Düsseldorf, Universiẗat, Diss., 2002.

[No abstract available] / Applied Science, Faculty of / Chemical and Biological Engineering, Department of / Graduate

Carbon stars are relatively uncommon, luminous, cool stars whose spectra exhibit exceptionally strong bands of carbon-containing molecules. This is direct evidence of extensive nucleosynthesis, as will occur in the late stages of stellar evolution. The two aspects investigated here are their luminosities and atmospheric carbon and nitrogen isotope ratios. The luminosities are derived through the study of those carbon stars which are members of double star systems. Since the companion star is apparently normal and thus of known luminosity, the carbon star luminosity is directly attainable. Photometry and spectroscopy of suspected binaries yield absolute visual magnitudes for a dozen stars as bright as -4.7, and bolo-metric magnitudes primarily in the range -4 to -8. This means they are slightly mere luminous than normal giants. The isotopic ratios have been deduced by a comparison of synthetic spectra with the observed near infrared stellar spectra. The synthetic spectra were calculated by direct integration of the flux emerging from an appropriate model atmosphere, and contain lines primarily of the Bed band system of the CN molecule. A new analysis technique, used in time series analysis, which is based on the mutual coherence of the spectra being compared and makes full use of the entire spectrum, has been employed. By varying the parameters describing the synthetic spectrum, including the isotopic ratio, the coherence can be maximized and the isotopic ratio of the stellar spectrum deduced. Results for five carbon stars yield ¹²C/¹³C ratios in the range 2.5 to 30. A search was also made for the isotopes ¹⁴C and ¹³N; ¹⁴C was not found, while a tentatively positive result is reported for ¹⁵N. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

No description available.

No description available.

Thesis (M. Arch.)--Massachusetts Institute of Technology, Dept. of Architecture, 1995. / Includes bibliographical references (p. 89-92). / With the much-commented upon shifts in the global economy and the problematizing of traditional social, economic, cultural, and political relationships, the role of architecture as a "public" practice has fallen under scrutiny. The "privatization of public space", resulting from the overt merging of "public" concerns (typically represented through the State) and "private" interests (in our society, usually defined by groups with significant power over investment decisions) is often taken as symptomatic of a general trend towards the breakdown of democracy itself. Here, however, it is important to differentiate between what can be termed the "public sphere", or the abstract discursive arena where thought is (re)produced and debated, and "public space", or the actual built spaces of personal encounter among strangers. Certainly, since the Enlightenment when the terms first acquired widespread currency, the latter has depended upon some conception of the former. / Eric Chia-Kong Mar. / M.Arch.

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Informe de Seminario para optar al grado de Licenciada en Ciencias Hist?ricas / Facultad de Filosof?a y Humanidades / Desde una perspectiva hist?rica, buscamos determinar las caracter?sticas particulares de la concepci?n de la muerte y de su ritualizaci?n, en el Jap?n moderno y contempor?neo. Entendidas como construcciones socioculturales, consideramos que su punto de proyecci?n es la comunidad, especialmente el grupo familiar (ie) cohesionado a trav?s de los lazos de reciprocidad y perpetuado en lo sagrado por medio de la veneraci?n a los ancestros. A pesar de sus transformaciones y manipulaciones, la familia japonesa a?n se entiende como una comunidad eterna, pues sus miembros se mantienen unidos a?n despu?s de su deceso, en una soluci?n de continuidad entre los vivos y los muertos. Postulamos, pues, que muerte no es entendida ni representada como un corte; sino como una transici?n entre vidas comunitarias, adem?s de una posibilidad de crecimiento para el alma y un acceso a lo sagrado igualitario para todos.

This thesis focuses on preparation of novel compounds suitable for nonlinear optics (NLO). In particular, the target property is the second harmonic generation (SHG) and the group of interest are salts of the cations with delocalized electrons which can serve as carriers of the NLO properties. In particular, four derivatives of the highly interesting molecule of guanidine were selected and their NLO potential was proven by quantum chemical computations. In total, twenty new structures were described and those with the noncentrosymmetric structure assembly were examined for the SHG efficiency. Four of the prepared compounds exhibited a noticeable SHG efficiency, two of them even comparable to urea. The most promising compound, the guanylurea hydrogen phosphite (GUHP), was examined in more detail while many interesting NLO properties were revealed. The results of this work are presented also in 10 attached publications which are an integral part of the thesis. Keywords: nonlinear optics, second harmonic generation, guanidine derivatives, guanylurea, N-phenylbiguanide, N,N-dimethylbiguanide, N,N,N˝-triphenylguanidine

Thiazyl chloride, the monomer of trichlorotrithiazene, reacts with fluorinated olefins to form N-chlorosulfenylaziridines. Four members of this new class of compounds have been prepared. Fluorine NMR, carbon-13 NMR, mass spectrometry, infrared spectroscopy, and elemental analysis have been used to characterize these compounds.