A Global Approach to Fiber nD Architectures and Self-Sealing Matrices: From Research to Production

Thermostructural composites (TSC) improvement is one of the key factors to ensure future competitiveness of aeronautical and space engines. The TSC technology developed in Snecma Propulsion Solide is based on continuous fiber-reinforced composites and carbon or ceramics matrices deposited by chemical vapor infiltration. This article presents a status of the latest improvements for cost savings of composite reinforcements (so-called texture) and specific matrices developed to increase both durability and temperature capability of previous ceramic composites, operating in oxidative environments.     

An Energetic N‐Oxide and N‐Amino Heterocycle and its Transformation to 1,2,3,4‐Tetrazine‐1‐oxide

This study reports the preparation of 1‐amino‐1,2,3‐triazole‐3‐oxide (DPX2) and its transformation to 1,2,3,4‐tetrazine‐1‐oxide. DPX‐2 provides insight into a novel N‐oxide/N‐amino high‐nitrogen system, being the first energetic material in this class. The ability of this material to undergo a nitrene insertion forming 1,2,3,4‐tetrazine‐1‐oxide was also studied, and evidence for this material, the first non‐benzoannulated 1,2,3,4‐tetrazine‐1‐oxide, is presented. The existence of both of these materials opens new strategies in energetic materials design. DPX2 was characterized chemically (Infrared, Raman, NMR, X‐ray) and as a high explosive in terms of energetic performances (detonation velocity, pressure, etc.) and sensitivities (impact, friction, electrostatic). DPX‐2 was found to possess good thermal stability and moderate sensitivities, indicating the viability of N‐amino N‐oxides as a strategy for the preparation of new energetic materials.     

Partial hepatic resection for ischemic graft damage after liver transplantation: a graft-saving option?

BACKGROUND: Intrahepatic biliary strictures or parenchymal infarcts may occur after liver transplantation as a complication of ischemic damage to the graft. In some selected cases the lesions appear to be confined to a part of the liver. We report our experience with partial graft resection in this setting. METHODS: From January 1984 to December 1991, 286 liver transplantations were performed in 257 recipients. Seven patients, three children and four adults, underwent partial hepatectomy 3 to 218 weeks after liver transplantation of a full-size graft. The clinical presentation included septic parenchymal infarcts (n = 4) and nonanastomotic biliary strictures (n = 3) complicating (n = 5) artery thrombosis or not (n = 2). There were four left hepatectomies, two left lobectomies, and one right hepatectomy. In four instances partial hepatectomy was performed after failed attempt at biliary reconstruction (n = 2) or arterial revascularization (n = 2). Partial graft resection was performed extrafascially without Pringle's maneuver and mobilization of the remnant liver to preserve its vascularization. RESULTS: No surgical complications occurred, and none of the patients experienced acute hepatic failure during the postoperative period. All patients were discharged home 10 to 96 days (median, 23 days) after liver resection. Two patients had recurrent ischemic cholangitis. One patient underwent successful regrafting for recurrent Budd-Chiari syndrome; one patient died of tumor recurrence. Six patients were alive with a follow-up ranging from 12 to 45 months. CONCLUSIONS: These results suggest that partial graft resection is a safe and graft-saving option after liver transplantation in selected patients with localized ischemic damage of the graft.     

A QoS architecture for quantitative service differentiation

For the past decade, a lot of Internet research has been devoted to providing different levels of service to applications. Initial proposals for service differentiation provided strong service guarantees, with strict per-flow bounds on delays, loss rates, and throughput, but required high overhead in terms of computational complexity and memory, both of which raise scalability concerns. Recently, the interest has shifted to class-based service architectures with low overhead. However, these newer service architectures only provide weak service guarantees, which do not always address the needs of applications. In this article we introduce a service architecture that supports strong per-class service guarantees, can be implemented with low computational complexity, and only requires maintenance of a little state information. A key mechanism of the proposed service architecture is that service rate allocation to classes is adaptive, and combined with buffer management. Furthermore, instead of using admission control or traffic policing, the proposed architecture exploits explicit congestion notification for the purpose of regulating the traffic entering the network.     

Fusion architectures for automatic subject indexing under concept drift

International Journal on Digital Libraries - Indexing documents with controlled vocabularies enables a wealth of semantic applications for digital libraries. Due to the rapid growth of scientific...     

Genauigkeit der Bestimmung von Blasengrößen aus Messdaten eines Leitfähigkeits‐Gittersensors

An experimental study to assess the accuracy of a wire‐mesh sensor with a temporal and spatial resolution of 5 kHz and 4.8 mm in dependence of bubble size has been carried out. As a reference, single air bubbles with a defined bubble size of 2 – 12 mm are injected in a stagnant liquid phase. The results show a higher uncertainty for bubble diameters below the grid resolution of the sensor. In this case, the bubble size depends strongly on the local bubble position within the mesh grid during its passage.     

Bemessungsnomogramme für Stahlbetonkonsolen

In diesem Beitrag werden Nomogramme für die Bemessung von Stahlbetonkonsolen vorgestellt. Basierend auf den entsprechenden Bemessungsmodellen kann für eine gegebene Stahlbetonkonsole und eine Beanspruchung die Bewehrungsmenge des Zuggurts bestimmt werden. In den Nomogrammen sind alle relevanten Anwendungsgrenzen eingearbeitet. Die Praxistauglichkeit der Nomogramme wird anhand eines Beispiels erläutert. Support for the analysis by concrete brackets. In this contribution nomograms are introduced for the structural analysis of concrete brackets. Based on the appropriate design codes the reinforcement for the tension strut can be determined. In these nomograms all relevant limitations are incorporated. The application of the nomograms is shown using an example.     

BCI Competition 2003--Data set III: probabilistic modeling of sensorimotor mu rhythms for classification of imaginary hand movements

Brain-computer interfaces require effective online processing of electroencephalogram (EEG) measurements, e.g., as a part of feedback systems. We present an algorithm for single-trial online classification of imaginary left and right hand movements, based on time-frequency information derived from filtering EEG wideband raw data with causal Morlet wavelets, which are adapted to individual EEG spectra. Since imaginary hand movements lead to perturbations of the ongoing pericentral mu rhythm, we estimate probabilistic models for amplitude modulation in lower (10 Hz) and upper (20 Hz) frequency bands over the sensorimotor hand cortices both contra- and ipsilaterally to the imagined movements (i.e., at EEG channels C3 and C4). We use an integrative approach to accumulate over time evidence for the subject's unknown motor intention. Disclosure of test data labels after the competition showed this approach to succeed with an error rate as low as 10.7%.