RFID im Blickpunkt wirtschaftlicher Überlegungen

Diese Recherche zeigt, dass sich die Bedeutung, die dem Thema RFID in den Medien und der ?ffentlichen Diskussion derzeit beigemessen wird, auch in der Anzahl der im Internet zu findenden Seiten niederschl?gt. Dabei bewegt sich die Qualit?t der betrachteten Angebote überwiegend auf einem hohen Niveau, was vor allem auf Seiten der kommerziellen Anbieter nicht weiter verwundert, da es sich bei RFID doch um einen zunehmend st?rker umk?mpften Markt handelt, auf dem es hei?t, potenzielle Kunden für sich zu akquirieren. Es darf mit Spannung erwartet werden, wie sich das Informationsangebot wandelt, wenn tats?chlich das prognostizierte exponentielle Wachstum des RFID-Marktes eintritt.     

Three-dimensional MHD high-resolution computations with CWENO employing adaptive mesh refinement

Until recently, numerical simulations of discontinuities in highly super-Alfvénic plasmas have been severely limited by comparatively crude resolution and accuracy. Significant progress in the numerical simulation of such plasmas was achieved with the recently implemented Central Weighted Essentially Non-Oscillatory (CWENO) scheme. Combining this technique with that of adaptive mesh refinement (AMR), we have developed a third-order numerical scheme, which is able to efficiently capture strong gradients on spatial scales being small compared to the overall scale of the plasma system considered. Here, we first describe important algorithmic aspects of the scheme as well as the physics included in it. Second, we present the results of various performance tests. And, third, we illustrate its application to ‘real world problems’ using the example of the dynamics of a Sedov-type explosion.     

Die Langzeit-Korrosionsgeschwindigkeit des passiven Eisens in anaeroben alkalischen Lösungen

The long-term corrosion rate of passive iron in anaerobic alcaline solutions Gas generation is an important issue in safety assessments of low and intermediate level radioactive repositories. In this connection the hydrogen production from corrosion of passive iron in saturated calcium hydroxide, in dilute alkali hydroxide and cement porewater solutions has been determined. The measurements were performed manometrically using fusion sealed glass cells, the measurement periods being between 275 and 560 days. In 0.1 M and 0.04 M alkali hydroxide solutions the initial hydrogen generation rate was 12 mmol/m²yr corresponding to a linear corrosion rate of 64 nm/yr. The reaction rate decreases with time. The smallest value obtained after 330 days is 0.3 mmol/m²yr corresponding to 1.5 nm/yr. The influence on iron of the saturated calcium hydroxide solution and the calcic porewater solutions differs from that of the alkali hydroxide solutions. At pH 12.5 the hydrogen generation rate remains practically constant up to breaking off the experiment, the value being about 1 mmol/m²yr corresponding to 5 nm/yr.     

Das elektrochemische verhalten frischer bruchflächen einer AlZnMg-legierung

It is shown that the breakdown potential E_D1 at the grain boundary is more negative than the breakdown potential E_D2 of the grain surfaces in an AlZnMg alloy based on the pure metals. s.c.c.-susceptible samples differ from insusceptible modifications in the current—time integral after the forced break in the range E_D1 < E < E_D2.     

Loss-Aversion with Kinked Linear Utility Functions

Prospect theory postulates that the utility function is characterized by a kink (a point of non-differentiability) that distinguishes gains from losses. In this paper we present an algorithm that efficiently solves the linear version of the kinked-utility problem. First, we transform the non-differentiable kinked linear-utility problem into a higher dimensional, differentiable, linear program. Second, we introduce an efficient algorithm that solves the higher dimensional linear program in a smaller dimensional space. Third, we employ a numerical example to show that solving the problem with our algorithm is 15 times faster than solving the higher dimensional linear program using the interior point method of Mosek. Finally, we provide a direct link between the piece-wise linear programming problem and conditional value-at-risk, a downside risk measure.     

Multiple-objective decision analysis applied to chemical engineering

Chemical engineers are now being faced with new decisions involving multiple (and often conflicting) objectives as a result of increases in the scale and complexity of chemical plants and a re-evaluation of their performance criteria. Reliability and environmental impacts are now considered to be as important as economic efficiency, and this must be taken into account in process design, production planning and control.This paper describes methods for solving these multiple-objective optimization problems and gives an overview of the existing software. Selected applications of multiple-objective analysis are discussed—these include the design of a twin-screw extruder, the control of a film-hardening process and a production planning problem.     

Elektrochemische Untersuchungen an aluminiumreichen intermetallischen Phasen

Electrochemical investigations into aluminium-rich intermetallic phases An electrochemical characterization has been made of Al₃Fe, Al₆Mn, Al₃Mg₂, Al₂Cu and MgZn₂ phases in chloride containing and chloride-free electrolytes of different pH values. The rupture potentials were determined and a study was made on hydrogen overvoltage and passivation behaviour. The results are used to interprete the corrosion behaviour of heterogeneous aluminium alloys. The good corrosion behaviour of low iron AlMn-alloys can be understood in terms of the high hydrogen-overvoltage on Al₆Mn.     

Polarisationsmessungen an Kurzschlußelementen und Schweißverbindungen aus Aluminiumlegierungen

Polarization measurements on short-circuit couples and weldments of aluminium alloys In order to study the corrosion behaviour of welded AlZnMg alloys potential/path profiles were registered under anodic polarization in sodium chloride solutions. Using theoretical considerations it is shown that this method is particularly suitable for aluminium alloys because current break-through occurs in such solutions. The performance of the method was checked with the aid of model couples of two alloys having different break-through potentials.