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  • 1
    Electronic Resource
    Electronic Resource
    Vortex dynamics in oscillatory chemical systems (1991)
    Woodbury, NY : American Institute of Physics (AIP)
    Chaos 1 (1991), S. 421-434 
    Details
    ISSN: 1089-7682
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Vortex core dynamics is studied in the Brusselator both near to and far from the Hopf bifurcation line for random and pair initial conditions. Extensive simulations are carried out for a pair of counter-rotating vortices close to the Hopf bifurcation line. Provided the vortices are not so far apart that wave-front annihilation produces strong gradients between their centers, the simulation results compare favorably with theories based on the complex Ginzburg–Landau equation. Far from the Hopf line the vortex core dynamics changes character and phenomena such as periodic motion of the vortex centers arise.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.165852
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  • 2
    Electronic Resource
    Electronic Resource
    Molecular cloning of the ViaB region of Salmonella typhi (1991)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 90 (1991), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract The ViaB region required for Vi antigen production in Salmonella typhi was cloned. The plasmid pGBM124 containing a 14-kb S. thypi chromosomal DNA fragment conferred the ability to produce Vi antigen on Escherichia coli HB101 and ViaB-deleted S. typhi GIFU10007-3. Tn5 insertion analysis showed that the 14-kb DNA was split into three regions. Region 1 and region 2 are involved in the biosynthesis of Vi polysaccharide. Region 3 is involved in translocation of the Vi polysaccharide to the cell surface. Southern blot hybridization showed that regions 2 and 3 but not region 1, were considerably homologous to the DNA of Vi-positive Citrobacter freundii.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6968.1991.tb05124.x
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  • 3
    Electronic Resource
    Electronic Resource
    Effect of Deep Cryogenic Treatment on Carbide Precipitation and Mechanical Properties of Tool Steel (2006)
    s.l. ; Stafa-Zurich, Switzerland
    Solid state phenomena Vol. 118 (Dec. 2006), p. 9-14 
    Details
    ISSN: 1662-9779
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Physics
    Notes: It is well known that the durability of tool steel could be improved by deep cryogenictreatment. It has been assumed that the increase of service life of tool steel caused by decrease ofretained austenite and/or by formation of nano-scale fine η-carbide. But the principles of deepcryogenic treatment remain unclear yet. In this research, to manifest the effect of deep cryogenictreatment on wear resistance, the specimen was emerged in liquid nitrogen for 20 hours for deepcryogenic treatment after austenitizing and the following tempering temperature was varied. Themicrostructure of specimens was observed using TEM and the mechanical properties and wearresistance were examined. As the tempering temperature increased, the carbides became larger andfine carbides were formed above certain temperature. In the case of deep cryogenic treatedspecimen, the number of carbides increased while the carbides size was decreased, furthermore, thefine carbide forming temperature was lowered also. It was considered that the deep cryogenictreatment increased the driving force for the nucleation of carbides. As tempering temperatureincreased, hardness decreased while wear resistance and impact energy increased. The deepcryogenic treated specimens showed this tendency more clearly. It was considered that the wearresistance is affected not only to the hardness but also to the precipitation of fine carbides, and thiscarbide evolution can be optimized through the deep cryogenic treatment
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/22/transtech_doi~10.4028%252Fwww.scientific.net%252FSSP.118.9.pdf
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  • 4
    Electronic Resource
    Electronic Resource
    An Investigation of the Melt-Out and Heat Checking Phenomena in Surface Modified Hot Die Steel for Aluminum Die Casting (2006)
    s.l. ; Stafa-Zurich, Switzerland
    Solid state phenomena Vol. 118 (Dec. 2006), p. 443-450 
    Details
    ISSN: 1662-9779
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Physics
    Notes: For hot die steel, failure is mostly caused by heat checking and melt-out on its surfaceswhich are in contact with molten metals. In the present research, resistances to melt-out and heatchecking of surface modified H13 hot die steels, such as gas nitriding(GN) andmicro-blasting(MB), were investigated. The evaluation of melt-out behavior was carried out bymeasuring the mean depth from the original surface after immersion. To examine the thermalfatigue resistance, a cyclic thermal shock system consisting of induction heating and water sprayquenching was constructed. The value of Lm is proposed as the index representing the susceptibilityto crack initiation and propagation. The melt-out depth was the lowest for the GN treated surface.MB-GN and MB-GN-MB treated specimens also showed good resistance to melt-out. In the case ofGN treatment, while the white layer was completely melted out, the diffusion layer still existedeven after immersion for 43 hours. This implies that nitriding significantly reduced the rate ofmelt-out. From the total crack number, it is seen that crack initiation was reduced to the extent ofhalf after surface treatment. This result means that the residual compressive stress and nitrided layerwere beneficial to crack initiation resistance
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/23/transtech_doi~10.4028%252Fwww.scientific.net%252FSSP.118.443.pdf
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  • 5
    Electronic Resource
    Electronic Resource
    Effect of Surface Condition on Melt-Out of Die-Casting Mould (2006)
    s.l. ; Stafa-Zurich, Switzerland
    Solid state phenomena Vol. 118 (Dec. 2006), p. 509-514 
    Details
    ISSN: 1662-9779
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Physics
    Notes: In order to understand the melt-out mechanism of H13 die casting mould material,microstructural investigation was conducted for the immersion-tested surface in Al-alloy melt. Thesurface condition of H13 tool steel was modified by varying nitriding conditions and by surfaceblasting. In particular, long-term behavior of melt-out phenomena during immersion testing of up to43 hours was focused in this article. It was observed that an ion-nitrided H13 surface showed higherresistance towards melt-out than a gas-nitrided or blasted surface. This was related to the surfacelayers that are normally formed by nitriding
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/23/transtech_doi~10.4028%252Fwww.scientific.net%252FSSP.118.509.pdf
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  • 6
    Electronic Resource
    Electronic Resource
    A finite volume technique to simulate the flow of a viscoelastic fluid (1991)
    Springer
    Computational mechanics 8 (1991), S. 43-55 
    Details
    ISSN: 1432-0924
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Hydrodynamically developing flow of Oldroyd B fluid in the planar die entrance region has been investigated numerically using SIMPLER algorithm in a non-uniform staggered grid system. It has been shown that for constant values of the Reynolds number, the entrance length increases as the Weissenberg number increases. For small Reynolds number flows the center line velocity distribution exhibit overshoot near the inlet, which seems to be related to the occurrence of numerical breakdown at small values of the limiting Weissenberg number than those for large Reynolds number flows. The distributions of the first normal stress difference display clearly the development of the flow characteristics from extensional flow to shear flow.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00370547
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  • 7
    Electronic Resource
    Electronic Resource
    Effect of ampicillin on mefloquine pharmacokinetics in thai males (1991)
    Springer
    European journal of clinical pharmacology 40 (1991), S. 631-633 
    Details
    ISSN: 1432-1041
    Keywords: Mefloquine ; ampicillin ; Thai subjects ; pharmacokinetics ; enterohepatic recycling ; drug interaction ; adverse effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The kinetics of a single oral dose of mefloquine given either alone or with ampicillin has been studied in 8 healthy Thai male volunteers. There was a significantly higher maximum whole blood mefloquine concentration after coadministration with ampicillin (1648 vs 1228 ng·ml−1), as well as a significantly reduced terminal half life (15.3 vs 17.7 days), mean residence time (20.1 vs 23.4 days) and volume of distribution at steady state (14.1 vs 19.4 l·kg−1). Although there was no significant change in the AUC from zero time to infinity, the AUC from zero time to 5 days was significantly increased by ampicillin (4.86 vs 3.27 μg·ml−1 day). These changes in mefloquine disposition after antibiotic treatment may be due both to an increase in fractional bioavailability and a reduction in the enterohepatic recycling of mefloquine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00279985
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  • 8
    Electronic Resource
    Electronic Resource
    Nephrotoxicity of sodium dichromate depending on the route of administration (1991)
    Springer
    Archives of toxicology 65 (1991), S. 537-541 
    Details
    ISSN: 1432-0738
    Keywords: Sodium dichromate ; Nephrotoxicity ; Hepatotoxicity ; Lipid peroxidation ; Phenobarbital
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A comparison of the effects of intraperitoneal and subcutaneous routes of administration of sodium dichromate on nephrotoxicity in rats was studied. Dichromate when injected subcutaneously (SC group) produced a higher degree of nephrotoxicity than when administered intraperitoneally (IP group). It caused severe progressive proteinuria followed by polyuria and glucosuria, reaching maximum levels at 3 days after treatment in the SC group, whereas it produced mild proteinuria without glucosuria in the IP group. The dose-dependent increases in blood urea nitrogen (BUN) and creatinine concentrations, shown in the SC group, were not observed in the IP group. However, between the two groups, there were no great differences in either the urinary excretion rate of chromium or the electrophoretic patterns of urinary protein in the day 1 urine specimens. Pretreatment of phenobarbital (PB) had no remarkable effect on the dichromate-induced nephrotoxicity. In contrast, it potentiated dichromate-induced hepatotoxicity, the indices of which were the elevation in serum alanine aminotransferase (ALT) activity and hepatic lipid peroxide formation. These results suggest that the dependence of dichromate-induced nephrotoxicity on the route of administration is related to the chemical forms of chromium reaching the kidney, and the necrotizing property of dichromate results from its metabolic fate in vivo.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01973713
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  • 9
    Electronic Resource
    Electronic Resource
    Study on Evaluation of AE Signals at Weld Region of SA 516 Steel (2006)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 321-323 (Oct. 2006), p. 1729-1732 
    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: The purpose of this study is to find out the method to detect AE signals at around thenotch tip and to evaluate the AE signal characteristics for the basemetal, PWHT(post weld heattreatment) and weldment specimens of SA-516 steel during bend test. AE signals were produced inthe process of plastic deformation. AE signal strength and amplitude of the weldment was thestrongest, followed by PWHT specimen and basemetal. More AE signals were produced from theweldment because of the oxides, and discontinuous mechanical properties. The stronger AE signalstrength, amplitude and more AE event counts for the weldment were shown
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/52/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.321-323.1729.pdf
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  • 10
    Electronic Resource
    Electronic Resource
    Effect of Surface Treatment on the Life of AISI H13 Steel Core Pin for Die-Casting (2006)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 326-328 (Dec. 2006), p. 1181-1184 
    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: The Effect of die surface modification on the physiochemical melt-out phenomenon wasinvestigated. To measure the melt-out resistance more accurately, the mean depth measurementmethod after immersion in molten Al-alloy was proposed instead of the conventional weight changemethod. The validity of the mean depth method was verified by the comparison with the fieldservice test of core-pin. The several kind of nitriding, such as gas nitriding, ion nitriding, salt-bathnitriding and TNHT[removed info] process of PHILOS TECHNOLOGIES, INC were employed to changesurface condition and their effects on melt out resistance were examined by the immersion test andthe field service test of core pins. The melt-out depth was decreased with the nitriding treatmentsand in case of ion-nitrided specimen showed 2.8 times lower dissolution depth than as heat treatedspecimen. The white compound layer play a important role in the prevention of physiochemicalreaction, therefore, the TNHT process, which does not form the white layer, was less effective inthe view point of melt-out phenomenon only. The field test result using core-pins for producingautomobile engine parts showed similar tendency with the mean depth method and this implies thatthe mean depth method reflects the melt-out resistance of the modified surfaces effectively
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/52/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.326-328.1181.pdf
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