomalies

Design optimization of hot stamping tooling produced by additive manufacturing

The design flexibility of Additive Manufacturing (AM) can be utilized to develop innovative and sustainable hot stamping tools with enhanced quenching capability compared to tools manufactured by conventional manufacturing processes. This study proposes a concept for hot stamping tools with integrated lattice structures that selectively substitute a die's solid areas. A lattice structure demonstrates reduced thermal mass and can affect the ability of the tool to absorb heat from the blank and the rate at which the tool is cooled between two consecutive stamping cycles. This study explores the design space of a hot stamping tool with integrated lattice structures. It presents the optimized design for an effective compromise between cooling performance, structural integrity, and several other design parameters shown in the study. The proposed method utilizes a 2D thermo-mechanical finite element analysis model of a single cooling channel combined with Design of Experiments (DoE) to reduce the computational cost. The results show that the integration of lattice structure cannot only deliver improved cooling performance with minimum change in the dimensions of the cooling system but also achieves a faster AM build time since less material is required to be printed

Sequential double second-order nonlinear optical switch by an acido-triggered photochromic cyclometallated platinum(ii) complex.

International audienceAn unprecedented DTE-based Pt(II) complex, 2(o), which stands as the first example of a sequential double nonlinear optical switch, induced first by protonation and next upon irradiation with UV light is presented

Boron difluorides with formazanate ligands:redox-switchable fluorescent dyes with large stokes shifts

The synthesis of a series of (formazanate)boron difluorides and their 1-electron reduction products is described. The neutral compounds are fluorescent with large Stokes shifts. DFT calculations suggest that a large structural reorganization accompanies photoexictation and accounts for the large Stokes shift. Reduction of the neutral boron difluorides occurs at the ligand and generates the corresponding radical anions. These complexes are non-fluorescent, allowing switching of the emission by changing the ligand oxidation state

Guanine can direct binding specificity of Ru-dppz complexes to DNA through steric effects

X-ray crystal structures of three Λ-[Ru(L)2dppz]2+ complexes (L=phen, bpy) bound to d((5BrC)GGC/GCCG) show the compounds intercalated at a 5´-CG-3´ step. The compounds bind through canted intercalation, with the binding angle determined by the guanine-NH2 group, in contrast to symmetrical intercalation previously observed at 5´-TA-3´ sites. This result suggests that canted intercalation is preferred at 5´-CG-3´ sites even though the site itself is symmetrical, and we hypothesise that symmetrical intercalation in a 5´-CG-3´ step could give rise to a longer luminescence lifetime than canted intercalation