Scheduling of non-repetitive lean manufacturing systems under uncertainty using intelligent agent simulation

World-class manufacturing paradigms emerge from specific types of manufacturing systems with which they remain associated until they are obsolete. Since its introduction the lean paradigm is almost exclusively implemented in repetitive manufacturing systems employing flow-shop layout configurations. Due to its inherent complexity and combinatorial nature, scheduling is one application domain whereby the implementation of manufacturing philosophies and best practices is particularly challenging. The study of the limited reported attempts to extend leanness into the scheduling of non-repetitive manufacturing systems with functional shop-floor configurations confirms that these works have adopted a similar approach which aims to transform the system mainly through reconfiguration in order to increase the degree of manufacturing repetitiveness and thus facilitate the adoption of leanness. This research proposes the use of leading edge intelligent agent simulation to extend the lean principles and techniques to the scheduling of non-repetitive production environments with functional layouts and no prior reconfiguration of any form. The simulated system is a dynamic job-shop with stochastic order arrivals and processing times operating under a variety of dispatching rules. The modelled job-shop is subject to uncertainty expressed in the form of high priority orders unexpectedly arriving at the system, order cancellations and machine breakdowns. The effect of the various forms of the stochastic disruptions considered in this study on system performance prior and post the introduction of leanness is analysed in terms of a number of time, due date and work-in-progress related performance metrics

Mineralogy and chemistry of amphiboles and thermobarometry of Papikion Mt pluton, Rhodope, Northern Greece.

O πλουτωνίτης του Παπικίου Όρους που διεισδύει στο Δόμο του Κάρδαμου, αποτελείται από Bi, Hbl και Bi-Hbl τύπους πετρωμάτων. Σε αυτή την εργασία μελετάται η σχέση μεταξύ των αμφιβόλων του κάθε πετρογραφικού τύπου που τις περιέχει. Οι αμφίβολοι του κεροστιλβικού γρανοδιορίτη (Hbl GRD), του βιοτιτικού-κεροστιλβικού διορίτη (Bi-Hbl DR)και του κεροστιλβικού διορίτη (Hbl DR) ταξινομούνται κυρίως ως μαγνησιοκεροστίλβες και σιδηροκεροστίλβες και οι αμφίβολοι του βιοτιτικούκεροστιλβικού γρανοδιορίτη (Bi-Hbl GRD) ως σιδηροεδενίτες και χαστινγκσίτες. Πρέπει να σημειωθεί ότι ορισμένα δείγματα περιέχουν κρυστάλλους αμφιβόλου που παρουσιάζουν κοσκινινοειδή υφή με χαλαζία. Αυτές οι κοσκινοειδείς αμφίβολοι δεν διαφέρουν χημικά από τις υπόλοιπες. Η υφή αυτή μπορεί να προέρχεται από την αποδόμηση των φεμικών ορυκτών ενός αφομοιωμένου ξενόλιθου όπως οι πυρόξενοι αλλά και η ίδια η κεροστίλβη, αφήνοντας πίσω χαλαζία. Χρησιμοποιώντας το γεωβαρόμετρο Al στην κεροστίλβη και το γεωθερμόμετρο κεροστίλβης-πλαγιοκλάστου, υπολογί-στηκαν ελάχιστη πίεση κρυστάλλωσης 4,6 - 5,2 kbar και θερμοκρασίες 700 - 740 °C για το Bi-Hbl DR και 6,4 έως 7,4 kbar και θερμοκρασίες από 620 έως 700 °C στην ομάδα DR.. O Hbl GRD δείχνει τις χαμηλότερες τιμές Ρ-Τ, με μέση πίεση κρυστάλλωσης περίπου 3 kbar και με μέση θερμοκρασία περίπου 600 °C. Papikion Mt pluton which intrudes Kardamos Dome, consists of biotite (Bi), hornblende (Hbl) and biotite-hornblende (Bi-Hbl) bearing rock types. In this work the relationship among the amphiboles of each Hbl-bearing rock type is studied. Moreover, their minimum crystallization pressure and temperature are estimated. The amphiboles of the Hbl granodiorite (GRD), the Bi-Hbl diorite (DR) and the Hbl diorite (DR) are classified mainly as magnesiohornblende and ferrohornblende and the amphiboles of the Bi-Hbl GRD as ferroedenite and hanstingsite. It is to note that some samples contain amphibole crystals showing a sieved texture with quartz. These sieved amphiboles have no chemical differences from the rest amphibole crystals. This texture can probably derive from the breakdown of mafic minerals of an assimilated xenolith such as pyroxenes and hornblende itself, leaving quartz. Using the Al-in-hornblende geobarometer and the plagioclase-hornblende geothermometer), minimum crystallization pressures from 4.6 to 5.2 kbar and temperatures from 700 to 740 °C were estimated for the Bi-Hbl GRD. The DR shows crystallization pressures ranging from 6.4 to 7.4 kbar and temperatures ranging from 620 to 700 °C. The Hbl GRD shows the lowest P-T values, thus an average crystallization pressure about 3 kbar and an average temperature about 600 °C were estimated

High origin of a superficial ulnar artery arising from the axillary artery: anatomy, embryology, cinical significance and a review of the literature

The superficial ulnar artery (SUA) is an ulnar artery of high origin that lies superficially in the forearm. Its reported frequency ranges from 0.17% to 2%. During anatomical dissection in our department we observed a unilateral case of SUA in a 75-year-old white male human cadaver. It originated from the right axillary artery at the level of the junction of the two median nerve roots and followed a looping course, crossing over the lateral root of the median nerve and running lateral to it in the upper and middle thirds of the arm, whereas in the inferior third of the arm the SUA crossed over the median nerve and ran medially to it. In the cubital fossa, it passed superficially over the medial side of the ulnar aponeurosis and coursed subcutaneously in the ulnar side of the forearm superficially to the forearm flexor muscles. In the hand the SUA anastomosed with the superficial palmar branch of the radial artery, creating the superficial palmar arch. Additionally, it participated in the development of the deep palmar arch. The axillary artery, after the origin of the SUA, continued as the brachial artery and divided into the radial and common interosseous arteries in the cubital fossa. The normal ulnar artery was absent. No muscular or other arterial variations were observed in this cadaver. The embryological interpretation of this variation is difficult and it may arise as a result of modifications to the normal pattern of capillary vessel maintenance and regression. The existence of a SUA is undoubtedly of interest to the clinician as well as to the anatomist. This report presents a case of unilateral SUA along with a review of the literature, embryological explanation and analysis of its clinical significance

Taylor-Couette instability in disk suspensions: Experimental observation and theory

Using the well-known hydrodynamic theory for dilute suspensions of spheroids, we have previously predicted the destabilization of Taylor-Couette flow due to anisotropic viscous stresses induced by suspended disk-shaped particles [Gillissen and Wilson, Phys. Rev. Fluids 3, 113903 (2018)]. Here we provide experimental evidence for the destabilization mechanism using suspensions of mica flakes. There is good qualitative agreement between the experiment and theory in the mica concentration dependence of the critical speed for instability onset and of the axial wavelength of the corresponding Taylor vortices. Quantitative differences are attributed to hydrodynamic interactions between the disks, which we account for in the theory in an ad hoc fashion using rotary diffusion

Superconductivity and spin-glass like behavior in system with Pd sheet sandwiched between graphene sheets

Pd-metal graphite (Pd-MG) has a layered structure, where each Pd sheet is sandwiched between adjacent graphene sheets. DC magnetization and AC magnetic susceptibility of Pd-MG have been measured using a SQUID magnetometer. Pd-MG undergoes a superconducting transition at $T_{c}$ ($= 3.63 \pm 0.04$ K). The superconductivity occurs in Pd sheets. The relaxation of $M_{ZFC}$ (aging), which is common to spin glass systems, is also observed below $T_{c}$. The relaxation rate $S(t)$ shows a peak at a characteristic time $t_{cr}$, which is longer than a wait time $t_{w}$. The irreversibility between $\chi_{ZFC}$ and $\chi_{FC}$ occurs well above $T_{c}$. The susceptibility $\chi_{FC}$ obeys a Curie-Weiss behavior with a negative Curie-Weiss temperature ($-13.1 \leq \Theta \leq -5.4$ K). The growth of antiferromagnetic order is limited by the disordered nature of nanographites, forming spin glass-like behavior at low temperatures in graphene sheets.Comment: 21 pages, 15 figures; submitted to J. Phys.: Condensed Matte