Decomposition of nitrogen and dinitrogen oxides on copper and copper(I) oxide in elemental analysis by reaction gas chromatography

The decomposition of NO and N₂O on Cu and Cu₂O packings was studied in view of the simultaneous determination of N and S in organic compounds by the Pregl-Dumas method in a system of reaction gas chromatography, and the mass balance of the reactions taking place was carried out. The amounts of NO and N₂O that are decomposed on the reduction packing at temperatures within 883 and 1263 °K are quoted. The reduction activity of both packings toward NO decreases with increasing temperature, while both the reduction and sorption activity of Cu₂O is markedly lower than that of the Cu one. No significant sorption of NO was observed at temperatures within 883 and 923 °K and no sorption of gaseous N₂ and N₂O occurred on either packing.     

Interaction Processes for Unions of Facets,the Asymptotic Behaviour with Increasing Intensity

In the series of models with interacting particles in stochastic geometry, a further contribution presents the facet process which is defined in arbitrary Euclidean dimension. In 2D, 3D specially it is a process of interacting segments, flat surfaces, respectively. Its investigation is based on the theory of functionals of finite spatial point processes given by a density with respect to a Poisson process. The methodology based on L ₂ expansion of the covariance of functionals of Poisson process is developed for U-statistics of facet intersections which are building blocks of the model. The importance of the concept of correlation functions of arbitrary order is emphasized. Some basic properties of facet processes, such as local stability and repulsivness are shown and a standard simulation algorithm mentioned. Further the situation when the intensity of the process tends to infinity is studied. In the case of Poisson processes a central limit theorem follows from recent results of Wiener-Ito theory. In the case of non-Poisson processes we restrict to models with finitely many orientations. Detailed analysis of correlation functions exhibits various asymptotics for different combination of U-statistics and submodels of the facet process.     

Über eine halbautomatische mikrogravimetrische Schnellmethode zur Bestimmung von Kohlenstoff in organischen Verbindungen

Zusammenfassung Eine einfache gravimetrische Schnellmethode zur Kohlenstoffbestimmung wurde ausgearbeitet. Der Absorptionsapparat für Kohlendioxyd befindet sich im Wägeraum, ist durch eine Kapillare direkt mit der Verbrennungsapparatur verbunden und wird nach deren Spülung, ohne abgewischt zu werden, sogleich gewogen. Die Gesamtdauer der Bestimmung beträgt 10 Minuten. Die Genauigkeit der Methode ist die gleiche wie bei anderen üblichen Methoden.

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Summary A simple gravimetric rapid method for determining carbon was developed. The absorption apparatus for carbon dioxide is located in the weighing room; it is connected directly with the combustion apparatus by means of a capillary, and after the latter is swept out is weighed immediately without being wiped off. The total time for a determination is 10 minutes. The precision of the method is the same as that of other customary methods.

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Résumé On a mis au point une méthode de dosage gravimétrique du carbone, simple et rapide. L'appareil d'absorption du gaz carbonique se trouve sur la balance, directement relié par un capillaire à l'appareil de combustion. Il est pesé aussitôt après son lavage, sans être essuyé. La durée totale du dosage s'élève à 10 minutes. L'exactitude de la méthode est la même que celle des autres méthodes habituelles.

     

Planar Segment Processes with Reference Mark Distributions,Modeling and Estimation

Methodology and Computing in Applied Probability - The paper deals with planar segment processes given by a density with respect to the Poisson process. Parametric models involve reference...     

Central limit theorem for Gibbsian U-statistics of facet processes

A special case of a Gibbsian facet process on a fixed window with a discrete orientation distribution and with increasing intensity of the underlying Poisson process is studied. All asymptotic joint moments for interaction U-statistics are calculated and the central limit theorem is derived using the method of moments.     

Phase transition in a multiferroic Ni-Mn-Ga single crystal

ABSTRACT

We studied martensitic phase transformation, crystal structure and twinned microstructure of resulting martensite of a Ni-Mn-Ga single crystal as essential conditions for magnetic shape memory effect. Thermal dependence of electric resistivity, magnetic susceptibility and dilatation measurements were measured to characterise kinetics of the transformation. With the help of XRD analysis and optical microscopy we evaluated the hierarchical twinning microstructure in the 10M martensite.     

Thermal behavior of Fe<Subscript>2</Subscript>O<Subscript>3</Subscript>/TiO<Subscript>2</Subscript> mesoporous gels

Summary Titania-based photocatalytic materials were prepared by sol-gel method using Fe³⁺ and polyethyleneglycol (PEG₆₀₀) as additives. Thermogravimetry (TG), differential thermal analysis (DTA) and evolved gas analysis (EGA) with MS detection were used to elucidate processes that take place during heating of Fe³⁺ containing titania gels. The microstructure development of the Fe₂O₃/TiO₂ gel samples with and without PEG₆₀₀ admixtures was characterized by emanation thermal analysis (ETA) under in situ heating in air. A mathematical model was used for the evaluation of ETA results. Surface area and porosity measurements of the samples dried at 120&deg;C and the samples preheated for 1 h to 300 and 500&deg;C were compared. From the XRD measurements it was confirmed that the crystallization of anatase took place after thermal heating up to 600&deg;C.