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Calculations Shows (calculation + shows)
Selected AbstractsSynthesis of Novel Nickel Sulfide Submicrometer Hollow Spheres,ADVANCED MATERIALS, Issue 9 2003Y. Hu Nickel sulfide uniform hollow spheres (see scanning electron microscopy image, Figure) have been successfully synthesized by ,-irradiation of a PMMA,CS2,ethanol aqueous solution that contains NiSO4·6H2O at room temperature. Calculation shows that the diameter of the NiS hollow spheres is 500 nm and the thickness of shell is ,,20 nm. A possible growth mechanism is also presented. [source] ECCD Experiments Using the Upgraded Launching System in Heliotron JCONTRIBUTIONS TO PLASMA PHYSICS, Issue 6-7 2010K. Nagasaki Abstract Electron cyclotron current drive (ECCD) experiments have been made in Heliotron J by using an upgraded EC launching system. A focused Gaussian beam is injected with the parallel refractive index, N||, ranging from -0.05 to 0.6. Ray tracing calculation shows that the EC power is more localized than that in the previous launching system. In the initial ECCD experiment, the EC injection angle has been successfully scanned as designed. Comparison between perpendicular and oblique launching experiments shows that for standard configuration, the EC current of 1 kA is driven at N|| , 0.3 in the Fisch-Boozer direction, and the bootstrap current flows up to 1 kA. A large increase in electron cyclotron emission (ECE) signals has been observed when the EC current was driven (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] A theoretical study on fullerene-dizincocene hybridsJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 6 2009Guohua Gao Abstract Using the density functional theory, we investigated the possible formation of fullerene-dizincocene hybrids, specifically C60*-Zn-Zn-Cp*, C60*-Zn-Zn-C60*, C70*-Zn-Zn-Cp*, and C70*-Zn-Zn-C70*, where C60*, Cp*, and C70* represent C60(CH3)5, C5(CH3)5, and C70(CH3)5 radicals. Our calculation shows that these hybrids have HOMO-LUMO gaps which are larger than has been experimentally identified for C60*-Fe-Cp. In addition, the strength of the ZnZn bonds is similar to that in Cp*-Zn-Zn-Cp* which was also synthesized recently. Furthermore, heterohybrids, C60*-Zn-Zn-Cp* and C70*-Zn-Zn-Cp* are expected to exist in equilibria with homohybrids, C60*-Zn-Zn-C60* and C70*-Zn-Zn-C70*, in which heterohybrids are much more favored. On the other hand, another hybrid involving Sc3N@C68 as a fullerene unit is not highly probable. © 2008 Wiley Periodicals, Inc. J Comput Chem, 2009 [source] 3-D Inviscid Transonic Condensing Flow around a Swept WingPROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2003K.A. Goodheart Transonic condensing flow is an interesting phenomena because of the large change in temperature over a small area. This drop in temperature allows the moist air to condense. It is the purpose of this paper to examine the effect of sweep on condensing flow. The geometry of the wing model starts with NACA-0014 at the wall and reduces to a NACA-0010 at the tip. The span of the wing is 2.5 times the maximum chord length. The effect of sweep is examined by comparing a model wing with a sweep angle of 11.3 with a straight trailing edge that has no thickness and then a straight leading edge with a 11.3 trailing edge sweep. The free stream Mach number is 0.8 and angle of attack is 0. A 2-D calculation shows that the NACA-0014 and NACA-0010 have a region of supersonic flow but due to the effect of sweep the sonic line does not extend to the tip. This change of the supersonic region influences the area of condensation on the wing. The swept wing has a lower total drag coefficient for the adiabatic and all condensation cases compared to the straight leading edge wing and second for the each wing the trend of increasing drag with humidity is shown. [source] 3D Architecture and Load Partition in Eutectic Al-Si Alloys,ADVANCED ENGINEERING MATERIALS, Issue 12 2009Guillermo Requena Abstract The changes of the three dimensional architecture of a eutectic AlSi12 alloy during heat treatment are revealed by means of synchrotron holotomography. The non-destructive nature of the holotomography technique allows to analyze the same volumes in different thermal conditions. The results show a disintegration of the interconnected eutectic Si-lamellae into isolated elongated particles. The load carrying capacity of both types of Si morphologies is studied by in situ neutron diffraction during compression tests. The experimental results are compared to those obtained using a micromechanical model developed for metal matrix composites based on a homogenization approach. The correlation between experiments and calculations shows that the interconnectivity of Si must be considered to account for the strength exhibited by the eutectic alloy. The present study bridges the gap between the already available two-dimensional studies of architecture and properties of the binary AlSi12 alloy and new three-dimensional studies of more complex systems based on this alloy. [source] The effects of inhomogeneous isotope distribution on the vibrational properties of isotope enriched double walled carbon nanotubesPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 11 2007V. Zólyomi Abstract The radial breathing mode in the Raman spectrum of 13C isotope enriched single walled carbon nanotubes is inhomogeneously broadened due to the random distribution of isotopes. We study this effect theoretically using density functional theory within the local density approximation and compare the result with experiments on isotope engineered double walled carbon nanotubes in which the inner tubes were grown from a mixture of 13C enriched fullerenes and natural fullerenes. As explained by the calculations, this synthesis procedure leads to an increased inhomogeneity compared to a case when only enriched fullerenes are used. The good agreement between the measurements and calculations shows the absence of carbon diffusion along the tube axis during inner tube growth, and presents a strong support of the theory that inner tube growth is governed by Stone,Wales transformations following the interconnection of fullerenes. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Polymorphism in the nitrate salt of the [Mn(acetylacetonate)2(H2O)2]+ ionACTA CRYSTALLOGRAPHICA SECTION B, Issue 3 2010A. R. Biju The crystallization of [Mn(acac)2(H2O)2]+ from solutions containing excess nitrate leads to the formation of four polymorphs. All polymorphs contain two different types of complex ions, one containing essentially coplanar acac ligands and the other in which the two acac ligands together assume a chair conformation. Molecular modelling using DFT (density-functional theory) calculations shows that the coplanar conformation is the electronically stable one. The hydrogen bonding between the trans -water molecules and the nitrate ion produces a one-dimensional chain of 12-membered rings, which are further organized into a two-dimensional network via a lattice water molecule. Lattice-energy calculations have been carried out to compare the stabilities of the four polymorphs. [source] Dimensionierung von Vakuumwasserhaltungen im tertiären FeinsandBAUTECHNIK, Issue 7 2004Peter-Michael Mayer Dr.-Ing. Der Entwurf umfangreicher Vakuumwasserhaltungen ist aufgrund fehlender allgemeingültiger analytischer Berechnungsverfahren bisher auf Abschätzungen und Erfahrungen angewiesen. Vorliegende Untersuchungen zeigen exemplarisch für eine 80 m lange und 37 m breite Spundwandbaugrube im tertiären Feinsand, wie mittels räumlicher Finite-Element-Modelle die erforderliche Anzahl und Tiefe von Vakuumtiefbrunnen zur Grundwasserabsenkung berechnet werden kann. Die Auswirkungen von Schichtanisotropien bzw. lokaler Bereiche mit hoher Durchlässigkeit auf das erreichte Absenkziel und die geförderten Pumpmengen werden aufgezeigt. Darüberhinaus wird auch der Wasserdruck auf die Spundwand analysiert. Die Bedeutung zeitabhängiger Strömungsberechnungen wird durch die Verbindung von Aushub und Wasserhaltung deutlich und kann durch instationäre Betrachtungen erfaßt werden. Der Vergleich von in-situ-Messungen und Berechnungsergebnissen zeigt die Leistungsfähigkeit, aber auch die Grenzen numerischer Strömungsmodelle bei der Abschätzung des Ausführungsrisikos und möglicher wirtschaftlicher Optimierungen. Dimensioning of vacuum dewaterings in tertiary fine sand. Because of outstanding valid analytical solutions, the study of extensive dewatering depends actually only on estimations and experiences. This paper show, for a 80 m long and 37 m large excavation in fine sand, how to calculate the requested number and depth of vacuum deep well for the lowering of the groundwater level by Finite-Element-Models. The effects of anisotropic layer and layer with local ranges with high porosity for the achieved lowering and pumping capacity have been showed. Additionally the water pressure on sheet pile wall was also analyzed. The significance of transient flow calculations becomes clearly by the connection of excavation and dewatering. The comparison of in-situ measurements and results of calculations shows the performance but also the limits of the numerical flow models on the estimation of the execution risks and possible improvement on dewatering process. [source] | |||||||||||||||||||