Physical properties of edible films based on cassava starch as affected by the plasticizer concentration

The aim of this work was to investigate the effect of glycerol contents on physical properties of cassava starch films. The films were prepared from film-forming solutions (FFS) with 2g cassava starch/100g water and 0, 15, 30 and 45g glycerol/100g starch, and were analysed to determine its mechanical properties by tensile tests, the glass-transition temperature (T-g) by differential scanning calorimetry (DSC) and the crystallinity by X-ray diffraction (XRD). The infrared spectra of the films were also recorded. The resistance values of the films decreased, while those of the elasticity increased with an increase in glycerol concentration due to the plasticizer effect of glycerol, which was also observed in DSC curves. The T-g of the films prepared decreased with the glycerol content. However, for samples with 30 and 45g glycerol/100g starch, two T-g curves were observed, probably due to a phase separation phenomenon. According to the XRD diffractograms, the films with 0 and 15gglycerol/100g starch presented an amorphous character, but some tendency to show crystalline peaks were observed for films with 30 and 45g glycerol/100g starch. The results obtained with Fourier transform infrared (FTIR) corroborated these observations. Copyright (C) 2007 John Wiley & Sons, Ltd.

Electronic and optical properties of grossular garnet (Ca(3)Al(2)Si(3)O(12)): An ab initio study

The electronic and optical properties of grossular garnet are investigated using density functional theory (DFT) within generalized gradient approximation (GGA). The calculated lattice parameters are in good agreement with the experiment data. The electronic structure shows that grossular has a direct band gap of 5.22 eV. The dielectric functions, reflective index, extinction coefficient, reflectivity and energy-loss spectrum are calculated. The optical properties of grossular are discussed based on the band structure calculations. The O 2p states and Si 3s play a major role in these optical transitions as initial and final states, respectively. The absorption spectrum is localized in the ultraviolet range between 30 and 250 nm. Finally, we concluded that pure grossular crystal does not absorb radiation in the visible range. (c) 2009 Elsevier B.V. All rights reserved.

First evidence of crystalline KHSO(4):Mn grown by an aqueous solution method and the investigation of the effect of ionizing radiation exposure

In this work, KHSO(4):Mn crystals doped with Mn and K(2)SO(4) were synthesized using an aqueous solution method. The samples were exposed to ionizing radiation in order to observe the effects on their physical properties. Raman spectroscopy was used to identify the structure of the crystals by detecting the vibrational frequencies of the crystalline lattice. Electron paramagnetic resonance (EPR) was used to study the creation of paramagnetic centers arising from exposure to ionizing radiation. This new synthesis method produces high quality K(2)SO(4) and KHSO(4):Mn crystals and allows control of structural, morphological, optical and magnetic properties. (C) 2009 Elsevier B.V. All rights reserved,

The electronic and optical properties of sodalite (Na(8)Al(6)Si(6)O(24)Cl(2)) from first principles

This study reports the results of ab initio electronic and optical calculations for pure socialite crystal using the linear augmented plane wave (LAPW) method within density functional theory (DFT). The calculated electronic structure revealed predominantly orbital characters of the valence band and the conduction band, and enabled us to determine the type and the value of the fundamental gap of the compound. The imaginary part of the dielectric tensor, extinction coefficient and refraction index were calculated as functions of the incident radiation wavelength. It is shown that the O 2p states and Na 3s states play the major role in optical transitions as initial and final states, respectively. The absorption spectrum is localized in the ultraviolet range between 40 and 250 nm. Furthermore, we concluded that the material does not absorb radiation in the visible range. (C) 2009 Elsevier Ltd. All rights reserved.

Magnetic and optical characterization of Mn-doped PbS nanocrystals supported in oxide glass matrix

The evidence of successful growth of Mn-doped PbS (Pb(1-x)Mn(x)S) nanocrystals (NCs) in SiO(2)-Na(2)CO(3)-Al(2)O(3)-PbO(2)-B(2)O(3) template, using the fusion method, is reported on in this study. The as-grown Pb(1-x)Mn(x)S NC is characterized using optical absorption, electron paramagnetic resonance, and atomic force microscopy. The data are discussed in terms of two distinct scenarios, namely a core-doped and a shell-doped nanostructure. (C) 2008 Elsevier B.V. All rights reserved.

Does the TL supralinearity occur during irradiation in alkali halides?

In the last ten to fifteen years, there has been a predominant belief that the linear-supralinear-sublinear behaviour of the TL response of alkali halides to the radiation dose necessarily occurs in the heating stage for TL reading. It is based on the assumption that coloration in these crystals grows linear-sublinearly with the dose during irradiation. Since both colour centre and TL centre are based on the same point defects the TL response should also grow linear-sublinearly with dose. In 1950, half a dozen authors showed that the coloration of F-centres in KCl takes place in two stages, the second one being responsible for non-linear behaviour. In this paper, we show that indeed in NaCl both F-centre and TL grow linear-supralinear-sublinearly with the dose during irradiation.

"Livros em festa" : a cultura organizacional da Feira do Livro de Porto Alegre

A Feira do Livro de Porto Alegre é um ritual de compra e venda de livros realizado, ininterruptamente há 51 anos, na Praça da Alfândega. Este trabalho objetivou desvendar a cultura organizacional do evento atentando para os fatos administrativos levado a efeito na Praça. Para tanto, os seguintes objetivos específicos foram traçados: a) verificar os aspectos culturais compartilhados ou não entre os membros da Comissão Executiva da Feira do Livro; b) identificar os palcos, os atores, os autores e os homenageados presentes na cultura organizacional da Feira do Livro; e, c) identificar e analisar os significados atribuídos pelos diferentes atores da Feira (organizadores/ proprietários de livrarias/ vendedores/ compradores/ escritores) ao livro. O método que permitiu a realização dessa pesquisa foi o etnográfico, tendo como técnicas de pesquisa a observação participante, as entrevistas semi-estruturadas e consulta a materiais documentais. O Referencial que deu suporte as análises foram provenientes da Antropologia e da Administração, constituindo, um trabalho interdisciplinar. Tanto os conceitos de rituais (TURNER, 1974; VAN GENNEP, 1978; DAMATTA, 1978-97; PEIRANO, 2001-03 e TEIXEIRA, 1988) quanto o de cultura organizacional (CAVEDON, 2001) permitiram considerar que a cultura organizacional da Feria do Livro de Porto Alegre apresenta aspectos que a homogeneízam como aspectos que a heterogeneízam, sendo que ambos influenciam sobremaneira nos fatos administrativos levados a efeito na Praça. Além disso, desvendar os aspectos divergentes dessa cultura permitiu expor as lutas simbólicas existentes no grupo de participantes deste evento, de modo que, atentar para a heterogeneidade cultural propicia elucidar a distribuição do poder dentro da organização. No que tange aos aspectos homogeneizantes é perceptível que os mesmos colaboram para a manutenção do status quo social. No caso especifico do objeto de estudo, por sua intrínseca relação entra a organização e a sociedade, emerge de forma evidente que tanto a identidade do porto-alegrense influencia na cultura organizacional do rito quanto à organização do ritual auxilia na construção da identidade desses “citadinos”, uma vez que a identidade se dá pela via relacional.

Feiras livres : cidades de um só dia, aprendizados para a vida inteira

La tesis problematiza constelaciones creativas de saberes marcados por múltiples subjetividades en un espacio singular de las ciudades: la feria libre. Lugar de cambios financieros, pero también afectivos, simbólicos y míticos, ese espacio se mantiene al lado de los lugares comerciales asépticos y climatizados como son los supermercados e hipermercados de los espacios urbanos y de las metrópolis. Las ferias, por su carácter itinerante y sus personajes nómades modernos, son capaces de suscitar múltiples observaciones, divagaciones, afecciones y construcción de conocimientos. En la feria libre del barrio de Alecrim en la ciudad de Natal-RN/Brasil, principal contexto de referencia de esta investigación, en medio de tantos estímulos movilizadores de los órganos de los sentidos, salta a los ojos el elevado contingente de niños y adolescentes ejerciendo las múltiples actividades laborales. En Brasil el trabajo infantil es encajado en prohibiciones prescritas por leyes que recubren singularidades. Sin la pretensión de negar la importancia de tales convenciones y reglas, las reflexiones aquí puestas ultrapasan las amarras homogeneizantes del discurso oficial instituido de prohibición, problematizando a partir de la feria la idea de una caótica y pulsante aula al aire libre en la cual se construyen saberes más próximos de una lógica del sensible (Claude Lévi-Strauss). La feria es un laboratorio de construcción de conocimientos pertinentes (Edgar Morin), aquellos que religan fenómeno y contexto sin oponer manipulación y tiempo real de aplicabilidad de los saberes construidos. En esa escuela sin paredes, puertas, ventanas, cuadros negros o programas, los saberes de la tradición (Conceição Almeida) son probados y compartidos por niños y adolescentes que viven constantemente con un tipo de cambio de bienes y palabras en permanente construcción. En los puestos de la feria y para más allá de ellos encontramos sujetos híbridos (Bruno Latour) que se estructuran por medio de mecanismos creativos capaces de hacerlos navegar en las incertidumbres caóticas de sus vidas. Los aprendizajes de la feria fueron o son la pulsión de reinvención de esos sujetos aparentemente encarcelados en el conformismo como fatalidad última, portadores de historias embarazadas de simbologías tristes y felices que exponen la cara de un humano en permanente combustión, construcción e incertidumbre

Aníbal Pinto Santa Cruz

El 3 de enero falleció don Aníbal Pinto Santa Cruz, desde 1986 Director de esta Revista. El hecho nos invade de profundo pesar, y deja un hondo vacío en la institución. La Comisión Económica de las Naciones Unidas para América Latina y el Caribe se benefició por muchos años del brillo intelectual y la calidad humana de Don Aníbal, quien por varios años se desempeñó como Director de la División de Desarrollo Económico. Más que eso, fue una de las personalidades que le dio una clara identidad institucional a la Secretaría de la CEPAL. A la profundidad y lucidez de sus análisis sobre Chile y su proceso de desarrollo, unía una auténtica vocación latinoamericana, que lo llevó a realizar sólidos y valiosos aportes al progreso de las ideas en nuestra región. Pertenecía por derecho propio al selecto grupo de aquellos pensadores que mediante nuevas categorías y conceptos abren a los demás una visión enriquecida de la realidad. No es sorprendente, por lo tanto, que en toda la región existan discípulos y ex alumnos suyos. Persona de gran generosidad intelectual e impaciencia ante el saber convencional y las intolerancias de cualquier lado del espectro académico o político, Aníbal Pinto recibió el reconocimiento de la comunidad académica internacional, expresado en el Premio Iberoamericano de Economía "Raúl Prebisch", el Doctorado Honoris Causa de la Universidad de Campinas, en Brasil, y el Premio Nacional de Humanidades y Ciencias Sociales de Chile, 1995. En meses recientes, recibió dos distinciones adicionales: la primera, de sus colegas de la CEPAL, que le rindieron un homenaje con ocasión del quincuagésimo aniversario de las Naciones Unidas; la segunda, al presentarse una recopilación de sus escritos publicada por la Universidad Nacional Autónoma de México en un acto que se llevó a cabo en la Feria del Libro de Santiago, en diciembre pasado. La CEPAL ha tenido la infinita suerte de contar entre sus cuadros con grandes personalidades que han dejado un legado de valores, principios e ideas-fuerza; si se quiere, forjadores de instituciones. Es más, si hay algo que distingue a la CEPAL del resto de las entidades de las Naciones Unidas, es ese hecho. Entre los nombres que más resonarán, sin duda figurará el de Aníbal Pinto. Por eso, y por sus excepcionales cualidades humanas, lo recordaremos con afecto y admiración.

Notas de la CEPAL Nº 57

Ambiciosas metas para desarrollar Sociedades de Información hacia 2010Recesión en Estados Unidos reduciría remesas hacia América LatinaSesenta años de la CEPAL: su contribución al desarrollo de América Latina y el Caribe y los desafíos emergentes. Columna de opinión de José Luis Machinea, Secretario Ejecutivo de la CEPALPrecisiones. Presupuestar en América Latina y el Caribe. Por Ricardo MartnerIndicadores. Desarrollo de TIC en la regiónLa Feria va a la plaza: "Experiencias en innovación social", Porto Alegre 2007Publicaciones recientesCalendario de eventos

Evidências da relação entre evolução da gestão ambiental e a adoção de práticas de Green Supply Chain Management no setor eletroeletrônico brasileiro

The objective of this research is to examine if the environmental management evolution is positively related towards the adoption of green supply chain management practices (GSCM) by companies in the electronics sector in Brazil. To reach this objective, a quantitative research was conducted by survey with 100 companies in the electronics sector in Brazil. The collected data were processed using descriptive statistics, Exploratory Factor Analysis and Structural Equation Modeling. The most important results are: in the sample, GSCM practices to the recovery of investment, as the resale of scrap and other waste materials, and the adequacy with legislation and auditing, obtained high scores; and research hypothesis (H1) was confirmed and considered statistically valid, indicating that, in fact, the evolution of environmental management influences the adoption of GSCM practices.

Magnetic and optical investigation of 40SiO(2)center dot 30Na(2)O center dot 1Al(2)O(3)center dot(29-x) B2O3 center dot xFe(2)O(3) glass matrix

Samples of 40SiO(2)center dot 30Na(2)O center dot 1Al(2)O(3)center dot(29 - x)B2O3 center dot xFe(2)O(3) (mol%), with 0.0 <= x <= 17.5, were prepared by the fusion method and investigated by electron paramagnetic resonance (EPR), optical absorption (OA) and Mossbauer spectroscopy (MS). The EPR spectra of the as-synthesized samples exhibit two well-defined EPR signals around g = 4.27 and g = 2.01 and a visible EPR shoulder around g = 6.4, assigned to isolated Fe3+ ion complexes (g = 4.27 and g = 6.4) and Fe3+-based clusters (g = 2.01). Analyses of both EPR line intensity and line width support the model picture of Fe3+-based clusters built in from two sources of isolated ions, namely Fe2+ and Fe3+; the ferrous ion being used to build in iron-based clusters at lower x-content (below about x = 2.5%) whereas the ferric ion is used to build in iron-based clusters at higher x-content (above about x = 2.5%). The presence of Fe2+ ions incorporated within the glass template is supported by OA data with a strong band around 1100 nm due to the spin-allowed E-5(g)-T-5(2g) transition in an octahedral coordination with oxygen. Additionally, Mossbauer data (isomer shift and quadrupole splitting) confirm incorporation of both Fe2+ and Fe3+ ions within the template, more likely in tetrahedral-like environments. We hypothesize that ferrous ions are incorporated within the glass template as FeO4 complex resulting from replacing silicon in non-bridging oxygen (SiO3O-) sites whereas ferric ions are incorporated as FeO4 complex resulting from replacing silicon in bridging-like oxygen silicate groups (SiO4). (C) 2012 Elsevier Masson SAS. All rights reserved.