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  • 1
    Publication Date: 2003-08-01
    Print ISSN: 1420-682X
    Electronic ISSN: 1420-9071
    Topics: Biology , Medicine
    Published by Springer
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Heat and mass transfer 29 (1994), S. 463-470 
    ISSN: 1432-1181
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Description / Table of Contents: Zusammenfassung Es werden drei verschiedene Methoden herangezogen, um die Erfüllung der Ausflußbedingung bei der Berechnung des konvektiven Wärmeübergangs von einem zweidimensionalen Fluidstrahl an die Wände eines rechteckigen Hohlraumes zu erzwingen. Diese seien kurz bezeichnet als: (1) lokales Massenerhaltungsprinzip, (2) Einkomponentenprinzip, (3) Vollausbildung des Strömungsprofils. Unter Verwendung dieser drei Prinzipien ermittelte numerische Lösungen wurden mit experimentell (Naphtalin-Sublimationsmethode) gefundenen Ergebnissen verglichen. Es zeigte sich, daß Methode (3) ungeeignet ist, Methode (2) gute Ergebnisse für den Hohlraumboden liefert, aber an den Seitenwänden qualitativ von den Versuchsdaten abweicht und daß Methode (1) die beste Übereinstimmung bewirkt. Bei Problemen, welche starke Rezirkulationsströmungen am Austritt des zur Berechnung vorgegebenen Kontrollraumes erwarten lassen, sollte daher dieser Methode der Vorzug gegeben werden.
    Notes: Abstract Three practices of treating outflow boundary condition were adopted in computations for convective heat transfer of a two-dimensional jet impinging in a rectangular cavity. The three practices were local mass conservation method, local one-way method and fully developed assumption. The numerical solutions of the three methods were compared with test data obtained via, naphthalene sublimation technique. It was found that the fully developed assumption was inappropriate, and the local one-way method could provide reasonably good results for the cavity bottom, while for the lateral wall the results with this method qualitatively differed from the test data. The solution with the local mass conservation method was the best. It thus suggested that for a problem expected with a strong recirculating flow at the exit of the computation domain, the local mass conservation method be adopted to treat the outflow boundary condition.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 4 (1993), S. 127-131 
    ISSN: 1573-4838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: It has been proposed that a hydrated silica plays an important role in forming a biologically active apatite layer on the surfaces of bioactive glasses and glass-ceramics in the body. Recent experiments have shown that a silica hydrogel actually induces apatite formation on its surface in a simulated body fluid (SBF). In the present study the process of apatite formation on silica gel was investigated by means of thin-film X-ray diffraction, Fourier-transformed infrared reflection spectroscopy and scanning electron microscopic observation of the surface of the silica gel, as well as the measurement of changes in the ion concentration of the fluid. It was found that the induction period for the apatite nucleation on the surface of the silica gel was about 6 days. Once the apatite nuclei were formed they grew, taking a spherulitic form by consuming the calcium and phosphate ions from the surrounding fluid. Each spherulite consisted of a lot of flake that clustered into a petal-like morphology. The flake was carbonate-containing hydroxyapatite of small-crystallites and/or defective structure. The Ca/P ratio of the apatite was estimated as 1.5–1.6. Thus, the apatite formed was able to induce secondary nucleation of the apatite.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of sol gel science and technology 7 (1996), S. 27-34 
    ISSN: 1573-4846
    Keywords: bioactivity ; bone-bonding ; hydroxyapatite ; titania gel ; bioactive coating
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The sol-gel prepared titania (TiO2) has recently been demonstrated with a promising bioactivity [1]. It forms a chemical bond with the living bone in the body, although the bonding is not very strong. The present study is intended to improve the bone-bonding ability of the titania gel. The goal is achieved by impregnating the titania with hydroxyapatite (Ca10(PO4)6(OH)2). The processing route includes the following steps: (1) the titania sol solution was prepared; (2) the solution was mixed with fine hydroxyapatite (HA) powders; (3) the mixture was used to produce a coating on a commercial pure titanium (c.p. Ti) or Ti6A14V plate by a dip coating technique; (4) the coating was fired at 400–600°C. The resulting coating is a composite consisting of hydroxyapatite embedded in the matrix of the titania gel. Such HA-TiO2 composite coating is capable of inducing the hydroxyapatite precipitation from a simulated body fluid. When implanted in femurs of goat, the composite coating shows a bonding with bone. Its bone-bonding strength is twice as high as that of the pure titania gel coating. The results indicate that impregnating with hydroxyapatite is a promising way to increase the bioactivity of the titania gel.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1573-4838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract A bioactive glass containing (in wt%) SiO2 48, P2O5 9.5, Na2O 20 and CaO 22.5 was transformed into a glass-ceramic through a heat treatment. The apatite formation on the surface of this glass-ceramic was examined in a simulated physiological solution. The data from X-ray diffraction, infrared reflection spectroscopy, scanning electron microscopy together with energy-dispersive X-ray analysis and composition imaging of backscattered electrons showed that the formation of the surface apatite layer depends on the relative amount of residual glassy phase in the glass-ceramic. The apatite layer was found to formin vitro on its surface if the glass-ceramic contained a residual glassy phase in a relative proportion more than a limiting volume. It lay on a layer rich in silica. However, only, a silica-rich layer was developed within the surface region of the glass-ceramic during the interaction with solution if the glass was almost completely crystallized. It is proposed that the apatite formation on the surface of the glass-ceramic is mainly caused by its residual glass. The residual glass facilitating apatite formation is considered to provide a negatively charged surface developed during its corrosion in the surrounding solution. The negatively charged surface attracts calcium ions and creates a solution within the glass — solution interface that is highly supersaturated with respect to hydroxyapatite. This leads to the formation of apatite on the surface of the glass-ceramic.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Experiments in fluids 6 (2004), S. 135-137 
    ISSN: 1432-1114
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Few body systems 9 (1990), S. 11-23 
    ISSN: 1432-5411
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A four-body quantum-mechanical system is studied and through suitable manipulations of its wave functions, dominant shapes and modes of internal motion are ascribed to a number of its low-lying 0+ states.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 19 (1975), S. 277-284 
    ISSN: 1434-6036
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The apparent Dingle temperature of the 3rd zone needles in several alloys of Zn−Mn, Zn−Cr and Zn−Fe has been determined from the absolute amplitude of the de Haas-van Alphen effect over the temperature range 1.6 K to 4.2 K and the field range 0 to 9 kG. The results show clearly that potential scatteringnot spin scattering dominates in all three systems. In addition, a “cross-over” behaviour in the de Haas-van Alphen amplitudes results from the scattering of the magnetic moments of the impurity spin.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1435-1536
    Keywords: Micelles ; Ethylene oxide-propylene oxide block copolymers ; Aggregation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The aggregation behaviour of two ethylene oxide-propylene oxide block copolymers (PEO-PPO-PEO) in aqueous solution has been investigated in the presence of added salts (KCNS, KI, KBr, KCl and KF) by viscosity, cloud point, light scattering, pulse gradient spin echo NMR, and solubilization measurements. The salts have a strong effect on the cloud points of the pluronics. Both P-85 and L-64 form micelles which increase in size and change into elongated shapes when the cloud point is approached. The changes of size and shape of the micelles, revealed by the intrinsic viscosity and rheological properties, seem to occur at the same temperature relative to the cloud point, independent of the nature of the salt. The onset of micelle formation is also shifted in the same direction as the cloud point by the salts, but by a much smaller amount.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Archives of environmental contamination and toxicology 26 (1994), S. 408-414 
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract Consumer food ingredients may enter the terrestrial environment as constituents of municipal sludge which is used as a beneficial fertilizer source in land application. Evaluation of the plant/soil response to specific organic constituents, in the presence and absence of municipal sludge, is thus an important scientific component. Olestra is a consumer ingredient used in savory snacks to eliminate fat content and reduce calories in these foods. The fat substitute olestra is a mixture of hexa, hepta, and octaesters of sucrose with medium and long-chain fatty acids. Experiments were conducted of plant response in olestra mixtures with soil or municipal sludge/soil over a range from 0–1,000 mg olestra/kg dry soil. The plants grown from seed were corn, fescue, wheat, and soybean, with the latter two continued to seed production maturity. The comparison of effects rationale used in this study requires some consistent response to be measured and removes emphasis from singular, statistically significant response. The investment in multiple measures of plant response, separate periods of time, and appropriate multiple controls are necessary to place emphasis on consistent trends for a comparison rationale. For olestra, the notion of consistent effects permits the conclusion that more highly saturated solid olestra did not impact plant growth at concentrations of 0–1,000 mg olestra/kg dry soil in soil alone or in sludge/soil mixtures. The absence of effects occurred with germination, height, and biomass parameters.
    Type of Medium: Electronic Resource
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