Scheduling railway traffic at a construction site

We consider the problem of rescheduling trains in the case where one track of a railway section consisting of two tracks in opposing directions is closed due to construction activities. After presenting an appropriate model for this situation we derive a polynomial algorithm for the subproblem of finding an optimal schedule with minimal latenesss if the subsequences of trains for both directions outside the construction site are fixed. Based on this algorithm we propose a local search procedure for the general problem of finding good schedules and report test results for some real world instances. Received: December 8, 1999 / Accepted: May 2, 2001     

Alternating Current Electrophoretic Deposition of Antibacterial Bioactive Glass-Chitosan Composite Coatings

Alternating current (AC) electrophoretic deposition (EPD) was used to produce multifunctional composite coatings combining bioactive glass (BG) particles and chitosan. BG particles of two different sizes were used, i.e., 2 μm and 20–80 nm in average diameter. The parameter optimization and characterization of the coatings was conducted by visual inspection and by adhesion strength tests. The optimized coatings were investigated in terms of their hydroxyapatite (HA) forming ability in simulated body fluid (SBF) for up to 21 days. Fourier transform infrared (FTIR) spectroscopy results showed the successful HA formation on the coatings after 21 days. The first investigations were conducted on planar stainless steel sheets. In addition, scaffolds made from a TiAl4V6 alloy were considered to show the feasibility of coating of three dimensional structures by EPD. Because both BG and chitosan are antibacterial materials, the antibacterial properties of the as-produced coatings were investigated using E. coli bacteria cells. It was shown that the BG particle size has a strong influence on the antibacterial properties of the coatings.     

Dr. Dr. h. c. Kurt Lindner zur Vollendung des 70. Lebensjahres

Ohne Zusammenfassung     

Copper-induced changes in the properties of arsenic chalcogenides

The influence of the presence of Cu in the amount between 1% and 6% in arsenic chalcogenide glasses is examined through a study of the electronic energy levels by means of x-ray photoelectron and x-ray emission spectroscopy, through an investigation of the low-energy tunneling systems by means of phonon echoes at 0.37 K, and through an examination of the photodarkening and the photoinduced dichroism caused by polarized Ar⁺ laser irradiation. Possible links between the various effects are examined. The Cu atoms become an integral part of the amorphous lattice structure and strongly influence the photodarkening, but they do not have a significant effect on the tunneling systems or the dichroism. It is concluded that the tunneling levels and the dichroism involve only local configurations, while the photodarkening involves larger-scale areas of the lattice. Fiz. Tekh. Poluprovodn. 32, 976–981 (August 1998)     

Novel Heterobimetallic Radiotheranostic: Preparation,Activity, and Biodistribution

A novel Ru^II(arene) theranostic complex is presented. It is based on a 1,4,7,10‐tetraazacyclododecane‐1,4,7,10‐tetraacetic acid macrocycle bearing a triarylphosphine and can be tracked in vivo by using the γ emission of ¹⁵³Sm atoms. Notably, the heteroditopic ligand can be selectively metalated with ruthenium at the phosphorus atom despite the presence of other functionalities that are prone to metal coordination. Subsequent labeling with radionuclides such as ¹⁵³Sm can then be performed easily. The resulting heterobimetallic complex exhibits favorable solubility and stability properties in biologically relevant media. It also shows in vitro cytotoxicity in line with that expected for this type of metallodrug, and is nontoxic to the organism as a whole. As a proof of concept, initial studies in healthy mice were performed to obtain information about the uptake, biodistribution, and excretion of the radiolabeled complex.     

The geodesic dynamic relaxation method for problems of equilibrium with equality constraint conditions

This paper presents an extension to the existing dynamic relaxation method to include equality constraint conditions in the process. The existing dynamic relaxation method is presented as a general, gradient‐based, minimization technique. This representation allows for the introduction of the projected gradient, discrete parallel transportation and pull back operators that enable the formulation of the geodesic dynamic relaxation method, a method that accounts for equality constraint conditions. The characteristics of both the existing and geodesic dynamic relaxation methods are discussed in terms of the system's conservation of energy, damping (viscous, kinetic, and drift), and geometry generation. Particular attention is drawn to the introduction of a novel damping approach named drift damping. This technique is essentially a combination of viscous and kinetic damping. It allows for a smooth and fast convergence rate in both the existing and geodesic dynamic relaxation processes. The case study was performed on the form‐finding of an iconic, ridge‐and‐valley, pre‐stressed membrane system, which is supported by masts. The study shows the potential of the proposed method to account for specified (total) length requirements. The geodesic dynamic relaxation technique is widely applicable to the form‐finding of force‐modeled systems (including mechanically and pressurized pre‐stressed membranes) where equality constraint control is desired. Copyright © 2014 John Wiley & Sons, Ltd.     

Design of a Microchannel‐Nanochannel‐Microchannel Array Based Nanoelectroporation System for Precise Gene Transfection

A micro/nano‐fabrication process of a nanochannel electroporation (NEP) array and its application for precise delivery of plasmid for non‐viral gene transfection is described. A dip‐combing device is optimized to produce DNA nanowires across a microridge array patterned on the polydimethylsiloxane (PDMS) surface with a yield up to 95%. Molecular imprinting based on a low viscosity resin, 1,4‐butanediol diacrylate (1,4‐BDDA), adopted to convert the microridge‐nanowire‐microridge array into a microchannel‐nanochannel‐microchannel (MNM) array. Secondary machining by femtosecond laser ablation is applied to shorten one side of microchannels from 3000 to 50 μm to facilitate cell loading and unloading. The biochip is then sealed in a packaging case with reservoirs and microfluidic channels to enable cell and plasmid loading, and to protect the biochip from leakage and contamination. The package case can be opened for cell unloading after NEP to allow for the follow‐up cell culture and analysis. These NEP cases can be placed in a spinning disc and up to ten discs can be piled together for spinning. The resulting centrifugal force can simultaneously manipulate hundreds or thousands of cells into microchannels of NEP arrays within 3 minutes. To demonstrate its application, a 13 kbp OSKM plasmid of induced pluripotent stem cell (iPSC) is injected into mouse embryonic fibroblasts cells (MEFCs). Fluorescence detection of transfected cells within the NEP biochips shows that the delivered dosage is high and much more uniform compared with similar gene transfection carried out by the conventional bulk electroporation (BEP) method.     

Form finding methodology for force-modelled anticlastic shells in glass fibre textile reinforced cement composites

The reinforcement of a specifically developed fine grained cement matrix with glass fibre textiles in high fibre volume fractions creates a fire safe composite that has-besides its usual compressive strength-an important tensile capacity and omits the need for any steel reinforcement. Strongly curved shells made of textile reinforced cement composites (TRC) can cover medium (up to 15 m) span spaces with three times smaller shell thicknesses than conventional steel-reinforced concrete shells. This paper presents a methodology to generate force-modelled anticlastic shell shapes that exploit both the tensile and compressive load carrying capacities of TRC. The force-modelling is based on the dynamic relaxation form finding method developed for gravity (in this case self-weight) loaded systems. The potential of the presented methodology to develop structurally sound anticlastic shell shapes is illustrated by four case studies.     

Der Fischotter(Lutra lutra) im Spiegel der deutschen und ?sterreichischen Jagdstatistiken zwischen 1830 und 1936

Zusammenfassung Die Angaben über den Fischotter(Lutra lutra), die in den deutschen und österreichischen Jagdstatistiken aus der Zeit von 1830 bis 1936 enthalten sind, werden ausgewertet. Ziel ist es, anhand der Fang-und Abschußziffern Grundlagen für die Schätzung der Populationsentwicklung und der Populationsdichte zu erarbeiten. Der Betrachtung liegt ein Territorium von ca. 641 000 km² — das Deutsche Reich vor 1914 und Österreich in seinen heutigen Grenzen — zugrunde. Eine etwa sechs Jahrzehnte umfassende dynamische Betrachtung der ausgewiesenen Wildertragszahlen läßt einen von wirtschaftlichen Überlegungen bestimmten verstärkten Eingriff in den Fischotterbestand während der letzten zwei Jahrzehnte des 19. Jahrhunderts erkennen, doch weichen die Fang- und Abschußziffern vor und nach dieser als Ottersturm bezeichneten Periode nicht wesentlich voneinander ab. Lokale Populationen mögen hierdurch bereits stark dezimiert worden sein. Eine Gefährdung der Art bestand jedoch noch nicht. Der rapide Rückgang bis zum völligen Zusammenbruch der Fischotterpopulation vollzog sich erst vom zweiten bis vierten Jahrzehnt unseres Jahrhunderts und ist vornehmlich auf veränderte Umweltbedingungen zurückzuführen. Die Zahlen für das der Untersuchung zugrunde liegende Territorium lassen außerdem eine abnehmende Populationsdichte von Norden und Westen nach Süden und Osten erkennen. In Pommern, Schleswig-Holstein, Hessen-Nassau und Brandenburg lebten auf je 10 000 ha erheblich mehr Fischotter als in Süd- und Ostdeutschland oder gar in Österreich. Eine konsequente Deutung der statistischen Zahlen erlaubt die Ermittlung der Kreise (in Deutschland) bzw. der Bezirkshauptmannschaften in Österreich als kleinsten territorialen Einheiten mit dem an der Jagdfläche gemessenen höchsten Fischotterertrag. In den achtziger und neunziger Jahren des vorigen Jahrhunderts wurden im Deutschen Reich und den deutsch sprechenden Teilen Österreichs etwa 6000 bis 6500, in den vorhergehenden Jahrzehnten des vorigen und im ersten Jahrzehnt unseres Jahrhunderts etwa 3500 bis 4500 Fischotter erlegt.

---

The otter (Lutra lutra) as seen in German and Austrian hunting statistics between 1830 and 1936

Summary The data on the otter(Lutra lutra) which appear in the German and Austrian hunting statistics for the period 1830 to 1936 are analysed. The aim is to work out bases for the estimation of population development and density with the aid of the figures for capture and shooting. The study is based on a territory of around 641 000 km² — the German Reich prior to 1914 and Austria within its present borders. A dynamic study, covering almost six decades, of the game statistics shows an increased attack on the otter population for commercial reasons during the last two decades of the 19th century. The capture and shooting figures before and after this period of otter attack do not, however, differ from one another to any great extent. Many local populations may well have been decimated as a result. However, the species was not endangered by it. The rapid decline, leading to the complete collapse of the otter population, took place only from the 2nd to the 4th decades of the 20th century and is attributable to changed environmental conditions. Figures for the study area also show a decreasing population density from the north and west to the south and east. In Pomerania, Schleswig-Holstein, Hessen-Nassau and Brandenburg there lived considerably more otters per 10 000 ha than in south and east Germany or in the whole of Austria. Using these statistics, one is able to discover those Kreise (in Germany) and Bezirkshauptmannschaften (in Austria), being the smallest territorial unites in each case, with the highest otter potential measured against the hunting area. In the 1880s and 1890s between 6000 and 6500 otters were killed in the German Reich and the German-speaking parts of Austria. In the previous decades of last century and in the first decade of this century, the figure was between 3500 and 4500.

---

La Loutre (Lutra lutra) à travers les statistiques de chasse allemandes et autrichiennes entre 1830 et 1936

Résumé Un dépouillement des données sur la Loutre(Lutra lutra), contenues dans les statistiques de chasse allemandes et autrichiennes des années 1830 à 1936, s'est fixé pour objectif de rassembler des éléments, à partir des tableaux de tir et de capture, permettant d'évaluer la dynamique et la densité de population de l'espèce. La référence territoriale porte sur quelque 641 000 km correspondant à l'Empire germanique d'avant 1914 et les limites actuelles de l'Autriche. L'évolution de la production de gibier au cours de quelque 6 déciennes révèle un prélèvement accru, économiquement justifié, dans la population de la Loutre au cours des deux dernières décennies de ce siècle; les chiffres de capture et de tir relevés avant et après cette période — connue sous le nom de «période d'invasion de la Loutre» («Ottersturm») —, ne s'écartent cependant pas significativement les uns des autres. Ceci n'exclut pas que des populations locales aient d'ores et déjà pu être décimées; une menace pour l'espèce n'existait pas encore. La régression rapide précédant l'écroulement total de la population de la Loutre ne se consomma qu'à partir de la 2ème à la 4ème décienne du siècle présent et doit être attribuée principalement à l'altération des conditions de milieu. Les chiffres disponibles pour l'étude de la région géographique considérée laissent en outre apparaître une densité de population décroissante du Nord vers l'Ouest, vers le Sud et vers l'Est. En Poméranie, Schleswig-Holstein, Hesse-Nassau et Brandebourg se tenait un nombre beaucoup plus important de loutres par unité de surface de 10 000 ha que dans le Sud et l'Est de l'Allemagne voire même qu'en Autriche. Une interprétation conséquente des données statistiques permet de relever les districts, soit les unités territoriales les plus petites, pour lesquels la production de loutres par territoire de chasse était la plus élevée. Au cours des années 80 et 90 du siècle passé, 6.000 à 6.500 loutres ont été tirées dans l'Empire germanique et dans les régions germanophones de l'Autriche; au cours des décennies antérieures du XIXème siècle et pendant la première décennie du XXème siècle, 3.500 à 4.500 loutres ont été abattues.