Phase relations in the systems Cu–O–R2O3(R = Tm, Lu) and Gibbs energies of formation of Cu2R2O5 compounds

The phase relations in the systems Cu–O–R2O3(R = Tm, Lu) have been determined at 1273 K by X-ray diffraction, optical microscopy and electron probe microanalysis of samples equilibrated in evacuated quartz ampules and in pure oxygen. Only ternary compounds of the type Cu2R2O5 were found to be stable. The standard Gibbs energies of formation of the compounds have been measured using solid-state galvanic cells of the type, Pt|Cu2O + Cu2R2O5+ R2O3‖(Y2O3)ZrO2‖CuO + Cu2O‖Pt in the temperature range 950–1325 K. The standard Gibbs energy changes associated with the formation of Cu2R2O5 compounds from their binary component oxides are: 2CuO(s)+ Tm2O3(s)→Cu2Tm2O5(s), ΔG°=(10400 – 14.0 T/K)± 100 J mol–1, 2CuO(s)+ Lu2O3(s)→Cu2Lu2O5(s), ΔG°=(10210 – 14.4 T/K)± 100 J mol–1 Since the formation is endothermic, the compounds become thermodynamically unstable with respect to component oxides at low temperatures, Cu2Tm2O5 below 743 K and Cu2Lu2O5 below 709 K. When the chemical potential of oxygen over the Cu2R2O5 compounds is lowered, they decompose according to the reaction, 2Cu2R2O5(s)→2R2O3(s)+ 2Cu2O(s)+ O2(g) The equilibrium oxygen potential corresponding to this reaction is obtained from the emf. Oxygen potential diagrams for the Cu–O–R2O3 systems at 1273 K are presented.

Electronic structure of early 3d-transition-metal oxides by analysis of the 2p core-level photoemission spectra

The electronic structures of a wide range of early transition-metal (TM) compounds, including Ti and V oxides with metal valences ranging from 2+ to 5+ and formal d-electron numbers ranging from 0 to 2, have been investigated by a configuration-interaction cluster model analysis of the core-level metal 2p x-ray photoemission spectra (XPS). Inelastic energy-loss backgrounds calculated from experimentally measured electron-energy-loss spectra (EELS) were subtracted from the XPS spectra to remove extrinsic loss features. Parameter values deduced for the charge-transfer energy Delta and the d-d Coulomb repulsion energy U are shown to continue the systematic trends established previously for the late TM compounds, giving support to a charge-transfer mechanism for the satellite structures. The early TM compounds are characterized by a large metal d-ligand p hybridization energy, resulting in strong covalency in these compounds. Values for Delta and U suggest that many early TM compounds should be reclassified as intermediate between the charge-transfer regime and the Mott-Hubbard regime.

Chiral synthons from carvone. Part 53. First enantiospecific synthesis of (-)-9-pupukeanone

The first enantiospecific total synthesis of (-)-9-pupukeanone, starting from (R)-carvone employing a combination of Michael-Michael reaction and an intramolecular rhodium carbenoid C H insertion reaction as key steps, is described. (C) 2002 Elsevier Science Ltd. All rights reserved.

Effect of neodymium (Nd) doping on the dielectric and ferroelectric characteristics of sol-gel derived lead zirconate titanate (53/47) thin films

The results of the studies on the effect of rare earth Nd doping on the phase formation behavior and electrical properties of sol-gel derived Pb-1.05(Zr0.53Ti0.47)O-3 (PZT) thin films are presented. The perovskite phase is obtained up to 5 at. % doping and beyond that pyrochlore phase was found to coexist with the perovskite phase in all the films. The transition temperature of undoped lead zirconate titanate (PZT) film was found to be reduced with Nd doping. The Nd doped films also exhibited typical relaxor-type behavior and a diffuse phase transition, similar to that observed in relaxor materials. The introduction of Nd into the PZT lattice probably introduces disorder in the B site of ABO(3) lattice, which causes the observed dielectric relaxation. Efforts were made to isolate the irreversible component contributions in low field dielectric and high field polarization switching behavior. (C) 2001 American Institute of Physics.

Decomposition temperatures of Cu2Ln2O5 (Ln = Tb, Dy, Ho, Er, Tm, Yb, and Lu) compounds

The equilibrium decomposition temperatures of Cu2Ln2O5 (Ln = Tb, Dy, Ho, Er, Tm, Yb, and Lu) compounds have been measured using a combined DTA-TGA apparatus under a flowing Ar + O2 gas mixture, in which the partial pressure of oxygen was controlled at 5.0 × 103 Pa. The Cu2Ln2O5 compounds yield Ln2O3 and Cu2O on decomposition. The decomposition temperature increases monotonically with the atomic number of the lanthanide element. This suggests that the stability of the Cu2Ln2O5 compounds with respect to the component binary oxides increases with decreasing radius of the Ln3+ ion.

studies in terpenoids .53. revision of the structure assigned to a monoterpene isolated from piqueria-trinervia

Unambiguous synthesis of 2-methyl-3-isopropenylanisole (View the MathML source) and 2-isopropenyl-3-methylanisole (View the MathML source) has led to revision, from (View the MathML source) to (View the MathML source), of the structure assigned to a monoterpene phenol ether isolated from View the MathML source.

Thermodynamics of TmRhO3, Phase Equilibria, and Chemical Potentials in the System Tm-Rh-O

Phase equilibria in the system Tm-Rh-O at 1200 K is established by isothermal equilibration of selected compositions and phase identification after quenching to room temperature. Six intermetallic phases (Tm3Rh, Tm7Rh3, Tm5Rh3, Tm3Rh2, TmRh, TmRh2 +/-delta) and a ternary oxide TmRhO3 are identified. Based on experimentally determined phase relations, a solid-state electrochemical cell is devised to measure the standard free energy of formation of orthorhombic perovskite TmRhO3 from cubic Tm2O3 and beta-Rh2O3 in the temperature range from (900 to 1300) K. The results can be summarized as: Delta G(f,ox)(o) +/- 104/J.mol(-1) = -46474 + 3.925(T/K). Invoking the Neumann-Kopp rule, the standard enthalpy of formation of TmRhO3 from its constituent elements at 298.15 K is estimated as -1193.89 (+/- 2.86) kJ.mol(-1). The standard entropy of TmRhO3 at 298.15 K is evaluated as 103.8 (+/- 1.6) J.mol(-1).K-1. The oxygen potential-composition diagram and three-dimensional chemical potential diagram at 1200 K and temperature-composition diagrams at constant partial pressures of oxygen are computed from thermodynamic data. The compound TmRhO3 decomposes at 1688 (+/- 2) K in pure oxygen and at 1583 (+/- 2) K in air at standard pressure.

Chromium isotope variations (delta Cr-53/52) in mantle-derived sources and their weathering products: Implications for environmental studies and the evolution of delta Cr-53/52 in the Earth's mantle over geologic time

Here we report chromium isotope compositions, expressed as delta Cr-53/ 52 in per mil (&) relative to NIST 979, measured in selected Cr-rich minerals and rocks formed by the primary magmatic as well as the secondary metamorphic and weathering processes. The main objectives of this study were: (i) to further constrain the isotope composition of the Earth's mantle Cr inventory and its possible variation during geological history, based on the analysis of globally distributed and stratigraphically constrained mantle-derived chromites; and (ii) to investigate the magnitude and systematics of Cr isotope fractionation during oxidative weathering and secondary alteration (i. e., hydration, serpentinization) of the magmatic Cr sources. Specifically, we analyzed delta Cr-53/ 52 in a set of globally distributed mantle-derived chromites (FeMgCr2O4, n = 30) collected from various locations in Europe, Asia, Africa and South America, and our results confirm that a chromite-hosted Earth's mantle Cr inventory is uniform at - 0.079 +/- 0.129& (2SD), which we named here as a ` canonical' mantle d 53/ 52 Cr signature. Furthermore our dataset of stratigraphically constrained chromites, whose crystallization ages cover most of the Earth's geological history, indicate that the bulk Cr isotope composition of the chromite-hosted mantle inventory has remained uniform, within about +/- 0.100&, since at least the Early Archean times (similar to 3500 million years ago, Ma). To investigate the systematics of Cr isotope fractionation associated with alteration processes we analyzed a number of secondary Cr-rich minerals and variably altered ultramafic rocks (i. e., serpentinized harzburgites, lherzolites) that revealed large positive delta Cr-53/ 52 anomalies that are systematically shifted to higher values with an increasing degree of alteration and serpentinization. The degree of aqueous alteration and serpentinization was quantified by the abundances of fluid-mobile (Rb, K) elements, and by the Loss On Ignition (LOI) parameter, which determines the amount of structurally bound water (OH/ H2O) present in secondary hydrated minerals like serpentine. Overall, we observed that altered ultramafic rocks that yielded the highest LOI values, and the lowest amounts of fluid mobile elements, also yielded the heaviest delta Cr-53/ 52 signatures. Therefore, we conclude that secondary alteration (i.e., hydration, serpentinization) of ultramafic rocks in near-surface oxidative environments tend to shift the bulk Cr isotope composition of the weathered products to isotopically heavier values, pointing to a dynamic redox cycling of Cr in the Earth's crustal and near-surface environments. Hence, if validated by future

Prudentia Iuris, 2000, n° 53 (número completo)

Contenido: Editorial – Derecho Penal y Procesal Penal: Presentación – Jornadas de Derecho Procesal Penal: Los distintos proyectos de reforma al Código Procesal Penal de la Nación / Ricardo Gil Lavedra – Diferentes perfiles del ejercicio de la acción penal / Francisco D’Albora – El Ministerio Público Fiscal / José Cafferata Nores – El Ministerio Público Fiscal en Italia / Giorgio Cherubini – El Ministerio Público Fiscal en la provincia de Buenos Aires / Eduardo D’Empaire – El recurso extraordinario / Jorge Reynaldo Vanossi – La situación del imputado / Hernán Munilla Lacasa – Incorporación de prueba al debate / Roberto Raúl Daray – El recurso de casación en el nuevo Código Procesal Penal de la provincia de Buenos Aires / Carlos A. Mahiques – El procesado en estado de cautividad / Jorge Kent – Jornadas Internacionales de Derecho Penal: El derecho penal y el orden social / Alfredo Battaglia – Del Comité Especial a la Conferencia de Roma / Juan Manuel Gramajo – La protección de la vida inocente en vísperas del siglo veintiuno / Alberto Rodríguez Varela – Derecho Laboral : nuevas normas y doctrinas: Reformas laborales. Leyes 25.013, 25.165 y 25.250 / Jorge Rodríguez Mancini ; Juan A. Confalonieri (h), comentario de Héctor César Guisado – Recargos en indemnizaciones por despido : Ley 25.323 / Hugo Roberto Mansueti – In Memoriam – Recensiones

Sapientia, 1959, Vol. XIV, nº 53 (número completo)

Contenido: Soledad y presencia de la persona humana / Octavio N. Derisi – El significado y el alcance del “ese” en Santo Tomás / Octavio N. Derisi – Examen de la doctrina husserliana sobre el conocimiento como constitución de su objeto / Juan A. Casaubón – Implicación material en Juan de Santo Tomás / Alberto Moreno – Notas y comentarios -- Bibliografía

Deputados brasileiros : repertório biográfico : 53ª legislatura, 2007-2011

Reúne as informações pessoais e sobre a vida profissional e política dos 513 deputados eleitos no pleito de 3 de outubro de 2006, no momento inicial da 53ª Legislatura, tendo por objetivo constituir-se em importante fonte de pesquisa e de preservação da memória da Câmara dos Deputados.

Funcionamento dos guardas municipais nas principais capitais do país, considerando : a. se atuam com poder de polícia; b. se substituem a polícia militar na falta de efetivo desta instituição; c. se auxiliam a polícia militar no combate ao crime; d. se têm porte de arma; e e. se contribuem para a segurança pública

Consultoria Legislativa - Área XVII - Segurança Pública e Defesa Nacional.

Emendas individuais ao orçamento da união dos deputados federais do Estado da Paraíba da 53ª legislatura : uso eleitoral das emendas individuais ao orçamento

O presente trabalho consiste na análise das emendas individuais ao Orçamento da União dos deputados federais do Estado da Paraíba, na 53ª legislatura, para verificar se elas atendem as prioridades sociais da população, baseando-se no Índice de Desenvolvimento Humano onde identificamos o índice de pobreza elevado, ou se elas são destinadas mais com intuito de lograr êxito nas campanhas eleitorais. São analisadas também quais as principais áreas que as emendas são destinadas e se há ou não privilégios em sua destinação, de acordo com o colegiado eleitoral dos parlamentares. Para tanto, descrevemos um pouco sobre o Estado e posteriormente apresentamos uma visão geral do orçamento. Conclui-se que fica comprovado o quanto é presente a oligarquia na política do Estado e, por isso, revela as ações paroquialistas dos deputados que utilizam as emendas orçamentárias individuais para levar benefícios para seus redutos eleitorais, bem como para localidades que possam lhe prospectar uma votação significativa e assim garantir sua reeleição ou eleição dos seus indicados.

A atuação do Conselho de Ética nos casos de quebra de decoro parlamentar nas 52ª e 53ª legislaturas

Propõe a avaliação das representações apreciadas pelo Conselho de Ética e Decoro Parlamentar da Câmara dos Deputados da 52ª e 53ª Legislaturas. Com base na análise do conjunto das representações protocoladas entre os anos 2003 a 2011, pretende-se responder se os instrumentos normativos e legais são eficazes no combate à quebra de decoro ou se de alguma forma favorecem a impunidade. Identifica os dispositivos legais que tratam do decoro parlamentar, como o Código de Ética e Decoro Parlamentar da Câmara dos Deputados, a Constituição da República Federativa do Brasil e o Regimento Interno da Câmara dos Deputados. São ainda relacionados alguns processos que resultaram em perda de mandato ou que fixaram normas interpretativas.