Die Wechselwirkung von N3F mit Lewis-Säuren und HF. N3F als möglicher Vorläufer für die Synthese von N3+-Salzen

Triazadienyl fluoride, N3F, forms stable adducts with BF3 and AsF5 at low temperatures, as demonstrated by infrared measurements. The Lewis acids are bonded to the Nα-atom of N3F, as deduced from the data for 15N-isotopically enriched N3F. The basicity of N3F is comparable to that of ethine and ethene, according to the HF stretching frequency of the N3F/HF complex isolated in an argon matrix. Despite the low NF bond energy (< 150 kJ/mol), abstraction of the fluoride ion and formation of an N3+ salt was not possible. The different behavior of N3F and ClN3 towards Lewis acids is discussed

Animal studies on Spacelab-3

The flight of two squirrel monkeys and 24 rates on Spacelab-3 was the first mission to provide hand-on maintenance on animals in a laboratory environment. With few exceptions, the animals grew and behaved normally, were free of chronic stress, and differed from ground controls only for gravity-dependent parameters. One of the monkeys exhibited symptoms of space sickness similar to those observed in humans, which suggests squirrel monkeys may be good models for studying the space-adaptation syndrome. Among the wide variety of parameters measured in the rats, most notable was the dramatic loss of muscle mass and increased fragility of long bones. Other interesting rat findings were those of suppressed interferon production by spleen cells, defective release of growth hormone by somatotrophs, possible dissociation of circadian pacemakers, changes in hepatic lipid and carbohydrate metabolism, and hypersensitivity of marrow cells to erythopoietin. These results portend a strong role for animals in identifying and elucidating the physiological and anatomical responses of mammals to microgravity

Animal studies on Spacelab-3

The flight of two squirrel monkeys and 24 rats on Spacelab-3 was the first mission to provide hands-on maintenance on animals in a laboratory environment. With few exceptions, the animals grew and behaved normally, were free of chronic stress, and differed from ground controls only for gravity dependent parameters. One of the monkeys exhibited symptoms of space sickness similar to those observed in humans, which suggests squirrel monkeys may be good models for studying the space adaptation syndrome. Among the wide variety of parameters measured in the rats, most notable was the dramatic loss of muscle mass and increased fragility of long bones. Other interesting rat findings were those of suppressed interferom production by spleen cells, defective release of growth hormone by somatrophs, possible dissociation of circadian pacemakers, changes in hepatic lipid and carbohydrate metabolism, and hypersensitivity of marrow cells to erythropoietin. These results portend a strong role for animals in identifying and elucidating the physiological and anatomical responses of mammals to microgravity

The Newcomb-Benford Law in Its Relation to Some Common Distributions

An often reported, but nevertheless persistently striking observation, formalized as the Newcomb-Benford law (NBL), is that the frequencies with which the leading digits of numbers occur in a large variety of data are far away from being uniform. Most spectacular seems to be the fact that in many data the leading digit 1 occurs in nearly one third of all cases. Explanations for this uneven distribution of the leading digits were, among others, scale- and base-invariance. Little attention, however, found the interrelation between the distribution of the significant digits and the distribution of the observed variable. It is shown here by simulation that long right-tailed distributions of a random variable are compatible with the NBL, and that for distributions of the ratio of two random variables the fit generally improves. Distributions not putting most mass on small values of the random variable (e.g. symmetric distributions) fail to fit. Hence, the validity of the NBL needs the predominance of small values and, when thinking of real-world data, a majority of small entities. Analyses of data on stock prices, the areas and numbers of inhabitants of countries, and the starting page numbers of papers from a bibliography sustain this conclusion. In all, these findings may help to understand the mechanisms behind the NBL and the conditions needed for its validity. That this law is not only of scientific interest per se, but that, in addition, it has also substantial implications can be seen from those fields where it was suggested to be put into practice. These fields reach from the detection of irregularities in data (e.g. economic fraud) to optimizing the architecture of computers regarding number representation, storage, and round-off errors

Eine echtzeitfähige Anwendung für die Steuerung, Regelung und Überwachung sowie die Messdatenerfassung einer experimentellen Verdampferstrecke im Labormaßstab

At the Institute for Energy Systems at the Technical University of Munich a laboratory scale evaporation test rig has been constructed as a pilot plant for a full scale test rig currently under construction. Measurement and control functions have been implemented using NI LabView software in combination with a NI cRIO hardware system. The deterministic control functions are executed on the real time controller of the cRIO system. The deterministic monitoring of critical quantities for the plant’s safety is performed using the FPGA block of the cRIO chassis. Parallel to the deterministic processes, a non-deterministic function for communication exchanges data with a host PC with a user interface. On the host PC, the current state of the plant is displayed to the user, commands to the plant can be entered. At the same time, data can be automatically logged at a rate specified by the user