A class of almost C_0(K)-C*-algebras

We consider in this paper the family of exponential Lie groups Gn,µ, whose Lie algebra is an extension of the Heisenberg Lie algebra by the reals and whose quotient group by the centre of the Heisenberg group is an ax + b-like group. The C*-algebras of the groups Gn,µ give new examples of almost C0(K)-C*-algebras.

Kinetic and product studies for the oxidtion of organic sulfides and sulfoxides in the presence of transition metal complexes

Rates and products of the oxidation of diphenyl sulfide, phenyl methyl sulfide, p-chlorophenyl methyl sulfide and diphenyl sulfoxide have been determined. Oxidants included t-Bu02H alone, t-Bu02H plus molybdenum or vanadium catalysts and the molybdenum peroxo complex Mo0(02)2*HMPT. Reactions were chiefly carried out in ethanol at temperatures ranging from 20° to 65°C. Oxidation of diphenyl sulfide by t-Bu02H in absolute ethanol at 65°C followed second-order kinetics with k2 = 5.61 x 10 G M~1s"1, and yielded only diphenyl sulfoxide. The Mo(C0)g-catalyzed reaction gave both the sulfoxide and the sulfone with consecutive third-order kinetics. Rate = k3[Mo][t-Bu02H][Ph2S] + k^[Mo][t-Bu02H][Ph2S0], where log k3 = 12.62 - 18500/RT, and log k^ = 10.73 - 17400/RT. In the absence of diphenyl sulfide, diphenyl sulfoxide did not react with t-Bu02H plus molybdenum catalysts, but was oxidized by t-Bu02H-V0(acac)2. The uncatalyzed oxidation of phenyl methyl sulfide by t-Bu02H in absolute ethanol at 65°C gave a second-order rate constant, k = 3.48 x 10~"5 M^s""1. With added Mo(C0)g, the product was mainly phenyl methyl sulfoxide; Rate = k3[Mo][t-Bu02H][PhSCH3] where log k3 = 22.0 - 44500/RT. Both diphenyl sulfide and diphenyl sulfoxide react readily with the molybdenum peroxy complex, Mo0(02)2'HMPT in absolute ethanol at 35°C, yielding diphenyl sulfone. The observed features are mainly in agreement with the literature on metal ion-catalyzed oxidations of organic compounds by hydroperoxides. These indicate the formation of an active catalyst and the complexation of t-Bu02H with the catalyst. However, the relatively large difference between the activation energies for diphenyl sulfide and phenyl methyl sulfide, and the non-reactivity of diphenyl sulfoxide suggest the involvement of sulfide in the production of an active species.

Photoacoustic effect: Some applications in laser technology

The discovery of the Photoacoustic (PA) effect was a remarkable achievement and was relegated to the scientific footnotes of the nineteenth century. However, after the advent of lasers and sophisticated electronics this effect was rediscovered and it has established itself as an important research and analytical tool in numerous areas, including physics, chemistry, biology and medicine. Quite recently, this phenomenon has made its impact in the field of laser technology for applications such as the developments of highly efficient active media for lasers, high quality optics and sensitive laser power monitoring devices. This thesis presents the work carried out by the author in this field during the past few years at the Department of Physics in Cochin University of Science and Technology. The studies discussed here are mostly based on the development of a sensitive PA laser power meter and its various applications using different laser systems available in the laboratory. This includes the development of a current regulated CW C0 laser and its application in material processing. The thesis contains seven chapters which by and large are self contained with separate abstracts and references. The first chapter which is divided into two parts presents an introduction to the PA effect and its present status. Part A reviews the basic theory of laser and gives a sum mary of various lasers and their applications. Part B presents a brief description of PA effect and its suitability as a spectroscopic tool followed by its applications to various branches of science and technology.

Chemical Evaluation of Selected Organics and Trace Metals in the Mangrove Macroflora Of Cochin

Mangroves are considered to play a significant role in global carbon cycling. Themangrove forests would fix CO2 by photosynthesis into mangrove lumber and thus decrease the possibility of a catastrophic series of events - global warming by atmospheric CO2, melting of the polar ice caps, and inundation of the great coastal cities of the world. The leaf litter and roots are the main contributors to mangrove sediments, though algal production and allochthonous detritus can also be trapped (Kristensen et al, 2008) by mangroves due to their high organic matter content and reducing nature are excellent metal retainers. Environmental pollution due to metals is of major concern. This is due to the basic fact that metals are not biodegradable or perishable the way most organic pollutants are. While most organic toxicants can be destroyed by combustion and converted into compounds such as C0, C02, SOX, NOX, metals can't be destroyed. At the most the valance and physical form of metals may change. Concentration of metals present naturally in air, water and soil is very low. Metals released into the environment through anthropogenic activities such as burning of fossils fuels, discharge of industrial effluents, mining, dumping of sewage etc leads to the development of higher than tolerable or toxic levels of metals in the environment leading to metal pollution. Of course, a large number of heavy metals such as Fe, Mn, Cu, Ni, Zn, Co, Cr, Mo, and V are essential to plants and animals and deficiency of these metals may lead to diseases, but at higher levels, it would lead to metal toxicity. Almost all industrial processes and urban activities involve release of at least trace quantities of half a dozen metals in different forms. Heavy metal pollution in the environment can remain dormant for a long time and surface with a vengeance. Once an area gets toxified with metals, it is almost impossible to detoxify it. The symptoms of metal toxicity are often quite similar to the symptoms of other common diseases such as respiratory problems, digestive disorders, skin diseases, hypertension, diabetes, jaundice etc making it all the more difficult to diagnose metal poisoning. For example the Minamata disease caused by mercury pollution in addition to affecting the nervous system can disturb liver function and cause diabetes and hypertension. The damage caused by heavy metals does not end up with the affected person. The harmful effects can be transferred to the person's progenies. Ironically heavy metal pollution is a direct offshoot of our increasing ability to mass produce metals and use them in all spheres of existence. Along with conventional physico- chemical methods, biosystem approachment is also being constantly used for combating metal pollution

Finite element method for the accurate solution of diatomic molecules

We present the Finite-Element-Method (FEM) in its application to quantum mechanical problems solving for diatomic molecules. Results for Hartree-Fock calculations of H_2 and Hartree-Fock-Slater calculations of molecules like N_2 and C0 have been obtained. The accuracy achieved with less then 5000 grid points for the total energies of these systems is 10_-8 a.u., which is demonstrated for N_2.

An anharmonic force field for SO3

An anharmonic force field for SO3 based on the valence force model has been investigated. The results of extending the model to include some further estimated cubic interaction potential constants have also been investigated. The phenomenological parameters calculated from both model force fields agree with those few values which have been experimentally determined. A calculation of the inertia defect has been made, and thus the value of C0 has been determined. The equilibrium structure has been determined to be: re = 1.4184 ± 0.0010 Å.

Qualidade física de um Latossolo Vermelho cultivado com soja submetido a níveis de compactação e de irrigação

Manter uma boa qualidade física do solo é importante para preservar o meio ambiente, além de maximizar a produtividade das plantas. Um solo compactado poderá interferir na densidade, na porosidade e na resistência do solo à penetração, influenciando no crescimento radicular. A presente pesquisa objetivou avaliar a qualidade física de um Latossolo Vermelho eutroférrico, textura argilosa, com a cultivar de soja CAC-1, submetido a quatro níveis de compactação e três níveis de irrigação, utilizando os atributos físicos do solo, assim como a correlação do sistema radicular com a produtividade da cultura. O delineamento experimental foi em blocos ao acaso, com parcelas subdivididas, com quatro repetições. Os níveis de compactação foram: C0 = 0, C2 = 2, C4 = 4 e C6 = 6 passadas, no mesmo local, de um trator de 11 t. Foram coletadas amostras indeformadas de solo nas entrelinhas da cultura da soja, para determinação dos atributos físicos, nas camadas de 0-0,10 e 0,10-0,20 m. A produtividade máxima da soja foi obtida com a resistência do solo à penetração de 0,71 MPa. O sistema radicular correlacionou-se inversamente com a produtividade da soja.

Effect of acibenzolar-S-methyl and Saccharomyces cerevisiae on the activation of Eucalyptus defences against rust

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Atividade de quitinases e peroxidases em folhas de eucalipto em diferentes estágios de desenvolvimento após tratamento com acibenzolar-S-metil (ASM) e inoculação com Puccinia psidii

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efeito de indutores bióticos e abióticos na atividade de quitinase e peroxidase e no controle da ferrugem causada por Puccinia psidii em eucalipto

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Utilização de análise de segregantes agrupados na identificação de marcadores ligados a genes que controlam a resistência à ferrugem (Puccinia psidii Winter) em Eucalyptus sp.

Devido a grande importância da cultura de Eucalyptus no Brasil, empresas do setor florestal têm buscado através de programas de melhoramento genético, reduzir as perdas de produção e atender a demanda do mercado de papel e celulose. Um exemplo, é a busca por genes de resistência a doenças, principalmente a ferrugem causada por Puccinia psidii Winter, que resulta em redução da produtividade em plantas altamente suscetíveis. No presente trabalho, mudas de Eucalyptus pertencentes a uma geração F1, provenientes do cruzamento controlado entre parentais híbridos E. grandis X E. urophylla, sendo eles resistente e suscetível, foram inoculadas com Puccinia psidii em casa de vegetação e acompanhadas até o aparecimento dos sintomas da ferrugem. Foram classificadas, em dois grupos: resistentes (ausência de sintomas) e suscetíveis (presença de sintomas e esporulação). As amostras de DNA foram comparadas com o uso de marcadores moleculares associado ao método de BSA (Bulked Segregant Analysis). O polimorfismo entre os grupos foi geneticamente relacionado ao loco que determina a característica de resistência ou sucetibilidade. Dentre os 720 primers testados, 19 foram polimórficos, porém, apenas o marcador AK 01 manteve-se presente, quando testado em todos os indivíduos da população, mostrando-se a uma distância genética estimada de 20 cM em repulsão ao gene de resistência.

Effect of combined bending strain and thermal cycling on the voltage-current characteristic curves of Bi-2223 tapes

High critical temperature superconductors are evolving from a scientific research subject into large-scale application devices. In order to meet this development demand they must withstand high current capacity under mechanical loads arising from thermal contraction during cooling from room temperature down to operating temperature (usually 77 K) and due to the electromagnetic forces generated by the current and the induced magnetic field. Among the HTS materials, the Bi2Sr2Ca2Cu3Ox, compound imbedded in an Ag/AgMg sheath has shown the best results in terms of critical current at 77 K and tolerance against mechanical strain. Aiming to evaluate the influence of thermal stress induced by a number of thermal shock cycles we have evaluated the V-I characteristic curves of samples mounted onto semicircular holders with different curvature radius (9.75 to 44.5 mm). The most deformed sample (epsilon = 1.08%) showed the largest reduction of critical current (40%) compared to the undeformed sample and the highest sensitivity to thermal stress (I-c/I-c0 = 0.5). The V-I characteristic curves were also fitted by a potential curve displaying n-exponents varying from 20 down to 10 between the initial and last thermal shock cycle.

Qualidade estrutural de um latossolo vermelho submetido à compactação

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)