7,498 research outputs found

    Computerized analytical technique for design and analysis of a Sabatier reactor subsystem Final engineering report

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    Mathematical model for computerized evaluation of Sabatier reaction kinetics in oxygen recovery from carbon dioxid

    Coherence of femtosecond single electrons exceeds biomolecular dimensions

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    Time-resolved diffraction and microscopy with femtosecond electron pulses provide four-dimensional recordings of atomic motion in space and time. However, the limited coherence of electron pulses, reported in the range of 2–3 nm, has so far prevented the study of complex organic molecules with relevance to chemistry and biology. Here we characterize the coherence of femtosecond single-electron pulses that are generated by laser photoemission. We show how the absence of space charge and the minimization of the source size allow the transverse coherence to be extended to 20 nm at the sample position while maintaining a useful beam diameter. The extraordinary coherence is experimentally demonstrated by recording singleelectron diffraction snapshots from a complex organic molecular crystal and identifying more than 80 sharp Bragg reflections. Further optimization affords promise for coherences of 100 nm. These advances will allow time-resolved imaging of functional dynamics in biological systems, uniting picometre and femtosecond resolutions in a compact, table-top instrumentation.publishe

    Holomorphic Supercurves and Supersymmetric Sigma Models

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    We introduce a natural generalisation of holomorphic curves to morphisms of supermanifolds, referred to as holomorphic supercurves. More precisely, supercurves are morphisms from a Riemann surface, endowed with the structure of a supermanifold which is induced by a holomorphic line bundle, to an ordinary almost complex manifold. They are called holomorphic if a generalised Cauchy-Riemann condition is satisfied. We show, by means of an action identity, that holomorphic supercurves are special extrema of a supersymmetric action functional.Comment: 30 page

    Extended X-ray emission in radio galaxies: the peculiar case of 3C 305

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    Extended X-ray structures are common in Active Galactic Nuclei (AGNs). Here we present the first case of a Compact Steep Spectrum (CSS) radio galaxy, 3C 305, in which the X-ray radiation appears to be associated with the optical emission line region, dominated by the [O III]5007. On the basis of a morphological study, performed using the comparison between the X-rays, the optical and the radio band, we argue that the high energy emission has a thermal nature and it is not directly linked to the radio jet and hotspots of this source. Finally, we discuss the origin of the extended X-ray structure connected with the optical emission line region following two different interpretations: as due to the interaction between matter outflows and shock-heated environment gas, or as due to gas photoionized by nuclear emission.Comment: 5 pages, 2 figures, Accepted for publication in The ApJL Comments: references and affilitations correcte

    Applications of ethylene vinyl acetate as an encapsulation material for terrestrial photovoltaic modules

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    Terrestrial photovoltaic modules must undergo substantial reductions in cost in order to become economically attractive as practical devices for large scale production of electricity. Part of the cost reductions must be realized by the encapsulation materials that are used to package, protect, and support the solar cells, electrical interconnects, and other ancillary components. As many of the encapsulation materials are polymeric, cost reductions necessitate the use of low cost polymers. The performance and status of ethylene vinyl acetate, a low cost polymer that is being investigated as an encapsulation material for terrestrial photovoltaic modules, are described

    Elastic Wave Propagation and Scattering in Austenitic Steel

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    Ultrasonic nondestructive testing of austenitic steel welds is very difficult, because fundamental wave propagation and scattering effects in such complicated anisotropic environments are only hardly understood [1, 2]. Therefore, a step-by-step evaluation of elastic wave propagation in transversely isotropic media has been initiated. Under the assumption of transverse isotropy the numerical EFIT code (Elastodynamic Finite Integration Technique) [3] - [7] was extended to anisotropic homogeneous media. It allows 3D computation of quasi pressure and quasi shear as well as surface waves in transverse isotropic media. Results for finite aperture transducer radiation and crack scattering in a single crystal austenitic weld are presented; measurements of amplitude dynamics, A-Scans and C-Scans confirm the EFIT simulations [8]

    Stormy weather in 3C 196.1: nuclear outbursts and merger events shape the environment of the hybrid radio galaxy 3C 196.1

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    We present a multi-wavelength analysis based on archival radio, optical and X-ray data of the complex radio source 3C 196.1, whose host is the brightest cluster galaxy of a z=0.198z=0.198 cluster. HST data show Hα\alpha+[N II] emission aligned with the jet 8.4 GHz radio emission. An Hα\alpha+[N II] filament coincides with the brightest X-ray emission, the northern hotspot. Analysis of the X-ray and radio images reveals cavities located at galactic- and cluster- scales. The galactic-scale cavity is almost devoid of 8.4 GHz radio emission and the south-western Hα\alpha+[N II] emission is bounded (in projection) by this cavity. The outer cavity is co-spatial with the peak of 147 MHz radio emission, and hence we interpret this depression in X-ray surface brightness as being caused by a buoyantly rising bubble originating from an AGN outburst ∼\sim280 Myrs ago. A \textit{Chandra} snapshot observation allowed us to constrain the physical parameters of the cluster, which has a cool core with a low central temperature ∼\sim2.8 keV, low central entropy index ∼\sim13 keV cm2^2 and a short cooling time of ∼\sim500 Myr, which is <0.05<0.05 of the age of the Universe at this redshift. By fitting jumps in the X-ray density we found Mach numbers between 1.4 and 1.6, consistent with a shock origin. We also found compelling evidence of a past merger, indicated by a morphology reminiscent of gas sloshing in the X-ray residual image. Finally, we computed the pressures, enthalpies EcavE_{cav} and jet powers PjetP_{jet} associated with the cavities: Ecav∼7×1058E_{cav}\sim7\times10^{58} erg, Pjet∼1.9×1044P_{jet}\sim1.9\times10^{44} erg s−1^{-1} for the inner cavity and Ecav∼3×1060E_{cav}\sim3\times10^{60} erg, Pjet∼3.4×1044P_{jet}\sim3.4\times10^{44} erg s−1^{-1} for the outer cavity.Comment: 14 pages, 4 figures, ApJ accepte

    Prop-fan data support study

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    Updated parametric prop-fan data packages are presented and the rationale used in developing the new prop-fan data is detailed. These data represent Hamilton Standard's projections of prop-fan characteristics for aircraft that are expected to be in-service in the 1985 to 1990 time frame. The basic prop-fan configuration was designed for efficient cruise operation at 0.8 Mach number and 10,668M altitude. The design blade tip speed is 244 mps and the design power loading is 301 KW/M squared
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