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  • 1
    Electronic Resource
    Electronic Resource
    Determination of Fluorine in Catalysts Containing Alumina and Silica (1955)
    s.l. : American Chemical Society
    Analytical chemistry 27 (1955), S. 1429-1431 
    Details
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ac60105a019
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  • 2
    Electronic Resource
    Electronic Resource
    A quantitative study of the flow around an impulsively started circular cylinder (1992)
    Springer
    Experiments in fluids 13 (1992), S. 137-146 
    Details
    ISSN: 1432-1114
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The detailed flow structure behind an impulsively started circular cylinder has been investigated experimentally. The Reynolds number based on the steady state velocity and the diameter of the cylinder was 500 to 3,000. This work is unique in that unsteady spatial velocities were measured simultaneously by a quantitative visualization technique — Laser Induced Photochemical Anemometry (LIPA). The surface vorticity at g/q = π/2 and vorticity distribution behind the cylinder in the Lagrangian coordinates (i.e. coordinates fixed on the cylinder) were calculated from the measured velocities. The surface vorticity shows in the early stage of flow development a close agreement with the previous results obtained by analytical and numerical approaches. The large-field velocity and vorticity information provides an insight into the formation process of the vortices downstream of the cylinder. In addition to the quantitative information, the results of visualized flow pattern obtained by LIPA technique are also presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00218160
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  • 3
    Electronic Resource
    Electronic Resource
    Vortex ring/viscous wall layer interaction model of the turbulence production process near walls (1988)
    Springer
    Experiments in fluids 6 (1988), S. 305-315 
    Details
    ISSN: 1432-1114
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract An experimental simulation of the interaction of vortex ring-like eddies with the sublayer of a turbulent boundary layer is investigated. An artificially generated vortex ring interacting with a Stokes' layer enables investigation of the interaction with reproducible initial conditions and in the absence of background turbulence. All of the observed features in the turbulent boundary layer production process such as the streaky structure, the pockets, the hairpin vortices, streak lift-up, oscillation, and breakup, have been observed to form. The model shows us that hairpin vortices can pinchoff and reconnect forming new vortex ring-like eddies. Interestingly, the model includes interactions that occur with low probability in the turbulent boundary layer, but which contribute significantly to transport, and may be the events most readily controllable.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00538821
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  • 4
    Electronic Resource
    Electronic Resource
    A simple apparatus for determining column density and absolute photoabsorption cross sections (2000)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 71 (2000), S. 1564-1568 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: This article presents a simple measuring apparatus that is capable of measuring column density and absolute photoabsorption cross sections. The apparatus includes a simple high-temperature heatpipe furnace, an MKS Instruments Baratron, a hydrogen discharge lamp, and an optical detecting system. The heatpipe furnace provides an absorbing medium with a steady total pressure in a closed system so that the column density can be obtained using the ideal gas relation. The apparatus is designed for a working temperature range below 1000 K and a pressure range up to 10 Torr. Encountered experimental difficulties and their found solutions will be discussed in detail. In this work, the absolute photoabsorption cross section of Mg is measured near the 3s threshold using this apparatus. The absolute photoabsorption cross section result at the 3s threshold, which is 2.1±0.3 Mb, is in good agreement with hook method data (2.36 Mb). © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1150494
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  • 5
    Electronic Resource
    Electronic Resource
    Error analysis of Rijnhuizen tokamak project Thomson scattering data (1999)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 70 (1999), S. 1999-2011 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: At the Rijnhuizen tokamak project a double pulse multiposition Thomson scattering diagnostic has been operational since 1996. It has been installed for the study of small scale structures in electron temperature (Te) and density (ne). This diagnostic measures Te and ne with high spatial resolution (3 mm full width at half maximum, i.e., 2% of the minor radius) and high accuracy (3%–4% of Te and 2%–3% of ne in the range of 50 eV–6 keV and ne=5×1019 m−3.) In this article an extensive error analysis is performed on both statistical and systematic deviations. It is found that the instrument function of the detection branch has a smoothing effect on the noise. This reduces the statistical error on the Te and ne measurements on each spatial position, because the resolution of the instrument is oversampled. The long tail of the instrument profile of the entire diagnostic has a significant effect on the systematic deviations in the Te and ne determination. However, it does not affect the relative size of the small scale structures on Te and ne, and for this this reason does not hamper the study of these structures. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1149702
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  • 6
    Electronic Resource
    Electronic Resource
    A high resolution multiposition Thomson scattering system for the Rijnhuizen Tokamak Project (1997)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 68 (1997), S. 3380-3392 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A high resolution multiposition Thomson scattering setup to measure the electron temperature (Te) and density (ne) of a hot plasma is described. The system is operational at the Rijnhuizen Tokamak Project. Light from a high power pulsed ruby laser is scattered by the free plasma electrons and relayed to a Littrow polychromator for spectral analysis. The spectrally and spatially resolved light is detected by a GaAsP photocathode. The two-dimensional image is intensified and recorded with a charge-coupled device camera.Te in the range of 50 eV–6 keV can be measured at 115 spatial elements of 2.6 mm length along the laser beam. The observation error is 〈6% at ne=2×1019 m−3 and smaller for higher ne. The high resolution and accuracy enabled the observation of small scale structures in Te and ne. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1148345
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  • 7
    Electronic Resource
    Electronic Resource
    Photon recycling system for multiposition tangential Thomson scattering : Proceedings of the tenth topical conference on high temperature plasma diagnostics (1995)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 66 (1995), S. 501-503 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Multiposition tangential Thomson scattering makes it possible to measure the profiles of the local drift velocity and current density of a tokamak plasma. To achieve a reasonably small observational error (20%) a high photon yield is required. In this paper we propose an optical system to increase the photon yield by about a factor of 7. Photons from a pulsed ruby laser are captured in a ring cavity by means of an electro-optical switch. The trapped laser beam recirculates about 14 times through the sampling volume which is part of the cavity, increasing the laser energy of 25 J to an effective energy of about 140 J. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1146330
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  • 8
    Electronic Resource
    Electronic Resource
    Double pulse Thomson scattering system at RTP : Proceedings of the eleventh topical conference on high temperature plasma diagnostics (1997)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 68 (1997), S. 721-724 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: In this article a double pulse multiposition Thomson scattering diagnostic, under construction at RTP, is discussed. Light from a double pulsed ruby laser (pulse separation: 10–800 μs, max. 2×12.5 J) is scattered by the free electrons of the tokamak plasma and relayed to a Littrow polychromator for spectral analysis. The spectrally resolved light is recorded by two ICCD detectors. Simulations show that the system sensitivity will be such that electron temperatures in the range of 100 eV–7 keV can be determined with an accuracy as good as 2%–3% for electron densities of 1020 m−3, with a spatial resolution down to 2.6 mm. With this diagnostic the dynamics of small scale structures in the electron temperature profile will be studied. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1147685
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  • 9
    Electronic Resource
    Electronic Resource
    Calibration procedure and data processing for a TV Thomson scattering system (2001)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 72 (2001), S. 3514-3527 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Calibration procedures for Thomson scattering systems based on television-like cameras, so-called TVTS systems, are described. The TVTS systems of the Rijnhuizen Tokamak Project (RTP), the TJ-II stellarator, and the Torus Experiment for Technology Oriented Research (TEXTOR) tokamak combine a 10–15 J ruby laser as a source with an intensified charge coupled device camera as a detector. A tungsten strip lamp in combination with an integrating sphere is used to calibrate all ∼105 pixels of the camera relatively to each other. Rayleigh scattering on hydrogen or nitrogen is used to perform an absolute calibration of the complete detection system. Great emphasis is placed on possible systematic errors on the determination of the electron temperature Te and density ne due to the calibration, such as tungsten lamp temperature, detoriation of the detection window, long term stability, laser beam alignment, and detector linearity. The long term stability of the system was tested by comparing different sets of calibration factors. Over a period of 1/2 yr the values of the calibration factors varied by less than 5%. Using the same Thomson scattering data but different sets of calibration factors the Te values varied even less than 1%. A two camera technique was used to search for possible unknown systematic errors in the determination of Te profiles. It appears that these systematic errors are about half of the observational error on Te. Density fluctuations can be determined with an accuracy equal to the statistical error of ∼3%, while the systematic error on ne appeared to be ∼10%, which can be corrected for using interferometer data. As a result, these TVTS systems can measure Te and ne profiles with ∼100 (RTP) or 120 (TEXTOR) spatial elements along the full plasma diameter with observational errors on Te of ∼6% in the range of 25 eV–6 keV, at ne=2×1019 m−3 and 10 J laser energy. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1386896
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  • 10
    Electronic Resource
    Electronic Resource
    Room-temperature optically pumped blue-green vertical cavity surface emitting laser (1995)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 67 (1995), S. 1668-1670 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Surface emitting laser operation at room temperature at λ=496 nm by ps pulsed optical injection has been demonstrated in a II–VI separate confinement heterostructure containing three 80 A(ring) thick (Zn,Cd)Se quantum wells (QW). The vertical cavity was formed by low loss, dielectric, distributed Bragg mirrors, yielding a quality factor for the structure of approximately Q≈2000. The room-temperature threshold excitation corresponds to an absorbed optical energy density of 1.4 μJ/cm2 or, equivalently, to an estimated electron-hole pair density of 1×1012 cm−2. At T=200 K, quasicontinuous wave operation was obtained at an average output power of up to 1 mW and an output/input conversion efficiency of 20%. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.115051
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