Adsorption of di-2-pyridyl ketone salicyloylhydrazone on Amberlite XAD-2 and XAD-7 resins: Characteristics and isotherms

The adsorption of DPKSH onto Amberlite XAD-2 (styrene resin) and XAD-7 (acrylic ester resin) has been investigated, at (25 +/- 1)degrees C and pH 4.7. The experimental equilibrium data were fitted to the Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) models. These three models provide a very good fit for both resins and the respective constants K(L), K(F), and K(DR) were calculated. For the same DPKSH concentration interval, the minimum time of contact for adsorption maximum at XAD-7 was smaller than at XAD-2 and the maximum amount of DPKSH adsorbed per gram of XAD-2 is smaller than at XAD-7. The investigation indicates that the mean sorption energy (E) characterizes a physical adsorption and the surfaces of both resins are energetically heterogeneous. The constants obtained in these studied systems were correlated and compared with those obtained for the silica gel/DPKSH system. (C) 2008 Published by Elsevier Inc.

Spectrophotometric determination of zinc in pharmaceutical and biological samples with di-2-pyridyl ketone benzoylhydrazone: A simple, fast, accurate and sensitive method

A simple, fast, accurate, and sensitive spectrophotometric method was developed to determine zinc(II). This method is based on the reaction of Zn(II) with di-2-pyridyl ketone benzoylhydrazone (DPKBH), at pH=5.5 and 50% (v/v) ethanol. Beers law was obeyed in the range 0.020-1.82 mu g mL(-1) with a molar apsorptivity of 3.64 x 10(4) L mol(-1) cm(-1), and a detection limit (3) of 2.29 mu g L-1. The action of some interfering ions was verified and the developed method applied to pharmaceutical and biological samples. The results were then compared with those obtained by using a flame atomic absorption technique.

L’insegnamento online delle lingue all’Università del Dalarna (Svezia) : Esperienze di collaborazione internazionale e prospettive future

This paper describes the on-line teaching strategies for languages adopted at the University of Dalarna (Sweden) and the experience of a collaboration carried out with the Language Centre of the University of Parma that led to the administration of an international course in Italian for specific purposes. According to the results of its first administration, the promotion of advanced forms of "virtual mobility" together with the prospective of a joint degree in Italian language and culture will be outlined.

Osservazioni sul lessico di alcune lettere del Seicento del capitano Lorenzo Adami

Analisi di alcuni termini svedesi presenti nelle lettere di Lorenzo Adami, inviato nel 1665 a Stoccolma dalla regina Cristina di Svezia.

Gli studi italiani sulla regina Cristina di Svezia negli ultimi cinquant'anni

Queen Christina of Sweden (1626-1689)) is probably the most important individual to directly link the cultures of Sweden and Italy, and thus fascinate scholars over the last four centuries. In the last fifty years, research on and interest in this monarch has been particularly intense. This has led to current international scientific debate concerning all the different cultural expressions in which Queen Cristina was particularly involved. However, until now there has been lacking a comprehensive work to illustrate the development of scientific research in Italian on Queen Christina. This article, therefore, without claiming to be exhaustive, aims to fill this gap by identifying the main direction of current research. The article, after briefly introducing previous works (both Italian and Swedish), demonstrates how the first major renaissance of international studies on Queen Cristina took place in Sweden in the early 1960s. Even more important was the subsequent turning point in 1989, when the tercentenary of the death of Queen Christina was celebrated and the Azzolino Collection at the Biblioteca Comunale in Jesi was opened. The article focuses on the studies in Italian during this latter period. To make the exposition more organic and, importantly, more accessible to those readers interested in only one particular aspect of the scientific studies about Queen Christina, the studies in Italian since 1689 are divided into different subject areas.

A dimeric tellurastannoxane carbonate cluster, tetra-tert-butyl-di-µ3-carbonato-tetrakis-[4-(N,N-dimethylamino)phenyl]di-µ-oxo-ditelluriumditin chloroform tetrasolvate

The title compound, [Sn₂Te₂(C₄H₉)₄(CO₃)₂O₂(C₈H₁₀N)₄]·4CHCl₃ or [(p-Me₂NC₆H₄)₂TeOSn^tBu₂CO₃]₂·4CHCl₃, contains an almost planar centrosymmetric inorganic Sn₂Te₂O₈C₂ core and hypercoordinated Sn and Te atoms. The structure features four secondary intramolecular Te...O contacts.

Ab initio calculations, Raman and NMR investigation of the plastic crystal di-methyl pyrrolidinium iodide

Above 110 °C the symmetric di-methyl-pyrrolidinium iodide salt forms a plastic crystal phase of interest in the area of new electrolyte materials. In this study ab initio calculations of this material has been conducted in order to assign the vibrational spectra. Raman spectroscopy measurements on the solid salt as well as on the salt dissolved in different solvents has been performed and these have been compared to the theoretical spectra. Furthermore, Raman spectra as a function of temperature have been recorded to investigate possible changes in inter-ionic interaction and/or structure through the phase transition. 1H NMR linewidth measurements as a function of temperature showed a large decrease in linewidth above 100 °C, attributed here to an increase in mobility in agreement with a previously reported phase transition at ~110 °C.

Plane wave scattering by a spherical di-electric particle in motion : a relativistic extension of the Mie theory

Light scattering from small spherical particles has applications in a vast number of disciplines including astrophysics, meteorology optics and particle sizing. Mie theory provides an exact analytical characterization of plane wave scattering from spherical dielectric objects. There exist many variants of the Mie theory where fundamental assumptions of the theory has been relaxed to make generalizations. Notable such extensions are generalized Mie theory where plane waves are replaced by optical beams, scattering from lossy particles, scattering from layered particles or shells and scattering of partially coherent (non-classical) light. However, no work has yet been reported in the literature on modifications required to account for scattering when the particle or the source is in motion relative to each other. This is an important problem where many applications can be found in disciplines involving moving particle size characterization. In this paper we propose a novel approach, using special relativity, to address this problem by extending the standard Mie theory for scattering by a particle in motion with a constant speed, which may be very low, moderate or comparable to the speed of light. The proposed technique involves transforming the scattering problem to a reference frame co-moving with the particle, then applying the Mie theory in that frame and transforming the scattered field back to the reference frame of the observer.

The corrosion inhibition of aluminium alloy 7075-T651 with cerium and Mischmetal di phenyl phosphate

Previous studies have shown that cerium diphenyl phosphate (Cedpp) 3 is a very effective inhibitor of corrosion of aluminium alloys in chloride solutions. This paper describes the results of further studies using electrochemical and constant immersion corrosion tests to compare the effectiveness of Ce(dpp) 3 and Mischmetal diphenyl phosphate Mm(dpp) 3 as inhibitors of corrosion pitting on AA7075-T651 aluminium alloy. The results shows that both Ce(dpp) 3 and Mm(dpp) 3 are excellent inhibitors of pitting corrosion of this alloy in very aggressive environments of continuously aerated 0.1M and 1.0M sodium chloride (NaCl) solutions. Polarisation tests indicate that these compounds act as a cathodic inhibitors by reducing the rate of the oxygen reduction reaction, which results in a decreased corrosion current density and a separation of the corrosion potential from the pitting potential. This inhibition is thought to be due to the formation of a surface film consisting of rare earth metal oxide, aluminium oxide and a cerium-aluminium organo-phosphate complex. Surface analysis data from scanning electron microscopy and X-ray Energy Dispersive Spectroscopy show the complex nature of this protective film. This work further develops our understanding about the mechanisms through which these complex films form, and how inhibition occurs in the presence of these compounds.

"Comida di buteco" : o botequim, um pedaço da alma carioca, em uma iniciativa de construção de comunidade virtual de marca

O botequim é um estabelecimento que serve comida caseira, em porções generosas e a baixo custo, também servindo petiscos típicos e bebidas, isto num ambiente informal, com arquitetura e decoração típicas. Durante muito tempo teve sua imagem associada ao ócio e ao vício, ao ponto dos proprietários rejeitarem a associação dos seus estabelecimentos ao termo botequim. Esta visão mudou com a recente valorização do termo botequim, através do lançamento de guias como o “Rio Botequim”, “Guia Veja Comer & Beber”, das colunas “Pé-limpo” e “Pé-sujo”, ambas publicadas no caderno “Rio Show” do jornal O Globo, e do concurso “Comida di Buteco”. Apesar de haver em todo território brasileiro 297.000 estabelecimentos semelhantes que ocupam em torno de 1.600.000, não são facilmente encontrados estudos que abordem o botequim de um ponto de vista empresarial. Objeto deste estudo o concurso “Comida di Buteco” foi criado em 2000 e atualmente acontece em 16 cidades de 8 estados brasileiros e conta com mais de 370 estabelecimentos concorrentes. O presente estudo tem por objetivo apresentar de que maneira os organizadores do concurso incentivam através de sua página no Facebook a formação de uma comunidade virtual de marca em torno do concurso e se esta se estende aos botequins participantes. Para a realização deste objetivo esta pesquisa se apoia em um referencial teórico mapeado dentro da literatura disponível sobre: o botequim; o concurso “Comida di Buteco”; marca e a criação de seus significados; comunidade de marca e comunidade virtual de marca. Optou-se por abordar o fenômeno de forma qualitativa usando-se a etnografia como metodologia para a coleta de dados e no tratamento destes aplicou-se a análise de discurso mediado por computador. O resultado da análise é confrontado com o referencial teórico e conclui-se que a organização do concurso “Comida di Buteco” incentiva a formação de uma comunidade virtual de marca em torno do concurso, através da troca de informações e opiniões, da divulgação do concurso e estabelecimentos, do incentivo a autoconsciência de grupo. Não foi possível comprovar se esta comunidade se estende aos estabelecimentos concorrentes, porém verificou-se que estes tiram proveito da divulgação de suas marcas pelo concurso.