The behaviour of a single catalyst pellet for the selective hydrogenation of ethyne in ethene

The steady-state and dynamic behaviour of a single Pd---Al2O3 catalyst particle is studied for the selective hydrogenation of ethyne in the presence of ethene, without addition of carbon monoxide. The particle-to-gas heat transfer in the reactor is characterized. During selective hydrogenation, not only the ignition and the extinction phenomena but also oscillatory behaviour is observed. The nature of the single and multipeak oscillations is discussed. With a dynamic model, based on relatively simple kinetic equations and an additional slow mechanism, e.g. the formation of ethylidyne on the catalyst surface, the qualitative features of this system can be described

The Effects of Environmental Context on Correct and False Recognition Memory

The Effects of Environmental Context on Correct and False Recognition Memory Kevin Kuper This study investigates how human memory, both correct recognition and false recognition memory can be influenced by environmental context. For the study, participants were randomly assigned to one of the two groups. Both groups received lists of semantically related words and were asked to remember them in a typical lab. Then, for the recognition memory test, one group of the participants moved into a new room, which looked very different from the first room (different context condition), while the other group stayed in the same room (same context condition). Performance was measured as the rate of ‘yes’ responses to the test words. For the targets, which were the words presented during the study session, recognition memory performance was greater for the same context condition than for the different context condition. For the critical lures, which were the words not presented during the study session but related to the sematic categories, recognition memory performance did not differ between the two conditions. The results provide evidence for the context-dependent memory of correct recognition and suggest that environment context has no or little effect on false recognition

Positive and Negative Ion Motion in Thermal Oxide on Silicon by Radiochemical and MOS ANALYSIS

Metal-oxide-silicon capacitor and radiochemical analyses of anion in sodium contamination failure mod

CESAM-voorspellingen voor 1990-1994

Het CESAM-model is lets minder optimistisch over de Nederlandse economic dan het\ud Centraal Planbureau. Zowel ten opzichte van de Macro Economische Verkenning als het pas verschenen Centraal Economisch Plan voorspelt CESAM een geringere produktie- en investeringsgroei. Een lichtpuntje is de geringere inflatie. Een tijdelijke loskoppeling van de gulden van de D-mark heeft volgens CESAM positieve gevolgen voor de Nederlandse economic. Ook verhoging van de overheidsinvesteringen kan voordelen bieden

Improved methods for simulating nearly extremal binary black holes

Astrophysical black holes could be nearly extremal (that is, rotating nearly as fast as possible); therefore, nearly extremal black holes could be among the binaries that current and future gravitational-wave observatories will detect. Predicting the gravitational waves emitted by merging black holes requires numerical-relativity simulations, but these simulations are especially challenging when one or both holes have mass $m$ and spin $S$ exceeding the Bowen-York limit of $S/m^2=0.93$. We present improved methods that enable us to simulate merging, nearly extremal black holes more robustly and more efficiently. We use these methods to simulate an unequal-mass, precessing binary black hole coalescence, where the larger black hole has $S/m^2=0.99$. We also use these methods to simulate a non-precessing binary black hole coalescence, where both black holes have $S/m^2=0.994$, nearly reaching the Novikov-Thorne upper bound for holes spun up by thin accretion disks. We demonstrate numerical convergence and estimate the numerical errors of the waveforms; we compare numerical waveforms from our simulations with post-Newtonian and effective-one-body waveforms; we compare the evolution of the black-hole masses and spins with analytic predictions; and we explore the effect of increasing spin magnitude on the orbital dynamics (the so-called "orbital hangup" effect).Comment: 18 pages, 18 figure

Photoemission spectroscopy and sum rules in dilute electron-phonon systems

A family of exact sum rules for the one-polaron spectral function in the low-density limit is derived. An algorithm to calculate energy moments of arbitrary order of the spectral function is presented. Explicit expressions are given for the first two moments of a model with general electron-phonon interaction, and for the first four moments of the Holstein polaron. The sum rules are linked to experiments on momentum-resolved photoemission spectroscopy. The bare electronic dispersion and the electron-phonon coupling constant can be extracted from the first and second moments of spectrum. The sum rules could serve as constraints in analytical and numerical studies of electron-phonon models.Comment: 4 page