Comparing Metaheuristic Algorithms for Sonet Network Design Problems

This paper considers two problems that arise in the design of optical telecommunication networks when a ring-based topology is adopted, namely the SONET Ring Assignment Problem and the Intraring Synchronous Optical Network Design Problem. We show that these two network topology problems correspond to graph partitioning problems with capacity constraints: the first is a vertex partitioning problem, while the latter is an edge partitioning problem. We consider solution methods for both problems, based on metaheuristic algorithms. We first describe variable objective functions that depend on the transition from one solution to a neighboring one, then we apply several diversification and intensification techniques including Path Relinking, eXploring Tabu Search and Scatter Search. Finally we propose a diversification method based on the use of multiple neighborhoods. A set of extensive computational results is used to compare the behaviour of the proposed methods and objective functions.     

Ionization for Three Dimensional Time-Dependent Point Interactions

We study the time evolution of a three dimensional quantum particle under the action of a time-dependent point interaction fixed at the origin. We assume that the strength of the interaction (t) is a periodic function with an arbitrary mean. Under very weak conditions on the Fourier coefficients of (t), we prove that there is complete ionization as t, starting from a bound state at time t=0. Moreover we prove also that, under the same conditions, all the states of the system are scattering states.On leave from Dipartimento di Matematica, Università di Roma, La Sapienza, Italy.     

Structural characterisation of the silica and alumina Zener pinning phases in nanocrystalline CeO2 by 29Si and 27Al nuclear magnetic resonance

Nanocrystalline CeO₂ samples have been manufactured using sol-gel techniques, containing either 15 % silica or 10 % alumina by weight to restrict growth of the ceria nanocrystals during annealing by Zener pinning. ²⁹Si and ²⁷Al MAS NMR have been used to investigate the structure of these pinning phases over a range of annealing temperatures up to 1000 °C, and their effect on the CeO₂ morphology has been studied using electron microscopy. The silica pinning phase resulted in CeO₂ nanocrystals of average diameter 19 nm after annealing at 1000 °C, whereas the alumina pinned nanocrystals grew to 88 nm at the same temperature. The silica pinning phase was found to contain a significant amount of inherent disorder indicated by the presence of lower n Qⁿ species even after annealing at 1000 °C. The alumina phase was less successful at restricting the growth of the ceria nanocrystals, and tended to separate into larger agglomerations of amorphous alumina, which crystallised to a transition alumina phase at higher temperatures.     

10B NMR studies of lithium borate glasses

¹⁰B NMR studies have been carried out on lithium borate glasses over the entire glass-forming region of the system. Using the ideas of Krogh-Moe, the relative abundances of the various structural groupings are inferred from the data by fitting computer-simulated lineshapes to the experimental spectra. Structural model are proposed which are consistent with the data: for 0.4 R < 1.0, where R = mol% Li₂O/mol% B₂O₃, the model states that diborate and tetraborate units are proportionately destroyed to form metaborate units and loose BO₄ units; for 1.0 < R < 1.86, the model states that metaborate units and loose BO₄ units are destroyed linearly but not proportionately to form pyroborate and orthoborate units. These results are compared with earlier ¹¹B NMR studies from this laboratory.     

Bestimmung von Propyphenazon in Blut

Ohne Zusammenfassung

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Determination of propyphenazone in blood

     

Beitrag zur Bestimmung von 2-Oxo-pyrrolidin-Derivaten aus biologischem Material

Zusammenfassung 2-Oxo-1-pyrrolidin-essigsäure-Derivate lassen sich weder UV-spektroskopisch, colorimetrisch noch fluorimetrisch bestimmen, GC-Bestimmungen sind nur bedingt anwendbar. Zur Bestimmung von 2-Oxo-1-pyrrolidin-essigsäure, deren Amid, Hydrazid sowie 1,2-Bis(2-oxo-pyrrolidin-1-essigsäure)-hydrazid bzw. ,-Bis(2-oxo-1-pyrrolidinacetamido)-alkanen in biologischem Material eignet sich die Extraktion der gefriergetrockneten Analysenproben mit Chloroform/Methanol-Gemischen, Dünnschicht-Chromatographie auf Kieselgel und Detektion mit verschiedenen Sprühreagentien. Durch Flächengrößenvergleich/Scannen sind Bestimmungen aus Vollblut, Plasma, Organhomogenaten und Urin möglich. Die Anwendbarkeit der Methode wird am Beispiel von Stabilitätsprüfungen in biologischem Material, Resorptionsnachweisen, Plasma- und Urinspiegeln bei Ratten, Hunden und Menschen demonstriert.

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Contribution to the determination of 2-oxo-pyrrolidine derivatives in biological material

Summary Determination of 2-oxo-1-pyrrolidine-acetic acid derivatives cannot be carried out either spectroscopically, colorimetrically or fluorimetrically, and GC determination is only conditionally suitable. For the determination of 2-oxo-1-pyrrolidine-acetic acid, its amide, hydrazide as well as 1,2-bis (2-oxo-pyrrolidine-1-acetic acid)-hydrazide and ,-bis(2-oxo-1-pyrrolidine-acetamido)-alkanes in biological material, a suitable method is the extraction of freeze-dried analytical samples with chloroform/methanol mixtures, TLC on silica gel and detection with various spray reagents. Determinations from whole blood, plasma, organ homogenates and urine are possible by spot area comparison or scanning. The practicability of the method is demonstrated with the example of stability tests in biological material, proof of absorption, and determination of plasma and urine levels in rats, dogs and in man.

     

Bestimmung renal eliminierten Benzhydrols und dessen Glucuronids. Potentielle Metaboliten von Diphenylmethyläther- und Diphenylmethylamin-Derivaten

Analytical and Bioanalytical Chemistry -     

Behavior of noncoalescing and nonwetting drops in stable and marginally stable states

Experiments have demonstrated the possibility of suppressing the coalescence of two bodies of the same liquid or the wetting of a solid by a normally wetting liquid using thermocapillary convection to drive thin films of lubricating, surrounding gas. Several aspects regarding coalescence, wetting and their suppression are discussed here, such as: i) the minimum gas pressure necessary to sustain noncoalescence under a given applied load, ii) the load capable of being supported by the film for a given relative displacement of the two surfaces, and iii) interstitial film evolution following rupture due to an excessive load.