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The growing prevalence of overeating disorders is a key contributor to the worldwide obesity epidemic. Dysfunction of particular neural circuits may trigger deviations from adaptive feeding behaviors. The lateral hypothalamus (LH) is a crucial neural substrate for motivated behavior including feeding, but the precise functional neurocircuitry that controls LH neuronal activity to engage feeding has not been defined. We observed that inhibitory synaptic inputs from the extended amygdala preferentially innervate and suppress the activity of LH glutamatergic neurons to control food intake. These findings help explain how dysregulated activity at a number of unique nodes can result in a cascading failure within a defined brain network to produce maladaptive feeding.

Una strategia per l’incremento delle prestazioni delle turbine a gas consiste nella riduzione del trafilamentodei gas nella zona ad alta temperatura della turbomacchina grazie alla riduzione della distanza tra lasommità delle palette e la copertura protettiva della cassa della turbina. A tal fine sono stati studiati sistemiabradibili realizzati mediante diverse tecniche. Sono stati realizzati sistemi compositi compositi a baseCoNiCrAlY/Al2O3 mediante tecnica Air Plasma Spray (APS), a base NiCrAlY/graphite mediante tecnica LaserCladding e barriere termiche spesse e porose. Le resistenze all’ossidazione e alla fatica termica dei rivestimentisono state valutate per mezzo di prove di ossidazione isoterma e ciclica. I rivestimenti compositiCoNiCrAlY/Al2O3 e NiCrAlY/graphite dopo 1000 ore a 1100°C non hanno mostrato rilevanti modificazionimicrostrutturali. La resistenza all’ossidazione dei nuovi rivestimenti compositi soddisfa le specifiche deiproduttori, gli “Original Equipment Manufacturer” (OEM). Le barriere termiche spesse e porose superano i testdi fatica termica imposti dalle procedure degli OEM. La durezza di tali rivestimenti suggerisce il loro uso incombinazione con palette dotate di rivestimento abrasivo sull’estremità. Le barriere termiche hanno mostratobuone caratteristiche di abradibilità.

International audience; Partial Discharge (PD) measurements have been proposed as a relatively economic and simple-to-apply experimental technique for retrieving information on the health state of an electrical cable. A set of PD measurements have been collected by Enea Ricerca sul Sistema Elettrico (ERSE), for building a diagnos-tic system of electrical cable health state. These experimental data may contain contradictory information which remarkably reduce the performance of the state classifier. In the present work, a novel technique based on the Adaboost algorithm is proposed for identifying contradictory PD patterns within an a priori analysis aimed at improving the diagnostic performance. Adaboost is a bootstrap-inspired, ensemble-based algorithm which has been effectively used for addressing classification problems.

Eighth International Symposium on High Voltage Engineering, August 23-27, 1993, Yokohama, Japan

TiO2 thin coatings were prepared, on various substrates, through evaporation of metallic titanium in an oxidizing atmosphere by modified electric arc physical vapor deposition (EA-PVD). The coatings were characterized chemically (by means of XPS and SIMS) and from the structural point of view (by means of XRD and Raman spectroscopy), in order to understand the factors which lead to homoge-neous coatings with high anatase content. The type of substrate is the main parameter that influence the crystal structure of the coatings: when stainless steel is used as substrate the coatings consist es-sentially of rutile, while on glass substrates coatings containing mainly anatase are obtained. The photocatalytic activity of the samples upon UVA irradiation was tested by using phenol as the target molecule. Phenol in the solution can be photocatalytically and rapidly degraded through the EA-PVD anatase TiO2 coatings.

Fortschritte auf dem Gebiet der Festigkeit, Risszähigkeit und Lebensdauer von Keramik Zur Charakterisierung des Versagensverhaltens keramischer Werkstoffe sind Festigkeits- und Risszähigkeitsmessungen erforderlich. Weist eine Keramik noch den Effekt des unterkritischen Risswachstums auf, sind auch Lebensdauermessungen unter statischer Belastung von großer Wichtigkeit. Neuere Beiträge der Autoren zur Untersuchungs-Methodik sind in diesem Bericht zusammengefasst. Teil A befasst sich mit der Berechnung der maximalen Spannungen in runden Scheiben unter Kugelbelastung. Hierbei werden der “ball-on-ring test”, der “ball-on-3-balls test” und der kürzlich von den Verfassern entwickelte „3-balls-on-3-balls test“ betrachtet. Als praktische Anwendung der ermittelten Spannungen im “ball-on-3-balls test” wird das bei grobkörnigem Aluminiumoxid gefundene stabile Bruchverhalten als Effekt einer stark ansteigenden Risswiderstandskurve diskutiert. In Teil B wird auf eine von den Verfassern entwickelte Methode eingegangen, die es gestattet, sehr kurze Kerben mit extrem kleinen Kerbradien zu erzeugen. Bei einer ZrO2-Keramik konnten Kerbradien von unter 0.1 μm bei einer Kerbtiefe von nur 40μm erzeugt werden. Derartig kurze und scharfe Kerben sollten geeignet sein, das Verhalten natürlicher Risse in Keramiken anzunähern. Schließlich wird in Teil C über eine Prozedur berichtet, die sich dafür eignet, eine vorhandene Anzahl an Lebensdauer-Versuchsproben optimal auszunutzen. Hierbei kann aus der erneuten Verwendung von auf niederem Lastniveau angefallenen „Durchläufern“ zusätzliche Information über das Risswachstumsgesetz gewonnen werden. Die Methode wird an Lebensdauermessungen von SIALON in destilliertem Wasser von 20°C demonstriert.

Recently, the claim was made that cracks in silicate glasses propagate by the nucleation, growth, and coalescence of cavities at crack tips, which is the same way as in metals but at a much smaller scale. This hypothesis for crack growth is based in part on the measurement of surface displacements near the tip of an emerging crack, which is the point at which a crack front intersects the side surface of the specimen. Surface displacements measured by atomic force microscopy were less than theoretically predicted. The difference between the theoretical and experimental displacements was attributed to a plastic zone surrounding the tip of the moving crack. In this paper, we show that the theoretical analysis used earlier was based on an incorrect assumption about the functional dependence of the displacement with distance from the crack tip. We use a full three-dimensional finite element analysis combined with an asymptotic solution of the crack geometry to obtain a solution to the surface displacement problem. We show that the calculated displacements are fully consistent with those experimentally measured by using an atomic force microscope. No divergence from elastic behavior is observed. Our results support the view that crack propagation in glass is entirely brittle. No evidence for plasticity at the crack tips is obtained.