Propriedade rural, posse e meio ambiente: uma ponderação harmoniosa

A presente tese tem por objetivo defender, sob a visão do direito civil-constitucional e da função promocional do direito, a inter-relação entre os direitos de posse, propriedade e do meio ambiente e a possibilidade de uma ponderação harmoniosa em caso de desequilíbrio entre esses direitos. Utiliza-se para tanto a dimensão analítica, empírica e normativa. A dimensão analítica tem por objetivo investigar os conceitos jurídicos envolvidos na pesquisa, especialmente em relação à propriedade e à sua função socioambiental. A relação entre tais conceitos sobressai através da análise da função socioambiental da propriedade, da posse enfatizando-se os aspectos da legislação ambiental. O direito fundamental ao meio ambiente é estudado como direito e dever de todos conforme disposto no art. 225 da Constituição de 1988, e, nesse ponto, diretamente eficaz nas relações interprivadas. Aborda-se, na dimensão empírica e normativa essencialmente aspectos práticos, com foco na jurisprudência, especialmente do Supremo Tribunal Federal (STF) e do Superior Tribunal de Justiça (STJ). A ponderação harmoniosa entre a propriedade, a posse e o meio ambiente, busca o equilíbrio na efetivação desses direitos, inclusive mediante a aplicação dos princípios do direito econômico. Por meio da ponderação, é possível alcançar, de forma mais eficiente do que o modelo tradicional de subsunção, uma resposta adequada e fundamentada para os casos difíceis, especialmente na efetivação e na restauração do equilíbrio entre a posse, a propriedade e o meio ambiente quando esses princípios, no caso concreto, colidem uns com os outros. Sobretudo, pretende-se concretizar os direitos fundamentais segundo exigências do pós-positivismo, por meio da aproximação entre o Direito e a Ética, com o fim de se alcançar a Justiça para o caso concreto.

Cyclotron harmonic emission in a Penning discharge

Microwave noise emission at the harmonics of the electron cyclotron frequency from the magnetized plasma column of a Penning discharge is investigated experimentally. The harmonic emission spectrum is observed using oxygen gas in a variety of discharge configurations. It is found that grid stabilization of the plasma column has very little effect on the emission spectrum. Measurements of the shape and location of the harmonic emission lines are described in detail. On the basis of a microwave interferometer measurement of the electron density, it is concluded that the existence of a hybrid layer somewhere on the plasma column is a necessary condition for the observation of harmonic emission. The relaxation time and the cathode voltage dependence of the harmonic emission are investigated using a pulse modulation technique. It is found that the emission intensity increases rapidly with the magnitude of the cathode voltage and that the relaxation time decreases with increasing neutral gas pressure. High intensity nonharmonic radiation is observed and identified as resulting from a beam-plasma wave instability thereby eliminating the same instability as a possible source of the harmonic emission. It is found that the collective experimental results are in reasonable agreement with the single particle electrostatic radiation theory of Canobbio and Croci.

Spectroscopic investigations of inter- and intramolecular processes in crystalline benzene

I. Introductory Remarks

A brief discussion of the overall organization of the thesis is presented along with a discussion of the relationship between this thesis and previous work on the spectroscopic properties of benzene.

II. Radiationless Transitions and Line broadening

Radiationless rates have been calculated for the ³B_1u→¹A_1g transitions of benzene and perdeuterobenzene as well as for the ¹B_2u→¹A_1g transition of benzene. The rates were calculated using a model that considers the radiationless transition as a tunneling process between two multi-demensional potential surfaces and assuming both harmonic and anharmonic vibrational potentials. Whenever possible experimental parameters were used in the calculation. To this end we have obtained experimental values for the anharmonicities of the carbon-carbon and carbon-hydrogen vibrations and the size of the lowest triplet state of benzene. The use of the breakdown of the Born-Oppenheimer approximation in describing radiationless transitions is critically examined and it is concluded that Herzberg-Teller vibronic coupling is 100 times more efficient at inducing radiationless transitions.

The results of the radiationless transition rate calculation are used to calculate line broadening in several of the excited electronic states of benzene. The calculated line broadening in all cases is in qualitative agreement with experimental line widths.

III. ³B_1u←¹A_1g Absorption Spectra

The ³B_1u←¹A_1g absorption spectra of C₆H₆ and C₆D₆ at 4.2˚K have been obtained at high resolution using the phosphorescence photoexcitation method. The spectrum exhibits very clear evidence of a pseudo-Jahn-Teller distortion of the normally hexagonal benzene molecule upon excitation to the triplet state. Factor group splitting of the 0 – 0 and 0 – 0 + v exciton bands have also been observed. The position of the mean of the 0 – 0 exciton band of C₆H₆ when compared to the phosphorescence origin of a C₆H₆ guest in a C₆D₆ host crystal indicates that the “static” intermolecular interactions between guest and hose are different for C₆H₆ and C₆D₆. Further investigation of this difference using the currently accepted theory of isotopic mixed crystals indicates that there is a 2cm^-1 shift of the ideal mixed crystal level per hot deuterium atom. This shift is observed for both the singlet and triplet states of benzene.

IV. ³E_1u←¹A_1g, Absorption Spectra

The ³E_1u←¹A_1g absorption spectra of C₆H₆ and C₆D₆ at 4.2˚K have been obtained using the phosphorescence photoexcitation technique. In both cases the spectrum is broad and structureless as would be expected from the line broadening calculations.