21 research outputs found

    Acoustic tests of duct-burning turbofan jet noise simulation

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    The results of a static acoustic and aerodynamic performance, model-scale test program on coannular unsuppressed and multielement fan suppressed nozzle configurations are summarized. The results of the static acoustic tests show a very beneficial interaction effect. When the measured noise levels were compared with the predicted noise levels of two independent but equivalent conical nozzle flow streams, noise reductions for the unsuppressed coannular nozzles were of the order of 10 PNdB; high levels of suppression (8 PNdB) were still maintained even when only a small amount of core stream flow was used. The multielement fan suppressed coannular nozzle tests showed 15 PNdB noise reductions and up to 18 PNdB noise reductions when a treated ejector was added. The static aerodynamic performance tests showed that the unsuppressed coannular plug nozzles obtained gross thrust coefficients of 0.972, with 1.2 to 1.7 percent lower levels for the multielement fan-suppressed coannular flow nozzles. For the first time anywhere, laser velocimeter velocity profile measurements were made on these types of nozzle configurations and with supersonic heated flow conditions. Measurements showed that a very rapid decay in the mean velocity occurs for the nozzle tested

    Acoustic tests of duct-burning turbofan jet noise simulation: Comprehensive data report. Volume 2: Model design and aerodynamic test results

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    The selection procedure is described which was used to arrive at the configurations tested, and the performance characteristics of the test nozzles are given

    Acoustic tests of duct-burning turbofan jet noise simulation: Comprehensive data report. Volume 1, section 2: Full size data

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    Acoustic data are presented scaled to a full size engine by a factor of 8 on a 96.9 m (320 ft) arc and a 731.5 m (2400 ft) sideline

    Acoustic tests of duct-burning turbofan jet noise simulation: Comprehensive data report. Volume 1, section 3: Data plots

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    Acoustic data plots are presented which were obtained in the tests on scale nozzles for use on duct-burning turbofan engines

    Acoustic tests of duct-burning turbofan jet noise simulation: Comprehensive data report. Volume 1, section 1: Model scale data

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    Model scale data on a 12.2 m (40 ft) arc are presented which were obtained in the hot, static acoustic tests on eleven nozzle designs suitable for use on duct-burning turbofan engines

    Known drugs identified by structure-based virtual screening are able to bind sigma-1 receptor and increase growth of huntington disease patient-derived cells

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    Huntington disease (HD) is a devastating and presently untreatable neurodegenerative disease characterized by progressively disabling motor and mental manifestations. The sigma-1 receptor (σ1R) is a protein expressed in the central nervous system, whose 3D structure has been recently determined by X-ray crystallography and whose agonists have been shown to have neuro-protective activity in neurodegenerative diseases. To identify therapeutic agents against HD, we have implemented a drug repositioning strategy consisting of: (i) Prediction of the ability of the FDA-approved drugs publicly available through the ZINC database to interact with σ1R by virtual screening, followed by computational docking and visual examination of the 20 highest scoring drugs; and (ii) Assessment of the ability of the six drugs selected by computational analyses to directly bind purified σ1R in vitro by Surface Plasmon Resonance and improve the growth of fibro-blasts obtained from HD patients, which is significantly impaired with respect to control cells. All six of the selected drugs proved able to directly bind purified σ1R in vitro and improve the growth of HD cells from both or one HD patient. These results support the validity of the drug repositioning procedure implemented herein for the identification of new therapeutic tools against HD

    Character and spatial distribution of OH/H<SUB>2</SUB>O on the surface of the moon seen by M<SUP>3</SUP> on Chandrayaan-1

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    The search for water on the surface of the anhydrous Moon had remained an unfulfilled quest for 40 years. However, the Moon Mineralogy Mapper (M3) on Chandrayaan-1 has recently detected absorption features near 2.8 to 3.0 micrometers on the surface of the Moon. For silicate bodies, such features are typically attributed to hydroxyl- and/or water-bearing materials. On the Moon, the feature is seen as a widely distributed absorption that appears strongest at cooler high latitudes and at several fresh feldspathic craters. The general lack of correlation of this feature in sunlit M3 data with neutron spectrometer hydrogen abundance data suggests that the formation and retention of hydroxyl and water are ongoing surficial processes. Hydroxyl/water production processes may feed polar cold traps and make the lunar regolith a candidate source of volatiles for human exploration

    Specifying and Validating Probabilistic Inputs for Prescriptive Models of Decision Making over Time

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    Optimization models for making decisions over time in uncertain environments rely on probabilistic inputs, such as scenario trees for stochastic mathematical programs. The quality of model outputs, i.e., the solutions obtained, depends on the quality of these inputs. However, solution quality is rarely assessed in a rigorous way. The connection between validation of model inputs and quality of the resulting solution is not immediate. This chapter discusses some efforts to formulate realistic probabilistic inputs and subsequently validate them in terms of the quality of solutions they produce. These include formulating probabilistic models based on statistical descriptions understandable to decision makers; conducting statistical tests to assess the validity of stochastic process models and their discretization; and conducting re-enactments to assess the quality of the formulation in terms of solution performance against observational data. Studies of long-term capacity expansion in service industries, including electric power, and short-term scheduling of thermal electricity generating units provide motivation and illustrations. The chapter concludes with directions for future research

    Housing Squats as “Educational Sites of Resistance”: The Process of Movement Social Base Formation in the Struggle for the House

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    This paper aims to contribute to the scholarly work on the internal dynamics of contemporary housing movements. In particular, it explores the spatial strategies through which squat inhabitants change the configuration of the squat to turn an abandoned building into a house for multiple families. The main argument is that these strategies, requiring horizontal participation and solidarity, catalyse the transformation of a sum of people dispossessed of the house into a collective, political subject. Therefore, the author proposes to analyse housing squats as “educational sites of resistance”. The findings come from the author’s participant observation of Rome’s housing movement organisation Coordinamento Cittadino di Lotta per la casa. In addition to providing empirical knowledge, the paper aims to offer inputs for investigating to what extent the process of politicisation is shaped by the space and what constitute the peculiarities of a so-recomposed collective subjec
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