989 resultados para NUCLEAR SCIENCE


Relevância:

60.00% 60.00%

Publicador:

Resumo:

Organic nonlinear optical single crystals of Methyl para-Hydroxy Benzoate (MHB) have been grown using gel-solution technique. These crystals are cut along z-axis and are bombarded with Ag14+ ions of energy 100 MeV. The results show an increase in refractive index at the ion irradiated region. The dielectric constant of the irradiated crystal is increased more than 15 times compared to that of a nonirradiated crystal. The result of these changes and comparative study of second harmonic generation (SHG) efficiency before and after irradiation is discussed.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

El presente trabajo tiene como finalidad caracterizar conceptos y elementos clave del caos y de la complejidad existente en la relacin entre las organizaciones y la comunidad. Esta relacin parte de la base de satisfacer las necesidades de los actores involucrados y, as mismo, mejorar el desempeo de cada uno, y contribuir al bienestar de la sociedad y a la perdurabilidad de las empresas. Para alcanzar el objetivo planteado, inicialmente se hace necesario contextualizar conceptos que estarn presentes durante todo el escrito. Por esto se expondrn trminos como teora de la complejidad, teora del caos, los aspectos ms representativos de la relacin comunitaria y el marketing y su impacto en las comunidades. La teora de la complejidad permitir entender los sistemas como un todo, en donde las relaciones e interacciones de cada una de sus diferentes partes nos conducen a innumerables escenarios posibles. Tambin se buscar entender la importancia de la relacin organizacin-comunidad, ya que la comunidad puede jugar un papel determinante cuando las organizaciones se adaptan a los cambios. Es de suma importancia establecer relaciones estratgicas con la comunidad, entendiendo a la comunidad como un sistema o grupo social con determinadas caractersticas, que permitan tanto a las organizaciones como a la misma comunidad entender, comprender y satisfacer eficazmente las necesidades subyacentes y, as, llegar a establecer un entorno de retroalimentacin continua y sostenibilidad a lo largo del tiempo. Actualmente, el funcionamiento del mundo ha cambiado en cierta medida, ya que antes la base del conocimiento se centraba en funcin del orden y la regularidad. Ahora, en cambio, se destaca la creatividad y la dinmica que son causadas por el desorden y la irregularidad presentes en los sistemas. El mundo se plantea como un grupo de innumerables sistemas auto-organizados, donde su funcionamiento puede provocar resultados impredecibles o aleatorios. La materia de complejidad en los sistemas se ha desarrollado por diferentes autores segn aproximaciones desde diferentes ramas de la ciencia, como la ciberntica, basada en los mecanismos de retroalimentacin y control; desde la teora general de los sistemas, que da nfasis en el dinamismo presente en los sistemas y cmo la organizacin est presente en su estructura. En el presente proyecto se realizar un estudio de tipo terico-conceptual: se seleccionarn las bases de datos, fuentes de informacin y los documentos ms representativos o que proporcionen la mayor informacin posible que permita el completo entendimiento de la investigacin y de sus alcances propuestos. Es as que esta investigacin busca aportar ms elementos dentro de los diferentes estudios que pretenden explicar y mejorar la perdurabilidad de las empresas bajo las diferentes lneas de investigacin. A travs del tiempo, el GIPE ha ido evolucionando de acuerdo con los resultados de las investigaciones y se ha centrado en cuatro lneas de investigacin: Liderazgo, Realidad, Estrategia y Gerencia. El proyecto de investigacin Relacin de las organizaciones con el medio y marketing hace parte de la lnea de gerencia y busca identificar oportunidades gerenciales para las organizaciones que las acerquen al conocimiento y manejo de las reas funcionales (Facultad de Administracin, 2013). Adems, el proyecto se adentra en las organizaciones en entornos complejos y su relacin con la comunidad, y se observa as la organizacin como un ser vivo que contribuye al bienestar de la sociedad que, finalmente, es lo que garantiza su perdurabilidad.

Relevância:

60.00% 60.00%

Publicador:

Relevância:

60.00% 60.00%

Publicador:

Relevância:

60.00% 60.00%

Publicador:

Resumo:

The radiation food processing has been demonstrating great effectiveness in the attack of pathogenic agents, while little compromising nutritional value and sensorial properties of foods. The mate (Ilex paraguariensis), widely consumed product in South America, generally in the form of infusions with hot or cold water, calls of chimarrao or terere, it is cited in literature as one of the best sources phenolic compounds. The antioxidants action of these constituent has been related to the protection of the organism against the free radicals, generated in alive, currently responsible for the sprouting of some degenerative illness as cancer, arteriosclerosis, rheumatic arthritis and cardiovascular clutters among others. The objective of that work was to evaluate the action of the processing for gamma radiation in phenolic compounds of terere beverage in the doses of 0, 3, 5, 7 and 10 kGy. The observed results do not demonstrate significant alterations in phenolic compounds of terere beverage processed by gamma radiation. Crown Copyright (C) 2009 Published by Elsevier Ltd. All rights reserved.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Activity concentrations of dissolved U-234, U-238, Ra-226 and Ra-228 were determined in ground waters fromtwo deep wells drilled in Morungaba Granitoids (Southern Brazil). Sampling was done monthly for little longer than 1 year. Significant disequilibrium between U-238, U-234 and Ra-226 were observed in all samples. The variation of U-238 and U-234 activity concentrations and U-234/U-238 activity ratios is related to seasonal changes. Although the distance between the two wells is short (about 900m), systematic differences of activity concentrations of U isotopes, as well as of U-234/U-238, Ra-226/U-234 and Ra-228/Ra-226 activity ratios were noticed, indicating distinct host rock-water interactions. Slightly acidic ground water percolation through heterogeneous host rock, associated with different recharge processes, may explain uranium and radium isotope behavior. (c) 2008 Elsevier Ltd. All rights reserved.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

The Br (0.0022 +/- A 0.0006 gL(-1)), Ca (0.113 +/- A 0.012 gL(-1)), Cl (3.07 +/- A 0.36 gL(-1)), K (2.63 +/- A 0.14 gL(-1)), Mg (0.045 +/- A 0.002 gL(-1)) and Na (2.09 +/- A 0.10 gL(-1)) concentrations were determined in whole blood of SJL/J mice using the Neutron Activation Analysis (NAA) technique. Eleven whole blood samples were analyzed in the IEA-R1 nuclear reactor at IPEN (So Paulo, Brazil). These data contribute for applications in veterinary medicine related to biochemistry analyses using whole blood. Moreover, the correlation with human blood estimation allows to checking the similarities for studying muscular dystrophy using this model animal.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

The objective of this study was to evaluate the effects of different gamma-radiation doses on the growth of Alternaria alternata in artificially inoculated cereal samples. Seeds and grains were divided into four groups: Control Group (not irradiated), and Groups 1, 2 and 3, inoculated with an A. alternata spore suspension (1 x 10(6) spores/mL) and exposed to 2, 5 and 10 kGy, respectively. Serial dilutions of the samples were prepared and seeded on DRBC (dichloran rose bengal chloramphenicol agar) and DCMA (dichloran chloramphenicol malt extract agar) media, after which the number of colony-forming units per gram was determined in each group. In addition, fungal morphology after irradiation was analyzed by scanning electron microscopy (SEM). The results showed that ionizing radiation at a dose of 5 kGy was effective in reducing the growth of A. alternata. However, a dose of 10 kGy was necessary to inhibit fungal growth completely. SEM made it possible to visualize structural alterations induced by the different gamma-radiation doses used. (C) 2009 Elsevier Ltd. All rights reserved.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

The TCABR data analysis and acquisition system has been upgraded to support a joint research programme using remote participation technologies. The architecture of the new system uses Java language as programming environment. Since application parameters and hardware in a joint experiment are complex with a large variability of components, requirements and specification solutions need to be flexible and modular, independent from operating system and computer architecture. To describe and organize the information on all the components and the connections among them, systems are developed using the extensible Markup Language (XML) technology. The communication between clients and servers uses remote procedure call (RPC) based on the XML (RPC-XML technology). The integration among Java language, XML and RPC-XML technologies allows to develop easily a standard data and communication access layer between users and laboratories using common software libraries and Web application. The libraries allow data retrieval using the same methods for all user laboratories in the joint collaboration, and the Web application allows a simple graphical user interface (GUI) access. The TCABR tokamak team in collaboration with the IPFN (Instituto de Plasmas e Fusao Nuclear, Instituto Superior Tecnico, Universidade Tecnica de Lisboa) is implementing this remote participation technologies. The first version was tested at the Joint Experiment on TCABR (TCABRJE), a Host Laboratory Experiment, organized in cooperation with the IAEA (International Atomic Energy Agency) in the framework of the IAEA Coordinated Research Project (CRP) on ""Joint Research Using Small Tokamaks"". (C) 2010 Elsevier B.V. All rights reserved.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

The triple- and quadruple-escape peaks of 6.128 MeV photons from the (19)F(p,alpha gamma)(16)O nuclear reaction were observed in an HPGe detector. The experimental peak areas, measured in spectra projected with a restriction function that allows quantitative comparison of data from different multiplicities, are in reasonably good agreement with those predicted by Monte Carlo simulations done with the general-purpose radiation-transport code PENELOPE. The behaviour of the escape intensities was simulated for some gamma-ray energies and detector dimensions; the results obtained can be extended to other energies using an empirical function and statistical properties related to the phenomenon. (C) 2010 Elsevier B.V. All rights reserved.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

The ground state thermal neutron cross section and the resonance integral for the (165)Ho(n, gamma)(166)Ho reaction in thermal and 1/E regions, respectively, of a thermal reactor neutron spectrum have been measured experimentally by activation technique. The reaction product, (166)Ho in the ground state, is gaining considerable importance as a therapeutic radionuclide and precisely measured data of the reaction are of significance from the fundamental point of view as well as for application. In this work, the spectrographically pure holmium oxide (Ho(2)O(3)) powder samples were irradiated with and without cadmium covers at the IEA-RI reactor (IPEN, Sao Paulo), Brazil. The deviation of the neutron spectrum shape from 1/E law was measured by co-irradiating Co, Zn, Zr and Au activation detectors with thermal and epithermal neutrons followed by regression and iterative procedures. The magnitudes of the discrepancies that can occur in measurements made with the ideal 1/E law considerations in the epithermal range were studied. The measured thermal neutron cross section at the Maxwellian averaged thermal energy of 0.0253 eV is 59.0 +/- 2.1 b and for the resonance integral 657 +/- 36b. The results are measured with good precision and indicated a consistency trend to resolve the discrepant status of the literature data. The results are compared with the values in main libraries such as ENDF/B-VII, JEF-2.2 and JENDL-3.2, and with other measurements in the literature.