Modern Teaching and Training in Metallurgical Engineering

This contribution deals with advanced educational technologies needed to equip customers from higher education institutions, research and industry with efficient tools supporting their work and operating new skills‐training methods. The challenges are reducing the training costs, improving quality and increasing the number of graduates in engineering departments. The concept of a Virtual Lab based on the combination of various teaching methods and tools is presented. Principles of mathematisation in metallurgical education and training are discussed. An example of online course designed in the form of Virtual Lab is demonstrated.     

Bemerkungen zum Biot-Savartschen Gesetz

Übersicht Die folgende Arbeit verfolgt u. a. auch didaktische Absichten. Das Biot-Savartsche Gesetz wird oft falsch oder mindestens sehr mißverständlich dargestellt und auch auf unzulässige Weise benutzt. Ausgangspunkt der Mißverständnisse ist die auch in vielen Lehrbüchern anzutreffende unkorrekte Aussage, man könne einem von StromI durchflossenen Linienelement ds ein magnetostatisches Feld dB [entsprechend der Gleichung (32) des folgenden Beitrags] zuordnen. Im folgenden werden derartige Aussagen untersucht und in modifizierter Form korrekt dargestellt.

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Remarks concerning the Law of Biot-Savart

Contents The following paper is at least partly of a didactic nature. The Biot-Savart law of magnetostatics is often interpreted in an illegitimate manner and consequently applied incorrectly. The source of these misunderstandings and errors is the incorrect statement that a magnetic field dB [as given by equation (32) of this paper] is caused by an electric currentI flowing along a line element ds, a statement very popular also in many textbooks. Questions related to this problem are investigated and widespread misleading statements are replaced by correct ones.

     

Direkte und indirekte Randelementmethoden zur Bestimmung der Lage des Schubmittelpunktes beliebig geformter Stabquerschnitte

Zusammenfassung Die Koordinaten des Schubmittelpunktes eines beliebig berandeten Stabquerschnittes werden in dieser Arbeit aus der Torsionsverw?lbung des Querschnittes berechnet. Zur Bestimmung der Querschnittsverw?lbung wird die Randelementmethode (Boundary-Element-Method) herangezogen. Dabei entstehen durch verschiedene Vorgehensweisen mehrere Fredholmsche Integralgleichungen erster und zweiter Art, von denen jedoch nur bestimmte zur L?sung des genannten Problems geeignet sind. Einige direkte und indirekte Integralgleichungen werden hier für beliebig berandete Stabquerschnitte bezüglich ihrer Einsetzbarkeit untersucht und miteinander verglichen. Es zeigt sich dabei, da? auch eine Integralgleichung erster Art problemlos eingesetzt werden kann. Die Randelemente werden bei der numerischen L?sung der Integralgleichungen durch Polynome dritten Grades und die unbekannten Funktionen durch Polynome zweiten Grades approximiert, um eine glatte Berandung und stetigen Funktionenverlauf zu sichern.—Die Methode ist auf dünnwandige, dickwandige, offene und auf geschlossene Profile anwendbar. Numerische Ergebnisse für verschiedene Querschnittsformen aus den DIN-Normen zeigen die Effektivit?t sowohl der direkten als auch der indirekten Methode.     

Guaranteed inclusions for the complex generalized eigenproblem

A method is described which produces guaranteed bounds for a solution of the generalized complex eigenproblem. The method extends a similar approach for general systems of nonlinear equations to the special case of complex pencils, where under weaker assumptions stronger assertions can be proved.     

A structure/function study of polyaminoamide dendrimers as silica scale growth inhibitors

Dendrimers have attracted immense attention during the last decade due to their interesting properties both from a basic and an applied research viewpoint. Encapsulation of metal nanoparticles for catalysis, drug delivery and light harvesting are only some applications of dendrimers that are breaking new ground. A novel application of dendrimer technology is described in the present paper that relates to industrial water treatment. Industrial water systems often suffer from undesirable inorganic deposits. These can form either in the bulk or on metallic surfaces, such as heat exchangers or pipelines. Silica (SiO₂) scale formation and deposition is a major problem in high‐silica‐containing cooling waters. Scale prevention rather than removal is highly desired. In this paper, benchtop screening tests on various silica inhibition chemistries are reported, with emphasis on materials with a dendrimeric structure. Specifically, the inhibition properties of commercially available STARBURST^® polyaminoamide (PAMAM) dendrimers generations 0.5, 1, 1.5, 2, and 2.5 are investigated in detail together with other commonly‐used scale inhibitors. Experimental results show that inhibition efficiency largely depends on structural features of PAMAM dendrimers such as generation number and nature of the end groups. PAMAM dendrimers are effective inhibitors of silica scale growth at 40 ppm dosage levels. PAMAM dendrimers also act as silica nucleators, forming SiO₂–PAMAM composites. This occurs because the SiO₂ formed by incomplete inhibition interacts with cationic PAMAM‐1 and ‐2. The general scope of silica formation and inhibition in industrial waters is also discussed. Copyright © 2005 Society of Chemical Industry     

Mass change detection based on reduced measurements

Summary Changes in the mass matrix of a dynamic structure can be detected by using reduced measurements [1]. In the here proposed method the stiffness matrix is assumed to be correct. The missing measurements can be calculated by utilizing the connection between the measured and unmeasured quantities through the iterative process of identification of the tested structure. The missing measurements and to some extent the partial measurements obtained during the tests are treated as hidden functions of the mass parameters of the structure. This makes the Euclidean norm of the appropriate matrix to be minimized a nonlinear function of the parameters. This norm may have more than one minimum. The changes in the mass matrix must be identified by looking for the global mininum of the Euclidean norm. The global minimum can be found by changing the initial values of the mass parameters or by changing some special coefficients, or both.In order to identify the mass parameters of the structure the measured and the supplied missing quantities are forced to comply with the general laws for a linear structure. This compliance is achieved during any step of the iterative process.