Lean Six-Sigma in Aviation Safety: An implementation guide for measuring aviation system’s safety performance

The paper introduces a conceptual framework that could improve the safety performance measurement process and ultimately the aviation system safety performance. The framework provides an implementation guide on how organisations could design and develop a proactive, measurement tool for assessing and measuring the Acceptable Level of Safety Performance (ALoSP) at sigma (σ) level, a statistical measurement unit. In fact, the methodology adapts and combines quality management tools, a leading indicators programme and Lean-Six Sigma methodology to formally measure and continuously improve a stable and in-control safety management process by reducing safety defects and variability from core organisational processes and objectives. The implementation guide was empirically tested and validated with data collected and analysed within a period of nine months by the safety department of a complex aviation organisation operating a large transport aircraft fleet

Theory of the magnetoeletric effect in a lightly doped high-Tc cuprate

In a recent study Viskadourakis et al. discovered that extremely underdoped La_2CuO_(4+x) is a relaxor ferroelectric and a magnetoelectric material at low temperatures. It is further observed that the magnetoelectric response is anisotropic for different directions of electric polarization and applied magnetic field. By constructing an appropriate Landau theory, we show that a bi-quadratic magnetoelectric coupling can explain the experimentally observed polarization dependence on magnetic field. This coupling leads to several novel low-temperature effects including a feedback enhancement of the magnetization below the ferroelectric transition, and a predicted magnetocapacitive effect.Comment: 5 pages, 4 figure

Penetration Depth Measurements in MgB_2: Evidence for Unconventional Superconductivity

We have measured the magnetic penetration depth of the recently discovered binary superconductor MgB_2 using muon spin rotation and low field $ac$-susceptibility. From the damping of the muon precession signal we find the penetration depth at zero temperature is about 85nm. The low temperature penetration depth shows a quadratic temperature dependence, indicating the presence of nodes in the superconducting energy gap.Comment: 4 pages 3 figure

Skyrmions in a Doped Antiferromagnet

Magnetization and magnetoresistance have been measured in insulating antiferromagnetic La_{2}Cu_{0.97}Li_{0.03}O_{4} over a wide range of temperatures, magnetic fields, and field orientations. The magnetoresistance step associated with a weak ferromagnetic transition exhibits a striking nonmonotonic temperature dependence, consistent with the presence of skyrmions.Comment: 4+ pages, 3 figures (some low resolution), supplementary material (3 pages); discussion expanded, references added; as publishe

Source rock potential of the late Miocene Metochia Formation of Gavdos Island, Greece

Rock-Eval method was used to analyze 53 samples from late Miocene Metochia Formation of Gavdos Island (south of Crete Island) in order to characterize the contained organic matter and to evaluate its potential as source rock. The samples were collected from Metochia Section which consists of about 100 m thick marlssapropels alternations. Organic matter analysis showed that the studied succession could be subdivided into two parts. The lower one, which is generally rich in organic matter and the upper one, which is poor. In the lower part the rich horizons in organic matter are characterized by Kerogen type II, III and IV, with low oxygen content, and with fair to very good potential for gas and/or oil hydrocarbon generation. Additionally, the studied samples are thermally immature. Taking into account that the studied area has never been buried in such a depth to reach conditions of maturation, as well as, that the studied section in Gavdos is connected with Messara basin located in the northeastern and, finally, that the main part of Gavdos basin, which is situated between Gavdos and Crete islands, has continuously encountered subsidence, we could conclude that sediments of Metochia Formation could act as source rocks but in the more deep central part of the Gavdos basin. Key words: Neogene, Rock-eval pyrolysis, Organic matter. Η μέθοδος πυρόλυσης Rock-Eval χρησιμοποιήθηκε για την ανάλυση 53 δειγμάτων από τον Άνω Mειοκαινικό σχηματισμό των Μετοχίων της Γαύδου (νότια της Κρήτης) ώστε να εκτιμηθεί το δυναμικό του ως μητρικό πέτρωμα υδρογονανθράκων. Τα δείγματα ελήφθησαν από την τομή Μετόχια η οποία αποτελείται από μία παχιά ακολουθία, περίπου 100 m, εναλλαγών μαργών-σαπροπηλών. Η ανάλυση του οργανικού υλικού έδειξε ότι η μελετώμενη ακολουθία θα μπορούσε να χωριστεί σε δυο μέρη. Tο κατώτερο το οποίο είναι γενικά πλούσιο σε οργανικό υλικό και το ανώτερο το οποίο είναι φτωχό. Στο κατώτερο τμήμα οι πλούσιοι σε οργανικό υλικό ορίζοντες χαρακτηρίζονται από κηρογόνο τύπου II, III και IV, με χαμηλό περιεχόμενο οξυγόνο, με μέτριο έως πολύ καλό δυναμικό για την παραγωγή αέριων και υγρών υδρογονανθράκων. Επιπρόσθετα, τα μελετώμενα δείγματα είναι θερμικά ανώριμα. Λαμβάνοντας υπόψη ότι η περιοχής μελέτης δεν βρέθηκε σε τέτοιο βάθος ώστε να φτάσει σε συνθήκες ωρίμανσης, ότι η μελετώμενη τομή στην Γαύδο συνδέεται με την ΒΑ ευρισκόμενη λεκάνη της Μεσσαράς και τέλος ότι το κύριο τμήμα της λεκάνης της Γαύδου, το οποίο βρίσκεται μεταξύ Γαύδου και Κρήτης, υπέστη συνεχώς καταβύθιση, μπορούμε να υποθέσουμε ότι τα ιζήματα του σχηματισμού των Μετοχίων θα μπορούσαν να λειτουργήσουν ως μητρικά πετρώματα αλλά στο βαθύτερο κεντρικό τμήμα της λεκάνης της Γαύδου