Goal Programming Models for Assigning Search and Rescue Aircraft to Bases

This paper develops several variations of a goal programming model for optimally allocating a fleet of search and rescue aircraft to a fixed set of available and potentially available bases. In addition, the model determines the number of aircraft of each type from each base (at which that type has been stationed) to assign to the various search locations. The criterion for optimality is to maximize the probability of locating each distress in a specified time. These models are then modified to include fleet planning issues. Solution procedures relating to the models are discussed.     

Benetzbarkeit von Wollfasern

Ohne Zusammenfassung     

Concerning the fluorine NMR spectra of steroidal phosphorofluoridates

Additional spectral evidence suggests that the previously reported signal doubling in the ¹⁹F NMR spectra of certain steroidal phosphorofluoridates is better interpreted in terms of diastereoisomerism than by restricted rotation around the P? O bond.     

BLUE LIGHT RESPONSES IN NITRATE REDUCTASE MUTANTS OF NEUROSPORA CRASSA

Abstract— The role of nitrate reductase in the blue light responses of photosuppression and phase shifting of circadian conidiation was studied in Neurospora crassa. The photoresponses, as assayed in three nitrate reductase mutants (nit-1,nit–2 and nit-3), showed no significant differences as compared to the responses in a strain which could utilize nitrate. In addition, the responses occur on a medium which (i) represses nitrate reductase activity due to the presence of ammonium ion and arginine or (ii) results in the production of an inactive enzyme due to the presence of tungsten. Nitrate reductase appears to be of no or secondary importance as a photoreceptor in the responses studied.     

Sprayed liquid-gas extraction in combination with ion mobility spectrometry: a novel approach for the fast determination of semi-volatile compounds in air and from contaminated surfaces

We developed a fast, simple and highly-efficient enrichment procedure for trace levels of semi volatile organic compounds from air and surfaces and combined it with ion mobility spectrometry as field-deployable and rapid analytical technique. Our new technique, the sprayed liquid-gas extraction, was developed and optimized to allow the enrichment of semi volatile organic compounds. The air sample is pumped through a flow blurring nebulizer together with water. The sprayed liquid is collected and the organic compounds are transferred from the water phase to n-hexane via a miniscale liquid-liquid extraction. 50 μL of the n-hexane extract is applied to a fiber tape. After the n-hexane has evaporated, the fiber tape is transferred to the thermodesorber unit of a GDA-X ion mobility spectrometer (Airsense, Schwerin, Germany). The whole sampling and the sample preparation procedure takes no longer than 15 min and only requires 2.5 mL organic solvent. The method was optimized for Malathion, a widely used organophosphate insecticide and an accepted simulant for the nerve-agent, VX. Malathion provides defined ion mobility spectra in both, the positive and negative mode. The positive spectra show one major peak with a reduced mobility of 1.197 cm² Vs^?1 and an additional peak at 1.449 cm² Vs^?1 with lower intensity. A major product ion peak of 1.720 cm² Vs^?1 can be detected in negative mode together with an additional peak of low intensity at 1.403 cm² Vs^?1. The detection limit of the ion mobility spectrometer is approximately 20 ng absolute.     

Facile method for surface etching of silica aerogel monoliths

Degradation of three different endocrine disruptors (EDs) was thoroughly studied on prepared durable thin layers of titanium dioxide with an anatase crystalline structure. Specially constructed laboratory reactors bringing information on all individual processes (photolysis, photocatalysis, sorption) involved in decomposition of the studied EDs (17α-ethynylestradiol, bisphenol A and 4-nonylphenol) were applied. It was found that photolytic removal of EDs is the fastest degradation process; nevertheless, this method may be less effective regarding all indicators including toxicity. It was verified that individual degradation processes (photolysis and photocatalysis) showed a significantly different influence on toxicity of resulting solutions. During the photolytic process, EDs degradation caused increasing toxicity contrary to the photocatalytic process. Obtained results were corroborated by a mathematical model, which showed that a limitation step for photocatalysis is a sorption and for photolysis a toxicity of resulting products.

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