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  • 1
    Electronic Resource
    Electronic Resource
    Dynamic wall modeling for large-eddy simulation of complex turbulent flows (2002)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 14 (2002), S. 2043-2051 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The efficacy of large-eddy simulation (LES) with wall modeling for complex turbulent flows is assessed by considering turbulent boundary-layer flows past an asymmetric trailing-edge. Wall models based on turbulent boundary-layer equations and their simpler variants are employed to compute the instantaneous wall shear stress, which is used as approximate boundary conditions for the LES. It is demonstrated that, as first noted by Cabot and Moin [Flow Turb. Combust. 63, 269 (2000)], when a Reynolds-averaged Navier–Stokes type eddy viscosity is used in the wall-layer equations with nonlinear convective terms, its value must be reduced to account for only the unresolved part of the Reynolds stress. A dynamically adjusted mixing-length eddy viscosity is used in the turbulent boundary-layer equation model, which is shown to be considerably more accurate than the simpler wall models based on the instantaneous log law. This method predicts low-order velocity statistics in good agreement with those from the full LES with resolved wall-layers, at a small fraction of the original computational cost. In particular, the unsteady separation near the trailing-edge is captured correctly, and the prediction of surface pressure fluctuations also shows promise. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1476668
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  • 2
    Electronic Resource
    Electronic Resource
    COMPUTATIONAL PREDICTION OF FLOW-GENERATED SOUND (2006)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Fluid Mechanics 38 (2006), S. 483-512 
    Details
    ISSN: 0066-4189
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: This article provides a critical review of computational techniques for flow-noise prediction and the underlying theories. Hybrid approaches, in which the turbulent noise source field is computed and/or modeled separately from the far-field calculation, are afforded particular attention. Numerical methods and modern flow simulation techniques are discussed in terms of their suitability and accuracy for flow-noise calculations. Other topics highlighted include some important formulation and computational issues in the application of aeroacoustic theories, generalized acoustic analogies with better accounts of flow-sound interaction, and recent computational investigations of noise-control strategies. The review ends with an analysis of major challenges and key areas for improvement in order to advance the state of the art of computational aeroacoustics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1146/annurev.fluid.38.050304.092036
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  • 3
    Electronic Resource
    Electronic Resource
    Statics and dynamics of a single polymer chain confined in a tube (2001)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 114 (2001), S. 4724-4729 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The static and nonequilibrium dynamic properties of a single linear chain confined in a cylindrical tube are studied by Monte Carlo simulations using a continuous model and by scaling calculations. Chain lengths from N=30 to 150 are considered. For the static results, our simulation data are consistent with the scaling law proposed by de Gennes. That is, for thin tube, the length of tube occupied by the chain scales as R(parallel)∼ND−2/3 where D is the diameter of the tube. The nonequilibrium relaxation behavior of the chain, after the constraint is removed, is also studied. The relaxation time τ(parallel) is derived by scaling analysis as τ(parallel)∼N2D1/3. This result is compared with our Monte Carlo data and is discussed in the light of scaling theories. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1345879
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  • 4
    Electronic Resource
    Electronic Resource
    High-throughput oncogene mutation profiling in human cancer (2007)
    [s.l.] : Nature Publishing Group
    Nature genetics 39 (2007), S. 347-351 
    Details
    ISSN: 1546-1718
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Medicine
    Notes: [Auszug] Systematic efforts are underway to decipher the genetic changes associated with tumor initiation and progression. However, widespread clinical application of this information is hampered by an inability to identify critical genetic events across the spectrum of human tumors with adequate ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/ng1975
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  • 5
    Electronic Resource
    Electronic Resource
    The Design of Novel Scaffolds by Integrating Microbial Cellulose onto Plasma Treated Polypropylene (2008)
    s.l. ; Stafa-Zurich, Switzerland
    Advanced materials research Vol. 47-50 (June 2008), p. 1371-1374 
    Details
    ISSN: 1662-8985
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The effect of plasma treatment on physicochemical properties of a porous polypropylene(PP) membrane was studied. The treated porous membranes were used as substrates for Acetobacterxylinum to grow and produce microbial cellulose pellicle. The effects of modifications onwettability and morphology were correlated with the growth rate of microbial cellulose. The CO2,O2 and N2/H2 plasmas modification not only can increase the hydrophilicity of the membrane butalso enhance the growth of microbial cellulose. For 14 days of cultivation, the amount of microbialcellulose found on O2 treated substrate was approximately 2 folds of that on the untreatedmembranes
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/41/transtech_doi~10.4028%252Fwww.scientific.net%252FAMR.47-50.1371.pdf
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  • 6
    Electronic Resource
    Electronic Resource
    Plasma Polymerized Thin-Films for Biosensors (2008)
    s.l. ; Stafa-Zurich, Switzerland
    Advanced materials research Vol. 47-50 (June 2008), p. 1367-1370 
    Details
    ISSN: 1662-8985
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Plasma polymerization is an effective method to directly deposit ultra-thin film onsubstrates with advantageous properties such as good adhesion and biocompatibility. In this paper,the monomers containing amine groups with various unsaturated structures (propylamine,allylamine) are chosen to provide amine functionalities and to promote biocompatibilities for thepolymerized thin films. The deposition rates revealed by measuring the thickness of thin films arecharacterized by profilometer under various plasma conditions. FTIR and AFM are used to studythe chemical structures and morphology of the deposited thin films. In order to examine theapplicability of the deposited polymers for biosensors, the activities of the incorporatedbiomolecules on deposited thin films are analyzed. Chinese hamster ovary (CHO) cells arecultivated on the polymerized thin films. Both propylamine and allylamine polymerized thin filmsshow enhanced cell viability than on glass slide substrates
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/41/transtech_doi~10.4028%252Fwww.scientific.net%252FAMR.47-50.1367.pdf
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  • 7
    Electronic Resource
    Electronic Resource
    In Situ Observation of SSM Microstructure Formation during Cooling Slope Casting of an NH〈sub〉4〈/sub〉Cl-H〈sub〉2〈/sub〉O Alloy with Vibrating the Slope (2006)
    s.l. ; Stafa-Zurich, Switzerland
    Solid state phenomena Vol. 116-117 (Oct. 2006), p. 193-196 
    Details
    ISSN: 1662-9779
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Physics
    Notes: Vibrating the slope during cooling slope casting of a metallic alloy has shown helpful forcausing the microstructure more spherical and thinner in a previous research by the present authors.This paper gives results from a direct observation of the SSM microstructure formation duringcooling slope casting of an NH4Cl-H2O alloy with vibrating the slope. It is found that the vibrationexerted to the slope can break down the solidification shell formed at the surface of the slopethrough rapid chilling and produce effectively fine globular grains in the microstructures. The mainfactors affecting the fine grain formation include the chilling extent, frequency and amplitude of thevibration of the slope, and the superheat of the alloy melt, respectively. The higher vibrationfrequency and amplitude, the lower superheat of the alloy melt, and the lower chilling temperaturewill help the formation of finer globular grains
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/22/transtech_doi~10.4028%252Fwww.scientific.net%252FSSP.116-117.193.pdf
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  • 8
    Electronic Resource
    Electronic Resource
    Microstructure Evolution of a Zn-4wt.% Cu Hyperperitectic Alloy under Laser Surface Remelting (2005)
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 475-479 (Jan. 2005), p. 2611-2614 
    Details
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Laser surface remelting experiments on Zn-4.0wt.%Cu hyperperitectic alloy have been performed on a 5kW CW CO2 laser with the scanning velocities between 6 and 1207mm/s. Microstructures in both longitudinal and transverse section of the molten pools have been analyzed by optical microscope and SEM technique, and the average composition in the molten pools has been measured by Electron Probe Microanalysis(EPMA). With the increasing of growth rate, the microstructures of Zn-4.0 wt.%Cu alloy change from planar interface to lamellar structures and thencellular structures, and finally to absolute stability planar interface at a growth rate of 562mm/s, which shows reasonable agreement with that predicted by M-S theory
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/09/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.475-479.2611.pdf
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  • 9
    Electronic Resource
    Electronic Resource
    Research on Molten Pool Shape during Laser Rapid Forming through the Close-Range Continuous Photography (2005)
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 475-479 (Jan. 2005), p. 2615-2618 
    Details
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Laser Rapid Forming (LRF) is a new and advanced manufacture technology toaccomplish near net shape metal components with high performance for use in the aerospace, defense and chemical processing industries. In this paper the close-range continuous photography is used to take side views on the cladding zone in order to disclose inherent characteristic of the laser rapid forming process. The vivid molten pool shape is obtained by adopting image partition technology since the not molten area is eliminated from the photos. It is found that the molten pool size depended essentially on the LRF process parameters. With introducing the metal powders into the focus spot of the laser beam, the molten pool retains a segment arc raised outward and the molten pool free surface inclines to the axis of laser beam. Further results show that the molten pool inclination plays an important role on the microstructure of the LRF components
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/09/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.475-479.2615.pdf
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  • 10
    Electronic Resource
    Electronic Resource
    Low Temperature Explosion for Nanometer Active Materials (2006)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 324-325 (Nov. 2006), p. 193-196 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: This paper describes a new method for prediction of the Chapman–Jouguet detonationparameters of CaHbNcOdLieMnf explosives for mixture of some of low temperature explosionexplosives at [removed info]0 = 1000 kg/m3. Explosion temperatures of water-gel explosives and explosiveformulations are predicted using thermochemistry information. The methodology assumes that theheat of detonation of an explosive compound of products compositionH2O–CO2–CO–Li2O–MnO2–Mn2O3 can be approximated as the difference between the heats offormation of the detonation products and that of the explosive, divided by the formula weight of theexplosive. For the calculations in which the first set of decomposition products is assumed,predicted temperatures of explosion of water-gel explosives with the product H2O in the gas phasehave a deviation of 153.29 K from results with the product H2O in the liquid state. Lithium andmanganese oxides have been prepared by the explosion of water-gel explosives of the metal nitrates,M (NO3) x (M = Li, Mn) as oxidizers and glycol as fuels, at relative low temperature. We have alsoused the Dulong-Petit’s values of the specific heat for liquid phase H2O. Lithium manganese oxidepowders with chrysanthemum-like morphology secondary particles, but with smaller primaryparticles of diameters from 5 to 30 nm and a variety of morphologies were found. The oxidesproduced by this cheap method affirmed the validity of explosion synthesis of nano-size materialsfor lithium ion batteries
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/52/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.324-325.193.pdf
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