EXPERIMENTAL AND NUMERICAL INVESTIGATIONS OF FILM-COOLING EFFECTS ON THE AERODYNAMIC PERFORMANCE OF TRANSONIC TURBINE BLADES

ABSTRACT This paper presents results of experimental as well as numerical investigations of the aerodynamic performance of filmcooled transonic turbine blades. Taking into consideration to nondimensional similarity, the experiments were performed on a cascade test rig using superheated steam as fluid. The investigated blading corresponds to a typical high pressure turbine vane used in the high subsonic regime. In order to determine the effect of the blown-out cooling fluid on the aerodynamic performance of the cascade, the measurements were performed over a wide range of realistic exit Mach numbers, mass flow rate ratios, coolant injection locations and main-tocoolant flow density ratios. The paper presents the results of the experimental investigation in the form of outlet angles and loss terms, and compares and discusses these for a number of variations. It was found that below a critical mass flow ratio, the kinetic loss coefficient varies only little with flow rate whereas above this critical flow ratio, the loss coefficient increases rapidly. A comparison of the different injection locations shows that the suction side is very sensitive with regard to main flow disturbances while injection on the pressure side and the trailing edge only has a small effect of the loss terms. Consideration of different coolant-to-mainstream density ratios clarifies that the influence of this parameter on the loss terms can be neglected. The paper also addresses a simple numerical code which is based on the ,TOTLOS" model of Hansel and adapted to the above-mentioned problem, and compares and discusses the results of the experimental and numerical investigations

Growth hormone as concomitant treatment in severe fibromyalgia associated with low IGF-1 serum levels. A pilot study

<p>Abstract</p> <p>Background</p> <p>There is evidence of functional growth hormone (GH) deficiency, expressed by means of low insulin-like growth factor 1 (IGF-1) serum levels, in a subset of fibromyalgia patients. The efficacy of GH versus placebo has been previously suggested in this population. We investigated the efficacy and safety of low dose GH as an adjunct to standard therapy in the treatment of severe, prolonged and well-treated fibromyalgia patients with low IGF-1 levels.</p> <p>Methods</p> <p>Twenty-four patients were enrolled in a randomized, open-label, best available care-controlled study. Patients were randomly assigned to receive either 0.0125 mg/kg/d of GH subcutaneously (titrated depending on IGF-1) added to standard therapy or standard therapy alone during one year. The number of tender points, the Fibromyalgia Impact Questionnaire (FIQ) and the EuroQol 5D (EQ-5D), including a Quality of Life visual analogic scale (EQ-VAS) were assessed at different time-points.</p> <p>Results</p> <p>At the end of the study, the GH group showed a 60% reduction in the mean number of tender points (pairs) compared to the control group (p < 0.05; 3.25 ± 0.8 <it>vs</it>. 8.25 ± 0.9). Similar improvements were observed in FIQ score (p < 0.05) and EQ-VAS scale (p < 0.001). There was a prompt response to GH administration, with most patients showing improvement within the first months in most of the outcomes. The concomitant administration of GH and standard therapy was well tolerated, and no patients discontinued the study due to adverse events.</p> <p>Conclusion</p> <p>The present findings indicate the advantage of adding a daily GH dose to the standard therapy in a subset of severe fibromyalgia patients with low IGF-1 serum levels.</p> <p>Trial Registration</p> <p>NCT00497562 (ClinicalTrials.gov).</p

Study protocol of the iMPaCT project : A longitudinal cohort study assessing psychological determinants, sexual behaviour and chlamydia (re)infections in heterosexual STI clinic visitors

Acknowledgements We are grateful to the staff at the STI clinics of Amsterdam, Kennemerland, Hollands Noorden, Twente, who are involved in the recruitment and data collection of participants, and Marlous Ratten and Klazien Visser from Soapoli-online, who are involved in the coordination of laboratory testing of the home-based sampling kits at six-month follow-up. We also thank the staff at the STI department at the National Institute for Public Health and the Environment, especially Birgit van Benthem. Funding This project is funded by the Strategic Programme (SPR) of the National Institute for Public Health and the Environment (RIVM) (project number S/113004/01/IP). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Availability of data and materials The dataset (anonymised) generated during this study will be made available for interested parties on request.Peer reviewedPublisher PD

Rapid NEGF-based calculation of ballistic current in ultra-short DG MOSFETs for circuit simulation

Shrinking gate length in conventional MOSFETs leads to increasing short channel effects like source-to-drain (SD) tunneling. Compact modeling designers are challenged to model these quantum mechanical effects. The complexity lies in the set-up between time efficiency, physical model relation and analytical equations. Multi-scale simulation bridges the gap between compact models, its fast and efficient calculation of the device terminal voltages, and numerical device models which consider the effects of nanoscale devices. These numerical models iterate between Poisson- and Schroedinger equation which significantly slows down the simulation performance. The physicsbased consideration of quantum effects like the SD tunneling makes the non-equilibrium Green’s function (NEGF) to a stateof-the-art method for the simulation of devices in the sub 10 nm region. This work introduces a semi-analytical NEGF model for ultra-short DG MOSFETs. Applying the closed-form potential solution of a classical compact model, the model turns the NEGF from an iterative numerical solution into a straightforward calculation. The applied mathematical approximations speed up the calculation time of the 1D NEGF. The model results for the ballistic channel current in DG-MOSFETs are compared with numerical NanoMOS TCAD [1] simulation data. Shown is the accurate potential calculation as well as the good agreement of the current characteristic for temperatures down to 75 K for channel lengths from 6 nm to 20 nm and channel thickness from 1.5 nm to 3 nm

Ermittlung und Überprüfung der Datengrundlage für das Modell zur Einsparung von Treibhausgasen durch stoffliche Holznutzung im Bauwesen im Holzbau-GIS für die Stadt Menden

Um Entscheidungsträger von Kommunen in die Lage zu versetzen, die erreichbaren Treibhausgaseinsparungen durch den Einsatz von Holz als Baumaterial in ihre kommunalen Klimaschutzkonzepte in Selbstverwaltung integrieren zu können, wurde ein Berechnungsmodell entwickelt, welches die potenziellen Treibhausgaseinsparungen abschätzt. In diesem Beitrag wird die Ermittlung der Datengrundlage für dieses Modell vorgestellt. Grundlage des Berechnungsmodells bilden Datensätze, mit denen die Gebäude der Beispielkommune (Menden in Nordrhein-Westfalen) möglichst detailliert beschrieben werden können. Unter Berücksichtigung der Anforderungen an die Daten eignen sich hierfür vor allem Daten des Amtlichen Liegenschaftskatasters sowie ein 3d-Datensatz der Gebäude. Da das Gebäudealter aus diesen Datensätzen nicht bestimmt werden kann, wird die Ermittlung des Baualters anhand von historischen Orthophotos vorgenommen

The Catalysis of Nuclear Reactions by mu Mesons

In the course of a recent experiment involving the stopping of negative K mesons in a 10-inch liquid hydrogen bubble chamber, an interesting new reaction was observed to take place. The chamber is traversed by many more negative {mu} mesons than K mesons, so that in the last 75,000 photographs, approximately 2500 {mu}{sup -} decays at rest have been observed. In the same pictures, several hundred {pi}{sup -} mesons have been observed to disappear at rest, presumably by one of the ''Panofsky reactions''. For tracks longer than 10 cm, it is possible to distinguish a stopping {mu} meson from a stopping {pi} meson by comparing its curved path (in a field of 11,000 gauss) with that of a calculated template. In addition to the normal {pi}{sup -} and {mu}{sup -} stoppings, we have observed 15 cases in which what appears (from curvature measurement) to be a {mu}{sup -} meson comes to rest in the hydrogen, and then gives rise to a secondary negative particle of 1.7 cm range, which in turn decays by emitting an electron. (A 4.1-Mev {mu} meson from {pi} - {mu} decay has a range of 1.0 cm.) The energy spectrum of the electrons from these 15 secondary particles looks remarkably like that of the {mu} meson. There are four electrons in the energy range 50 to 55 Mev, and none higher; the other electrons have energies varying from 50 Mev to 13 Mev. The most convincing proof that the primary particle actually comes to rest, and does not--for example--have a large resonant cross section for scattering at a residual range of 1.7 cm, is the following: In five of the 15 special events, there is a large gap between the last bubble of the primary track and the first bubble of the secondary track. This gap is a real effect, and not merely a statistical fluctuation in the spacing of the bubbles, since in some cases the tracks form a letter X, and in another case the secondary track is parallel to the primary, but displaced transversely by about 1 mm at the end of the primary. These real gaps appear also (although perhaps less frequently) between some otherwise normal-looking {mu}{sup -} endings and the subsequent decay electron; they are thought to be the distance traveled by the small neutral mesic atom