Einfluß von hohem allseitigem Druck auf das Umwandlungsverhalten von Stählen

Untersuchungen (mit einer Tetraederamboβpresse) über den Einfluβ von allseitigem Druck (rd. 6,25 bis 34 kbar) auf das Umwandlungsverhalten von Stählen Gk 45 und 50 CrV 4 bei kontinuierlicher Abkühlung und isothermischer Versuchsführung. Darstellung der Ergebnisse in Zeit-Temperatur-Umwandlungsschaubildern und Folgerungen über die den Verschiebungen der Umwandlungslinien im Gefüge entsprechenden Vorgänge.     

Determination of phosphorus-, copper-, and zinc-containing human brain proteins by LA-ICPMS and MALDI-FTICR-MS

Human brain proteins containing phosphorus, copper, and zinc were detected directly in protein spots in gels of a human brain sample after separation by two-dimensional gel electrophoresis using laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS). A powerful laser ablation system with cooled laser ablation chamber was coupled to a double-focusing sector field ICPMS. The separated protein spots in 2D gels were fast screened using the optimized microanalytical LA-ICPMS technique measured at medium mass resolution with a focused laser beam (wavelength, 213 nm; diameter of laser crater, 50 mum; and laser power density, 3 x 10(9) W cm(-2)) with respect to selected three essential elements. Of 176 protein spots in 2D gel from a human brain sample, phosphorus, copper, and zinc were detected in 31, 43, and 49 protein spots, respectively. For the first time, uranium as a naturally occurring radioactive element was found in 20 selected protein spots. The detection limits for P, S, Cu, Zn and U were determined in singular protein spots with 0.0013, 1.29, 0.029, 0.063, and 0.000 01 mg g(-1), respectively. A combination of LA-ICPMS with matrix-assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry (MALDI-FTICR-MS) was applied for the identification of selected protein spots from human brain protein separated by 2D gel electrophoresis. Combining MALDI-FTICR-MS for the structure analysis of metal- and phosphorus-containing human brain proteins with LA-ICPMS, the direct analysis of heteroelements on separated proteins in 2D gels can be performed. For quantification of analytical LA-ICPMS data, the number of sulfur atoms per protein (and following the sulfur concentration) determined by MALDI-FTICR-MS was used for internal standardization. From the known sulfur concentration in protein, the concentration of other heteroelements was calculated. In addition, the number of phosphorylation and the phosphorylation sites of phosphorylated proteins in the human brain sample detected by LA-ICPMS were determined by MALDI-FTICR-MS. This technique allows the study of posttranslational modifications in human brain proteins.     

Carbon Nanotubes for Microelectronics?

Despite all prophecies of its end, silicon-based microelectronics still follows Moore's Law and continues to develop rapidly. However, the inherent physical limits will eventually be reached. Carbon nanotubes offer the potential for further miniaturization as long as it is possible to selectively deposit them with defined properties.     

Synthesis of BaTiO3 by soft chemistry routes

In this paper we report a comparison concerning the properties of BaTiO₃ (BTO) ceramics obtained by two soft chemical routes, modified Pechini method and thermal decomposition of oxalate-based precursor. XRD data show the formation of single phase BaTiO₃ with tetragonal symmetry when the polymeric citrate-based precursor was annealed at 850 °C, 2 h. In the case of oxalate based-precursor, longer thermal treatment is required to obtain BaTiO₃ free of any secondary phases. For BaTiO₃ powders prepared by modified Pechini method, TEM and SEM investigations revealed the obtaining of uniformly sized particles forming spherical agglomerates inside large, non-uniform and partially sintered aggregates. The powders synthesized via oxalate route show particles of various sizes, with the same tendency of spherical agglomerates formation, but unlike the modified Pechini synthesis, more uniform and smaller aggregates with well-defined hexagonal-like shape were noticed. The relative permittivity values of 6,478 and 5,088 at Curie temperatures of 127 and 130 °C and low dielectric losses (tan δ?=?0.012) at room temperature were obtained for ceramic samples synthesized via Pechini method and oxalate route, respectively.     

Zur Ermittlung der Normalkraft‐Verlängerung und Moment‐Krümmung‐Beziehungen der Stahlbetonbauteile im Grenzzustand der Gebrauchstauglichkei

Die Nachweise zur Begrenzung der Verformungen von Stahlbetonbauteilen sind infolge der Verwendung von Baustoffen höherer Festigkeiten immer wichtiger geworden, oft sogar maßgebend. Eine Verdopplung der Betondruckfestigkeit eines normalen Betons ruft eine etwa 20%ige Erhöhung des E_c‐Moduls hervor aber keine des Betonstahls, da E_s konstant ist. Dies und die dementsprechend schlanker gewordenen Stahlbetonbauteile führen zu größeren Verformungen – Verlängerungen, Durchbiegungen und/oder Verdrehungen – die deren Verhalten beeinträchtigen können. Die für die Ermittlung der Verformungen benötigten “Normalkraft‐mittlere Dehnungslinien”, bzw. “Moment‐mittlere Krümmungslinien” werden erläutert. About the Calculation of Displacements of Reinforced Concrete Members in the Serviceability Limit State The verification of reinforced concrete elements for the purpose of limiting deformations has become increasingly important, often even decisive, as a result of the use of higher strength materials. A doubling of the compressive strength of a normal concrete causes an increase of about 20% in the E_c‐module, and none of reinforcing steel, because E_s is constant. This and, accordingly, the slender reinforced concrete elements lead to larger deformations – elongations, deflections and/or rotations – which may affect their behaviour. The determination of “axial tensile force – mean strain diagrams”, respectively “bending moment – mean curvature diagrams”, needed for the calculation of the displacements, is explained.     

Evolutionary Multiobjective Optimization algorithm for multimedia delivery in critical applications through Content-Aware Networks

Critical applications which need to deliver multimedia through the Internet, may achieve the required quality of service thanks to the Content-Aware Networks (CAN). The key element of CAN is an efficient decision algorithm responsible for the selection of the best content source and routing paths for content delivery. This paper proposes a two-phase decision algorithm, exploiting the Evolutionary Multiobjective Optimization (EMO) approach. It allows to consider valid information in different time scales, adapting decision-maker to the evolving network and server conditions as well as to get the optimal solution in different shapes of Pareto front. The simulation experiments performed in a large-scale network model, confirm the effectiveness of the proposed two-phase EMO algorithm, comparing to other multi-criteria decision algorithms used in CAN.     

Zur Komposition von Raumfachwerken von Föppl bis Mengeringhausen

The composition of spatial frameworks – synopsis of the development from Föppl to Mengeringhausen. “Architecture is frozen music”. This phrase coined by the philosopher Arthur Schopenhauer (1788–1860) is often quoted in the relevant literature. If it also applies to structural engineering objects, the design work of structural engineers can be regarded as structural composition. This article elaborates this proposition and illustrates it using the example of the historic development of spatial frameworks.