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  • 1
    Electronic Resource
    Electronic Resource
    Rarefied, superorbital flows in an expansion tube (2004)
    Bradford : Emerald
    International journal of numerical methods for heat & fluid flow 14 (2004), S. 512-537 
    Details
    ISSN: 0961-5539
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: This paper describes a free-piston driven expansion tube and its instrumentation. The facility is used to generate rarefied flows at speeds of approximately 10?km/s. Although the flow in the tube itself is in the continuum regime, rarefied flow conditions are achieved by allowing the test gas to further expand as a free jet into the facility's test section. The test flow is surveyed to provide bar-gauge pressure measurements. Numerical simulation is then used to describe more fully the test flow properties. The flows produced are suitable for the aerodynamic testing of small models at superorbital speeds and should provide data that are suitable for the calibration of Direct Simulation Monte-Carlo codes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1108/09615530410532277
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Studies of X-chromosome inactivation in trisomies
    Amsterdam : Elsevier
    Trends in Genetics 5 (1989), S. 364 
    Details
    ISSN: 0168-9525
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0168-9525(89)90160-1
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Properties of zeolites in relation to their electronegativity: Acidity, carboniogenic activity and strength of interaction in transition metal complexes
    Amsterdam : Elsevier
    Journal of Inorganic and Nuclear Chemistry 40 (1978), S. 1919-1923 
    Details
    ISSN: 0022-1902
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/0022-1902(78)80256-5
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Rapid prototyping with sloping surfaces (1997)
    Bingley : Emerald
    Rapid prototyping journal 3 (1997), S. 12-19 
    Details
    ISSN: 1355-2546
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: TruSurf is a new system for building solid objects from layers with sloping surfaces that closely match the designed surface shape. The advantages of using sloping surfaces over stepped edges are improved surface finish, and decreased build time through the use of thicker layers. TruSurf uses B-spline surfaces to describe the part, and calculate the sloped path of the layer cutting medium. Describes operation of the system in detail and presents results from the production of some test parts. Discusses some ways for improving accuracy, including using principal directions of minimum surface curvature, and using a curved cutting medium to produce layers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1108/13552549710169246
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  • 5
    Electronic Resource
    Electronic Resource
    Adaptive slicing with sloping layer surfaces (1997)
    Bingley : Emerald
    Rapid prototyping journal 3 (1997), S. 89-98 
    Details
    ISSN: 1355-2546
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Presents an adaptive slicing procedure for improving the geometric accuracy of layered manufacturing techniques which, unlike previous procedures, uses layers with sloping boundary surfaces that closely match the shape of the required surface. This greatly reduces the stair case effect which is characteristic of layered components with square edges. Considers two measures of error, and outlines a method of predicting these measures for sloping layer surfaces. To cater for different manufacturing requirements, presents a method to produce parts with either an inside or outside tolerance, or a combination of both. Finally, considers some problems associated with surface joins, vertices, and inflection points and proposes some solutions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1108/13552549710185662
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    Paper (German National Licenses)
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  • 6
    Electronic Resource
    Electronic Resource
    Seven ring (X) chromosomes lacking the XIST locus, six with an unexpectedly mild phenotype (2000)
    Springer
    Human genetics 〈Berlin〉 106 (2000), S. 93-100 
    Details
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Small ring (X) chromosomes lacking the XIST gene at Xq13.2 have been associated with a severe phenotype that includes mental retardation, facial dysmorphism and congenital abnormalities. It has been hypothesised that the loss of XIST results in functional disomy for the sequences contained in the ring. We studied 47 females with a 45,X/46,r(X) karyotype and found seven to have an XIST-negative ring. Only one of the seven patients had the severe phenotype. The remaining six patients had physical phenotypes consistent with Turner syndrome. The rings were characterised cytogenetically and molecularly. The severe phenotype in one patient can be explained by the absence of XIST expression, the relatively large amount of Xp material in the ring and, possibly, the concomitant maternal uniparental isodisomy. We propose three explanations for the unexpectedly mild phenotypes in the remaining six patients; (1) the rings contained limited amounts of X-chromosome material, and sequences that, when functionally disomic, result in a severe phenotype were absent; (2) mosaicism resulting in the absence of the ring from tissues, such as the brain, which are important in the severe phenotype and (3) the presence of an inactive X in some tissues at some time, exemplified by the demonstration of XIST expression in one patient.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004399900221
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    Paper (German National Licenses)
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  • 7
    Electronic Resource
    Electronic Resource
    A compact shock-assisted free-piston driver for impulse facilities (1997)
    Springer
    Shock waves 7 (1997), S. 219-230 
    Details
    ISSN: 1432-2153
    Keywords: Key words: Free-piston driver, Impulse facility, Shock waves, Heat transfer, Hypervelocity flow
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics , Technology
    Notes: Abstract. A free-piston driver that employs entropy-raising shock processes with diaphragm rupture has been constructed, which promises significant theoretical advantages over isentropic compression. Results from a range of conditions with helium and argon driver gases are reported. Significant performance gains were achieved in some test cases. Heat losses are shown to have a strong effect on driver processes. Measurements compare well with predictions from a quasi-one-dimensional numerical code.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001930050078
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    Paper (German National Licenses)
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  • 8
    Electronic Resource
    Electronic Resource
    The numerical and experimental simulation of hypervelocity flow around the HYFLEX vehicle forebody (1999)
    Springer
    Shock waves 9 (1999), S. 57-67 
    Details
    ISSN: 1432-2153
    Keywords: Key words:Computational fluid dynamics, Shock tunnel, Blunt body, Hypersonic flow, Re-entry vehicle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics , Technology
    Notes: Abstract. Numerical and experimental techniques are used to model the flow and pressure distribution around the forebody of the HYFLEX hypersonic flight vehicle. We compare numerical simulation results with modified Newtonian theory and flight data to determine the accuracy of the computational fluid dynamics (CFD) technique used. The numerical simulations closely match the trends in flight data, and show that real gas effects have a small but significant influence on the nose pressure distribution. We also present pressure results from a scale-model tested in a shock tunnel, and compare them with simulation results. For the shock tunnel experiment, the model was placed such that part of the upper surface was in a region of the test flow where nonuniformities were significant, and it was shown that the numerical simulation could adequately capture these experimental flow features. The binary scaling parameter (describing the similarity in species dissociation between flight and model) was used to design the scale-model tests in the shock tunnel, and its effectiveness is discussed. We find that matching the flight Mach number in the shock tunnel experiment is not critical for reproducing flight pressure data, so long as flight velocity is matched, and binary scaling is maintained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001930050139
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    Paper (German National Licenses)
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  • 9
    Electronic Resource
    Electronic Resource
    A computational study of shock speeds in high-performance shock tubes (1998)
    Springer
    Shock waves 8 (1998), S. 79-91 
    Details
    ISSN: 1432-2153
    Keywords: Key words:Unstructured-grids, Solution-adaptive remeshing, Numerical dissipation, Shock speeds, Shock tubes flow
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics , Technology
    Notes: Abstract. This paper describes U2DE, a finite-volume code that numerically solves the Euler equations. The code was used to perform multi-dimensional simulations of the gradual opening of a primary diaphragm in a shock tube. From the simulations, the speed of the developing shock wave was recorded and compared with other estimates. The ability of U2DE to compute shock speed was confirmed by comparing numerical results with the analytic solution for an ideal shock tube. For high initial pressure ratios across the diaphragm, previous experiments have shown that the measured shock speed can exceed the shock speed predicted by one-dimensional models. The shock speeds computed with the present multi-dimensional simulation were higher than those estimated by previous one-dimensional models and, thus, were closer to the experimental measurements. This indicates that multi-dimensional flow effects were partly responsible for the relatively high shock speeds measured in the experiments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001930050101
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    Paper (German National Licenses)
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  • 10
    Electronic Resource
    Electronic Resource
    Novel catalytic membranes for selective reactions (1998)
    Springer
    Topics in catalysis 5 (1998), S. 125-132 
    Details
    ISSN: 1572-9028
    Keywords: transition metal complexes ; chiral catalysts ; Ti-containing zeolites ; polymers ; PDMS ; catalytic membrane reactor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A survey is given of the potentials of a new kind of catalytic membranes consisting of a catalyst that is immobilised in a dense polymer matrix. When homogeneous, catalytically active complexes are occluded, these membranes constitute a new way of heterogenation. In the case of solid state catalysts, these composite membranes can improve the activity of the catalyst by changing sorption or by allowing experimental set-ups in which solvents become redundant.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1019181431719
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    Paper (German National Licenses)
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