gravuras, desenhos de Tarsila do Amaral

A set of nine engravings of Tarsila do Amaral, donated to the Museum of Contemporary Art of the University of Sao Paulo in 1998, by the Central Bank of Brazil, raises questions about the circulation and appropriation of her work in Brazil. In this article, we recover the origin of the works in the album Tarsila: gravuras (Tarsila: engravings, 1971) and the serigraph Louvor à natureza (Praise to Nature, undated); we discuss the technical aspects of these works, placing them in the context of Tarsila's production of engravings and bringing them closer to the artist's drawings; finally, we develop new analyses of the works based on the images generated by the Infrared Reflectography examination. In this sense, the goal is to contribute to the conservation of the history of these works, resignifying their interpretation. Um conjunto de nove gravuras incorporado ao acervo do Museu de Arte Contemporânea da Universidade de São Paulo no ano de 1998, por doação do Banco Central do Brasil, levanta questões sobre a circulação e a apropriação da obra de Tarsila do Amaral no país. Neste artigo, recuperamos a procedência das obras do álbum Tarsila: gravuras (1971) e da serigrafia Louvor à natureza (s.d.); discutimos os aspectos técnicos dessas obras, situando-as no âmbito da produção de gravuras de Tarsila do Amaral e aproximando-as dos desenhos da artista; e, por fim, desenvolvemos novas análises sobre as obras a partir das imagens geradas pelo exame de Reflectografia no Infravermelho. Nesse sentido, o objetivo é contribuir para a conservação da história dessas obras, ressignificando a sua interpretação

Stopping power of Au for silver ions at low velocities

Energy loss measurements for the slowing down of Ag ions in Au, in the velocity range 1:6v0 < v < 4:4v0, where v0 is the Bohr velocity, are presented. The measurements were performed using the Doppler shift technique and also with a new method, where a secondary beam of low velocity heavy ions is produced by elastic scattering of the accelerated beam. The results are compared to the SRIM2000 calculations (www.srim.org) and to recent measurements in this velocity region

High spin states in \'La130\'.

Estados de spin elevado do núcleo duplamente ímpar ANTPOT.130 La foram estudados através de técnicas de espectroscopia gama em linha utilizando reações do tipo fusão-evaporação. Os raios gama de ANTPOT.130 La foram inicialmente identificados pelo método de reações cruzadas: ANTPOT.121 Sb (ANTPOT.12 C, 3n) ANTPOT.130 La e ANTPOT.124 Te (ANTPOT.10 B, 4n) ANTPOT.130 La. Foram realizadas medidas de função de excitação, distribuição angular e coincidência --t para a reação ANTPOT.121 Sb (ANTPOT.12 C, 3n) ANTPOT.130 La com energia de feixe de 54 MeV. Duas bandas rotacionais foram observadas com configurações h IND.11/2 g IND. 7/2 e h IND.11/2 g IND. 11/2 onde a segunda banda mostra um pequeno valor de signature splitting ( 50 KeV) que pode indicar uma forma ligeiramente triaxial. Os resultados experimentais serão comparados com os núcleos vizinhos ímpares e ímpar-ímpar e também interpretados segundo modelos de Roto mais duas quasipartículas e Cranked Shell Model.High-spin states in the doubly odd nucleus ANTPOT.130 La have been studied using in-beam spectroscopy techinques with fusion evaporation reactions. The ganma rays of ANTPOT.130 La were initially identified by cross-beam reactions ANTPOT.121 Sb (ANTPOT.12 C, 3n) ANTPOT.130 La and ANTPOT.124 Te (ANTPOT.10 B, 4n) ANTPOT.130 La. Excitation functions, angular distributions and --t coincidences were measured using the reaction ANTPOT.121 Sb (ANTPOT.12 C, 3n) ANTPOT.130 La at E IND.BEAM = 54 MeV. Two rotational bands were observed with the configuration h IND.11/2 g IND. 7/2 and h IND.11/2 g IND. 11/2. The second band shows a small signature splitting of 50 KeV which could indicate a slightly triaxial shape. The results will be compared with the framework of Triaxial Rotor plus Two-Quasiparticule Model as well as Cranked Shell Model

Transitional Nuclei in the region of A = 130

Com o objetivo de ampliar o conhecimento da estrutura dos núcleos duplamente ímpares da região de massa A = 130- 140, foram medidos os estados de spin elevado do ANTIPOT. 138 Pr, que se aproxima da camada fechada N = 82, através de técnicas de espectroscopia y em linha utilizando a reação ANTPOT. 128 Te (ANTIPOT. 14 N,4ny). Pela primeira vez, três bandas rotacionais foram observadas neste núcleo. Uma análise teórica da sistemática desta região foi feita com base nos modelos de \"Cranking Shell Model\" e \"Projected Shell Model\". De um modo geral, uma boa concordância foi obtida entre os resultados experimentais e teóricos. O primeiro modelo indica a coexistência de formas no ANTIPOT. 138 Pr (N=79}, enquanto o segundo sugere forma unicamente oblata. Por outro lado, os dois modelos prevêm uma transição de forma de prolato (N = 73) para oblato (N = 79) passando por uma região de triaxialidade em torno de N = 77.With the view of extending the systematics of the odd-odd, A = 130 - 140 mass region nuclei towards the N =82 closed shell, high spin states in 138Pr nucleus have been investigated with the 128 Te(l4N,4n7) reaction, using on-line 7-ray spectroscopy techniques. For the first time three rotational bands were observed in this nucleus. A theoretical analysis of the mass region A = 130 - 140 was carried out with the Cranking Shell Model and the Projected Shell Model. Generally speaking, a good agreement was obtained between the experimental and the theoretical results. The first model indicates a shape coexistence in the 138 Pr (N =79) nucleus, while the second one shows an oblate shape. On the other hand, both models suggest a shape transition from prolate (N=73) to oblate (N=79) passing through a triaxial region around N=77

Transitional Nuclei in the region of A = 130

Com o objetivo de ampliar o conhecimento da estrutura dos núcleos duplamente ímpares da região de massa A = 130- 140, foram medidos os estados de spin elevado do ANTIPOT. 138 Pr, que se aproxima da camada fechada N = 82, através de técnicas de espectroscopia y em linha utilizando a reação ANTPOT. 128 Te (ANTIPOT. 14 N,4ny). Pela primeira vez, três bandas rotacionais foram observadas neste núcleo. Uma análise teórica da sistemática desta região foi feita com base nos modelos de \"Cranking Shell Model\" e \"Projected Shell Model\". De um modo geral, uma boa concordância foi obtida entre os resultados experimentais e teóricos. O primeiro modelo indica a coexistência de formas no ANTIPOT. 138 Pr (N=79}, enquanto o segundo sugere forma unicamente oblata. Por outro lado, os dois modelos prevêm uma transição de forma de prolato (N = 73) para oblato (N = 79) passando por uma região de triaxialidade em torno de N = 77.With the view of extending the systematics of the odd-odd, A = 130 - 140 mass region nuclei towards the N =82 closed shell, high spin states in 138Pr nucleus have been investigated with the 128 Te(l4N,4n7) reaction, using on-line 7-ray spectroscopy techniques. For the first time three rotational bands were observed in this nucleus. A theoretical analysis of the mass region A = 130 - 140 was carried out with the Cranking Shell Model and the Projected Shell Model. Generally speaking, a good agreement was obtained between the experimental and the theoretical results. The first model indicates a shape coexistence in the 138 Pr (N =79) nucleus, while the second one shows an oblate shape. On the other hand, both models suggest a shape transition from prolate (N=73) to oblate (N=79) passing through a triaxial region around N=77

High spin states in \'La130\'.

Estados de spin elevado do núcleo duplamente ímpar ANTPOT.130 La foram estudados através de técnicas de espectroscopia gama em linha utilizando reações do tipo fusão-evaporação. Os raios gama de ANTPOT.130 La foram inicialmente identificados pelo método de reações cruzadas: ANTPOT.121 Sb (ANTPOT.12 C, 3n) ANTPOT.130 La e ANTPOT.124 Te (ANTPOT.10 B, 4n) ANTPOT.130 La. Foram realizadas medidas de função de excitação, distribuição angular e coincidência --t para a reação ANTPOT.121 Sb (ANTPOT.12 C, 3n) ANTPOT.130 La com energia de feixe de 54 MeV. Duas bandas rotacionais foram observadas com configurações h IND.11/2 g IND. 7/2 e h IND.11/2 g IND. 11/2 onde a segunda banda mostra um pequeno valor de signature splitting ( 50 KeV) que pode indicar uma forma ligeiramente triaxial. Os resultados experimentais serão comparados com os núcleos vizinhos ímpares e ímpar-ímpar e também interpretados segundo modelos de Roto mais duas quasipartículas e Cranked Shell Model.High-spin states in the doubly odd nucleus ANTPOT.130 La have been studied using in-beam spectroscopy techinques with fusion evaporation reactions. The ganma rays of ANTPOT.130 La were initially identified by cross-beam reactions ANTPOT.121 Sb (ANTPOT.12 C, 3n) ANTPOT.130 La and ANTPOT.124 Te (ANTPOT.10 B, 4n) ANTPOT.130 La. Excitation functions, angular distributions and --t coincidences were measured using the reaction ANTPOT.121 Sb (ANTPOT.12 C, 3n) ANTPOT.130 La at E IND.BEAM = 54 MeV. Two rotational bands were observed with the configuration h IND.11/2 g IND. 7/2 and h IND.11/2 g IND. 11/2. The second band shows a small signature splitting of 50 KeV which could indicate a slightly triaxial shape. The results will be compared with the framework of Triaxial Rotor plus Two-Quasiparticule Model as well as Cranked Shell Model

Evaluating the Presence of Porosity in Bazilian Archaeological Pottery associating X-radiography and Pixe.

X-Radiography technique has been used effectively for decades to evaluate and identify differences in homogeneities in samples. It is a simple, fast and non-destructive technique that provides a view of internal structure helping investigating manufacturing details of archaeological ceramics. Characteristics of the paste used in the matrix composition can be derived using PIXE technique through the determination of the major elemental composition allowing the calculation of its expected density. Combining this information with x-ray images is possible to check for differences in the average density of material indicating the presence of homogeneously distributed porosity or temper. The present work evaluates the porosity in a set of native Brazilian pottery sherds that were collected in the Aldeia Lalima archaeological site, located at Mato Grosso do Sul State.CNPqCAPE

Metal location and thickness in a multilayered sheet by measuring K alpha/K beta, L alpha/L beta and L alpha/L gamma X-ray ratios

When a multilayered material is analyzed by means of energy-dispersive X-ray fluorescence analysis, then the X-ray ratios of K alpha/K beta, or L alpha/L beta and L alpha/L gamma, for an element in the multilayered material, depend on the composition and thickness of the layer in which the element is situated, and on the composition and thickness of the superimposed layer (or layers). Multilayered samples are common in archaeometry, for example, in the case of pigment layers in paintings, or in the case of gilded or silvered alloys. The latter situation is examined in detail in the present paper, with a specific reference to pre-Columbian alloys from various museums in the north of Peru. (C) 2009 Elsevier B.V. All rights reserved.CNR (Consiglio Nazionale delle Ricerche)CNR (Consiglio Nazionale delle Ricerche

Infrared analysis of ion beam irradiated polymers

Irradiation with heavy ions can produce several modifications in the chain structure of polymers. These modifications can be related to scissioning and cross-linking of chemical bonds. which depend on the ion fluence and the density of energy deposited in the material. Stacked thin film Makrofol-KG (R) samples were irradiated with 350 MeV Au(26+) ions and FTIR absorption spectroscopy was used to determine the bond changes in the samples. Data on the absorption bands as a function of the fluence indicated a higher probability for simple-bonds scissioning than for double-bonds scissioning and no dependence on the number of double bonds breaking with ion fluence. Since sample irradiation was done in a non-track-overlapping regime, a novel process for double bonds formation is suggested: the excitation of a site in the material by only one incident ion followed by a double bond formation during the de-excitation process. (C) 2009 Elsevier B.V. All rights reserved