3,567 research outputs found

    Feed system design and experimental results in the uhf model study for the proposed Urbana phased array

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    The effects of atmospheric turbulence and the basis for the coherent scatter radar techniques are discussed. The reasons are given for upgrading the Radar system to a larger steerable array. Phase array theory pertinent to the system design is reviewed, along with approximations for maximum directive gain and blind angles due to mutual coupling. The methods and construction techniques employed in the UHF model study are explained. The antenna range is described, with a block diagram for the mode of operation used

    Effects of aircraft noise on flight and ground structures

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    Acoustic loads measured on jet-powered STOL configurations are presented for externally blown and upper surface blown flap models ranging in size from a small laboratory model up to a full-scale aircraft model. The implications of the measured loads for potential acoustic fatigue and cabin noise are discussed. Noise transmission characteristics of light aircraft structures are presented. The relative importance of noise transmission paths, such as fuselage sidewall and primary structure, is estimated. Acceleration responses of a historic building and a residential home are presented for flyover noise from subsonic and supersonic aircraft. Possible effects on occupant comfort are assessed. The results from these three examples show that aircraft noise can induce structural responses that are large enough to require consideration in the design or operation of the aircraft

    Cleavage of DFNA5 by caspase-3 during apoptosis mediates progression to secondary necrotic/pyroptotic cell death.

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    Apoptosis is a genetically regulated cell suicide programme mediated by activation of the effector caspases 3, 6 and 7. If apoptotic cells are not scavenged, they progress to a lytic and inflammatory phase called secondary necrosis. The mechanism by which this occurs is unknown. Here we show that caspase-3 cleaves the GSDMD-related protein DFNA5 after Asp270 to generate a necrotic DFNA5-N fragment that targets the plasma membrane to induce secondary necrosis/pyroptosis. Cells that express DFNA5 progress to secondary necrosis, when stimulated with apoptotic triggers such as etoposide or vesicular stomatitis virus infection, but disassemble into small apoptotic bodies when DFNA5 is deleted. Our findings identify DFNA5 as a central molecule that regulates apoptotic cell disassembly and progression to secondary necrosis, and provide a molecular mechanism for secondary necrosis. Because DFNA5-induced secondary necrosis and GSDMD-induced pyroptosis are dependent on caspase activation, we propose that they are forms of programmed necrosis

    Teaching Disruptive Students: An Indictment of Colorblind Teacher Education Programs

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    Teacher education programs do not sufficiently prepare White teachers to work with Black and Latino students in disciplinary alternative schools. From a critical race theory in education perspective, prepared White teachers are aware of their own ethnocentrism and, subsequently, develop anti-racist pedagogy and curricula

    Pengaruh Produk Domestik Bruto Riil, Nilai Tukar dan Tingkat Suku Bunga Riil terhadap Inflasi di Indonesia Periode 1994-2013

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    One of the problems in almost all countries in the world is the difficulty of maintaining the stability of the economy. Various policies, both fiscal policy and monetary policy carefully planned and then carried out to obtain the various targets of economic growth is expected to bring prosperity to the community. One of the efforts the fulfillment of the economic growth target is done by controlling the rate of inflation, both at regional and at national level. The inflation rate in the right figure is able to bring the economy towards positive growth. The purpose of this study was to determine the effect of the Gross Domestic Product (GDP) real exchange rate and real interest rates on inflation in this Indonesia.Penelitian using secondary data types. Analysis method used is the method of quantitative analysis using multiple regression analysis SPSS version 18.0. Results show the results of research conducted simultaneous real gross domestic product, the exchange rate, and real interest rates have a significant effect terhadapinflasi inflation in Indonesia for the period 1994-2013 with F 0.000 and 125.606 with sig R2sebesar value 0.952 which means 95.2% Inflation in Indonesia is influenced by real gross domestic product, the exchange rate, and the rate of the real man, while the remaining 4.8% is influenced by other factors not addressed in this study.Keywords: Gross Domestic Product (GDP) of the Rill, Exchange Rate, Real Interest Rate, Inflation

    The application of passive sampler (DGT) technology for improved understanding of metal behaviour at a marine disposal site

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    Metal behaviour and availability at a contaminated dredge material disposal site within UK waters has been investigated using Diffusive Gradient in Thin films (DGT) passive sampling technology. Three stations representing contrasting history and presence of maintenance dredge disposal, including a control station outside the disposal site, have been studied and depth profiles of fluxes of different metals (Fe, Mn, Pb, Cu, Cd, Cr, Ni, Zn) to the binding gel (Chelex 100) have been derived. Higher flux rates and shallower mobilisation of metals (Mn and Fe) to the binding gel were observed at the disposal stations compared to the control station. Here we describe metal mobilization at different depths, linking the remobilization of Fe2+ and Mn2+ to the sediment (re)supply of other heavy metals of interest with a focus on Cd, Ni and Pb and as they are on the Water Framework Directive (WFD) list of priority substances and OSPAR list of priority pollutants. Results showed that Cd, Pb and Ni exhibited signs of resupply at the sediment-water interface (SWI). There was a potential increased mobilisation and source to the water column of Pb and Ni at the disposal site stations, but there was no Cd source, despite higher total loadings. This information has the potential to improve our current understanding of metal cycles at disposal sites. This work can be used as an indication of likely metal bioavailability and also assist in determining whether the sites act as sources or sinks of heavy metals. This information could assist disposal site monitoring and dredge material licensing

    Recent Advances to Estimation of Fixed-Interface Modal Models Using Dynamic Substructuring

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    In 2010, Allen & Mayes proposed to estimate the fixed-interface modes of a structure by measuring the modes of the structure bolted to a fixture and then applying constraints to the fixture using the transmission simulator method. While the method proved useful, and has indeed been used in studies since that point, a few peculiarities were noted. First, in some cases the estimated fixed-base natural frequencies were observed to converge very slowly to the true values (in simulated experiments) as the number of constraints was increased. To formulate these constraints, prior studies used only the free-interface modes of the fixture or the measured modes of the assembly. This work extends that to consider other sets of constraints, showing improved results. Furthermore, in some prior studies it has been observed that there were errors of more than 10% in the natural frequencies even when the fixture motion was hundreds of times smaller than the motion of the structure of interest (and so it had presumably been removed). This work explores this phenomenon, seeking to use the strain energy in the fixture, to the extent that it can be estimated using a test-analysis model for the fixture, as a metric to predict frequency error. The proposed methods are explored by applying them to simulated measurements from a beam and from the NASA Space Launch System coupled to the Mobile Launcher
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