Monte Carlo study of the two-dimensional kinetic Blume-Capel model in a quenched random crystal field

We investigate by means of Monte Carlo simulations the dynamic phase transition of the two-dimensional kinetic Blume-Capel model under a periodically oscillating magnetic field in the presence of a quenched random crystal-field coupling. We analyze the universality principles of this dynamic transition for various values of the crystal-field coupling at the originally second-order regime of the corresponding equilibrium phase diagram of the model. A detailed finite-size scaling analysis indicates that the observed nonequilibrium phase transition belongs to the universality class of the equilibrium Ising ferromagnet with additional logarithmic corrections in the scaling behavior of the heat capacity. Our results are in agreement with earlier works on kinetic Ising models.Comment: 25 pages (APS preprint style), 13 figures, 1 tabl

Multicanonical simulations of the 2D spin-1 Baxter-Wu model in a crystal field

We investigate aspects of universality in the two-dimensional (2D) spin-$1$ Baxter-Wu model in a crystal field $\Delta$ using a parallel version of the multicanonical algorithm employed at constant temperature $T$. A detailed finite-size scaling analysis in the continuous regime of the $\Delta-T$ phase diagram of the model indicates that the transition belongs to the universality class of the $4$-state Potts model. The presence of first-order-like finite-size effects that become more pronounced as one approaches the pentacritical point of the model is highlighted and discussed.Comment: 6 pages, 6 figures, XXXII IUPAP Conference on Computational Physic

Uterine Embolization as a New Treatment Option in Adenomyosis Uteri

Adenomyosis is characterized by the development of endometrial ectopic glands and tissue in the myometrium layer in depth greater than 2.5 mm from the endometrial surface of the separative area by -myomas well as by hypertrophy and hyperplasia of the smooth muscles of the myometrium. This is filtration, not mere displacement, of the myometrium, from the endometrium. Clinical symptoms include dysmenorrhea and menorrhagia. It is diffuse (adenomyosis) or focal (adenomyoma), asymmetrically affects the uterine wall of premenopausal women (usually the posterior) and often coexists with myomas. The pathogenesis of adenomyosis remains unknown. The treatment options are: drug therapy, invasive treatment of fibroids: myomectomy (open—intra-abdominal, laparoscopic, hysteroscopic), hysterectomy, myolysis—cryocatalysis, microwave or radiofrequency thermal catalysis (RF-ablation), ultrasound focus catalysis (FUS), laser photocatalysis and percutaneous selective uterine artery embolization (UAE). Embolization remains an alternative and not a substitute of hysterectomy. The medical indication is made on a case-by-case basis, depending on age, desire for pregnancy and the clinical symptoms of adenomyosis

Εργαστηριακή διερεύνηση της εξόρυξης ασβεστολίθου περιοχής Τριπόλεως με μηχανικά μέσα

220 σ.Η παρούσα διπλωματική εργασία έχει ως αντικείμενο την διερεύνηση της δυνατότητας εξόρυξης ασβεστολίθου με μηχανικά μέσα. Για το σκοπό αυτό συγκεντρώθηκαν δείγματα από την περιοχή της Τρίπολης και συγκεκριμένα από το λατομείο με την επωνυμία Καγιάννης Χρήστος & Σια Ο.Ε. που βρίσκεται στο 3ο χιλιόμετρο Τρίπολης – Καλαμάτας κοντά στο χωριό Βαλτέτσι. Η δυνατότητα να εξορυχθεί ένα πέτρωμα με μηχανικά μέσα καθορίζεται από την εξορυξιμότητα του, δηλαδή την ευκολία ή την δυσκολία που παρουσιάζει στην εξόρυξή του. Εκφράζεται με οικονομικά και επιχειρησιακά χαρακτηριστικά της εξόρυξης όπως η απόδοση της μηχανικής εξόρυξης, η ειδική κατανάλωση ενέργειας εκσκαφής και η φθορά των κοπτικών εργαλείων. Μεταξύ των παραμέτρων που την επηρεάζουν, οι ιδιότητες της μάζας του προς εξόρυξη πετρώματος είναι καθοριστικής σημασίας για την εκτίμησή της. Προκειμένου να γίνει μια πλήρης περιγραφή των μηχανικών και φυσικών ιδιοτήτων του πετρώματος εκτελούνται μια σειρά από εργαστηριακές δοκιμές. Τέτοιες δοκιμές όπως η δοκιμή μονοαξονικής θλίψης, η δοκιμή αντιδιαμετρικής θλίψης, η δοκιμή σκληρότητας Shore, η δοκιμή κοπής και η δοκιμή αποξεστικότητας Cerchar είναι δυνατό να δώσουν μια προκαταρκτική εκτίμηση της εξορυξιμότητας ενός πετρώματος. Η φθορά των κοπτικών εργαλείων έχει σημαντική επίδραση στην εξορυξιμότητα των πετρωμάτων. Λόγω της σταδιακής απομάκρυνσης του μετάλλου από το κοπτικό και της μεταβολής της γεωμετρίας του, το κοπτικό πρέπει να αναπτύξει πολύ μεγαλύτερες δυνάμεις για το ίδιο αποτέλεσμα με συνέπεια την μείωση της απόδοσης του εξορυκτικού εξοπλισμού και την αύξηση της ειδικής κατανάλωσης ενέργειας εκσκαφής. Καθοριστικό κριτήριο βελτιστοποίησης της οικονομικότητας της μηχανικής εξόρυξης πετρωμάτων είναι η ελαχιστοποίηση της ειδικής ενέργειας εκσκαφής. Ειδική ενέργεια εκσκαφής ονομάζεται η ενέργεια που απαιτείται για την απόσπαση από τη φυσική του θέση πεπερασμένου όγκου πετρώματος. Προκειμένου να γίνει παραμετρική ανάλυση για την διαστασιολόγηση και την πρόβλεψη της απόδοσης μηχανήματος απαιτείται ενδελεχής γνώση των δυνάμεων που αναπτύσσονται κατά την κοπή. Τέλος, η ειδική ενέργεια εκσκαφής είναι συνάρτηση πολλών παραγόντων όπως η απόσταση μεταξύ διαδοχικών κοπτικών άκρων σε μια κεφαλή ή ένα τύμπανο κοπής, το βάθος της κοπής κ.ά.Subject of this thesis is the investigation of the excavability of limestone with mechanical means. For this purpose limestone samples have been prepared from the Kagiannis Christos quarry which is located near the 3rd kilometer of the Tripoli – Kalamata highway near the village Valtetsi, and an extensive laboratory investigation has been performed. The excavability of a rock by mechanical means is a measure of the ease and energy requirements for the breakage and excavation of rock from its original, insitu location. Excavability can be expressed on the basis of financial and operational characteristics of the excavation as is the performance of the excavating machine, the specific energy required for the excavation and the wear of the cutting tools. Among the parameters that influence excavability, the rock properties are of decisive importance for its estimate. In order to make a complete description of the mechanical and physical properties of the intact rock, a series of laboratory tests have been performed. With tests such as the uniaxial compressive strength test, Brazilian test, Shore hardness test, core cuttability test and Cerchar abrasiveness test it is possible to determine a preliminary estimate of the excavability of a rock. The wear of cutting tools has an important effect on the excavability of a rock. Due to the progressive removal of metal chips from the cutting edge and the change of its geometry, the cutting tool is expected to develop higher forces for the same result, reducing the performance of the excavating equipment and increasing the specific energy consumption of the excavation. The lowest specific energy criterion is fundamental in the optimization process of an excavation project. Specific energy is defined as the energy required to excavate a unit volume of rock. In order to conduct parametric analysis to predict the performance of a given machine or define the machine required to achieve a certain advance – production rate, a thorough knowledge of the forces developing during rock cutting is required. Finally, specific energy is a function of many parameters such as spacing, depth of cut etc.Νικόλαος Δ. Βασιλόπουλο

Universality aspects of the two-dimensional spin-1 Baxter-Wu model in a crystal field

We study the question of universality in the two-dimensional spin-$1$ Baxter-Wu model in the presence of a crystal field $\Delta$. We employ extensive numerical simulations of two types, providing us with complementary results: Wang-Landau sampling at fixed values of $\Delta$ and a parallelized variant of the multicanonical approach performed at constant temperature $T$. A detailed finite-size scaling analysis in the regime of second-order phase transitions in the $(\Delta, T)$ phase diagram indicates that the transition belongs to the universality class of the $4$-state Potts model. Previous controversies with respect to the nature of the transition are discussed and possibly attributed to the presence of strong finite-size effects, especially as one approaches the pentacritical point of the model.Comment: 10 pages, 12 figures, 1 table, version to be published in Phys. Rev.

Self-Healing of Semantically Interoperable Smart and Prescriptive Edge Devices in IoT

Smart homes enhance energy efficiency without compromising residents’ comfort. To support smart home deployment and services, an IoT network must be established, while energy-management techniques must be applied to ensure energy efficiency. IoT networks must perpetually operate to ensure constant energy and indoor environmental monitoring. In this paper, an advanced sensor-agnostic plug-n-play prescriptive edge-to-edge IoT network management with micro-services is proposed, supporting also the semantic interoperability of multiple smart edge devices operating in the smart home network. Furthermore, IoT health-monitoring algorithms are applied to inspect network anomalies taking proper healing actions/prescriptions without the need to visit the residency. An autoencoder long short-term memory (AE-LSTM) is selected for detecting problematic situations, improving error prediction to 99.4%. Finally, indicative evaluation results reveal the mitigation of the IoT system breakdowns

Functional Carbon Materials Derived through Hypergolic Reactions at Ambient Conditions

Carbon formation from organic precursors is an energy-consuming process that often requires the heating of a precursor in an oven at elevated temperature. In this paper, we present a conceptually different synthesis pathway for functional carbon materials based on hypergolic mixtures, i.e., mixtures that spontaneously ignite at ambient conditions once its ingredients contact each other. The reactions involved in such mixtures are highly exothermic, giving-off sizeable amounts of energy; hence, no any external heat source is required for carbonization, thus making the whole process more energy-liberating than energy-consuming. The hypergolic mixtures described here contain a combustible organic solid, such as nitrile rubber or a hydrazide derivative, and fuming nitric acid (100% HNO3) as a strong oxidizer. In the case of the nitrile rubber, carbon nanosheets are obtained, whereas in the case of the hydrazide derivative, photoluminescent carbon dots are formed. We also demonstrate that the energy released from these hypergolic reactions can serve as a heat source for the thermal conversion of certain triazine-based precursors into graphitic carbon nitride. Finally, certain aspects of the derived functional carbons in waste removal are also discussed