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Sample records for rietveld aplicando funcoes

  1. Structural analysis of a carbonated hydroxyapatite by the Rietveld method using different profile functions; Analise estrutural de uma hidroxiapatita carbonatada pelo metodo de Rietveld aplicando funcoes de perfil diferentes

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, Jorge C. de [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil). Dept. de Matematica], e-mail: jcaraujo@iprj.uerj.br; Moreira, Elizabeth L.; Moraes, Valeria Conde Alves [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil)], e-mail: beth@cbpf.br, e-mail: conde@cbpf.br; Moreira, Ana Paula D. [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Inst. de Quimica. Dept. de Quimica Analitica], e-mail: duarteap@gmail.com

    2008-10-15

    The crystal structure of the synthetic hydroxyapatite with 12.8 ({+-} 0,64) wt. % CO{sub 3}{sup 2-} ion content was analyzed by X-ray diffraction using the Rietveld refinement method employing Pearson VII and pseudo-Voigt functions to fit the X-ray profile. The results obtained for unit cell parameters when compared to pattern hydroxyapatite showed a decrease in the a (=b) parameter and an increase in the c parameter without significant difference between the functions employed. The separation of the anisotropic broadening of reflections originated from unit cell strains indicated that this effect is dominant in reflection line broadening, principally to hkl plans with an interatomic distance lower than 2,24 angstrom. Modifications in the atomic coordinates of C atom were noted mainly in PO{sub 4}{sup 3-} (B site) and OH{sup -} (A site) sites. The average crystallite size in the crystallography axis directions (002 and 300) suggests equi axial morphology. The results obtained to CO{sub 3}{sup 2}- content were 11.72 ({+-} 0,64) wt. % to Pearson VII and 13.20 ({+-} 0,64) wt. % to pseudo-Voigt function. The refinement of the occupancy factors to C atoms in both sites PO{sub 4}{sup 3-}(B) and OH{sup -} (A) indicated higher insertion in phosphate site than hydroxide site. However, the relative occupancy of the C atom observed in the B site is lower than in the A site. (author)

  2. Rietveld analysis system RIETAN (translation)

    International Nuclear Information System (INIS)

    Izumi, Fujio

    1991-09-01

    This is the manual of the RIETAN system (a Rietveld analysis program) which is originally written in Japanese by Fujio Izumi. The manual consists of two parts. Part I is a general description of the fundamental concepts and methods of the RIETAN system. Part II is the user's manual of the RIETAN which mainly describes in detail how to create user's data sets, procedures of Rietveld analysis and how to read the results of analysis. (author)

  3. Rietveld originals : Handle with care!

    NARCIS (Netherlands)

    Zijlstra, H.

    2009-01-01

    The work of architect Gerrit Th. Rietveld (1888 – 1964) is appreciated throughout the world. Many of the well-known buildings he designed have survived to the present. Some have been restored or refurbished, depending on the condition of the building, current needs of the building users, etc.

  4. Rietica - a visual Rietveld program

    International Nuclear Information System (INIS)

    Hunter, B.A.

    2000-01-01

    Full text: Rietica is a Rietveld analysis program that allows interaction with the refinement process on a cycle by cycle basis using a graphic interface. Rietica was developed to aid in the creation and updating of the Rietveld input files, as well as to control the LHPM program. It is a Windows 95 based program allowing point and click control of all the functionality of LHPM. Some of the features of the Rietica program are: multiple x-ray and/or neutron histograms (datasets) allowing different scales, zeros, peak profile types and values, backgrounds, wavelengths, preferred orientations for each histogram - all of which are refinable, (1) ability to calculate and refine neutron time-of-flight (TOF) data, (2) ability to refine Δf' and Δf'' now allows extra flexibility with synchrotron diffraction data, (3) can interpolate x-ray form factors from a series of (sin(θ)/λ, f) values (eg Bessel functions), (4) a new absorption correction formula allowing μR > 1.0 for cylindrical geometry and a flat plate absorption correction based surface roughness, (5) new background functions, (6) quantitative phase analysis routines, (7) point and click data entry and program control, (8) data display and easy background and excluded region input via mouse control, (9) control of the refinement process, including automatic updating of the calculated pattern display after each step, (10) can refine using 3 strategies: a) a point and click mode of data entry and refinement control (beginners/intermediate/advanced users); b) a manual editing of the input file, but still with all the benefits of the visual interface and online graphics (intermediate/advanced users); and c) a Basic scripting language that can be used to control the refinement process and graphics output. It could be used, say, for automatic refinement of large numbers of datasets (advanced users). The program currently reads in LHPM and GSAS/Fullprof/DWBS experiment files and export in a variety of formats. The

  5. Rietveld analysis, powder diffraction and cement

    International Nuclear Information System (INIS)

    Peterson, V.

    2002-01-01

    Full text: Phase quantification of cement is essential in its industrial use, however many methods are inaccurate and/or time consuming. Powder diffraction is one of the more accurate techniques used for quantitative phase analysis of cement. There has been an increase in the use of Rietveld refinement and powder diffraction for the analysis and phase quantification of cement and its components in recent years. The complex nature of cement components, existence of solid solutions, polymorphic variation of phases and overlapping phase peaks in diffraction patterns makes phase quantification of cements by powder diffraction difficult. The main phase in cement is alite, a solid solution of tricalcium silicate. Tricalcium silicate has been found to exist in seven modifications in three crystal systems, including triclinic, monoclinic, and rhombohedral structures. Hence, phase quantification of cements using Rietveld methods usually involves the simultaneous modelling of several tricalcium silicate structures to fit the complex alite phase. An industry ordinary Portland cement, industry and standard clinker, and a synthetic tricalcium silicate were characterised using neutron, laboratory x-ray and synchrotron powder diffraction. Diffraction patterns were analysed using full-profile Rietveld refinement. This enabled comparison of x-ray, neutron and synchrotron data for phase quantification of the cement and examination of the tricalcium silicate. Excellent Rietveld fits were achieved, however the results showed that the quantitative phase analysis results differed for some phases in the same clinker sample between various data sources. This presentation will give a short introduction about cement components including polymorphism, followed by the presentation of some problems in phase quantification of cements and the role of Rietveld refinement in solving these problems. Copyright (2002) Australian X-ray Analytical Association Inc

  6. A summary of available Rietveld and related software resources

    International Nuclear Information System (INIS)

    Cranswick, L.M.D

    1999-01-01

    Full text: There is a wide variety of Rietveld software available from both commercial and academic institutions. These resources will be reviewed along with the importance of validating Rietveld quantitative analysis results and gaining skills in complementary areas. This part of the workshop will mention a number of relevant programs and their main functionality: Rietveld software, Rietveld utilities, Rietveld friendly software and other powder diffraction utilities. Some of the main benefits of appreciating the availability of a wide range of software include: cross validation of results, data quality and diffractometer alignment, exploring new areas of research and analysis, solving new problems, nuances that occur as part of Rietveld analysis. Copyright (1999) Australian X-ray Analytical Association Inc

  7. Mathematical aspects of Rietveld refinement and crystal structure ...

    Indian Academy of Sciences (India)

    Administrator

    The core mathematics, goodness-of-fit parameters of Rietveld refinement technique is introduced for structural ... transducers in medical and solar applications (Obmann ..... Prince 1985 in Structure and statistics in crystallography (ed.).

  8. A modified Rietveld method to model highly anisotropic ceramics

    International Nuclear Information System (INIS)

    Tutuncu, G.; Motahari, M.; Daymond, M.R.; Ustundag, E.

    2012-01-01

    High energy X-ray diffraction was employed to probe the complex constitutive behavior of a polycrystalline ferroelectric material in various sample orientations. Pb(Zn,Nb)O 3 –Pb(Zr,Ti)O 3 (PZN–PZT) ceramics were subjected to a cyclic bipolar electric field while diffraction patterns were taken. Using transmission geometry and a two-dimensional detector, lattice strain and texture evolution (domain switching) were measured in multiple sample directions simultaneously. In addition, texture analysis suggests that non-180° domain switching is coupled with lattice strain evolution during uniaxial electrical loading. As a result of this material’s high strain anisotropy, the full-pattern Rietveld method was inadequate to analyze the diffraction data. Instead, a modified Rietveld method, which includes an elastic anisotropy term, yielded significant improvements in the data analysis results.

  9. Profile agreement indices in Rietveld and pattern-fitting analysis

    International Nuclear Information System (INIS)

    Hill, R.J.; Fischer, R.X.

    1990-01-01

    Two definitions of profile agreement indices are now in common use for estimating the degree of fit in Rietveld refinement and in structure-independent pattern-fitting methods of powder diffraction analysis. In the original program written by Rietveld, the background was subtracted and the 'non-peak' regions of the pattern were removed from further consideration in a preliminary data-reduction stage prior to structure refinement. However, the agreement indices used in many of the more recent programs retain the background counts in the observed step intensities and include all portions of the pattern in the sums. These latter definitions are strongly dependent on the signal-to-noise ratio and on the relative amount of 'background-only' regions and do not, therefore, provide a sound basis for comparing the degree of fit of peak profile and crystal structure model refinements in the general case. The extent of this dependence is illustrated quantitatively using conventional and synchrotron X-ray and constant-wavelength and time-of-flight neutron data sets with different inherent background levels and peak densities. The unweighted background-corrected peak-only profile agreement index R' p =Σ i vertical strokeY io -Y ic vertical stroke/Σ i vertical strokeY io -Y ib vertical stroke (and, to a lesser extent, its weighted equivalent) is recommended as the most appropriate criterion of fit for comparative work between diffraction patterns of all kinds. (orig.)

  10. Chemical analysis of superconductor material by Rietveld method; Analise quimica de material superconductor atraves do metodo de Rietveld

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Junior, E.S.; Gomes Junior, G.G.; Ogasawara, T., E-mail: georges@metalmat.ufrj.b [Universidade Federal do Rio de Janeiro (COPPE/UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-Graduacao de Engenharia. Dept. de Eng. Metalurgica e Materiais; Bispo, E.R.; Polasek, A. [Centro de Pesquisas de Energia Eletrica (CEPEL), Rio de Janeiro, RJ (Brazil); Amorim, H.S. [Universidade Federal do Rio de Janeiro (IF/UFRJ), RJ (Brazil). Inst. de Fisica

    2010-07-01

    Among the main superconducting systems, the system Bi-Sr-Ca-Cu-O is extremely important because it presents two stages of high superconducting critical temperature. To manufacture samples of the superconducting phase (Bi, Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}Ox (Bi-2223) were used oxides and carbonates of high purity. The mixture was calcined and sintered for 100-200h in air. To characterize the material we used X-ray diffraction, SEM / EDS and measurement of critical temperature (Tc). The Rietveld method was used for structure refinement, and quantification of phases and to estimate the chemical composition of samples in order to obtain greater control of chemical composition using only the data of X-ray diffraction. The results were compared with the refinement results of X-ray fluorescence and was observed a discrepancy of about 8%. This result indicates that the Rietveld method can be an interesting alternative to perform chemical analysis. (author)

  11. Rietveld analysis and electronic bands structure on Tc superconductors systems

    International Nuclear Information System (INIS)

    Aldea, N.; Tiusan, C. V.; Sandu, V.

    1999-01-01

    A procedure for simultaneous refinement of structural and micro-structural disorder parameters for polycrystalline YBa 2 Cu 3 O 7-x system is proposed. It is based on Rietveld method combined with Fourier analysis for broadened peaks Another purpose of this paper consists in electronic structure determination studied by using the self-consistent Tight Binding Linear Muffin-Tin Orbital Atomic Spheres Approximation TB-LMTO-ASA methods. The Rietveld method uses an analytical function that describes the profiles, usually pseudo-Voigt (pV) or Pearson VII (PVII). The parameters of the analytical profiles describe its amplitude, position and peak shape. The full width at half maximum (FWHM) is supposed to vary with the diffraction angle in agreement with the Caglioti, Paoletti and Ricci's relationship. The best structural parameters are determined in the least squares sense by the minimisation a classical residual using the Marquardt method. In this case, the peak profiles were modelled by the pseudo-Voigt function corrected by the instrumental asymmetry. The physical information obtained are: scale factor, lattice parameters, atomic position and displacements, atomic occupation numbers, temperature factor (isotropy or anisotropy), preferred orientation parameter, crystalline size and micro-strain along different crystallographic directions, distributions of crystallite size and micro-strain functions. This procedure was implemented on computer code and it has a friendly graphical interface based on pull down menus technique. From the experimental point of view the X-ray diffraction data were collected using a horizontal powder diffractometer in the Bragg-Brentano (BB) geometry with a Ni filtered CuKα, λ = 1.54178 A, at room temperature using a DRON 2 set-up. The diffraction profiles were measured with a proportional gas detector, a single channel pulse-height discrimination and a standard associated counting circuit. The electronic band calculations are based on the TB

  12. Gerrit Rietveld. Casas después de la Schroeder

    Directory of Open Access Journals (Sweden)

    Rafael García

    1997-07-01

    Full Text Available Las historias de la arquitectura moderna han incidido una y otra vez en un reducido número de obras que por su insistente atención, han llegado a convertirse en hitos imprescindibles. Entre estos edificios canónicos y prácticamente obligados, está la célebre casa Schröder-Schräder (1924' del arquitecto holandés Gerrit Rietveld. Ampliamente conocida por el público interesado, su gran popularidad ha tenido sin embargo, el efecto de dejar en segundo plano el resto de su obra arquitectónica. A ello se debe añadir además, el hecho de que su trayectoria está fundamentalmente asociada al movimiento neoplasticista, lo que ha tenido por resultado desviar la atención de una obra posterior, más difícilmente clasificable. Sin embargo, ello no significa que dicha obra sea en absoluto carente de atractivo.

  13. Full quantitative phase analysis of hydrated lime using the Rietveld method

    International Nuclear Information System (INIS)

    Lassinantti Gualtieri, Magdalena; Romagnoli, Marcello; Miselli, Paola; Cannio, Maria; Gualtieri, Alessandro F.

    2012-01-01

    Full quantitative phase analysis (FQPA) using X-ray powder diffraction and Rietveld refinements is a well-established method for the characterization of various hydraulic binders such as Portland cement and hydraulic limes. In this paper, the Rietveld method is applied to hydrated lime, a non-hydraulic traditional binder. The potential presence of an amorphous phase in this material is generally ignored. Both synchrotron radiation and a conventional X-ray source were used for data collection. The applicability of the developed control file for the Rietveld refinements was investigated using samples spiked with glass. The results were cross-checked by other independent methods such as thermal and chemical analyses. The sample microstructure was observed by transmission electron microscopy. It was found that the consistency between the different methods was satisfactory, supporting the validity of FQPA for this material. For the samples studied in this work, the amount of amorphous material was in the range 2–15 wt.%.

  14. Full quantitative phase analysis of hydrated lime using the Rietveld method

    Energy Technology Data Exchange (ETDEWEB)

    Lassinantti Gualtieri, Magdalena, E-mail: magdalena.gualtieri@unimore.it [Dipartimento Ingegneria dei Materiali e dell' Ambiente, Universita Degli Studi di Modena e Reggio Emilia, Via Vignolese 905/a, I-41100 Modena (Italy); Romagnoli, Marcello; Miselli, Paola; Cannio, Maria [Dipartimento Ingegneria dei Materiali e dell' Ambiente, Universita Degli Studi di Modena e Reggio Emilia, Via Vignolese 905/a, I-41100 Modena (Italy); Gualtieri, Alessandro F. [Dipartimento di Scienze della Terra, Universita Degli Studi di Modena e Reggio Emilia, I-41100 Modena (Italy)

    2012-09-15

    Full quantitative phase analysis (FQPA) using X-ray powder diffraction and Rietveld refinements is a well-established method for the characterization of various hydraulic binders such as Portland cement and hydraulic limes. In this paper, the Rietveld method is applied to hydrated lime, a non-hydraulic traditional binder. The potential presence of an amorphous phase in this material is generally ignored. Both synchrotron radiation and a conventional X-ray source were used for data collection. The applicability of the developed control file for the Rietveld refinements was investigated using samples spiked with glass. The results were cross-checked by other independent methods such as thermal and chemical analyses. The sample microstructure was observed by transmission electron microscopy. It was found that the consistency between the different methods was satisfactory, supporting the validity of FQPA for this material. For the samples studied in this work, the amount of amorphous material was in the range 2-15 wt.%.

  15. Rietveld refinement with time-of-flight powder diffraction data from pulsed neutron sources

    International Nuclear Information System (INIS)

    David, W.I.F.; Jorgensen, J.D.

    1990-10-01

    The recent development of accelerator-based pulsed neutron sources has led to the widespread use of the time-of-flight technique for neutron powder diffraction. The properties of the pulsed source make possible unusually high resolution over a wide range of d spacings, high count rates, and the ability to collect complete data at fixed scattering angles. The peak shape and other instrument characteristics can be accurately modelled, which make Rietveld refinement possible for complex structures. In this paper we briefly review the development of the Rietveld method for time-of-flight diffraction data from pulsed neutron sources and discuss the latest developments in high resolution instrumentation and advanced Rietveld analysis methods. 50 refs., 12 figs., 14 tabs

  16. Quantitative phase analysis of a highly textured industrial sample using a Rietveld profile analysis

    International Nuclear Information System (INIS)

    Shin, Eunjoo; Huh, Moo-Young; Seong, Baek-Seok; Lee, Chang-Hee

    2001-01-01

    For the quantitative phase analysis on highly textured two-phase materials, samples with known weight fractions of zirconium and aluminum were prepared. Strong texture components prevailed in both zirconium and aluminum sheet. The diffraction patterns of samples were measured by the neutron and refined by the Rietveld method. The preferred orientation correction of diffraction patterns was carried out by means of recalculated pole figures from the ODF. The present Rietveld analysis of various samples with different weight fractions showed that the absolute error of the calculated weight fractions was less than 7.1%. (author)

  17. Estilos de liderança de professores: aplicando o modelo de estilos parentais

    Directory of Open Access Journals (Sweden)

    Ana Priscila Batista

    Full Text Available Professores orientam os comportamentos das crianças estabelecendo diferentes climas emocionais no uso das estratégias educativas em sala de aula. Esse trabalho busca delinear uma análise dos estilos de liderança de professores aplicando o modelo de estilos parentais. Inicialmente, foi feita uma análise de literatura realizando uma busca nas bases de dados: Scielo, Science Direct e Scopus, utilizando os descritores: teachers' leadership styles, teachers' teaching styles e school leadership. Com essa busca constatou-se que existem diversas definições, formas de análise e variáveis estudadas, conforme a teoria adotada. Posteriormente, foi realizada a análise da relação professor-aluno aplicando o modelo de estilos parentais, que apresenta uma análise do sistema das relações a partir de duas dimensões: responsividade e exigência. Assim, foram categorizados quatro estilos de liderança: autoritário, permissivo, negligente e participativo. Conclui-se que o modelo de estilo parental fornece uma boa base teórica para pautar a análise dos estilos de liderança de professores.

  18. Quantitative phase analysis of uranium carbide from x-ray diffraction data using the Rietveld method

    International Nuclear Information System (INIS)

    Singh Mudher, K.D.; Krishnan, K.

    2003-01-01

    Quantitative phase analysis of a uranium carbide sample was carried out from the x-ray diffraction data by Rietveld profile fitting method. The method does not require the addition of any reference material. The percentage of UC, UC 2 and UO 2 phases in the sample were determined. (author)

  19. Combined PDF and Rietveld studies of ADORable zeolites and the disordered intermediate IPC-1P

    Czech Academy of Sciences Publication Activity Database

    Morris, S. A.; Wheatley, P. S.; Položij, M.; Nachtigall, P.; Eliášová, Pavla; Čejka, Jiří; Lucas, T. C.; Hriljac, J. A.; Pinar, A. B.; Morris, R. E.

    2016-01-01

    Roč. 45, č. 36 (2016), s. 14124-14130 ISSN 1477-9226 R&D Projects: GA ČR GBP106/12/G015 Institutional support: RVO:61388955 Keywords : Distribution functions * Rietveld refinement * Zeolites Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.029, year: 2016

  20. EL APARADOR DE RIETVELD DEL MUSEO NACIONAL DE ARTES DECORATIVAS (MADRID.

    Directory of Open Access Journals (Sweden)

    María Villalba Salvador

    2012-01-01

    Full Text Available Este artículo trata de hacer una aproximación al estudio de una de las piezas más relevantes de la historia del diseño de mobiliario de vanguardia: el aparador de Rietveld, también conocido como Buffet Elling. Su diseño data de 1919, y responde a la estética propia del autor en aquellos años posteriores a la Primera Guerra Mundial, cuyas piezas son coincidentes con los planteamientos artísticos del grupo De Stijl. Es representativo de los principios básicos de la obra de Rietveld, uno de los pioneros del funcionalismo junto con J.J.P. Oud, en cuanto a la opción por el diseño y la arquitectura, y por la producción en masa y el diseño industrial accesible al conjunto de la sociedad. Merece destacar la colaboración de Gerard A. Van de Groenekan, asistente de Rietveld a lo largo de toda su trayectoria artística. Esta pieza nos ayuda a estudiar el pensamiento de Gerrit Th. Rietvel en relación con el diseño de vanguardia.This article tries to be an approach to the study of one of the most relevant pieces of furniture in the history of the design of avant-garde furniture: Rietveld´s dresser, also known as Elling Buffet. It was designed in 1919, and it shows the author´s aesthetics in the years that followed World War I, with pieces that are much related to the artistic orientation of the group De Stijl. It clearly shows the main characteristics of Rietveld´s work, one of the pioneers of functionalism, together with J.J.P. Oud, regarding design and architecture, mass production and industrial design accessible to society as a whole. It is worth mentioning the collaboration of Gerard A. Van de Groenekan, Rietveld´s assistant throughout his artistic trajectory. This piece of furniture helps us study Rietveld´s thinking regarding avant-garde design.

  1. Characterization of barium titanate powder doped with sodium and potassium ions by using Rietveld refining

    International Nuclear Information System (INIS)

    Andrade, M.C.; Assis, J.T.; Pereira, F.R.

    2009-01-01

    A solid-reaction synthesis of doped barium titanate was done by employing barium carbonates, sodium, potassium and titanium oxides with classic procedures. Rietveld refining of X ray diffraction data of perovskite samples with tetragonal symmetry was applying and show good agreement. Besides, the treatment performed from 600 deg C produces nanocrystals of barium titanate with average size of 33 nm. The presence of endothermic peaks related to BaTiO 3 formation at relatively low temperatures was determined by thermal analysis. A pseudo-Voigt Thompson-Cox-Hastings function was used to fit the standard samples of barium titanate. The Rietveld method has showed be efficient to detect the influences of temperature and doping on barium titanate microstructures. (author)

  2. Quantitative determination of the crystalline phases of the ceramic materials utilizing the Rietveld method

    International Nuclear Information System (INIS)

    Kniess, C.T.; Prates, P.B.; Lima, J.C. de; Kuhnen, N.C.; Riella, H.G.; Maliska, A.M.

    2009-01-01

    Ceramic materials have properties defined by their chemical and micro-structural composition. The quantification of the crystalline phases is a fundamental stage in the determination of the structure, properties and applications of a ceramic material. Within this context, this study aims is the quantitative determination of the crystalline phases of the ceramic materials developed with addition of mineral coal bottom ash, utilizing the X ray diffraction technique, through the method proposed by Rietveld. For the formulation of the ceramic mixtures a {3,3} simplex-lattice design was used, giving ten formulations of three components (two different types of clays and coal bottom ash). The crystalline phases identified in the ceramic materials after sintering at 1150 deg C during two hours are: quartz, tridimite, mullite and hematite. The proposed methodology utilizing the Rietveld method for the quantification relating to crystalline phases of the materials was shown to be adequate and efficient. (author)

  3. Micro-structural study and Rietveld analysis of fast reactor fuels: U–Mo fuels

    International Nuclear Information System (INIS)

    Chakraborty, S.; Choudhuri, G.; Banerjee, J.; Agarwal, Renu; Khan, K.B.; Kumar, Arun

    2015-01-01

    U–Mo alloys are the candidate fuels for both research reactors and fast breeder reactors. In-reactor performance of the fuel depends on the microstructural stability and thermal properties of the fuel. To improve the fuel performance, alloying elements viz. Zr, Mo, Nb, Ti and fissium are added in the fuel. The first reactor fuels are normally prepared by injection casting. The objective of this work is to compare microstructure, phase-fields and hardness of as-cast four different U–Mo alloy (2, 5, 10 and 33 at.% Mo) fuels with the equilibrium microstructure of the alloys. Scanning electron microscope with energy dispersive spectrometer and optical microscope have been used to characterize the morphology of the as-cast and annealed alloys. The monoclinic α'' phase in as-cast U-10 at.% Mo alloy has been characterized through Rietveld analysis. A comparison of metallographic and Rietveld analysis of as-cast (dendritic microstructure) and annealed U-33 at.% Mo alloy, corresponding to intermetallic compound, has been reported here for the first time. This study will provide in depth understanding of microstructural and phase evolution of U–Mo alloys as fast reactor fuel. - Highlights: • U–Mo alloys in as-cast as well as in annealed conditions have been studied using Optical Microscope, SEM, XRD. • The monoclinic α'' phase in as-cast U-10 at.% Mo alloy has been characterized through Rietveld analysis. • The dendritic microstructure of γ-(U,Mo) and B.C.C. ‘Mo’ phase of 33 at.% U–Mo alloy have been analysed. • Rietveld analysis has been done to optimize lattice parameters and calculate phase fractions in annealed alloys. • The Vickers microhardness of U_2Mo phase shows lower hardness than two phase microstructures in annealed alloys.

  4. Micro-structural study and Rietveld analysis of fast reactor fuels: U–Mo fuels

    Energy Technology Data Exchange (ETDEWEB)

    Chakraborty, S., E-mail: sibasis@barc.gov.in [Radiometallurgy Division, Bhabha Atomic Research Centre, Mumbai, 400085 (India); Choudhuri, G. [Atomic Fuels Division, Bhabha Atomic Research Centre, Mumbai, 400085 (India); Banerjee, J. [Radiometallurgy Division, Bhabha Atomic Research Centre, Mumbai, 400085 (India); Agarwal, Renu [Product Development Division, Bhabha Atomic Research Centre, Mumbai, 400085 (India); Khan, K.B.; Kumar, Arun [Radiometallurgy Division, Bhabha Atomic Research Centre, Mumbai, 400085 (India)

    2015-12-15

    U–Mo alloys are the candidate fuels for both research reactors and fast breeder reactors. In-reactor performance of the fuel depends on the microstructural stability and thermal properties of the fuel. To improve the fuel performance, alloying elements viz. Zr, Mo, Nb, Ti and fissium are added in the fuel. The first reactor fuels are normally prepared by injection casting. The objective of this work is to compare microstructure, phase-fields and hardness of as-cast four different U–Mo alloy (2, 5, 10 and 33 at.% Mo) fuels with the equilibrium microstructure of the alloys. Scanning electron microscope with energy dispersive spectrometer and optical microscope have been used to characterize the morphology of the as-cast and annealed alloys. The monoclinic α'' phase in as-cast U-10 at.% Mo alloy has been characterized through Rietveld analysis. A comparison of metallographic and Rietveld analysis of as-cast (dendritic microstructure) and annealed U-33 at.% Mo alloy, corresponding to intermetallic compound, has been reported here for the first time. This study will provide in depth understanding of microstructural and phase evolution of U–Mo alloys as fast reactor fuel. - Highlights: • U–Mo alloys in as-cast as well as in annealed conditions have been studied using Optical Microscope, SEM, XRD. • The monoclinic α'' phase in as-cast U-10 at.% Mo alloy has been characterized through Rietveld analysis. • The dendritic microstructure of γ-(U,Mo) and B.C.C. ‘Mo’ phase of 33 at.% U–Mo alloy have been analysed. • Rietveld analysis has been done to optimize lattice parameters and calculate phase fractions in annealed alloys. • The Vickers microhardness of U{sub 2}Mo phase shows lower hardness than two phase microstructures in annealed alloys.

  5. Profex: a graphical user interface for the Rietveld refinement program BGMN

    OpenAIRE

    Doebelin, Nicola; Kleeberg, Reinhard

    2015-01-01

    Profex is a graphical user interface for the Rietveld refinement program BGMN. Its interface focuses on preserving BGMN’s powerful and flexible scripting features by giving direct access to BGMN input files. Very efficient workflows for single or batch refinements are achieved by managing refinement control files and structure files, by providing dialogues and shortcuts for many operations, by performing operations in the background, and by providing import filters for CIF and XML crystal str...

  6. Application of the Rietveld method to assess chromium(VI) speciation in chromite ore processing residue

    International Nuclear Information System (INIS)

    Chrysochoou, Maria; Dermatas, Dimitris

    2007-01-01

    The Rietveld method allows the quantification of crystalline phases and amorphous material identified by X-ray powder diffraction (XRPD) and other diffraction methods. The method assists in determining the speciation of contaminants in solid matrices both qualitatively and quantitatively in a statistically defensible approach, as it does not focus on a microscale. Rietveld was applied to chromite ore processing residue (COPR), a cementitious waste containing hexavalent chromium. Calcium aluminum chromium oxide hydrates (CACs) were the crystalline phases identified by XRPD that bind Cr 6+ in COPR according to their chemical formula. Rietveld quantification, combined with mass balances on Cr 6+ , showed that CACs may bind Cr 6+ in variable percentages, ranging from 25% to 85%. Analysis of duplicate samples showed that material variability is the predominant factor of uncertainty in evaluating the role of CACs in Cr 6+ speciation, provided that a consistent quantification strategy is pursued. The choice of strategy was performed on the basis of the pertinent literature, preliminary analyses of the equipment and the software settings, and mass balances. The correlation between the average CAC-bound Cr 6+ concentration and the total Cr 6+ for five samples (R 2 = 0.94), extracted from different zones and soil borings, suggests that CACs are a primary sink for Cr 6+ in COPR

  7. Modulation wave approach to the structural parameterization and Rietveld refinement of low carnegieite

    International Nuclear Information System (INIS)

    Withers, R.L.; Thompson, J.G.

    1993-01-01

    The crystal structure of low carnegieite, NaAlSiO 4 [M r =142.05, orthorhombic, Pb2 1 a, a=10.261(1), b=14.030(2), c=5.1566(6) A, D x =2.542 g cm -3 , Z=4, Cu Kα 1 , λ=1.5406 A, μ=77.52 cm -1 , F(000)=559.85], is determined via Rietveld refinement from powder data, R p =0.057, R wp =0.076, R Bragg =0.050. Given that there are far too many parameters to be determined via unconstrained Rietveld refinement, a group theoretical or modulation wave approach is used in order to parameterize the structural deviation of low carnegieite from its underlying C9 aristotype. Appropriate crystal chemical constraints are applied in order to provide two distinct plausible starting models for the structure of the aluminosilicate framework. The correct starting model for the aluminosilicate framework as well as the ordering and positions of the non-framework Na atoms are then determined via Rietveld refinement. At all stages, chemical plausibility is checked via the use of the bond-length-bond-valence formalism. The JCPDS file number for low carnegieite is 44-1496. (orig.)

  8. Dos artículos de Rietveld Comprensión. Nuevo Funcionalismo en la Arquitectura

    Directory of Open Access Journals (Sweden)

    Editor Cuaderno de Notas

    1995-12-01

    Full Text Available Los siguientes dos artículos de Rietveld (1888-1964 fueron publicados por primera vez en la revista i10 en 1928 y en De Vrije Bladen en 1932 respectivamente. Esta es su primera traducción al castellano, para lo que se ha partido de sus correspondientes traducciones inglesas; "Inzicht" (comprensión, en el libro de Theodore M.. Brown, The Work of G. Rietveld architect, Utrecht 1958, y "Nieuwe zakelijkheid in de Nederlandsche architectuur" (Nueva objetividad en la arquitectura holandesa, en la monografía-catálogo, Gerrit Rietveld 1888-1964. The complet works, Central Museum, Utrecht, 1992. En cuanto al último, de bastante mayor extensión, contaba originariamente con ilustraciones de obras de JA.Brinkman y L.C. van der Vlugt, A. Bodón, J. Duiker, J.J.P. Oud y Le Corbusier como único arquitecto extranjero representado, aparte de las de sus propio trabajo.

  9. EVALUACIÓN DEL DESEMPEÑO HIDRAULICO DE TRES GOTEROS APLICANDO AGUA RESIDUAL DE PORCICULTURA

    Directory of Open Access Journals (Sweden)

    RAFAEL OLIVEIRA BATISTA

    2012-01-01

    Full Text Available La realización de este trabajo tuvo por objetivo, analizar el desempeño hidráulico de tres goteros aplicando agua residual de porcicultura tratada. Fue montada una estructura hidráulica de evaluación constituida de tres tipos de goteros (G1, G2 y G3. Se mantuvo la presión del servicio en el inicio de las líneas laterales en 105 kPa y se cuantificaron en intervalo de 20 h, el caudal de los goteros hasta la obtención de un tiempo total de 160 h de operación del sistema. El nivel de taponamiento de los goteros fue obtenido por medio del coeficiente de variación del caudal (CVQ. Con la aplicación de agua residual de porcicultura, hubo un aumento del CVQ a lo largo del tiempo de funcionamiento, solamente en la sub-unidad con gotero G2. Los goteros de mayor caudal e menor largura de laberinto son menos susceptibles al taponamiento. La formación de biofilme fue resultado de la interacción entre sólidos suspendidos, azufre y bacterias, consistiendo en el principal factor de taponamiento parcial y total de los goteros.

  10. Micro-structural study and Rietveld analysis of fast reactor fuels: U-Mo fuels

    Science.gov (United States)

    Chakraborty, S.; Choudhuri, G.; Banerjee, J.; Agarwal, Renu; Khan, K. B.; Kumar, Arun

    2015-12-01

    U-Mo alloys are the candidate fuels for both research reactors and fast breeder reactors. In-reactor performance of the fuel depends on the microstructural stability and thermal properties of the fuel. To improve the fuel performance, alloying elements viz. Zr, Mo, Nb, Ti and fissium are added in the fuel. The first reactor fuels are normally prepared by injection casting. The objective of this work is to compare microstructure, phase-fields and hardness of as-cast four different U-Mo alloy (2, 5, 10 and 33 at.% Mo) fuels with the equilibrium microstructure of the alloys. Scanning electron microscope with energy dispersive spectrometer and optical microscope have been used to characterize the morphology of the as-cast and annealed alloys. The monoclinic α'' phase in as-cast U-10 at.% Mo alloy has been characterized through Rietveld analysis. A comparison of metallographic and Rietveld analysis of as-cast (dendritic microstructure) and annealed U-33 at.% Mo alloy, corresponding to intermetallic compound, has been reported here for the first time. This study will provide in depth understanding of microstructural and phase evolution of U-Mo alloys as fast reactor fuel.

  11. Study of crystallite size of yttria-stabilized zirconia powders by Rietveld method

    International Nuclear Information System (INIS)

    Leite, Wellington Claiton; Brinatti, Andre Mauricio; Ribeiro, Mauricio Aparecido; Andrade, Andre Vitor Chaves de; Chinelatto, Adriana Scoton Antonio; Chinelatto, Adilson Luiz

    2009-01-01

    The yttria-stabilized zirconia (YSZ) is used in a great variety of applications, for example, electrolytes of solid oxide fuel cells and oxygen sensors. In the study of YSZ, the particle size powders and sintering processes are important to define the final properties of the zirconia products. The objectives of this work were to determine the phases and the crystalline size using X-Ray Diffraction (XRD) data and the Rietveld Method (RM) of the YSZ powders obtained by chemical synthesis based on the Pechini method. It was used ZrOCl 2.8 H 2 O and Y(NO 3 ) 3.5 H 2 O as precursors reagents. After calcination at 550 deg C during 24 hours, the powder was analyzed by XRD and scanning electronic microscopy (SEM). From XRD and using Rietveld method were verified that there is only cubic phase with lattice parameter a = 5.1307(1) Å and the space group Fm3m. Due to substitution of the Zr atoms in the Y atoms sites, there were vacancies in 17.72 % of O atoms sites. However, the percentage of substitution of Zr atoms in Y atoms sites in the structure not was determinate because the curves of atomic scattering of them are very similar. Using Scherrer equation and considering anisotropy effect, the average crystalline size was determinate: 10,43 nm (c axis) and 10,39 (b axis). This spherical symmetry also observed for SEM. (author)

  12. Study the oxidation kinetics of uranium using XRD and Rietveld method

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Yanzhi; Guan Weijun; Wang Qinguo; Wang Xiaolin; Lai Xinchun; Shuai Maobing, E-mail: yanzhizh@163.com [China Academy of Engineering Physics, PO Box 919-71, Mianyang, Sichuan, 621900 (China)

    2010-03-15

    The surface oxidation of uranium metal has been studied by X-ray diffraction (XRD) and Rietveld method in the range of 50{approx}300deg. C in air. The oxidation processes are analyzed by XRD to determine the extent of surface oxidation and the oxide structure. The dynamics expression for the formation of UO{sub 2} was derived. At the beginning, the dynamic expression was nonlinear, but switched to linear subsequently for uranium in air and humid oxygen. That is, the growth kinetics of UO{sub 2} can be divided into two stages: nonlinear portion and linear portion. Using the kinetic data of linear portion, the activation energy of reaction between uranium and air was calculated about 46.0 kJ/mol. However the content of oxide as a function of time was linear in humid helium ambience. Contrast the dynamics results, it prove that the absence of oxygen would accelerate the corrosion rate of uranium in the humid gas. We can find that the XRD and Rietveld method are a useful convenient method to estimate the kinetics and thermodynamics of solid-gas reaction.

  13. Rietveld refinement of magnetic structures from pulsed-neutron-source powder-diffraction data

    International Nuclear Information System (INIS)

    Robinson, R.A.; Lawson, A.C.; Larson, A.C.; Von Dreele, R.B.; Goldstone, J.A.

    1994-01-01

    The General Structure Analysis System, GSAS, has recently been modified to include magnetic neutron- scattering cross-sections. Low-temperature diffraction data have been taken on the hexagonal noncollinear antiferromagnet UPdSn on both the HIPD and the NPD powder diffractometers ail LANSCE. The low-resolution data reveal that the magnetic structure has orthorhombic symmetry (magnetic space group P c m'c2 1 ) between 25K and 40K, and monoclinic symmetry (magnetic space group PC 1121 ) below 25K. The high-resolution data reveal that there are structural distortions with corresponding symmetry changes in each of these phases, to give chemical space groups Cmc2 1 and P2 1 , respectively, while the paramagnetic phase above 40K has space group P6 3 mc. Using GSAS, we have refined data sets from both diffractometers simultaneously, including both magnetic and structural cross-sections. Magnetoelastic coefficients for the distortions have been extracted and we have determined the sign of the coupling between the structural monoclinicity and the magnetic monoclinicity. The magnetic results from Rietveld refinement are in good agreement with model fitting to the integrated intensities of seven independent magnetic reflections and these, in turn, agree with measurements made on the same sample using the constant-wavelength reactor technique. Our results therefore validate, to some level, both the technique of using spallation sources for complicated magnetic structures and the specifics of the GSAS Rietveld code

  14. Study the oxidation kinetics of uranium using XRD and Rietveld method

    Science.gov (United States)

    Zhang, Yanzhi; Guan, Weijun; Wang, Qinguo; Wang, Xiaolin; Lai, Xinchun; Shuai, Maobing

    2010-03-01

    The surface oxidation of uranium metal has been studied by X-ray diffraction (XRD) and Rietveld method in the range of 50~300°C in air. The oxidation processes are analyzed by XRD to determine the extent of surface oxidation and the oxide structure. The dynamics expression for the formation of UO2 was derived. At the beginning, the dynamic expression was nonlinear, but switched to linear subsequently for uranium in air and humid oxygen. That is, the growth kinetics of UO2 can be divided into two stages: nonlinear portion and linear portion. Using the kinetic data of linear portion, the activation energy of reaction between uranium and air was calculated about 46.0 kJ/mol. However the content of oxide as a function of time was linear in humid helium ambience. Contrast the dynamics results, it prove that the absence of oxygen would accelerate the corrosion rate of uranium in the humid gas. We can find that the XRD and Rietveld method are a useful convenient method to estimate the kinetics and thermodynamics of solid-gas reaction.

  15. Separation of the overlapping effects in spectra for WDXRF using the Rietveld method

    International Nuclear Information System (INIS)

    Salvador, Vera Lucia Ribeiro

    2005-01-01

    This work presents a new methodology for the overlapping spectra separation obtained by the technique of wavelength dispersion X-ray fluorescence (WDXRF). This methodology allows to improve the conventional analytic results and to facilitate the determination of chemical species of a same element without chemical separation, by means of the separation of coming spectra of electronic transitions of valence electrons or chemical effects in internal electrons. With the software 'GSAS-EXPGUI' and the method of Rietveld overcomes the problem of overlapping lines of the present species in the sample and it facilitates the determination of the same ones simultaneously, without the need of samples patterns and calibration curves, what means an expressive gain in relation to other techniques. The preparation of the surface of the sample for the collection of the spectrum represents a critical stage for the acting of the analysis whose effects can be minimized being used the refinement of Rietveld, that allows the determination of the relationships of the intensities of the lines put upon by means of mathematical models, what establishes the basic conditions for obtaining of more precise results in the quantitative analysis. In the case of the determination of chemical species it can separate, for example Cr (III), Cr (VI) and Fe (II), Fe(III) that present overlapping of almost 100%. (author)

  16. Possibilities and limitations of parametric Rietveld refinement on high pressure data. The case study of LaFeO3

    International Nuclear Information System (INIS)

    Etter, Martin; Mueller, Melanie; Dinnebier, Robert E.; Hanfland, Michael

    2014-01-01

    Parametric Rietveld refinement is a powerful technique to apply directly physical or empirical equations to the refinement of in situ powder diffraction data. In order to investigate the possibilities and limitations of parametric Rietveld refinements for high pressure data four competitive crystallographic approaches were used to carry out a full structural investigation of the orthoferrite LaFeO 3 (Pbnm at ambient conditions) under high pressure up to 47 GPa. Approach A with traditional Rietveld refinement using atomic coordinates, Approach B where the Rietveld refinement was done by using the rigid body method, Approach C where symmetry modes were used and Approach D where the newly developed method of the rotational symmetry mode description for a rigid body was used. For all approaches sequential as well as parametric refinements were carried out, confirming a second order phase transition of LaFeO 3 to a higher symmetric phase (space group Ibmm) at around 21.1?GPa and an isostructural first order phase transition at around 38 GPa. Limitations due to non-hydrostatic conditions as well as the possibilities of a direct modeling of phase transitions with parametric Rietveld refinement are discussed in detail. (orig.)

  17. REMOCION DE LA MATERIA ORGANICA Y TOXICIDAD EN AGUAS RESIDUALES HOSPITALARIAS APLICANDO OZONO

    Directory of Open Access Journals (Sweden)

    DAYANA GRISALES PENAGOS

    2012-01-01

    Full Text Available Las aguas residuales hospitalarias se consideran como una de las principales fuentes de contaminantes emergentes, resultado de las diferentes actividades que allí se realizan y la excreción de las sustancias por los pacientes. Estudios han demostrado que estos componentes no son fácilmente removidos por medio de procesos de tratamiento convencionales como las plantas de tratamiento que emplean procesos biológicos. En este sentido el propósito de este trabajo consistió en evaluar la degradación de la materia orgánica presente en aguas hospitalarias reales aplicando ozono en diferentes condiciones de pH (3,0, 6,7, 10. Para esto se analizaron los valores de la UV254, la relación de biodegradabilidad DQO/DBO5 y el color (VIS436. Adicional a esto, se realizó un ensayo de toxicidad aguda, utilizando bulbos de cebolla común (Allium cepa L. Los resultados mostraron que con una dosis aplicada de ozono de 187 mgO3/h y valores de pH=10 la biodegradabilidad se aumento en un 70% y la toxicidad aguda se redujo en 62%, mientras que para valores de pH =3,0, se favoreció la remoción de la UV254 y el color. La aplicación de ozono demostró ser una alternativa viable para tratar efluentes hospitalarios como pretratamiento de un proceso biológico.

  18. The IPNS rietveld analysis software package for TOF [time-of-flight] powder diffraction data: Recent developments

    International Nuclear Information System (INIS)

    Rotella, F.J.; Richardson, J.W. Jr.

    1987-01-01

    A system of FORTRAN programs for the analysis of time-of-flight (TOF) neutron powder diffraction data via the Rietveld method at IPNS has been modified recently, making it possible to analyze data that exhibit diffraction maxima broadened due to anisotropic strain and that can be modeled by individual atomic anharmonic thermal vibrations. The observation of noncrystalline scattering in data from some powder samples has led to the development of software to fit such scattering by a function related to a radial distribution function through Fourier-filtering techniques. The ''user friendliness'' of the IPNS Rietveld package has been enhanced by the development of ''RIETVELD,'' a menu-based VAX/VMS command language routine for interactive file manipulation and program execution

  19. Determination of Cation Distributions in Mineral Structures by use of the Rietveld Full-Profile Refinement Technique

    International Nuclear Information System (INIS)

    Nord, A.G.

    1986-01-01

    Use of the Rietveld full-profile refinement technique with X-ray or neutron powder diffraction data for the determination of divalent-metal cation distributions in three mineral structure types (farringtonite, grafonite, sarcopside) is demonstrated. The accuracy of the conventional cation distribution coefficient Ksub(D) is about 5-10 percent with 24-46 parameters to be refined, and the averaged metal-oxygen distances are reliable and well correlated to the observed cation distribution pattern. In particular the usefulness of the Rietveld technique in combination with Moessbauer spectroscopy is stressed. Some concluding remarks are also given

  20. A research of the mineralogy phases of clinker in a spanish cement using the method of Rietveld

    International Nuclear Information System (INIS)

    Castanon Ana M; Garcia Granda Santiago; Guerrero Ana M; Gomez Fernandez Fernando

    2012-01-01

    In order to introduce continuously a quality control method in a Spanish cement factory to improve the final product feature new research methodology is being developed. The Rietveld method [1] has been successfully used to analyze the composition of the main phases of clinker. Using this methodologies, research has been carried out to quantize appropriately the minor phase of free lime which is extremely important in the clinker quality. This method leads to satisfactory results on samples with contents in CaO from 3%. These results are possible combining X- ray diffraction and fluorescence techniques as well as the chemical analysis data. Clinker, the Rietveld method, free lime.

  1. The use of the Rietveld method as an evaluation tool in the stages of production of nanostructured hard metal

    International Nuclear Information System (INIS)

    Batista, A.C.; Perpetuo, G.J.; Oliveira, H.C.P. de; Silva, T.R.G. da

    2014-01-01

    The processing of the composite WC-10% Co, with nanometric grain size was analyzed aiming at identifying changes undergone by the material during mixing and compaction steps. Use the X-ray diffraction and the Rietveld method to obtain accurate data on the behavior of powders before these steps. This paper describes the use of the Rietveld method as an evaluation tool to obtain information about the behavior of powders of WC and Co steps during mixing and compaction prior to sintering of the composite. (author)

  2. Profex: a graphical user interface for the Rietveld refinement program BGMN.

    Science.gov (United States)

    Doebelin, Nicola; Kleeberg, Reinhard

    2015-10-01

    Profex is a graphical user interface for the Rietveld refinement program BGMN . Its interface focuses on preserving BGMN 's powerful and flexible scripting features by giving direct access to BGMN input files. Very efficient workflows for single or batch refinements are achieved by managing refinement control files and structure files, by providing dialogues and shortcuts for many operations, by performing operations in the background, and by providing import filters for CIF and XML crystal structure files. Refinement results can be easily exported for further processing. State-of-the-art graphical export of diffraction patterns to pixel and vector graphics formats allows the creation of publication-quality graphs with minimum effort. Profex reads and converts a variety of proprietary raw data formats and is thus largely instrument independent. Profex and BGMN are available under an open-source license for Windows, Linux and OS X operating systems.

  3. Rietveld refinement of Y2O3 using the pearson VII profile shape function

    International Nuclear Information System (INIS)

    Smrcok, L.

    1989-01-01

    Very good agreement between the observed and the calculated intensities was obtained using the Pearson VII profile shape function. The variable exponent m could be refined only in the damped iterations involving exclusively the profile parameters. Simultaneous refinement of the m with the positional and/or thermal parameters has led to large oscillations of the shifts of almost all parameters. Precision of the refined atomic coordinates is better than those from previously published Rietveld refinement and is comparable with single crystal results. The degree of serial correlation in residuals has been determined by the use of the Durbin-Watson d statistic. Normal probability plot based on δR i has been almost linear with the slope greater than one. The weighting scheme with w i = 1/y oi has proved to be good first approximation. (author)

  4. Rietveld refinement and FTIR analysis of bulk ceramic Co3-xMnxO4 compositions

    Science.gov (United States)

    Meena, P. L.; Kumar, Ravi; Sreenivas, K.

    2013-02-01

    Co3-xMnxO4 (x = 0.0, 0.6, 1.2) prepared by solid state reaction method and characterized by powder X-ray diffraction (XRD) and Fourier transform infrared (FTIR). Lattice parameters (a), oxygen parameter (u), and ionic radii of cations have been determined through Rietveld analysis. Both a and u parameters are related to expansion of octahedral site as Mn content in Co3O4. Analysis of XRD data show that Mn (x ≤ 1.2) is accommodated at the octahedral site, while retaining the cubic spinel structure. FTIR results also confirm the same and signify strong interactions due to overlapping of Co and Mn octahedra.

  5. Crystal phase analysis of SnO2-based varistor ceramic using the Rietveld method

    International Nuclear Information System (INIS)

    Moreira, M.L.; Pianaro, S.A.; Andrade, A.V.C.; Zara, A.J.

    2006-01-01

    A second addition of l mol% of CoO to a pre calcined SnO 2 -based ceramic doped with 1.0 mol% of CoO, 0.05 mol% of Nb 2 O 5 and 0.05 mol% of Cr 2 O 3 promotes the appearance of a secondary phase, Co 2 SnO 4 , besides the SnO 2 cassiterite phase, when the ceramic was sintered at 1350 deg. C/2 h. This was observed using X-ray powder diffraction, scanning electron microscopy and energy dispersive X-ray techniques. Rietveld refinement was carried out to quantify the phases present in the ceramic system. The results of the quantitative analysis were 97 wt.% SnO 2 and 3 wt.% Co 2 SnO 4 . The microstructural analysis showed that a certain amount of cobalt ion remains into cassiterite grains

  6. Magnesium substitution in carbonated hydroxyapatite: Structural and microstructural characterization by Rietveld's refinement

    Energy Technology Data Exchange (ETDEWEB)

    Lala, S. [Materials Science Division, Department of Physics, The University of Burdwan, Golapbag, Burdwan 713104, West Bengal (India); Ghosh, M.; Das, P.K. [Department of Biological Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032 (India); Das, D. [UGC-DAE Consortium for Scientific Research, Kolkata 700098 (India); Kar, T. [Department of Materials Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032 (India); Pradhan, S.K., E-mail: skpradhan@phys.buruniv.ac.in [Materials Science Division, Department of Physics, The University of Burdwan, Golapbag, Burdwan 713104, West Bengal (India)

    2016-02-15

    Four stoichiometric compositions of nanocrystalline Mg doped carbonated hydroxyapatite (cHAp) powders are synthesized by mechanical alloying (ball milling) the powder mixtures of CaCO{sub 3}, CaHPO{sub 4}.2H{sub 2}O and MgO in open air at room temperature. FTIR analysis confirms the A-type carbonation in all milled HAp powder samples (A-cHAp). Microstructure characterization in terms of lattice imperfections and phase quantification of ball milled samples are made by analyzing XRD patterns employing Rietveld's structure refinement method. Transmission electron microscopy (TEM) study of 15 mol % Mg doped A-cHAp sample reveals microstructure similar to that obtained from XRD pattern analysis. Cumulative effect of Mg substitution and mechanical alloying results in amorphization of a major part of crystalline A-cHAp, analogous to native bone mineral. Rietveld analysis reveals that the Ca2 vacancy site is energetically more favorable for occupation of Mg substitution. MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay test reveals sufficiently high percentage cell viability confirming the cytocompatibility of the sample. - Graphical abstract: Mg substitution for Ca2 site. - Highlights: • Single phase Mg doped A-cHAp synthesized by mechanical alloying (MA). • FTIR analysis confirms A-type carbonation in HAp. • Amorphization of a part of crystalline A-cHAp due to MA and Mg insertion. • Mg{sup 2+} ions substitute the Ca2 vacancy site. • High cell viability under MTT assay.

  7. Integración de procesos de negocio aplicando servicios web

    Directory of Open Access Journals (Sweden)

    Darío Picón

    2014-09-01

    Full Text Available La Integración de Procesos de Negocio (Business Process Integration – BPI, utiliza una gran cantidad de servicios distribuidos, por lo que la comunicación entre estos servicios es clave para el buen funcionamiento del sistema. En este modelo de cooperación, la arquitectura Cliente-Servidor tradicional ya no es suficiente para la implementación de soluciones que soporten comunicación entre aplicaciones distribuidas, independientemente de la plataforma y del lenguaje de programación que utilizan estas aplicaciones. Por su parte, las Arquitecturas Orientadas a Servicios (Service Oriented Architectures - SOA proveen una estructura que posibilita el modelado de procesos y conexiones interorganizacionales. Mientras que la Gestión de Procesos de Negocio (Business Process Management - BPM es el conjunto de sistemas de software, herramientas y metodologías para gestionar tales requerimientos y, el Lenguaje de Ejecución de Procesos de Negocio (Business Process Execution Language - BPEL, es un lenguaje de orquestación de servicios que permite definir la forma en que cooperan entre sí los Servicios Web para alcanzar la lógica de negocio. En este escenario, existen buenas herramientas para asistir desde lo conceptual y desde lo práctico a la Integración de Procesos de Negocio aplicando Servicios Web. Entonces, la problemática se plantea al momento de vincular estas herramientas de manera apropiada para facilitar el proceso de definición e implementación de este tipo de sistemas y en particular, en el ámbito de las pequeñas y medianas empresas (PyMEs.En este trabajo se propone un modelo que hace posible el BPI mediante Servicios Web de una manera ágil y practica, facilitando su implementación. El mismo será aplicado metodológicamente a un Caso de Estudio en el dominio de las PyMEs, con el propósito de evaluar su eficiencia, evidenciar sus beneficios y hallar oportunidades de mejora.

  8. Ahorro de consumo de agua, aplicando técnicas de riego en jardines de la UNAC

    OpenAIRE

    Sánchez Hernández, Jaime Eloy

    2013-01-01

    La implementación del Proyecto "AHORRO DE CONSUMO DE AGUA, APLICANDO TECNICAS DE RIEGO EN JARDINES DE LA UNAC, con un sistema tecnificado de riego, específicamente por aspersión, se lograría ahorrar agua aproximadamente en un 50%. Además de personal de jardinería provista de mangueras (sistema de inundación) se dedicarían a otras labores que mejoren los jardines de la UNAC. Como corolario se tiene que no solo se ahorraría agua (pago de consumo a la empresa SEDAPAL), sino que al personal se...

  9. Aplicación de tratamiento electroquímico a baja intensidad de corriente para la extracción de cloruros en objetos arqueológicos de hierro de procedencia subacuática. Observación de la evolución de fases mineralógicas mediante XRD-Rietveld

    Directory of Open Access Journals (Sweden)

    Bethencourt, M.

    2004-12-01

    Full Text Available With the purpose of optimising a suitable methodology for the conservation of an archaeological object of iron, a low current intensities electrolytic treatment has been applied, to a piece of cast iron, proving to be effective in the extraction of chloride ions from the structure of akaganeite, principal corrosion product of iron in the marine medium. The monitoring of the electrolytic treatment has been proven by applying the "Rietveld" method to the patterns XRD of samples extracted from the corroded surface before and after the treatment. This method has permitted the unequivocal determination of the akaganeite and its chemical composition. This identification has been corroborated by means of SEM and EDS. After the electrolytic treatment, akaganeite was not present in the sample.

    Con objeto de optimizar una metodología adecuada para la conservación de una pieza de hierro arqueológico de fundición, se ha aplicado un tratamiento electrolítico a bajas intensidades de corriente, demostrando su efectividad en la extracción de iones cloruro de la estructura de akaganeita, principal producto de corrosión del hierro en medio marino. La monitorización del proceso se ha comprobado aplicando el método Rietveld a los patrones XRD de muestras extraídas de la superficie corroída antes y después del tratamiento. Este método ha permitido la determinación inequívoca de la akaganeita y la composición química de este oxihidróxido de hierro no estequiométrico. Dicha identificación se corrobora mediante SEM y EDS. Después del tratamiento electrolítico la akaganeita no está presente en la muestra.

  10. Modelamiento y simulación para analizar la contaminación del lago Titicaca aplicando lógica difusa

    OpenAIRE

    Benites Noriega, Juan

    2007-01-01

    El trabajo de investigación titulado "MODELAMIENTO Y SIMULACIÓN PARA ANALIZAR LA CONTAMINACIÓN DEL LAGO TITICACA, APLICANDO LÓGICA DIFUSA", se ha realizado en la ciudad de Puno con la finalidad de modelar y analizar la contaminación del Lago Titicaca, aplicando la lógica difusa para la conservación del medio ambiente y la sociedad; localizar las fuentes generadoras de la contaminación del Lago Titicaca, y mencionar como afecta la contaminación del Lago Titicaca en la salud de los habitantes q...

  11. Effect of data quality on quantitative phase analysis (QPA) using the Rietveld method

    International Nuclear Information System (INIS)

    Scarlett, N.; Madsen, I.; Lwin, T.

    1999-01-01

    Full text: Quantitative phase analysis using the Rietveld method has become a valuable tool in modern X-ray diffraction. XRD is a recognised research tool and has been successfully employed in the developmental stages of many industrial processes. It is now becoming increasingly important as a means of process control either (i) in site quality control laboratories or (ii) even on-line. In on-line applications, the optimisation of data collection regimes is of critical importance if rapid turn-around, and hence timely process control, is to be achieved. This paper examines the effect of data quality on the quantification of phases in well characterised suites of minerals. A range of data collection regimes has been systematically investigated with a view to determining the minimum data required for acceptable quantitative phase analyses. Data has been collected with variations in the following process factors: 1st step, width ranging from 0.01 to 0.3 deg 2θ ;2nd step, counting time ranging from 0.0125 to 4 sec/step 3rd step, upper limit in the scan range varying from 40 to 148 deg 2θ. The data has been analysed using whole-pattern (Rietveld) based methods using two distinctly different analytical approaches: (i) refinement of only pattern background and individual scale factors for each phase; (ii) refinement of unit cell dimensions, overall thermal parameters, peak width and shape in addition to the background and scale factors. The experimental design for this work included a ternary design of the three component phases (fluorite, CaF 2 ; zincite, ZnO; corundum, Al 2 O 3 ) to form seven mixtures of major and minor phases of different scattering powers and the combination of the three process factors (variables) to form a factorial plan. The final data generation plan is a combination/crossing of the three process variable factorial plan with the three component mixture plan. It allows a detailed data analysis to provide information on the effect of the process

  12. Mineralogical characterization of a highly-weathered soil by the Rietveld Method Caracterização mineralógica de um solo altamente intemperizado pelo Método de Rietveld

    Directory of Open Access Journals (Sweden)

    André Maurício Brinatti

    2010-08-01

    Full Text Available The mineralogical characterization through mineral quantification of Brazilian soils by X-ray diffraction data using the Rietveld Method is not common. A mineralogical quantification of an Acric Ferralsol from the Ponta Grossa region, state of Paraná, Brazil, was carried out using this Method with X-Ray Diffraction data to verify if this method was suitable for mineral quantification of a highly-weathered soil. The A, AB and B3 horizons were fractioned to separate the different particle sizes: clay, silt, fine sand (by Stokes Law and coarse sand fractions (by sieving, with the procedure free of chemical treatments. X-ray Fluorescence, Inductively Coupled Plasma Atomic Emission Spectrometry, Infrared Spectroscopy and Mössbauer Spectroscopy were used in order to assist the mineral identification and quantification. The Rietveld Method enabled the quantification of the present minerals. In a general way, the quantitative mineralogical characterization by the Rietveld Method revealed that quartz, gibbsite, rutile, hematite, goethite, kaolinite and halloysite were present in the clay and silt fractions of all horizons. The silt fractions of the deeper horizons were different from the more superficial ones due to the presence of large amounts of quartz. The fine and the coarse sand fractions are constituted mainly by quartz. Therefore, a mineralogical quantification of the finer fraction (clay and silt by the Rietveld Method was successful.A caracterização mineralógica por meio da quantificação dos minerais presentes em solos brasileiros por difração de raios X usando o Método de Rietveld é, ainda, pouco comum. Neste trabalho foi realizada a quantificação mineralógica de um Latossolo Vermelho ácrico da região de Ponta Grossa, Paraná, Brasil, utilizando o Método de Rietveld com dados de Difração de Raios X e também verificado se o método foi adequado na quantificação mineral de um solo altamente intemperizado. Os horizontes A

  13. Characterization of barium titanate powder doped with sodium and potassium ions by using Rietveld refining; Caracterizacao do po de titanato de bario dopado com ions sodio e potasio com o refinamento de Rietveld

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, M.C.; Assis, J.T.; Pereira, F.R., E-mail: mcalixto@iprj.uerj.b [Universidade do Estado do Rio de Janeiro (IPRJ/UERJ), Nova Friburgo, RJ (Brazil). Instituto Politecnico; Araujo, J.C. [Universidade do Estado do Rio de Janeiro (FFP/UERJ), Sao Goncalo, RJ (Brazil). Fac. de Formacao de Professores; Moreira, E.L.; Moraes, V.C.A.; Lopes, A.R. [Centro Brasileiro de Pesquisas Fisicas (CBPF/MCT), Rio de Janeiro, RJ (Brazil)

    2009-07-01

    A solid-reaction synthesis of doped barium titanate was done by employing barium carbonates, sodium, potassium and titanium oxides with classic procedures. Rietveld refining of X ray diffraction data of perovskite samples with tetragonal symmetry was applying and show good agreement. Besides, the treatment performed from 600 deg C produces nanocrystals of barium titanate with average size of 33 nm. The presence of endothermic peaks related to BaTiO{sub 3} formation at relatively low temperatures was determined by thermal analysis. A pseudo-Voigt Thompson-Cox-Hastings function was used to fit the standard samples of barium titanate. The Rietveld method has showed be efficient to detect the influences of temperature and doping on barium titanate microstructures. (author)

  14. Rietveld quantitative phase analysis of high surface area commercial alumina doped with niobia

    International Nuclear Information System (INIS)

    Gomes, L.B.; Pereira, A.S.; Pokorny, A.; Bergmann, C.P.

    2014-01-01

    The quantification of crystalline phases present in a given material can provide important information about the phenomena related to the diffusion of new elements in a ceramic matrix, as well as the formation and precipitation of minority phases and their microstructural evaluation. In this work, a high content of niobia (16 and 32 %w.t)was added to a high specific surface commercial alumina powder. The specimens were uniaxially pressed (200 MPa) and sintered in two stages: a first step at 1100°C for 3, 6 or 9 hours followed by a second step at 1350°C for 3 hours. The crystalline phases were analyzed by X-ray Diffraction (XRD) and quantified by the Rietveld method. The morphology of the samples was evaluated by Scanning Electron Microscopy (SEM). From the results obtained, some aluminum niobates phases expected for the Al_2O_3-Nb_2O_5 system could be identified as an intergranular phase and their relative fraction was quantified. (author)

  15. Rietveld refinement of the crystal structures of Rb2XSi5O12 (X = Ni, Mn

    Directory of Open Access Journals (Sweden)

    Anthony M. T. Bell

    2016-02-01

    Full Text Available The synthetic leucite silicate framework mineral analogues Rb2XSi5O12 {X = Ni [dirubidium nickel(II pentasilicate] and Mn [dirubidium manganese(II pentasilicate]} have been prepared by high-temperature solid-state synthesis. The results of Rietveld refinements, using X-ray powder diffraction data collected using Cu Kα X-rays, show that the title compounds crystallize in the space group Pbca and adopt the cation-ordered structure of Cs2CdSi5O12 and other leucites. The structures consist of tetrahedral SiO4 and XO4 units sharing corners to form a partially substituted silicate framework. Extraframework Rb+ cations sit in channels in the framework. All atoms occupy the 8c general position for this space group. In these refined structures, silicon and X atoms are ordered onto separate tetrahedrally coordinated sites (T-sites. However, the Ni displacement parameter and the Ni—O bond lengths suggest that for the X = Ni sample, there may actually be some T-site cation disorder.

  16. Neutron irradiated uranium silicides studied by neutron diffraction and Rietveld analysis

    International Nuclear Information System (INIS)

    Birtcher, R.C.; Mueller, M.H.; Richardson, J.W. Jr.; Faber, J. Jr.

    1989-11-01

    Uranium silicides have been considered for use as reactor fuels in both high power and low enrichment applications. However, U 3 Si was found to become amorphous under irradiation and to become mechanically unstable to rapid growth by plastic flow. U 2 Si 2 appears to be stable against amorphization at low displacement rates, but the extent of this stability is uncertain. Although the mechanisms responsible for plastic flow in U 3 Si and other amorphous systems are unknown, as is the importance of crystal structure for amorphization, it may not be surprising that these materials amorphize, in light of the fact that many radioactive nuclide - containing minerals are known to metaminctize (lose crystallinity) under irradiation. The present experiment follows the detailed changes in the crystal structures of U 3 Si and U 3 Si 2 introduced by neutron bombardment and subsequent uranium fission at room temperature. U-Si seems the ideal system for a neutron diffraction investigation since the crystallographic and amorphous forms can be studied simultaneously by combining conventional Rietveld refinement of the crystallographic phases with Fourier-filtering of the non-crystalline scattering component

  17. Análisis de las poblaciones de microorganismos fijadores de nitrógeno del suelo aplicando procedimientos metagenómicos

    OpenAIRE

    Calderoli, Priscila Anabel

    2016-01-01

    En este trabajo de tesis doctoral se llevó a cabo el análisis de las poblaciones de microorganismos fijadores de nitrógeno del suelo aplicando análisis independientes del cultivo. Se analizaron suelos de la principal región agrícola de la Argentina, la región pampeana.

  18. Quantitative study of Portland cement hydration by X-ray diffraction/Rietveld analysis and independent methods

    International Nuclear Information System (INIS)

    Scrivener, K.L.; Fuellmann, T.; Gallucci, E.; Walenta, G.; Bermejo, E.

    2004-01-01

    X-ray diffraction (XRD) is a powerful technique for the study of crystalline materials. The technique of Rietveld refinement now enables the amounts of different phases in anhydrous cementitious materials to be determined to a good degree of precision. This paper describes the extension of this technique to a pilot study of the hydration of a typical Portland cement. To validate this XRD-Rietveld analysis technique, its results were compared with independent measures of the same materials by the analysis of backscattered electron images (BSE/IA) and thermogravimetric analysis (TGA). In addition, the internal consistency of the measurements was studied by comparing the XRD estimates of the amounts of hydrates formed with the amounts expected to form from the XRD estimates of the amounts of anhydrous materials reacted

  19. PLANEACIÓN DE UN SISTEMA SILVOPASTORIL EN LADERA EN HUATUSCO, VERACRUZ APLICANDO EL MÉTODO NEZAHUALCÓYOTL

    Directory of Open Access Journals (Sweden)

    L. Quinto

    2009-01-01

    Full Text Available El estudio describe el diseño e implementación de un módulo silvopastoril en ladera aplicando el método Nezahualcóyotl para establecer el componente arbóreo compuesto por: Swietenia macrophylla King (caoba, Tabebuia rosea (Bertol DC. (roble y Cedrela odorata L. (cedro rojo. El terreno se ubicó en la zona de Huatusco; en él se construyeron a nivel cinco bordos-zanjas, sobre los bordos se plantaron cada 4 m e intercalados, los árboles con dos meses de crecimiento en vivero. A cuatro meses de la plantación la supervivencia fue similar (a=0.05 entre especies y superior a 80 %. El componente ganadero no se implementó en campo sólo se describió su diseño y planeación, este componente consistió de pradera de Brachiaria brizantha y bovinos a media ceba. Se describe el establecimiento de la pradera mediante cultivo de maíz en aparcería. Se identifican los principales rubros de egresos para el establecimiento del módulo silvopastoril aplicando el método Nezahualcóyotl estimando como costo $ 44,347.00 por cada tercio de hectárea. Se concluyó que el método Nezahualcóyotl es una opción para el establecimiento del componente arbóreo de un sistema silvopastoril en terrenos con pendiente.

  20. Tailoring diffraction technique Rietveld method on residual stress measurements of cold-can oiled 304 stainless steel plates

    International Nuclear Information System (INIS)

    Parikin; Killen, P.; Anis, M.

    2003-01-01

    Tailoring of diffraction technique-Rietveld method on residual stress measurements of cold-canailed stainless steel 304 plates assuming the material is isotopic, the residual stress measurements using X-ray powder diffraction is just performed for a plane lying in a large angle. For anisotropic materials, the real measurements will not be represented by the methods. By Utilizing of all diffraction peaks in the observation region, tailoring diffraction technique-Rietveld analysis is able to cover the limitations. The residual stress measurement using X-ray powder diffraction tailored by Rietveld method, in a series of cold-canailed stainless steel 304 plates deforming; 0, 34, 84, 152, 158, 175, and 196 % reduction in thickness, have been reported. The diffraction data were analyzed by using Rietveld structure refinement method. Also, for all cold-canailed stainless steel 304 plates cuplikans, the diffraction peaks are broader than the uncanailed one, indicating that the strains in these cuplikans are inhomogeneous. From an analysis of the refined peak shape parameters, the average root-mean square strain, which describes the distribution of the inhomogeneous strain field, was calculated. Finally, the average residual stresses in cold-canailed stainless steel 304 plates were shown to be a combination effect of hydrostatic stresses of martensite particles and austenite matrix. The average residual stresses were evaluated from the experimentally determined average lattice strains in each phase. It was found the tensile residual stress in a cuplikan was maximum, reaching 442 MPa, for a cuplikan reducing 34% in thickness and minimum for a 196% cuplikan

  1. The role of iron in tetrahedrite and tennantite determined by Rietveld refinement of neutron powder diffraction data

    DEFF Research Database (Denmark)

    Andreasen, Jens Wenzel; Makovicky, Emil; Lebech, Bente

    2008-01-01

    Rietveld refinement of neutron powder diffraction data on four samples of synthetic, iron-bearing tetrahedrite (Cu12-xFexSb4S13) with x = 0.28, 0.69, 0.91, 2.19 and four samples of synthetic tennantite (Cu12-xFexAs4S13) with x = 0.33, 0.38, 0.86, 1.5 indicate unambiguously that iron is incorporated...

  2. Quantitative determination of phases in ZrO2 (MgO) (Y2O3) using the Rietveld method

    International Nuclear Information System (INIS)

    Castro, Antonio Carlos de

    2007-01-01

    The key objective of this work is the crystallographic characterization of the zircon co-doped with Yttria and magnesium with the application of the Rietveld method for quantitative phase analysis of zircon polymorph (zircon monoclinic, tetragonal, and cubic). Samples of zircon polymorph were obtained from zircon doped with Yttria and magnesium at defined molar concentrations. The zircon polymorph stability during subeutetoid aging at 1350 deg C were investigated to determine ZrO 2 - MgO - Y 2 0 3 phases degradation and to define the solid solutions stability environment. ZrO 2 powders doped with 8 mol por cent of MgO and 1 mol por cent of Y 2 O 3 , and 9 mol por cent of MgO and 0 mol por cent of Y 2 O 3 have been prepared by chemical route using the co-precipitation method. These samples have been calcinate at 550 deg C, sintered at 1500 deg C and characterized by the Rietveld method using the X-ray diffraction data. The variation of the lattice parameter, changes in the phase composition and their microstructures are discussed. The application of the Rietveld method for quantitative phase analysis of zircon polymorph (zircon tetragonal and cubic) reveals no formation of tetragonal phase and indicating that the matrix is the cubic phase with low concentration of monoclinic phase.(author)

  3. Crystal structure analysis of LaMnO_3 with x-ray diffraction technique using the Rietveld method

    International Nuclear Information System (INIS)

    Engkir Sukirman; Wisnu Ari Adi; Yustinus Purwamargapratala

    2010-01-01

    Crystal structure analysis of LaMnO_3 using the Rietveld method has been carried out. The LaMnO_3 sample was synthesized with high energy mechanical milling from the raw materials of La_2O_3 and MnO_2 with the appropriate mol ratio. Milling were performed for 10 hours, pelletized and hereinafter sintered at 1350 °C for 6 hours. The sample characterizations covered the crystal structure and electric-magnetic properties of the materials by X-ray diffraction technique using the Rietveld method and the four point probe, respectively. The Rietveld refinement results based on the X-rays diffraction data indicate that the sample of LaMnO_3 is single phase with the crystal system: orthorhombic, the space group: Pnma No. 62 and the lattice parameters: a = 55.4405(9) Å; b = 7.717(1) Å dan c = 5.537(1) Å. The material owns Magnetic Resonance (MR) respond of 7 %, the mean value of crystallite size, D = 17 nm and lattice strain, e = - 0.5 %. So, the material go through a compressive strain, and according to the Nanda's strain model, it becomes a type G antiferromagnetic insulator. Because the insulator properties of the material does not change although being hit by the external magnetic field, hence the MR respond is only caused by the order of electron spin. Therefore at room temperature, LaMnO_3_._0 just exhibits a small MR respond. (author)

  4. Investigation on the evolution of microstructure and texture of electroplated Ni–Ti composite coating by Rietveld method

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yuantao, E-mail: zhaoyuantao@sjtu.edu.cn; Cai, Fei, E-mail: caifei32@126.com; Wang, Chengxi, E-mail: sjtucxw@sjtu.edu.cn; Chai, Ze, E-mail: zechaisjtu@163.com; Zhu, Kaiyuan, E-mail: xrd125@163.com; Xu, Zhou, E-mail: xuzhou@sjtu.edu.cn; Jiang, Chuanhai, E-mail: chjiang-sjtu@hotmail.com

    2015-10-30

    Highlights: • Ni–Ti composite coatings were prepared by electroplating. • Morphology and Ti content of Ni–Ti coatings were studied upon SEM and EDXS. • Microstructures of Ni–Ti coatings were studied upon the Rietveld method. • The texture of Ni–Ti coatings was studied upon the pole figure. - Abstract: Rietveld refinement was utilized to investigate the evolution of microstructure and texture of the Ni–Ti composite coatings electroplated at different applied current densities. Scanning Electron Microscope and Energy Dispersive Spectroscopy were utilized to investigate the morphology and chemical composition of the coatings. Relative texture coefficients (RTC) and measured pole figures were utilized to investigate the texture evolution of the coatings. The results showed that the surface morphology of the coatings changed from a colonial structure to a polyhedral one. And the incorporated Ti content decreased with increasing applied current density. As the applied current density increased, the crystallite sizes increased and their distribution got less uniform, and the microstrain and dislocation density decreased. The results of simulated pole figures obtained from Rietveld refinement illustrated that the texture of the coatings changed from no obvious texture to a strong [2 0 0] fiber texture with increasing applied current density. The texture evolution obtained from simulated pole figures was confirmed by the result of RTC and the measured pole figures. The evolutions of the microstructure and texture were derived from the change of the applied current density and incorporated Ti content in the Ni–Ti composite coatings.

  5. Rietveld refinement of the structures of 1.0 C-S-H and 1.5 C-S-H

    KAUST Repository

    Battocchio, Francesco; Monteiro, Paulo J.M.; Wenk, Hans-Rudolf

    2012-01-01

    Low-Q region Rietveld analyses were performed on C-S-H synchrotron XRD patterns, using the software MAUD. Two different crystal structures of tobermorite 11 Å were used as a starting model: monoclinic ordered Merlino tobermorite, and orthorhombic

  6. A research of the mineralogy phases of clinker in a spanish cement using the method of Rietveld

    International Nuclear Information System (INIS)

    Castanon, Ana M; Garcia, Granda Santiago; Guerrero, Ana M; Gomez Fernandez, Fernando

    2012-01-01

    In order to introduce continuously a quality control method in a Spanish cement factory to improve the final product feature new research methodology is being developed. The Rietveld method [1] has been successfully used to analyze the composition of the main phases of clinker. Using this methodologies, research has been carried out to quantize appropriately the minor phase of free lime which is extremely important in the clinker quality. This method leads to satisfactory results on samples with contents in CaO from 3%. These results are possible combining X- ray diffraction and fluorescence techniques as well as the chemical analysis data.

  7. Análisis de las poblaciones de microorganismos fijadores de nitrógeno del suelo aplicando procedimientos metagenómicos

    OpenAIRE

    Calderoli, Priscila Anabel

    2016-01-01

    En este trabajo de tesis doctoral se llevó a cabo el análisis de las poblaciones de microorganismos fijadores de nitrógeno del suelo aplicando análisis independientes del cultivo. Se analizaron suelos de la principal región agrícola de la Argentina, la región pampeana. Facultad de Ciencias Exactas

  8. Effect of powder sample granularity on fluorescent intensity and on thermal parameters in x-ray diffraction Rietveld analysis

    International Nuclear Information System (INIS)

    Sparks, C.J.; Specht, E.D.; Ice, G.E.; Kumar, R.; Zschack, P.; Shiraishi, T.; Hisatsune, K.

    1991-01-01

    The effect of sample granularity on diffracted x-ray intensity was evaluated by measuring the 2θ dependence of x-ray fluorescence from various samples. Measurements were made in the symmetric geometry on samples ranging from single crystals to highly absorbing coarse powders. A characteristic shape for the absorption correction was observed. A demonstration of the sensitivity of Rietveld refined site occupation parameters is made on CuAu and Cu 50 Au 44 Ni 6 alloys refined with and without granularity corrections. These alloys provide a good example of the effect of granularity due to their large linear x-ray absorption coefficients. Sample granularity and refined thermal parameters obtained from the Rietveld analysis were found to be correlated. Without a granularity correction, the refined thermal parameters are too low and can actually become negative in an attempt to compensate for granularity. A general shape for granularity correction can be included in refinement procedures. If no granularity correction is included, data should be restricted to above 30 degrees 2θ, and thermal parameters should be ignored unless extreme precautions are taken to produce >5 μm particles and high packing densities

  9. Synthesis and structural characterisation using Rietveld and pair distribution function analysis of layered mixed titanium-zirconium phosphates

    International Nuclear Information System (INIS)

    Burnell, Victoria A.; Readman, Jennifer E.; Tang, Chiu C.; Parker, Julia E.; Thompson, Stephen P.; Hriljac, Joseph A.

    2010-01-01

    Crystalline metal (IV) phosphates with variable zirconium-to-titanium molar ratios of general formula (Ti 1-x Zr x )(HPO 4 ) 2 .H 2 O have been prepared by precipitation of soluble salts of the metals with phosphoric acid and heating the amorphous solids in 12 M H 3 PO 4 in an autoclave. The new materials are structurally characterised by Rietveld analysis of synchrotron X-ray powder diffraction data and pair distribution function (PDF) analysis of high energy synchrotron X-ray total scattering data. A broad range of zirconium-titanium phosphate solid solutions were formed showing isomorphous substitution of titanium by zirconium in the α-titanium phosphate lattice and vice versa for titanium substitution into the α-zirconium phosphate lattice. In both cases the solubility is partial with the coexistence of two substituted phases observed in samples with nominal compositions between the solubility limits. - Graphical abstract: Layered phosphates of general formula (Ti 1-x Zr x )(HPO 4 ).H 2 O have been prepared by the hydrothermal treatment of amorphous gels in phosphoric acid and characterised by Rietveld analysis of high resolution synchrotron X-ray powder diffraction data and pair distribution function analysis of high energy synchrotron X-ray total scattering data.

  10. Possibilities and limitations of parametric Rietveld refinement on high pressure data. The case study of LaFeO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Etter, Martin; Mueller, Melanie; Dinnebier, Robert E. [Max-Planck-Institut fuer Festkoerperforschung, Stuttgart (Germany); Hanfland, Michael [European Synchrotron Radiation Facility (ESRF), Grenoble (France)

    2014-04-01

    Parametric Rietveld refinement is a powerful technique to apply directly physical or empirical equations to the refinement of in situ powder diffraction data. In order to investigate the possibilities and limitations of parametric Rietveld refinements for high pressure data four competitive crystallographic approaches were used to carry out a full structural investigation of the orthoferrite LaFeO{sub 3} (Pbnm at ambient conditions) under high pressure up to 47 GPa. Approach A with traditional Rietveld refinement using atomic coordinates, Approach B where the Rietveld refinement was done by using the rigid body method, Approach C where symmetry modes were used and Approach D where the newly developed method of the rotational symmetry mode description for a rigid body was used. For all approaches sequential as well as parametric refinements were carried out, confirming a second order phase transition of LaFeO{sub 3} to a higher symmetric phase (space group Ibmm) at around 21.1?GPa and an isostructural first order phase transition at around 38 GPa. Limitations due to non-hydrostatic conditions as well as the possibilities of a direct modeling of phase transitions with parametric Rietveld refinement are discussed in detail. (orig.)

  11. Determination of phases of {alpha} - Fe{sub 2}O{sub 3}: SiO{sub 2} compound by the Rietveld refinement

    Energy Technology Data Exchange (ETDEWEB)

    Palomares S, S.A. [Istituto Materiali Speciali per Elettronica e Magnetismo (MASPEC), Parco Area delle Scienze 37A-43010 Loc. Fontanni, Parma (Italy); Ponce C, S.; Martinez, J.R. [Facultad de Ciencias, Universidad Autonoma de San Luis Potosi, 78000 San Luis Potosi (Mexico); Ruiz, F. [Instituto Potosino de Investigacion Cientifica y Tecnologica, Av. V. Carranza 2025, San Luis Potosi (Mexico)

    2002-07-01

    We use a variation of the Rietveld refinement method to calculate the amorphous content of composites formed by a silica xerogel amorphous matrix and iron particles embedded into. In order to apply the Rietveld refinement to amorphous structures an initial crystalline model is assumed with the same composition as the material to be modelled. In this work we try to refine the structure of compounds using the program MAUD. It is shown how this program can be used to determine the amorphous and crystalline fractions in composites consisting of an amorphous matrix and incorporated iron oxide particles. The analysed compounds underwent different thermal treatments. (Author)

  12. Rietveld and impedance analysis of cold and hot rolled duplex and lean duplex steels for application in paper and pulp industry

    Energy Technology Data Exchange (ETDEWEB)

    Esteves, Luiza; Lins, Vanessa de Freitas Cunha, E-mail: luizaeq@yahoo.com.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Quimica; Paiva, Paulo Renato Perdigao [Centro Federal de Educacao Tecnologica de Minas Gerais (CEFET), Belo Horizonte, MG (Brazil); Viana, Adolfo Kalergis do Nascimento [APERAM South America, Timoteo, MG (Brazil)

    2017-01-15

    In this study, X-Ray Diffraction (XRD) and Rietveld Refinement were performed to identify and quantify the ferrite and austenite phase of cold and hot rolled duplex stainless steels (UNS S31803) and lean duplex stainless steels (UNS S32304). Electrochemical impedance spectroscopy (EIS) was applied to evaluate the chemical behavior of duplex and lean duplex stainless steels in white, green, and black liquors of paper and pulp industry. Rietveld analysis results showed a higher austenite content than the standard limit for duplex steels in the hot rolled condition. The hot rolling condition plays a major role in improving corrosion resistance in white liquor mainly for the lean duplex steel. (author)

  13. Rietveld and impedance analysis of cold and hot rolled duplex and lean duplex steels for application in paper and pulp industry

    International Nuclear Information System (INIS)

    Esteves, Luiza; Lins, Vanessa de Freitas Cunha; Viana, Adolfo Kalergis do Nascimento

    2017-01-01

    In this study, X-Ray Diffraction (XRD) and Rietveld Refinement were performed to identify and quantify the ferrite and austenite phase of cold and hot rolled duplex stainless steels (UNS S31803) and lean duplex stainless steels (UNS S32304). Electrochemical impedance spectroscopy (EIS) was applied to evaluate the chemical behavior of duplex and lean duplex stainless steels in white, green, and black liquors of paper and pulp industry. Rietveld analysis results showed a higher austenite content than the standard limit for duplex steels in the hot rolled condition. The hot rolling condition plays a major role in improving corrosion resistance in white liquor mainly for the lean duplex steel. (author)

  14. Rietveld analysis using powder diffraction data with anomalous scattering effect obtained by focused beam flat sample method

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Masahiko, E-mail: masahiko@spring8.or.jp; Katsuya, Yoshio, E-mail: katsuya@spring8.or.jp; Sakata, Osami, E-mail: SAKATA.Osami@nims.go.jp [Synchrotron X-ray Station at SPring-8, National Institute for Materials Science 1-1-1 Kouto, Sayo, Hyogo 679-5198 (Japan)

    2016-07-27

    Focused-beam flat-sample method (FFM) is a new trial for synchrotron powder diffraction method, which is a combination of beam focusing optics, flat shape powder sample and area detectors. The method has advantages for X-ray diffraction experiments applying anomalous scattering effect (anomalous diffraction), because of 1. Absorption correction without approximation, 2. High intensity X-rays of focused incident beams and high signal noise ratio of diffracted X-rays 3. Rapid data collection with area detectors. We applied the FFM to anomalous diffraction experiments and collected synchrotron X-ray powder diffraction data of CoFe{sub 2}O{sub 4} (inverse spinel structure) using X-rays near Fe K absorption edge, which can distinguish Co and Fe by anomalous scattering effect. We conducted Rietveld analyses with the obtained powder diffraction data and successfully determined the distribution of Co and Fe ions in CoFe{sub 2}O{sub 4} crystal structure.

  15. Synthesis of Zr-Si-O-N phases by carbonitriding reaction. Characterization of crystalline phases using the Rietveld method

    Directory of Open Access Journals (Sweden)

    Mazzoni A.D.

    2001-01-01

    Full Text Available Zirconium compounds are of great interest for ceramic application due to their excellent thermal and mechanical properties. Zirconium phases of the system Zr-O-C-N were obtained using carbonitriding reactions of zircon mineral (ZrO2.SiO2, under different reaction conditions. The reaction products were studied by X-ray diffraction (XRD using the Rietveld method. Silicon was employed as internal standard. Zirconium compounds formed were m-ZrO2 (monoclinic, beta"-zirconium oxynitride and a cubic Zr(C,N,O phase whose lattice parameter a o depends on the composition. The crystallite sizes of the three zirconium phases were determined also by XRD. The minority phases present are the ones of the Si-O-N-C system. The reaction conditions employed allows to obtain reaction products with low or without silicon content.

  16. Rietveld analysis using powder diffraction data with anomalous scattering effect obtained by focused beam flat sample method

    International Nuclear Information System (INIS)

    Tanaka, Masahiko; Katsuya, Yoshio; Sakata, Osami

    2016-01-01

    Focused-beam flat-sample method (FFM) is a new trial for synchrotron powder diffraction method, which is a combination of beam focusing optics, flat shape powder sample and area detectors. The method has advantages for X-ray diffraction experiments applying anomalous scattering effect (anomalous diffraction), because of 1. Absorption correction without approximation, 2. High intensity X-rays of focused incident beams and high signal noise ratio of diffracted X-rays 3. Rapid data collection with area detectors. We applied the FFM to anomalous diffraction experiments and collected synchrotron X-ray powder diffraction data of CoFe_2O_4 (inverse spinel structure) using X-rays near Fe K absorption edge, which can distinguish Co and Fe by anomalous scattering effect. We conducted Rietveld analyses with the obtained powder diffraction data and successfully determined the distribution of Co and Fe ions in CoFe_2O_4 crystal structure.

  17. In-situ high-energy X-ray diffraction and batch Rietveld refinement of phase changes in titanium aluminides

    International Nuclear Information System (INIS)

    Whitfield, R.

    2007-01-01

    Full text: We have used the Rietveld refinement method for the analysis of high-energy X-ray power diffraction for quantitatve phase analysis. This method has the advantage of being able to model the multiple phases appearing in the diffraction pattern and tell us about the composition of the phases of a sample as we change the temperature. It has been applied to various TiAl compounds allowing us to follow in detail the phase transitions of the intermetallics when heated to around 1400 0 Cand subsequently cooled. Small amounts of additives like V, Cr and Gd as well as signatures from different production processes can be seen to have an effect on the phase transitions. With increasing temperature we can see the evolution of the unit cell due to thermal expansion, chemical segregation and the relative proportion of phase changes

  18. Refinement by Rietveld method of a rolled sheet Al-Mg-Si 6063 alloy with preferential orientation

    International Nuclear Information System (INIS)

    Carrio, J.A.G.; Hattori, C.S.; Miranda, L.F.; Domingues Junior, N.I.; Lima, N.B.; Couto, A.A.; Aguiar, A.A.

    2010-01-01

    The Rietveld refinement of a sample with preferential orientation was accomplished using data of X ray diffraction of a rolled 6063 aluminum alloy. The refinement of the preferential orientation by spherical harmonic was accomplished using a symmetry of sample mmm (rolling) until the order of 8 and was compared with experimental pole figures. The four pole figures presented indicate a sharp texture of the planes (111), (200), (220) and (311). The calculated pole figures obtained from the refinement of the X ray diffraction spectrum can incur in mistakes of preferential orientation. This happens because the measure is restricted to the planes parallel to the surface without inference to the symmetry of the sample. (author)

  19. Application of the Rietveld method in structural analysis of catalysts based on CuO/CeO2

    International Nuclear Information System (INIS)

    Neiva, L.S.; Ribeiro, M.A.; Bispo, A.; Simoes, A.N.; Gama, L.

    2011-01-01

    This work has as aim to synthesize catalysts composed by CuO/CeO 2 by means two distinct methods of synthesis, they are: combustion synthesis and Pechini. The catalysts composed by CuO/CeO 2 were synthesized with CuO in condition of dopant element. The value of the CuO concentration ranged between 0 and 0.5 mol. Has been done a structural analysis related to how the kind of synthesis method used influences over physical characteristic of the catalytic material. The obtained catalysts were characterized by X-ray diffraction with refinement by Rietveld method. According to results, the synthesized catalysts showed crystalline structures formed mostly by CeO 2 phase, as expected, since this is the host matrix for the dopant element. The catalysts obtained by the Pechini method presented structures with a smaller amount of segregated phases formed by CuO, according to the results of the structural analysis. (author)

  20. Homogeneity characterisation of (U,Gd)O2 sintered pellets by X-ray diffraction powder analysis applying Rietveld method

    International Nuclear Information System (INIS)

    Leyva, Ana G.; Vega, Daniel R.; Trimarco, Veronica G.; Marchi, Daniel E.

    1999-01-01

    The (U,Gd)O 2 sintered pellets are fabricated by different methods. The homogeneity characterisation of Gd content seems to be necessary as a production control to qualify the process and the final product. The micrographic technique is the most common method used to analyse the homogeneity of these samples, this method requires time and expertise to obtain good results. In this paper, we propose an analysis of the X-ray diffraction powder patterns through the Rietveld method, in which the differences between the experimental data and the calculated from a crystalline structure model proposed are evaluated. This result allows to determine the cell parameters, that can be correlated with the Gd concentration, and the existence of other phases with different Gd ratio. (author)

  1. Application of the Rietveld method in powders of strontium-doped lanthanum manganite calcined in different temperatures

    International Nuclear Information System (INIS)

    Chiba, R.; Vargas, R.A.; Martinez, L.G.; Andreoli, M.; Seo, E.S.M.

    2010-01-01

    The strontium-doped lanthanum manganite (LSM) is a ceramic material used as cathode in device called High Temperature Solid Oxide Fuel Cell. In this work, the LSM was synthesized by the citrate technique with the objective to get powders without the formation of secondary phases, such as lanthanum oxide and the lanthanum hydroxide, harmful for the functional performance of the device. The definitive calcination temperatures had been 700, 900 and 1100 deg C, due the decomposition of the polymeric precursors to present stabilization from 480 deg C. The analysis by X-ray diffraction of the calcined powders in different temperatures shows the formation only of phase LSM of hexagonal crystalline structure, type pseudo-perovskite. Using the refinement of Rietveld was determined the parameters and volumes of unity cells, atomic positions and occupations. These results confirm that the chemical compositions obtained are similar to the nominal. (author)

  2. Influence of the milling time in the microstructural parameters of TA2O5-Al powder refined by Rietveld method

    International Nuclear Information System (INIS)

    Brito, R.A.; Mendes, M.W.D.; Alves Junior, C.; Costa, F.A. da; Gomes, U.U.

    2009-01-01

    Mechanical alloying (MA) is a solid-state powder processing technique involving repeated welding, fracturing, and re-welding of powder particles in a high energy mill. This process is used for producing of fine powders containing unique microstructures. The process starts with mixing of the powders in the desired proportion. Then, the mixture is milled using the established time in the high-energy mill. The powder particles are submitted to repeated cycles of cold working and fracture, and the final product correspond to a composite powder, containing characteristics different of the initial constituents. Ta 2 O 5 -Al powders were milled in a planetary ball mill for different times in order to evaluate the influence of the milling time in their microstructural parameters like crystallite size and micro deformation. The microstructural parameters were obtained by the Rietveld Method. The results showed that the microstructural parameters were influenced by the increase of the milling time. (author)

  3. Study of the superconducting compound Hg,Re-1223 by X-Ray diffraction with application of Rietveld method

    International Nuclear Information System (INIS)

    Putvinskis, Rodrigo

    2008-01-01

    The objective of this work was to study the crystal structure of the superconductor compound of nominal composition Hg 0,82 Re 0,18 Ba 2 Ca 2 Cu 3 O 8+δ and general formula Hg,Re- 1223 and different oxygen contents, by the X-ray diffraction technique, by using the Rietveld method. The studied samples present different oxygen stoichiometry because during the synthesis process, had been heat treated under different oxygen/argon gas mixtures in the ratios: 5:95, 10:90 and 15:85. The results of structural refinement for the samples show that different oxygen contents imply in different cell parameters, atomic positions and distances for the main phase of each sample. The segregation of two superconducting phases with the same crystal structure, but slightly different cell parameters was confirmed for the studied samples both by Rietveld analysis and anomalous X-ray diffraction experiments. It was also confirmed that one of the segregated phases does not incorporate Re cations its composition. The main phase, who incorporates the Re cations, is here called Hg,Re-1223 and the Re-free secondary phase is called Hg- 1223. It was found that the superconducting phases present different crystallite sizes and the sample treated under gas flow composed of 10% oxygen and 90% argon presents the highest fraction of superconducting phases. From these results it was possible to conclude that the sample produced from the precursor compound treated under flow of O 2 /Ar gas at the ratio 10/90 presents the better results for the synthesis of this superconducting compound. (author)

  4. Dirección del proyecto para la construcción del casco habitable del edificio multifamiliar Pramin, aplicando estándares del PMI

    OpenAIRE

    Cabrejos Canevaro, Omar; Garrido Lovón, Johan; Herrera Stoll, Alberto; Ramírez Apón, Ernesto

    2017-01-01

    La presente tesis tiene como objetivo principal el desarrollo de la Dirección de un proyecto para la construcción del Casco Habitable del Edificio Multifamiliar Pramin, ejecutado por la empresa Construcciones Corbus S.A., aplicando los estándares de la Guía del PMBOK, quinta edición, se busca lograr una ventaja competitiva sostenible en el tiempo a través de un modelo de dirección eficiente en sus procesos que sirva como base actualizable para la ejecución de cada proyecto de la empresa a fin...

  5. Reducción de costo total de inventario aplicando un modelo de control de inventario del tipo (s,S).

    OpenAIRE

    Matos Quispe, Cesar Anibal; Matos Quispe, Cesar Anibal; Matos Quispe, Cesar Anibal

    2012-01-01

    El presente informe de suficiencia propone un modelo de control de inventario para minimizar los costos totales de inventario, aplicando una política de inventario de tipo (s, S) que es un modelo de control de inventario de clase estocástica. Explica cómo se desarrolla el modelo mediante el uso de la simulación Monte Cario tanto para simular el modelo de inventario, así como también la metodología de optimización para obtener los valores de decisión. Para el modelo de simulación se conside...

  6. Evaluación de los efectos clínicos del blanqueamiento dental aplicando dos técnicas diferentes

    OpenAIRE

    Lahoud Salem, Victor; Mendoza Zapata, Janet; Uriarte Mora, Carlos; Munive Degregori, Arnaldo

    2014-01-01

    El objetivo del estudio fue evaluar los efectos clínicos del blanqueamiento dental aplicando dos técnicas diferentes. Técnica aplicada en consultorio. Técnica aplicada en Hogar. Fueron seleccionados 10 pacientes divididos en 2 grupos de 5 pacientes para cada técnica. Los criterios de evaluación fueron: duración de color, sensibilidad post operatoria, estado de salud gingival. Los resultados de la evaluación clínica a los 08 meses presentan 100% de estabilidad del color en los casos tratados c...

  7. Refinement of the crystal structure of lead titanate with different degrees of imperfection of cationic and anionic sublattices by the Rietveld method

    International Nuclear Information System (INIS)

    Akimov, A.I.; Savchuk, G.K.; Rubtsov, V.A.; Letko, A.K.

    2003-01-01

    The parameters of the crystal structure of lead titanate with different degrees of imperfection of the anionic and cationic sublattices are refined by the Rietveld method. The experiments are carried out on a DRON-4 diffractometer (CuK α radiation; 20 deg. d 5.0-6.0%

  8. Application of the Rietveld method in structural analysis of catalysts based on CuO/CeO{sub 2}; Aplicacao do metodo de Rietveld na analise estrutural de catalisadores a base de CuO/CeO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Neiva, L.S.; Ribeiro, M.A.; Bispo, A.; Simoes, A.N.; Gama, L., E-mail: lsoutoneiva@yahoo.com.br [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Departamento de Engenharia de Materiais

    2011-07-01

    This work has as aim to synthesize catalysts composed by CuO/CeO{sub 2} by means two distinct methods of synthesis, they are: combustion synthesis and Pechini. The catalysts composed by CuO/CeO{sub 2} were synthesized with CuO in condition of dopant element. The value of the CuO concentration ranged between 0 and 0.5 mol. Has been done a structural analysis related to how the kind of synthesis method used influences over physical characteristic of the catalytic material. The obtained catalysts were characterized by X-ray diffraction with refinement by Rietveld method. According to results, the synthesized catalysts showed crystalline structures formed mostly by CeO{sub 2} phase, as expected, since this is the host matrix for the dopant element. The catalysts obtained by the Pechini method presented structures with a smaller amount of segregated phases formed by CuO, according to the results of the structural analysis. (author)

  9. Study of selection and purification of Brazilian bentonite clay by elutriation: a XRF, SEM and Rietveld analysis

    Energy Technology Data Exchange (ETDEWEB)

    Alves, J.L.; Zanini, A.E.; Souza, M.E. de; Nascimento, M.L.F., E-mail: jeff_eq@yahoo.com.br, E-mail: mlfn@ufba.br [Universidade Federal da Bahia (UFBA/PROTEC/PEI), Salvador, BA (Brazil). Departamento de Engenharia Quimica

    2016-01-15

    Clays obtained from nature have a lot of impurities. Therefore, for best using of these materials, it is necessary its selection and purification. Thus, the aim of this work is to separate and to purify the smectite fractions using water as a solvent at a low flux mixed with a bentonite clay extracted from a mine in Vitoria da Conquista - Bahia / Brazil. For this a separation method of fractions of expandable clays based on the Stokes' Law was applied - this process is called elutriation, in order to ensure and to expand possible industrial applications of this material. The samples were characterized by analysis of X-ray diffraction, X-ray fluorescence and scanning electron microscopy. The Rietveld method enabled the quantification of main phase minerals: montmorillonite, kaolinite, nontronite and quartz, reaching 85% in mass of montmorillonite phase at the end of the process. Results showed that the method used was efficient to remove almost all quartz, carbonates and organic matter from the sample. It was also observed a monomodal grain size distribution of elutriated materials with thinner grains, around (18.1 ± 1.8) μm at the end of the process. It has been concluded that the method developed and applied showed promising characters to be applied to elutriate kilograms of clays and could be used in industrial scale. (author)

  10. Crystal structures of new cuprates containing CO3 analyzed by the Rietveld method of neutron powder diffraction

    International Nuclear Information System (INIS)

    Miyazaki, Y.; Yamane, H.; Kajitani, T.; Hiraga, K.; Hirai, T.; Morii, Y.; Funahashi, S.

    1993-01-01

    New compounds containing CO 3 groups, Sr 2 CuO 2 (CO 3 ), (C 0.4 Cu 0.6 )Sr 2 (Y 0.86 Sr 0.14 )Cu 2 O 7 and (C 0.35 Cu 0.65 )Sr 2 (Y 0.73 Ce 0.27 ) 2 Cu 2 O 9 , were prepared as stable phases at 1273-1303 K in a flowing gas of O 2 -CO 2 . The crystal structures of these compounds were refined by means of the Rietveld analysis for neutron powder diffraction data collected using a high resolution powder diffractometer (HRPD) in the JRR-3M reactor hall of the Japan Atomic Energy Research Institute (JAERI). Positions of CO 3 groups were satisfactorily determined. The distances of C-O bonds in the CO 3 groups were around 1.3A and the O-C-O angles were almost equal to the ideal bond angle of 120deg. (author)

  11. Rietveld profile analysis of calcined AlPO/sub 4/-11 using pulsed neutron powder diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Richardson, J.W. Jr.; Pluth, J.J.; Smith, J.V.

    1988-08-01

    Aluminium phosphate, AlPO/sub 4/, M/sub r/=121.95, orthorhombic, Icmm (disordered Al, P), Icm2 (ordered Al, P), a=13.5333(8), b=18.4845(10), c=8.3703(4) A, V=2094 A/sup 3/, Z=20, D/sub x/=1.93 g cm/sup -3/, T approx. = 295 K, R/sub wp/=0.031, R/sub F//sup 2/=0.109 (Icmm) and R/sub wp/=0.027, R/sub F//sup 2/=0.058 (Icm2) for 1017 independent reflections. Sample calcined at 873 K and dehydrated at 573 K. Time-of-flight neutron powder diffraction data were taken on the GPPD diffractometer at the Argonne National Laboratory Intense Pulsed Neutron Source. The structure was refined by Rietveld profile analysis in the range d=0.86-3.91 A in two space groups: Icmm assuming no ordering of Al and P, and Icm2 assuming strict alternation of Al and P on tetrahedral nodes. (orig./BHo).

  12. Influence of diopside: feldspar ratio in ceramic reactions assessed by quantitative phase analysis (X-ray diffraction - Rietveld method)

    International Nuclear Information System (INIS)

    Kuzmickas, L.; Andrade, F.R.D.; Szabo, G.A.J.; Motta, J.F.M.; Cabral Junior, M.

    2013-01-01

    White ceramics were produced with raw mixtures prepared with varying proportions of diopside-rich rock (0 to 20 wt.%) and potassic feldspar (40 to 20 wt.%), and fixed proportions of kaolinite (40 wt.%) and quartz (20 wt.%), fired in a temperature range from 1170 to 1210 deg C. The phases identified in the experimental ceramics were quartz, anorthite, mullite and glass, and their relative mass proportions were determined by X-ray diffraction (Rietveld method). The addition of diopside as a partial substitute for potassic feldspar causes the formation of a calcium silicate, analogous of the natural anorthite (CaSi 2 Al 2 O 8 ) in the ceramics, with proportional reduction in its glass and mullite contents. Water absorption and porosity of the ceramic bodies clearly decrease with increasing firing temperature, while the effect of the raw mixture composition on the physical and mechanical properties of the ceramics is less evident. Diopside-rich rock has low iron content (1.5 wt.% Fe 2 O 3 ) and, therefore, promotes white burning. (author)

  13. Study of selection and purification of Brazilian bentonite clay by elutriation: a XRF, SEM and Rietveld analysis

    Directory of Open Access Journals (Sweden)

    J. L. Alves

    2016-03-01

    Full Text Available Abstract Clays obtained from nature have a lot of impurities. Therefore, for best using of these materials, it is necessary its selection and purification. Thus, the aim of this work is to separate and to purify the smectite fractions using water as a solvent at a low flux mixed with a bentonite clay extracted from a mine in Vitória da Conquista - Bahia / Brazil. For this a separation method of fractions of expandable clays based on the Stokes' Law was applied - this process is called elutriation, in order to ensure and to expand possible industrial applications of this material. The samples were characterized by analysis of X-ray diffraction, X-ray fluorescence and scanning electron microscopy. The Rietveld method enabled the quantification of main phase minerals: montmorillonite, kaolinite, nontronite and quartz, reaching 85% in mass of montmorillonite phase at the end of the process. Results showed that the method used was efficient to remove almost all quartz, carbonates and organic matter from the sample. It was also observed a monomodal grain size distribution of elutriated materials with thinner grains, around (18.1 ± 1.8 μm at the end of the process. It has been concluded that the method developed and applied showed promising characters to be applied to elutriate kilograms of clays and could be used in industrial scale.

  14. Rietveld refinement and electronic structure studies for the Sm2FeMnO6 new complex perovskite

    International Nuclear Information System (INIS)

    Landinez Tellez, D.A.; Munevar, J.A.; Arbey Rodriguez, J.M.; Fajardo, F.; Roa-Rojas, J.

    2008-01-01

    We report synthesis and crystalline structure study of the Sm 2 FeMnO 6 new complex perovskite, by X-ray diffraction experiments and through the application of Rietveld refinement. Results revealed the crystallization of system in a structure given by Pmn21 (no. 31) space group and lattice parameters a=7.621(1) A, b=5.675(3) A and c=5.378(3) A. Ab initio calculations of density of states (DOS) and electronic structure were carried out for this perovskite-like system by the density functional theory (DFT) and using the full-potential linearized augmented plane waves (FP-LAPW) method. All calculations were carried out using spin polarization. Material evidences a conductor-like character, predominantly due to d-xy Fe orbital of the spin down channel. Magnetic response of system has contributions of Fe and Mn spin up orientation. The calculated magnetic moment in cell was 34.48 μ B and the magnetic moment in interstitial was 1.54 μ B

  15. Synthesis and refinement of ferroelectric ceramic BaBi4Ti4O15 (BBT) using Rietveld Methods

    International Nuclear Information System (INIS)

    Silva, P.M.O.; Sales, A.J.M.; Carneiro, J.C.S.; Sancho, E.O.; Sales, J.C.; Sombra, A.S.B.

    2012-01-01

    The lead zirconate titanate (PZT) has potential application in nonvolatile ferroelectric memory and capacitors, however this material is linked to environmental pollution. In order to remedy this problem, we propose the synthesis of the compound, BaBi 4 TI 4 O 15 (BBT) because of similarity to PZT. The phase of the BBT has been prepared by the method of solid state. Reagents (BaCO 3 , Bi 2 O 3 and TiO 2 ) were ground for 6 hours at 360 rpm in a planetary ball mill and suffered high energy heat treatment for 2 hours at temperatures of 850, 900, 950 and 1000 ° C. The calcined powder was characterized by X-ray diffraction (XRD) and refined by the program DBWSTools 2.3 Beta based on the Rietveld method. The results obtained confirmed the refinement of the single-phase with tetragonal structure BaBi 4 TI 4 O 15 for all samples. The sample calcined at 950 °C presented the best densification (7.508 g/cm³). (author)

  16. Influence of diopside: feldspar ratio in ceramic reactions assessed by quantitative phase analysis (X-ray diffraction - Rietveld method)

    Energy Technology Data Exchange (ETDEWEB)

    Kuzmickas, L.; Andrade, F.R.D.; Szabo, G.A.J. [Universidade de Sao Paulo (IGc/USP), SP (Brazil). Inst. de Geociencias. Dept. de Mineralogia e Geotecnia; Motta, J.F.M.; Cabral Junior, M., E-mail: lukuzmickas@gmail.com, E-mail: dias@usp.br, E-mail: gajszabo@usp.b, E-mail: motta.jf@gmail.com, E-mail: marsis@ipt.br [Instituto de Pesquisas Tecnologicas (IPT), Sao Paulo, SP (Brazil). Secao de Recursos Minerais e Tecnologia Ceramica

    2013-04-15

    White ceramics were produced with raw mixtures prepared with varying proportions of diopside-rich rock (0 to 20 wt.%) and potassic feldspar (40 to 20 wt.%), and fixed proportions of kaolinite (40 wt.%) and quartz (20 wt.%), fired in a temperature range from 1170 to 1210 deg C. The phases identified in the experimental ceramics were quartz, anorthite, mullite and glass, and their relative mass proportions were determined by X-ray diffraction (Rietveld method). The addition of diopside as a partial substitute for potassic feldspar causes the formation of a calcium silicate, analogous of the natural anorthite (CaSi{sub 2}Al{sub 2}O{sub 8}) in the ceramics, with proportional reduction in its glass and mullite contents. Water absorption and porosity of the ceramic bodies clearly decrease with increasing firing temperature, while the effect of the raw mixture composition on the physical and mechanical properties of the ceramics is less evident. Diopside-rich rock has low iron content (1.5 wt.% Fe{sub 2}O{sub 3}) and, therefore, promotes white burning. (author)

  17. Preparation and Crystal Structures of Some AIVB2IIO4 Compounds: Powder X-Ray Diffraction and Rietveld Analysis

    Directory of Open Access Journals (Sweden)

    K. Jeyadheepan

    2014-01-01

    Full Text Available The AIVB2IIO4 compounds such as cadmium tin oxide (Cd2SnO4 or CTO and zinc tin oxide (Zn2SnO4 or ZTO are synthesized by solid state reaction of the subsequent binary oxides. The synthesized powders were analyzed through the powder X-ray diffraction (PXRD. Cell search done on the PXRD patterns shows that the Cd2SnO4 crystallizes in orthorhombic structure with space group Pbam and the cell parameters as a=5.568(2 Å, b=9.894(3 Å, and c=3.193(1 Å and the Zn2SnO4 crystallizes as cubic with the space group Fd3 -m and with the cell parameter a=8.660(2 Å. Rietveld refinement was done on the PXRD patterns to get the crystal structure of the Cd2SnO4 and Zn2SnO4 and to define the site deficiency of atoms which causes the electrical properties of the materials.

  18. Study of selection and purification of Brazilian bentonite clay by elutriation: a XRF, SEM and Rietveld analysis

    International Nuclear Information System (INIS)

    Alves, J.L.; Zanini, A.E.; Souza, M.E. de; Nascimento, M.L.F.

    2016-01-01

    Clays obtained from nature have a lot of impurities. Therefore, for best using of these materials, it is necessary its selection and purification. Thus, the aim of this work is to separate and to purify the smectite fractions using water as a solvent at a low flux mixed with a bentonite clay extracted from a mine in Vitoria da Conquista - Bahia / Brazil. For this a separation method of fractions of expandable clays based on the Stokes' Law was applied - this process is called elutriation, in order to ensure and to expand possible industrial applications of this material. The samples were characterized by analysis of X-ray diffraction, X-ray fluorescence and scanning electron microscopy. The Rietveld method enabled the quantification of main phase minerals: montmorillonite, kaolinite, nontronite and quartz, reaching 85% in mass of montmorillonite phase at the end of the process. Results showed that the method used was efficient to remove almost all quartz, carbonates and organic matter from the sample. It was also observed a monomodal grain size distribution of elutriated materials with thinner grains, around (18.1 ± 1.8) μm at the end of the process. It has been concluded that the method developed and applied showed promising characters to be applied to elutriate kilograms of clays and could be used in industrial scale. (author)

  19. A Study on the quantification of hydration and the strength development mechanism of cementitious materials including amorphous phases by using XRD/Rietveld method

    International Nuclear Information System (INIS)

    Yamada, Kazuo; Hoshino, Seiichi; Hirao, Hiroshi; Yamashita, Hiroki

    2008-01-01

    X-ray diffraction (XRD)/Rietveld method was applied to measure the phase composition of cement. The quantative analysis concerning the progress of hydration was accomplished in an error of about the maximum 2-3% in spite of including amorphous materials such as blast furnace slag, fly ash, silica fume and C-S-H. The influence of the compressive strength on the lime stone fine powder mixture material was studied from the hydration analysis by Rietveld method. The two stages were observed in the strength development mechanism of cement; the hydration promotion of C 3 S in the early stage and the filling of cavities by carbonate hydrate for the longer term. It is useful to use various mixture materials for the formation of the resource recycling society and the durability improvement of concrete. (author)

  20. Assessment of firing conditions in old fired-clay bricks. The contribution of X-ray powder diffraction with the Rietveld method and small angle neutron scattering

    Czech Academy of Sciences Publication Activity Database

    Viani, Alberto; Sotiriadis, Konstantinos; Len, A.; Šašek, Petr; Ševčík, Radek

    2016-01-01

    Roč. 116, June (2016), s. 33-43 ISSN 1044-5803 R&D Projects: GA MŠk(CZ) LO1219 Keywords : fired- clay brick * Rietveld method * small angle neutron scattering * X-ray diffraction * firing temperature Subject RIV: AL - Art, Architecture, Cultural Heritage Impact factor: 2.714, year: 2016 http://www.sciencedirect.com/science/article/pii/S1044580316300870

  1. Crystal structures of iron bearing tetrahedrite and tennantite at 25 and 250 degrees C by means of Rietveld refinement of synchrotron data

    DEFF Research Database (Denmark)

    Friese, K.; Grzechnik, A.; Makovicky, E.

    2008-01-01

    Rietveld refinement of X-ray synchrotron data was performed for two synthetic tetrahedrite samples, with 0.61 and 1.83 Fe atoms, and two synthetic tennantite samples with 0.10 and 1.23 Fe atoms p.f.u. M-12(Sb,As)(4)S-13. Measurements were performed at 25 and 250 degrees C. For both the phases...

  2. Structural Rietveld refinement and vibrational study of MgCr{sub x}Fe{sub 2−x}O{sub 4} spinel ferrites

    Energy Technology Data Exchange (ETDEWEB)

    Sabri, K. [Laboratoire des Sciences et technique de l’Environnement et de la Valorisation, département de Génie des Procédés, Université de Mostaganem, Mostaganem (Algeria); Rais, A., E-mail: amrais@yahoo.com [Laboratoire des Sciences et technique de l’Environnement et de la Valorisation, département de Génie des Procédés, Université de Mostaganem, Mostaganem (Algeria); Taibi, K. [Laboratoire de Science et Génie des Matériaux, USTHB, Alger, Algéria (Algeria); Moreau, M.; Ouddane, B. [Laboratory of LASIR Spectrochemistry, University of Science and Technology, 59650 Villeneuve d’Ascq (France); Addou, A. [Laboratoire des Sciences et technique de l’Environnement et de la Valorisation, département de Génie des Procédés, Université de Mostaganem, Mostaganem (Algeria)

    2016-11-15

    Spinel ferrites with the general formula MgCr{sub x}Fe{sub 2−x}O{sub 4} (0≤x≤1) were synthesized by the standard ceramic technique and characterized by X-ray diffraction. The XRD patterns confirmed that the mixed ferrite samples are in the cubic spinel structure which is further validated by Rietveld refinement in the space group Fd3m. The crystal structure and cell parameters were refined by Rietveld analysis. The vibrational study was achieved using Fourier Transform-InfraRed (FT-IR) and Raman spectroscopy. From FT-IR band frequencies, the force constants K{sub t} and K{sub o} , for tetrahedral (A) and octahedral (B) sites respectively, have been calculated and discussed with the trend of bond lengths obtained from Rietveld refinement. For all compositions, Raman spectra revealed the five active modes showing the vibration of O{sup 2−} ions at both the A-site and B-site ions. The frequencies trend with chromium content of both FT-IR and Raman spectra showed a shift toward higher values for all modes.

  3. Quantitative phase analysis of alumina/calcium-hexaluminate composites using neutron diffraction data and the Rietveld method

    International Nuclear Information System (INIS)

    Asmi, D.; Low, I.M.; O'Connor, B.H.; Kennedy, S.J.

    2000-01-01

    Full text: The Al 2 O 3 -CaO system is the basis of an important class of high-temperature refractories in the steel industry. It contains a number of stable intermediate compounds which include C 3 A, C 12 A 7 , CA, CA 2 , and CA 6 . These calcium aluminates are also important constituents of high alumina cement and have been used to produce high-strength and high-toughness ceramic-polymer composite materials. More recently, alumina composites containing 30 wt% CA 6 platelets have been developed by An et al which show characteristics of self-reinforcement and enhanced toughening through crack-bridging. In this paper, we describe the use of high-temperature neutron diffraction to monitor the in-situ phase formation and abundances of calcium aluminates (CA, CA 2 , and CA 6 ) in alumina composites containing 5-50 wt % CA 6 .at temperatures in the range 1000 - 1600 deg C. These composites were produced using reaction sintering of alumina and calcium oxide. For comparison purposes, control samples of pure α-alumina and CA 6 were also produced. Determination of relative phase abundances in these materials has been performed using the standardless Rietveld refinement method. Results show that the relative phase abundance of calcium aluminates in the composites increased with temperature and in proportion with the amount of calcium oxide present. The formation temperatures of CA, CA 2 , and CA 6 have been observed to occur at 1000 deg , 1200 deg, and ∼1350 deg C respectively, which agree well with results obtained from x-ray diffraction, synchrotron radiation diffraction and differential thermal analysis

  4. The Rietveld method applied to the quantitative mineralogical analysis of some soil samples from Argentina Aplicación del método de Rietveld al análisis mineral��gico cuantitativo de algunas muestras de suelos de la Argentina

    Directory of Open Access Journals (Sweden)

    Stella M Zabala

    2007-07-01

    Full Text Available The mineralogical quantification of soils species is mainly obtained by analysis of X-ray diffraction (XRD patterns. The classic method, for these analyses, is limited to semi quantitative determinations due to the overlapping of different specie's peaks and processes of absorption of the constituents, the wide range of particle size distribution, etc. The use of the Rietveld method for XRD quantitative analysis, in mixtures of minerals, has allowed to improve the accuracy of the quantitative results and to extend it to complex systems, as soils, transforming it in a meaningful tool for soils investigation. In this work, quantitative results obtained by the application of classic and Rietveld methods, are compared in different soils samples from Argentina. A set of mixtures of minerals with similar composition to three studied samples, was also quantified by Rietveld method, with absolute error lower than 3%. Obtained results indicate that quantitative analysis by Rietveld method, can improve the results found by XRD classic method and may be used for the quantitative determination of soil minerals.La cuantificación mineralógica de componentes del suelo es obtenida principalmente por análisis de espectros de difracción de rayos X (DRX. El método clásico aplicado para dicho análisis está limitado a determinaciones semi-cuantitativas debido a la superposición de picos de las distintas especies y procesos de absorción de los constituyentes, el amplio rango de distribución de tamaño de partícula, etc. El uso del método de Rietveld para el análisis cuantitativo por DRX, en mezclas de minerales, ha permitido mejorar la exactitud de los resultados cuantitativos y extenderlo a sistemas complejos, como lo son los suelos, transformándose en una herramienta significativa para su investigación. En este trabajo se comparan los resultados cuantitativos obtenidos por la aplicación del método clásico y de Rietveld, a diferentes muestras de

  5. Quantitative determination of phases in ZrO{sub 2} (MgO) (Y{sub 2}O{sub 3}) using the Rietveld method; Determinacao quantitativa de fases em ZrO{sub 2} - MgO - Y{sub 2}O{sub 3} utilizando o metodo de Rietveld

    Energy Technology Data Exchange (ETDEWEB)

    Castro, Antonio Carlos de

    2007-07-01

    The key objective of this work is the crystallographic characterization of the zircon co-doped with Yttria and magnesium with the application of the Rietveld method for quantitative phase analysis of zircon polymorph (zircon monoclinic, tetragonal, and cubic). Samples of zircon polymorph were obtained from zircon doped with Yttria and magnesium at defined molar concentrations. The zircon polymorph stability during subeutetoid aging at 1350 deg C were investigated to determine ZrO{sub 2} - MgO - Y{sub 2}0{sub 3} phases degradation and to define the solid solutions stability environment. ZrO{sub 2} powders doped with 8 mol por cent of MgO and 1 mol por cent of Y{sub 2}O{sub 3}, and 9 mol por cent of MgO and 0 mol por cent of Y{sub 2}O{sub 3} have been prepared by chemical route using the co-precipitation method. These samples have been calcinate at 550 deg C, sintered at 1500 deg C and characterized by the Rietveld method using the X-ray diffraction data. The variation of the lattice parameter, changes in the phase composition and their microstructures are discussed. The application of the Rietveld method for quantitative phase analysis of zircon polymorph (zircon tetragonal and cubic) reveals no formation of tetragonal phase and indicating that the matrix is the cubic phase with low concentration of monoclinic phase.(author)

  6. Ambientes Virtuales Para la enseñanza de la Mecánica de Fluidos: Algunos ejemplos simplificados aplicando ANSYS

    Directory of Open Access Journals (Sweden)

    Watson L. Vargas

    2005-01-01

    Full Text Available Para que un ambiente de enseñanza virtual pueda soportar un aprendizaje real, dichos ambientes deben proveer interacciones enseñanza-aprendizaje de alto nivel. En este artículo, se muestra como una herramienta computacional como ANSYS puede proveer un ambiente virtual para el aprendizaje de la mecánica de fluidos no sólo a nivel de pregrado si no también a niveles superiores. Las simulaciones computacionales, --aplicando ANSYS/FLOTRAN-CFD o cualquiera otro software de capacidades similares--, en el contexto de la enseñanza de la mecánica de fluidos son de interés fundamental dado que soportan un ambiente de simulación poderoso que puede aplicarse no sólo a la comprensión de ideas y conceptos fundamentales sino tambien al diseño y optimización de procesos de aplicación práctica

  7. Assessment of firing conditions in old fired-clay bricks: The contribution of X-ray powder diffraction with the Rietveld method and small angle neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Viani, Alberto, E-mail: viani@itam.cas.cz [Institute of Theoretical and Applied Mechanics AS CR, Centre of Excellence Telč, Batelovská 485, CZ-58856 Telč (Czech Republic); Sotiriadis, Konstantinos [Institute of Theoretical and Applied Mechanics AS CR, Centre of Excellence Telč, Batelovská 485, CZ-58856 Telč (Czech Republic); Len, Adél [Wigner Research Centre for Physics HAS, Konkoly-Thege 29-33, 1121 Budapest (Hungary); Šašek, Petr; Ševčík, Radek [Institute of Theoretical and Applied Mechanics AS CR, Centre of Excellence Telč, Batelovská 485, CZ-58856 Telč (Czech Republic)

    2016-06-15

    Full characterization of fired-clay bricks is crucial for the improvement of process variables in manufacturing and, in case of old bricks, for restoration/replacement purposes. To this aim, five bricks produced in a plant in Czech Republic in the past have been investigated with a combination of analytical techniques in order to derive information on the firing process. An additional old brick from another brickyard was also used to study the influence of different raw materials on sample microstructure. The potential of X-ray diffraction with the Rietveld method and small angle neutron scattering technique has been exploited to describe the phase transformations taking place during firing and characterize the brick microstructure. Unit-cell parameter of spinel and amount of hematite are proposed as indicators of the maximum firing temperature, although for the latter, limited to bricks produced from the same raw material. The fractal quality of the surface area of pores obtained from small angle neutron scattering is also suggested as a method to distinguish between bricks produced from different raw clays. - Highlights: • Rietveld method helps in describing microstructure and physical properties of bricks. • XRPD derived cell parameter of spinel is proposed as an indicator of firing temperature. • SANS effectively describes brick micro and nanostructure, including closed porosity. • Fractal quality of pore surface is proposed as ‘fingerprint’ of brick manufacturing.

  8. PETROGRAPHY AND APPLICATION OF THE RIETVELD METHOD TO THE QUANTITATIVE ANALYSIS OF PHASES OF NATURAL CLINKER GENERATED BY COAL SPONTANEOUS COMBUSTION

    Directory of Open Access Journals (Sweden)

    Pinilla A. Jesús Andelfo

    2010-06-01

    Full Text Available

    Fine-grained and mainly reddish color, compact and slightly breccious and vesicular pyrometamorphic rocks (natural clinker are associated to the spontaneous combustion of coal seams of the Cerrejón Formation exploited by Carbones del Cerrejón Limited in La Guajira Peninsula (Caribbean Region of Colombia. These rocks constitute remaining inorganic materials derived from claystones, mudstones and sandstones originally associated with the coal and are essentially a complex mixture of various amorphous and crystalline inorganic constituents. In this paper, a petrographic characterization of natural clinker, aswell as the application of the X-ray diffraction (Rietveld method by mean of quantitative analysis of its mineral phases were carried out. The RIQAS program was used for the refinement of X ray powder diffraction profiles, analyzing the importance of using the correct isostructural models for each of the existing phases, which were obtained from the Inorganic Crystal Structure Database (ICSD. The results obtained in this investigation show that the Rietveld method can be used as a powerful tool in the quantitative analysis of phases in polycrystalline samples, which has been a traditional problem in geology.

  9. Structural studies of TiC1−xOx solid solution by Rietveld refinement and first-principles calculations

    International Nuclear Information System (INIS)

    Jiang, Bo; Hou, Na; Huang, Shanyan; Zhou, Gege; Hou, Jungang; Cao, Zhanmin; Zhu, Hongmin

    2013-01-01

    The lattice parameters, structural stability and electronic structure of titanium oxycarbides (TiC 1−x O x , 0≤x≤1) solid solution were investigated by Rietveld refinement and first-principles calculations. Series of TiC 1−x O x were precisely synthesized by sintering process under the vacuum. Rietveld refinement results of XRD patterns show the properties of continuous solid solution in TiC 1−x O x over the whole composition range. The lattice parameters vary from 0.4324 nm to 0.4194 nm decreasing with increasing oxygen concentration. Results of first-principles calculations reveal that the disorder C/O structure is stable than the order C/O structure. Further investigations of the vacancy in Ti 1−Va (C 1−x O x ) 1−Va solid solution present that the structure of vacancy segregated in TiO-part is more stable than the disorder C/O structure, which can be ascribed to the Ti–Ti bond across O-vacancy and the charge redistributed around Ti-vacancy via the analysis of the electron density difference plots and PDOS. - Graphical abstract: XRD of series of titanium oxycarbides (TiC 1−x O x , 0≤x≤1) solid solution prepared by adjusting the proportion of TiO in the starting material. Highlights: • Titanium oxycarbides were obtained by sintering TiO and TiC under carefully controlled conditions. • Rietveld refinement results show continuous solid solution with FCC structure in TiC 1−x O x . • The disorder C/O structure is stable than the order C/O structure. • Introduction of vacancy segregated in TiO-part is more stable than disorder C/O structure. • Ti–Ti bond across O-vacancy and the charge redistributed around Ti-vacancy enhance structural stability

  10. Rietveld refinement and dielectric relaxation of a new rare earth based double perovskite oxide: BaPrCoNbO{sub 6}

    Energy Technology Data Exchange (ETDEWEB)

    Bharti, Chandrahas, E-mail: bharti.chandrahas@gmail.com [Sensor and Actuator Division, CSIR-Central Glass and Ceramic Research Institute, 196, Raja SC Mullick Road, Kolkata 700032 (India); Das, Mrinmoy K.; Sen, A. [Sensor and Actuator Division, CSIR-Central Glass and Ceramic Research Institute, 196, Raja SC Mullick Road, Kolkata 700032 (India); Chanda, Sadhan; Sinha, T.P. [Department of Physics, Bose Institute, 93/1, Acharya Prafulla Chandra Road, Kolkata-700009 (India)

    2014-02-15

    A new rare earth based double perovskite oxide barium praseodymium cobalt niobate, BaPrCoNbO{sub 6} (BPCN) is synthesized by solid-state reaction technique. Rietveld analysis of X-ray diffraction (XRD) data shows that the compound crystallizes in a perovskite like tetragonal structure which belongs to the I4/mmm space group with lattice parameters a=b=5.6828(9) Å, c=8.063(2) Å. Structural analysis reveals 1:1 ordered arrangement for the Co{sup 2+} and Nb{sup 5+} cations over the six-coordinate B-sites of BPCN. The superlattice line (1 0 1) at 2θ=19.10° arising from the alternate ordering of Co{sup 2+} and Nb{sup 5+} sites is observed in the XRD pattern which confirms the presence of cation ordering in BPCN. Fourier transform infrared spectrum shows two phonon modes of the sample due to the antisymmetric NbO{sub 6} stretching vibration. The relaxation dynamics of the conductive process in BPCN is investigated in the temperature range 303 to 503 K and in the frequency range 100 Hz to 1 MHz using impedance spectroscopy. The relaxation mechanism of the sample in the framework of electric modulus formalism is modeled by Davidson–Cole model (DCM). The values of α (distribution of relaxation time) for the DCM varies from 0.1 to 0.3 which suggests the asymmetric distribution of relaxation time for BPCN. The activation energy of the sample, calculated from both conductivity and modulus spectra, are found to be almost the same ∼0.4 eV, which indicates that the conduction mechanism for BPCN is polaron hopping. The scaling behaviour of the imaginary part of electric modulus suggests that the relaxation follows the same mechanism at various temperatures. - Graphical abstract: Rietveld refinement plot for BPCN. Inset shows the schematic presentation of the BPCN tetragonal unit cell. The Co{sup 2+} atoms are located at the centers of the CoO{sub 6} (blue) octahedra. The Nb{sup 5+} atoms are located at the centers of the NbO{sub 6} (green) octahedra. Display Omitted

  11. Desempenho hidráulico de sistema de irrigação por gotejamento aplicando água residuária de suinocultura

    Directory of Open Access Journals (Sweden)

    Rafael Oliveira Batista

    2012-11-01

    Full Text Available Normal 0 21 false false false PT-BR X-NONE X-NONE A realização deste trabalho objetivou analisar o desempenho hidráulico de sistema de irrigação por gotejamento aplicando água residuária de suinocultura tratada. Foi montada uma estrutura hidráulica de avaliação, constituída de três tipos de gotejadores (G1, G2 e G3. Manteve-se a pressão de serviço no início das linhas laterais em 105 kPa, e quantificaram-se a intervalos de 20 h, as vazões dos gotejadores, até a obtenção de um tempo total de 160 h de operação do sistema. O nível de entupimento dos gotejadores foi obtido por meio do coeficiente de variação de vazão (CVQ. Com a aplicação da água residuária da suinocultura houve aumento do CVQ, ao longo do tempo de funcionamento, somente na subunidade com gotejador G2. Os gotejadores de maior vazão e menor comprimento de labirinto são menos suscetíveis ao entupimento. A formação de biofilme foi resultante da interação entre sólidos suspensos, enxofre e bactérias, consistindo no principal fator de entupimento parcial e total dos gotejadores.

  12. Rietveld structure refinement and elastic properties of MgAlxCrxFe2-2xO4 spinel ferrites

    Science.gov (United States)

    Thummer, K. P.; Tanna, Ashish R.; Joshi, Hiren H.

    2017-05-01

    MgAlxCrxFe2-2xO4 (x = 0.1, 03 & 0.6) ferrites are synthesized by solid state reaction method. The Rietveld refinement of X-ray diffraction (XRD) data confirms the cubic spinel structure with Fd3m space group. The Fourier Transform Infrared Transmission Spectroscopy (FTIR) is employed to study elastic properties of present systems at 300K. The force constants for tetrahedral (A) and octahedral (B) sites of the spinel lattice are determined by infrared spectral and X-ray diffraction analysis. The elastic constants like bulk modulus, rigidity modulus, Young's modulus, Poisson's ratio and Debye temperature are determined. The vibrational frequency of both the interstitial sites increases as Al-Cr content increases hence the force constant and elastic moduli for all the samples are found to increase for the present ferrite system.

  13. Analysis of Polymorphic Nanocrystals of TiO2 by X-Ray Rietveld Refinement and High-Resolution Transmission Electron Microscopy: Acetaldehyde Decomposition

    Directory of Open Access Journals (Sweden)

    R. Carrera

    2008-01-01

    Full Text Available In this work, TiO2 nanocrystals were synthesized by the sol-gel method. These materials were annealed at 200 and 500∘C; and characterized by the XRD-Rietveld refinement; and by BET and TEM. As for the low-temperature-treated sample (200∘C, nanocrystals with small crystallite sizes (7 nm and high abundance of anatase, coexisting with the brookite phase, were obtained. Meanwhile, the sample annealed at 500∘C showed an increased crystallite size (22 nm and an important polymorphic increment. The sample annealed at 200∘C showed a high activity in the photocatalytic decomposition of acetaldehyde.

  14. Rietveld refinement and dielectric studies of Bi{sub 0.8}Ba{sub 0.2}FeO{sub 3} ceramic

    Energy Technology Data Exchange (ETDEWEB)

    Kaswan, Kavita, E-mail: kaswan.kavita@gmail.com; Agarwal, Ashish; Sanghi, Sujata; Rangi, Manisha; Jangra, Sandhaya; Singh, Ompal [Department of Applied Physics, Guru Jambheshwar University of Science and Technology, Hisar 125001, Haryana (India)

    2016-05-23

    Polycrystalline Bi{sub 0.8}Ba{sub 0.2}FeO{sub 3} ceramic has been synthesized via conventional solid state reaction technique. The Rietveld refinement of x-ray powder diffraction revealed that the sample has a rhombohedral crystal structure (space group R3c). With increase in temperature, the values of dielectric constant (ϵ′) and dielectric loss (tan δ) are found to be increase at different frequencies which may be the result of increase in the number of charge carriers and their mobilities due to the thermal activation. Further the ac conductivity data is analyzed by using Jonscher’s universal power law. The values of frequency exponent ‘s’ lies in the range 0.2 ≤ s ≤ 0.7 and decreases with increase in temperature which can be explained on the basis of CBH (Correlated Barrier Height) model.

  15. Application of low current intensity electrolytic treatment for the chlorides extraction in underwater archaeological objects of iron. Observation of the mineralogical phases evolution through XRD-Rietveld

    International Nuclear Information System (INIS)

    Bethencourt, M.; Gil, M. L. A.; Fernandez-Lorenzo, C.; Santos, A.

    2004-01-01

    With the purpose of optimising a suitable methodology for the conservation of an archaeological object of iron, a low current intensities electrolytic treatment has been applied, to a piece of cast iron, proving to be effective in the extraction of chloride ions from the structure of akaganeite, principal corrosion product of iron in the marine medium. The monitoring of the electrolytic treatment has been proven by applying the Rietveld method to the patterns XRD of samples extracted from the corroded surface before and after the treatment. This method has permitted the unequivocal determination of the akaganeite and its chemical composition. This identification has been corroborated by means of SEM and EDS. After the electrolytic treatment, akaganeite was not present in the sample. (Author) 9 refs

  16. Study of effect of sintering time on the 2223 phase growth Bi-Pb-Sr-Ca-Cu-O superconductor by Rietveld method

    International Nuclear Information System (INIS)

    Parikin; Prasuad, W; Gunawan

    1996-01-01

    It has been reported that the sintering time is as important for the preparation of superconductor as the sintering temperature and method. This paper reports on the finding of the optimum sintering time in the preparation of the 2223 phase bismuth (Bi) superconductor. The samples were synthesized with nominal composition 1.84 : 0.34 : 1.91 : 2.03 : 3.06 from raw materials by solid state reaction and sintered at 860 o C for five days. The resintering were done three times, i.e. 24, 48 and 96 hours. The Rietveld analysis shows that the 2223 phase grows continuously as a function of the sintering time. The highest percentage of the 2223 phase (80.64%) were obtained at 96 hours sintering time. The result suggests that the 2223 phase can be obtained effectively by sintering with sufficiently long time

  17. Rietveld refinement, dielectric and magnetic properties of Nb modified Bi0.80Ba0.20FeO3 ceramic

    Science.gov (United States)

    Jangra, Sandhaya; Sanghi, Sujata; Agarwal, Ashish; Rangi, Manisha

    2018-05-01

    Bi0.80Ba0.20Fe0.95Nb0.05O3 ceramic has been prepared via conventional solid state reaction method. Structure analysis was carried out by X-ray diffraction (XRD) technique at room temperature. XRD pattern confirmed the crystalline nature of prepared sample. Rietveld analysis used for further structural investigations and confirmed the existence of rhombohedral symmetry (R3c space group). The dielectric response shows dispersion at lower frequency range and becomes frequency independent at high frequency. The approximation of conduction mechanism is determined by the temperature dependent behavior of frequency exponent `s'. Fitting results suggests the applicability of small polaron conduction mechanism at lower temperatures and CBH model at higher temperature. Room temperature magnetic measurements give the evidence of significant enhancement in magnetic properties with remanent magnetization (Mr = 0.1218 emu/g) and coercive field (Hc = 3.5342 kOe).

  18. Mineralogical analysis of clays in hardsetting soil horizons, by X-ray fluorescence and X-ray diffraction using Rietveld method

    International Nuclear Information System (INIS)

    Prandel, L.V.; Saab, S.C.; Brinatti, A.M.; Giarola, N.F.B.; Leite, W.C.; Cassaro, F.A.M.

    2014-01-01

    Diffraction and spectroscopic techniques have been shown to be suitable for obtaining physical and mineralogical properties in polycrystalline soil samples, and also in their precursor compounds. For instance, the X-ray fluorescence (XRF) spectroscopy allows obtaining the elemental composition of an investigated sample, while the X-ray diffraction (XRD) technique permits obtaining qualitative and quantitative composition of the soil minerals through the Rietveld method (RM). In this study Yellow Latosol (Oxisol), Yellow Argisol (Ultisol) and Gray Argisol (Ultisol) soil samples, classified as “hardsetting soils”, extracted from areas located at Northeast and Southeast of Brazilian coast were investigated. The soils and their fractions were analyzed in an EDX-700 and an XRD-6000 (Cu K α radiation). XRF results indicate high percentages of Si and Al, and small percentage of Fe and Ti in the investigated samples. The DRX data and RM indicate that there was a predominance of kaolinite and halloysite minerals (kaolin group minerals) in the clay fractions, which are presumably responsible for the formation of kaolinitic plasma in these soils. Also, the obtained results showed that the XRF, XRD techniques and RM were very helpful for investigating the mineralogical composition of a hardsetting soil. - Highlights: ► Elemental composition of soil samples through X-Ray fluorescence. ► Mineralogical quantification through X-ray diffraction and Rietveld method. ► Oxisol and Ultisol, Brazil ‘Barreiras’ formation. ► High amounts of Si and Al oxides and low amounts of Fe and Ti oxides. ► Predominance of kaolinite in the clay fraction

  19. Cuantificación de plaguicidas residuales en granos de maíz (Zea mays L. aplicando técnicas de evaluación residual

    Directory of Open Access Journals (Sweden)

    Dante Rojas

    2014-07-01

    Full Text Available El empleo de plaguicidas en la producción agrícola ha tomado marcada importancia para muchos sectores de la sociedad. Los productores agropecuarios necesitan realizar un tratamiento fitoterapeútico efectivo y la utilización de estos agroquímicos es una alternativa rentable. Sin embargo, la toxicidad de estas sustancias presenta un riesgo para la salud humana durante su fabricación y empleo. El objetivo del presente trabajo fue obtener información de los niveles y frecuencia de los principales residuos de pesticidas presentes en granos de maíz aplicando técnicas de evaluación multiresidual. El muestreo (basado en la Norma ISO 950:1979 fue realizado en cintas de embarque y terminales portuarias del Río Paraná y del sur de la Provincia de Buenos Aires (Argentina, dado que manejan más del 80 % de las exportaciones del país (Ingeniero White, Rosario/General San Martín/San Lorenzo, Villa Constitución y Quequén. Sobre un total de 192 muestras, 94 presentaron residuos de plaguicidas, siendo el orden de frecuencia de aparición de los mismos: fenitrotión (n = 40 > cipermetrina (n = 31 > pirimifós metil (n = 27 > deltametrina (n = 24 > clorpirifós metil (n = 23 > diclorvós (n = 18 > permetrina (n = 15 > clorpirifós etil (n = 12 > fenvalerato (n = 3 > malatión (n = 2 > endosulfán (n = 0; suma de alfa endosulfán, beta endosulfán y endosulfán sulfato. No se hallaron organoclorados. Considerando la legislación Argentina, solo 4 muestras presentaron niveles superiores a los Límites Máximos de Residuos (LMR, siendo cipermetrina el plaguicida involucrado. Sin embargo, según los LMR del Codex Alimentarius, todas las muestras presentaron niveles permitidos.

  20. Cuantificación de plaguicidas residuales en granos de maíz (Zea mays L. aplicando técnicas de evaluación residual

    Directory of Open Access Journals (Sweden)

    Dante Rojas

    2014-06-01

    Full Text Available El empleo de plaguicidas en la producción agrícola ha tomado marcada importancia para muchos sectores de la sociedad. Los productores agropecuarios necesitan realizar un tratamiento fitoterapeútico efectivo y la utilización de estos agroquímicos es una alternativa rentable. Sin embargo, la toxicidad de estas sustancias presenta un riesgo para la salud humana durante su fabricación y empleo. El objetivo del presente trabajo fue obtener información de los niveles y frecuencia de los principales residuos de pesticidas presentes en granos de maíz aplicando técnicas de evaluación multiresidual. El muestreo (basado en la Norma ISO 950:1979 fue realizado en cintas de embarque y terminales portuarias del Río Paraná y del sur de la Provincia de Buenos Aires (Argentina, dado que manejan más del 80 % de las exportaciones del país (Ingeniero White, Rosario/General San Martín/San Lorenzo, Villa Constitución y Quequén. Sobre un total de 192 muestras, 94 presentaron residuos de plaguicidas, siendo el orden de frecuencia de aparición de los mismos: fenitrotión (n = 40 > cipermetrina (n = 31 > pirimifós metil (n = 27 > deltametrina (n = 24 > clorpirifós metil (n = 23 > diclorvós (n = 18 > permetrina (n = 15 > clorpirifós etil (n = 12 > fenvalerato (n = 3 > malatión (n = 2 > endosulfán (n = 0; suma de alfa endosulfán, beta endosulfán y endosulfán sulfato. No se hallaron organoclorados. Considerando la legislación Argentina, solo 4 muestras presentaron niveles superiores a los Límites Máximos de Residuos (LMR, siendo cipermetrina el plaguicida involucrado. Sin embargo, según los LMR del Codex Alimentarius, todas las muestras presentaron niveles permitidos.

  1. Propuesta de mejora para la reducción de productos defectuosos en una planta de producción de neumáticos aplicando la metodología Six Sigma

    OpenAIRE

    Reinoso Vásquez, George

    2016-01-01

    La tesis se enfoca en desarrollar una propuesta de mejora para la reducción de productos defectuosos en una planta de producción de neumáticos aplicando la metodología Six Sigma desde el punto de vista de un sistema de mejora. Los expectativas de los clientes y el nivel de exigencia respecto a la calidad de los productos son cada vez mayores, esto obliga a las empresas busquen aumentar el valor percibido de sus productos como un elemento diferenciador y a la vez orienten sus...

  2. Detección automática de grietas de pavimento asfáltico aplicando características geométricas y descriptores de forma

    Directory of Open Access Journals (Sweden)

    Hernán Porras

    2012-01-01

    Full Text Available Las grietas son el principal daño en la superficie del pavimento, porque de estas se derivan los demás tipos de deterioros. La mayoría de grietas en imágenes de pavimento se encuentran con objetos no deseados y desconectadas. Para resolver este problema, se aplica el filtro mediana, para el suavizado de la imagen; el ajuste de contraste, para realzar la grieta; la segmentación, aplicando la media y la desviación estándar de los niveles de gris, para delimitar las grietas; el procesamiento morfológico, para fusionar separaciones estrechas; la eliminación de grietas falsas, aplicando características geométricas y descriptores de forma; y la conexión de grietas, para obtener grietas continuas. Los resultados experimentales fueron obtenidos de las imágenes de pavimento captadas por el sistema semiautomático y el algoritmo generador implementado. Las pruebas demostraron que las grietas fueron detectadas, con una sensibilidad de 81,72% y una especificidad de 99,96% para las imágenes captadas.

  3. Structural determination of new solid solutions [Y2-x Mx ][Sn2-x Mx ]O7-3x/2 (M = Mg or Zn by Rietveld method

    Directory of Open Access Journals (Sweden)

    Mohamed Douma

    2010-12-01

    Full Text Available New [Y2-x Mx][Sn2-x Mx]O7-3x/2 (0 ≤x≤ 0.30 for M = Mg and 0 ≤x≤ 0.36 for M = Zn solid solutions with the pyrochlore structure were synthesized via high-temperature solid-state reaction method. Powder X-ray diffraction (PXRD patterns and Fourier transform infrared (FT-IR spectra showed that these materials are new non-stoichiometric solid solutions with the pyrochlore type structure. The structural parameters for the solids obtained were successfully determined by Rietveld refinement based on the analysis of the PXRD diagrams. Lattice parameter (a of these solid solutions decreases when x increases in both series. All samples obtained have the pyrochlore structure Fd-3m, no. 227 (origin at center -3m with M2+ (M = Mg2+ or Zn2+ cations in Y3+ and Sn4+ sites, thus creating vacancies in the anionic sublattice.

  4. ESTUDIO DE LAS FASES MINERALÓGICAS DEL CLÍNKER EN UNA CEMENTERA ESPAÑOLA, UTILIZANDO EL MÉTODO DE RIETVELD

    Directory of Open Access Journals (Sweden)

    ANA M. CASTAÑÓN

    2012-01-01

    Full Text Available Con el objetivo de implantar un método de control de calidad de forma continua en una fábrica de cementos española, para mejorar las características del producto final, se están desarrollando nuevas metodologías de caracterización. El método de Rietveld [1] se ha utilizado con éxito para analizar la composición de las fases principales del clínker. Utilizando esta metodología, se ha llevado a cabo un estudio para cuantificar adecuadamente la fase minoritaria de Cal Libre, de gran importancia en la calidad del clínker. El método ha permitido obtener unos resultados satisfactorios en muestras cuyos contenidos superan el 3% de CaO. Estos resultados son posibles combinando adecuadamente las técnicas de difracción y fluorescencia de rayos-X, así como los resultados del análisis por vía química.

  5. Rietveld refinement of the structures of 1.0 C-S-H and 1.5 C-S-H

    KAUST Repository

    Battocchio, Francesco

    2012-11-01

    Low-Q region Rietveld analyses were performed on C-S-H synchrotron XRD patterns, using the software MAUD. Two different crystal structures of tobermorite 11 Å were used as a starting model: monoclinic ordered Merlino tobermorite, and orthorhombic disordered Hamid tobermorite. Structural modifications were required to adapt the structures to the chemical composition and the different interlayer spacing of the C-S-H samples. Refinement of atomic positions was done by using special constraints called fragments that maintain interatomic distances and orientations within atomic polyhedra. Anisotropic crystallite size refinement showed that C-S-H has a nanocrystalline disordered structure with a preferred direction of elongation of the nanocrystallites in the plane of the Ca interlayer. The quality of the fit showed that the monoclinic structure gives a more adequate representation of C-S-H, whereas the disordered orthorhombic structure can be considered a more realistic model if the lack of long-range order of the silica chain along the c-direction is assumed. © 2012 Elsevier Ltd. All rights reserved.

  6. Measurements of Residual Stresses In Cold-Rolled 304 Stainless Steel Plates Using X-Ray Diffraction with Rietveld Refinement Method

    International Nuclear Information System (INIS)

    Parikin; Killen, P; Rafterry, A.

    2009-01-01

    The determination of the residual stresses using X-ray powder diffraction in a series of cold-rolled 304 stainless steel plates, deforming 0, 34, 84, 152, 158, 175 and 196 % reduction in thickness has been carried out. The diffraction data were analyzed using the Rietveld structure refinement method. The analysis shows that for all specimens, the martensite particles are closely in compression and the austenite matrix is in tension. Both the martensite and austenite, for a sample reducing 34% in thickness (containing of about 1% martensite phase) the average lattice strains are anisotropic and decrease approximately exponential with an increase in the corresponding percent reduction (essentially phase content). It is shown that this feature can be qualitatively understood by taking into consideration the thermal expansion mismatch between the martensite and austenite grains. Also, for all cold-rolled stainless steel specimens, the diffraction peaks are broader than the unrolled one (instrumental resolution), indicating that the strains in these specimens are inhomogeneous. From an analysis of the refined peak shape parameters, the average root-mean square strain, which describes the distribution of the inhomogeneous strain field, was predicted. The average residual stresses in cold-rolled 304 stainless steel plates showed a combination effect of hydrostatic stresses of the martensite particles and the austenite matrix. (author)

  7. Rietveld refinement of the crystal structure of perovskite solar cells using CH3NH3PbI3 and other compounds

    Science.gov (United States)

    Ando, Yuji; Ohishi, Yuya; Suzuki, Kohei; Suzuki, Atsushi; Oku, Takeo

    2018-01-01

    The crystal structures of perovskite thin films including CH3NH3PbI3, CH3NH3Pb1-xSbxI3, and CH3NH3PbI3-yCly in the solar cell configuration were studied by using Rietveld refinement. For the CH3NH3PbI3 and CH3NH3Pb1-xSbxI3 samples, satisfactory agreement with the measured profiles was obtained with a weighted profile R-factor (Rwp) of as low as 3%. It was shown that the site occupancy of methylammonium (MA) was decreased in the antimonized cell due to the compensation effect of an increased positive charge brought about by replacing Pb2+ with Sb3+. Photovoltaic measurements showed that the power conversion efficiency was enhanced by adding a small amount of Sb to the CH3NH3PbI3 cell, but it was monotonically decreased as the mole fraction of Sb exceeded 0.03. This variation of the conversion efficiency was considered as a result of suppressed crystallization of PbI2 and carrier recombination via MA vacancies in the antimonized cells. In the case of CH3NH3PbI2.88Cl0.12 sample, the agreement with the measured profile with an Rwp of as high as 7% suggested the co-existence of cubic and tetragonal phases in the chlorinated cell.

  8. In situ X-ray Rietveld analysis of Ni-YSZ solid oxide fuel cell anodes during NiO reduction in H2

    International Nuclear Information System (INIS)

    Reyes Rojas, A; Esparza-Ponce, H E; Fuentes, L; Lopez-Ortiz, A; Keer, A; Reyes-Gasga, J

    2005-01-01

    A synthesis and characterization of solid oxide fuel cell (SOFC) anodes of nickel with 8%mol yttrium stabilized zirconia (Ni-YSZ) is presented. Attention was focused on the kinetics and phase composition associated with the transformation of NiO-YSZ to Ni-YSZ. The anodes were prepared with an alternative synthesis method that includes the use of nickel acetylacetonate as an inorganic precursor to obtain a highly porous material after sintering at 1400 deg. C and oxide reduction (NiO-YSZ → Ni-YSZ) at 800 deg. C for 8 h in a tubular reactor furnace using 10% H 2 /N 2 . The obtained material was compressed by unidirectional axial pressing into 1 cm-diameter discs with 15-66 wt% Ni and calcinated from room temperature to 800 deg. C. A heating rate of 1 deg. C min -1 showed the best results to avoid any anode cracking. Their structural and chemical characterization during the isothermal reduction were carried out by in situ time-resolved X-ray diffraction, refined with the Rietveld method (which allowed knowing the kinetic process of the reduction), scanning electron microscopy and X-ray energy dispersive spectroscopy. The results showed the formation of tetragonal YSZ 8%mol in the presence of nickel, a decrement in the unit cell volume of Ni and an increment of Ni in the Ni-YSZ anodes during the temperature reduction. The analysis indicated that the Johnson-Mehl-Avrami equation is unable to provide a good fit to the kinetics of the phase transformation. Instead, an alternative equation is presented

  9. X-ray diffraction analysis of stan nite, wurtz-stan nite and pseudo-cubic quaternary compounds by Rietveld method

    Energy Technology Data Exchange (ETDEWEB)

    Quintero, M.; Quintero, E.; Moreno, E.; Alvarez, S.; Rincon, C.; Grima, P.; Bocaranda, P.; Rivero, D. [Universidad de Los Andes, Centro de Estudios de Semiconductores, 5101 Merida (Venezuela, Bolivarian Republic of); Marquina, J. [Universidad de Los Andes, Centro de Estudios Avanzados en Optica, 5101 Merida (Venezuela, Bolivarian Republic of); Henao, J. A.; Macias, M. A., E-mail: mquinterg@gmail.com [Universidad Industrial de Santander, Facultad de Ciencias, Escuela de Quimica, Grupo de Investigacion en Quimica Estructural, Apdo. Aereo 678, Bucaramanga (Colombia)

    2014-07-01

    Room temperature X-ray powder diffraction measurements were carried out on nine polycrystalline samples of the Cu{sub 2}B{sup II}C{sup IV}X{sub 4} (B=Mn, or Fe, or Co; C=Si, or Ge, or Sn; X=S, or Se or Te) magnetic semiconductor compounds. The diffraction patterns were used to show the equilibrium conditions and to derive crystalline parameters values. The results showed that four of these compounds have a tetragonal stan nite structure with space group 142 m(N{sup o} 121), two and orthorhombic wurtz-stan nite structure with space group Pmn2{sub 1}(N{sup o} 31) and three of them and orthorhombic pseudo-cubic structure with space group F222 (N{sup o} 22). In each case, the structure was refined using the Rietveld method. When the obtained atomic parameter values for the tetragonal compounds were plotted as a function of molecular weight W, it was found that the values of the atomic positions, the cation-anion bond distances, tetragonal distortion and internal distortion of the compounds containing S and /or Se lay on different lines. Also, it was found that when the experimental points of the cation-anion bond distances d{sub Cu-VI}, d{sub II-VI} and d{sub IV-VI} were plotted against the effective lattice parameter a{sub c} = (V/N){sup 1/3}, a linear variation of these distances with a{sub c} was obtained. Values of the ionic energy gap C{sub i} and homopolar energy gap E{sub h} using the Phillips-Van Vechten scheme, with the present experimental crystallographic results as well as using the atomic data, were determined. It was found that the observed and predicted values of C{sub i} and E{sub h} lie on the same straight line. (Author)

  10. Structure of the new Tl(Ba sub 1.0 Sr sub 1.0) PrCu sub 2 O sub 7-x by Rietveld analysis

    International Nuclear Information System (INIS)

    Yang, P.; Fun, H. K.; Lee, T.J.; Ku, H.C.; Lai, C.C.

    1994-01-01

    The crystalline structure of Tl(Ba sub 1.0 Sr sub 1.0)PrCu sub 2 O sub 7-x was obtained at room temperature from x-ray powder diffraction with CuK sub α radiation using Rietveld analysis. Tl(Ba sub 1.0 Sr sub 1.0)PrCu sub 2 O sub 7-x isomorphous at both room temperature (300 K) and low temperature (100 K) with TlBa sub 2 ca Cu sub 2 O sub 7-x type (1212) structure, crystallized with space group P4/mmm and one formula in the unit cell. At 300 K, cell parameters a=3.8892(2) A, c=12.3099(6) A, the structure was refined with 25 parameters to R sub WP = 6.30%, R sub P = 4.38% for 3551 step intensities and R sub b = 5.01%, R sub f = 4.20% for 156 reflections. The goodness of fitting S=3.18. At 100K, cell parameters a=3.8866(4) A, c= 12.289(1) A, the structure was refined with 26 parameters to R sub WP = 8.42%, R sub P = 6.21% for 2676 step intensities and R sub b = 6.72%, R sub f = 5.28% for 120 reflections. The goodness of fitting S=2.32. Reasonable anisotropic thermal parameters were obtained. The compositions of Ba and Sr atoms were refined to about Ba sub 1.1 Sr sub 0.9 compared with the stoichiometric Ba sub 1.0 Sr sub 1.0

  11. Crystal structure refinement of Ba5Nb4O15 and Ba5Nb4O15-x by Rietveld analysis of neutron and X-ray diffraction data

    International Nuclear Information System (INIS)

    Pagola, S.; Leyva, G.; Casais, M.T.; Alonso, J.A.; Rasines, I.; Carbonio, R.E.

    1996-01-01

    Both X-ray and neutron diffraction data were analyzed by the Rietveld method, taking as starting structural model that of the Ba 5 Ta 4 O 15 structure. The results of such an analysis show that the progressive elimination of oxygen ions produce only small changes in the structure. A decrease in the unit-cell parameters as the number of oxygen vacancies increases has been observed, which can be correlated with a gradual loss of oxygen ions in the close-packed layers. No ordering of the oxygen vacancies was found even in the sample with the highest x value, x=0.56. (orig.)

  12. Descontaminación microbiana de la maca (Lepidium meyenii aplicando el sistema de esterilización orgánica (OSS para preservar sus propiedades nutricionales y sensoriales

    Directory of Open Access Journals (Sweden)

    Américo Guevara Pérez

    2016-01-01

    Full Text Available La investigación tuvo como objetivo aplicar el sistema de esterilización orgánica (OSS en maca, determinando los parámetros del proceso: tiempo y temperatura de inyección de vapor saturado que reduzcan el recuento de microorganismos aerobios, mohos, levaduras, E. Coli, salmonella y coliformes totales, y evaluando la influencia del proceso en el contenido total de glucosinolatos. La máxima descontaminación microbiana de la maca se logró aplicando una carga de 5 kg/saquillo, por 6 min. Con una temperatura de inyección de vapor saturado de 100 °C. Bajo estas condiciones, la reducción de la carga microbiana fue de 99,9% (< 10 UFC/g, 50% (< 10 UFC/g y 93,3% (< 10 UFC/g para aerobios, mohos, y levaduras, respectivamente; el comportamiento de patógenos fue muy similar al de la materia prima: E. coli < 3 UFC/g, ausencia de salmonella (25 g y < 3 UFC/g para coliformes totales. El contenido de glucosinolatos se mantuvo durante el proceso en 1,5 μmol/g, lo que evidenció que al aplicar la tecnología OSS se logra conservar la calidad nutricional, sensorial y funcional de la maca.

  13. Valoración de los Proyectos de Grado sobre Educación Ambiental en la Universidad, Aplicando la Hipótesis de Progresión

    Directory of Open Access Journals (Sweden)

    Alba Leonilde Suárez Arias

    2015-12-01

    Full Text Available Este trabajo  aplica la hipótesis de progresión como metodología para  la valoración de los proyectos de grado de los estudiantes en Educación Ambiental en la Universidad. Se han analizado, los proyectos realizados por los  alumnos de  la licenciatura en Biología y Educación Ambiental, en la Universidad del Quindío, Colombia. Cuyo objetivo  tiene la  formación de profesores para los diferentes niveles educativos. La hipótesis de progresión permite valorar  el cambio conceptual  presentado en los proyectos de grado no como un proceso puntual sino como un proceso de evolución de los contenidos. La investigación  muestra que los Proyectos fin de grado de los estudiantes de Biología y educación Ambiental  valorados aplicando la hipótesis de progresión tienen una visión aditiva y poco fundamentada   sobre la  incorpora ración de  la educación ambiental  en el currículo

  14. Formação de biofilme em gotejadores aplicando água residuária da despolpa dos frutos do cafeeiro = Formation of biofilm in drippers applying wastewater from pulping of the coffee fruits

    Directory of Open Access Journals (Sweden)

    Rafael Oliveira Batista

    2007-07-01

    Full Text Available Este trabalho teve por objetivo analisar a formação de biofilme em sistemas de irrigação por gotejamento aplicando água residuária da despolpa dos frutos do cafeeiro (ARC submetidas ou não à passagem em filtro orgânico. Para isso, foi montada uma estrutura hidráulica de avaliação, constituída de fitas gotejadores, não autocompensantes e posicionados no espaçamento de 0,3 m. Diante dos resultados obtidos, pode-se concluir que: águas residuárias da despolpa de frutos do cafeeiro apresentaram severo risco de entupimento de gotejadores, mesmo quando submetidas a tratamento prévio em filtros orgânicos.This work objectified to analyze the formation of biofilm in drip irrigation systems applying wastewater from pulping of the coffee fruits (ARC with and without ticket in organic filter. For that, a hydraulic structure of evaluation, constituted of drip tape, non pressure compensating, positioned in the spacing of 0,3 m. In accordance with the results obtained can be concluded that: wastewater from pulping of the coffee fruits presented severe risk of clogging of emitters, same when submitted the treatment in organic filters.

  15. Detección De Patrones De Deserción En Los Programas De Pregrado De La Universidad Mariana De San Juan De Pasto, Aplicando El Proceso De Descubrimiento De Conocimiento Sobre Base De Datos (Kdd) Y Su Implementación En Modelos MatemáTicos De Predicción

    OpenAIRE

    Argote, Ivan; Jimenez, Robinson

    2016-01-01

    La investigación titulada: “Detección de Patrones de Deserción en los Programas de Pregrado de la Universidad Mariana de San Juan de Pasto, aplicando el proceso de descubrimiento de conocimiento sobre base de datos (KDD) y su implementación en modelos matemáticos de predicción”. Es un proyecto que tiene como objetivo primordial Aportar al Proceso de Toma de Decisiones para disminuir los niveles Deserción Estudiantil en los programas de pregrado de la Universidad Mariana, mediante el descubrim...

  16. The new insight into the structure-activity relation of Pd/CeO2-ZrO2-Nd2O3 catalysts by Raman, in situ DRIFTS and XRD Rietveld analysis.

    Science.gov (United States)

    Yang, X; Yang, L; Lin, J; Zhou, R

    2016-01-28

    Pd/CeO2-ZrO2-Nd2O3 (CZN) catalysts with different CeO2/ZrO2 molar ratios were synthesized and have been characterized by multiple techniques, e.g. XRD in combination with Rietveld refinement, UV-Raman, XPS and in situ DRIFTS. The XRD pattern of CZN with CeO2/ZrO2 molar ratios ≥1/2 can be indexed satisfactorily to the fluorite structure with a space group Fm3̄m, while the XRD patterns of CZ12 only display diffraction peaks of the tetragonal phase (S.G. P42/nmc). Nd addition can effectively stabilize the cubic structure of the CZN support and increase the enrichment of defect sites on the surface, which may be related to the better catalytic activity of Pd/CZN12 catalysts compared with Pd/CZ12. The presence of moderate ZrO2 can increase the concentration of O* active species, leading to accelerate the formation of nitrate species and thus enhance the catalytic activity of NOx and HC elimination. The Pd-dispersion decreases with the increasing Zr content, leading to the decreased CO catalytic activity, especially for the aged catalysts. The change regularity of the OSC value is almost the same with the in situ dynamic operational window, demonstrating that the in situ dynamic operational window is basically affected by the OSC value.

  17. Implementation of GASBOL advanced functions; Implantacao do sistema de funcoes avancadas do GASBOL

    Energy Technology Data Exchange (ETDEWEB)

    Valeriano, Alexsander; Frota, Cristiane Souto [TBG - Transportadora Brasileira Gasoduto Bolivia Brasil S.A., Rio de Janeiro, RJ (Brazil); Frisoli, Caetano [TRANSPETRO - PETROBRAS Transporte S.A., Rio de Janeiro, RJ (Brazil)

    2003-07-01

    Real time simulation tools for gas pipelines are already a reality in control central rooms, providing safer and more efficient operations, complementing SCADA functionalities for gas pipeline supervision and monitoring. Different modules can compose this set of tools, also named Advanced Functions, for example: real time monitoring module; predictive module, used for operational strategies, planning for future operations and what if sceneries simulation; look ahead module, used to warn the operator for operational situations that might occur in the future; training simulator, used for operators training and qualification, among others. The application of these tools by natural gas transporter companies, seen as an important tool of decision and support to the operation team, increases the quality of services and creates a differential against market competitors. (author)

  18. Presence of a monoclinic (Pm) phase in the morphotropic phase boundary region of multiferroic (1 − x)Bi(Ni{sub 1/2}Ti{sub 1/2})O{sub 3}-xPbTiO{sub 3} solid solution: A Rietveld study

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, Rishikesh, E-mail: akhilesh-bhu@yahoo.com, E-mail: aksingh.mst@itbhu.ac.in; Singh, Akhilesh Kumar, E-mail: akhilesh-bhu@yahoo.com, E-mail: aksingh.mst@itbhu.ac.in [School of Materials Science and Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005 (India)

    2014-07-28

    We present here the results of structural studies on multiferroic (1 − x)Bi(Ni{sub 1/2}Ti{sub 1/2})O{sub 3}-xPbTiO{sub 3} solid solution using Rietveld analysis on powder x-ray diffraction data in the composition range 0.35 ≤ x ≤ 0.55. The stability region of various crystallographic phases at room temperature for (1 − x)Bi(Ni{sub 1/2}Ti{sub 1/2})O{sub 3}-xPbTiO{sub 3} is determined precisely. Structural transformation from pseudo-cubic (x ≤ 0.40) to tetragonal (x ≥ 0.50) phase is observed via phase coexistence region demarcating the morphotropic phase boundary. The morphotropic phase boundary region consists of coexisting tetragonal and monoclinic structures with space group P4mm and Pm, respectively, stable in composition range 0.41 ≤ x ≤ 0.49 as confirmed by Rietveld analysis. The results of Rietveld analysis completely rule out the coexistence of rhombohedral and tetragonal phases in the morphotropic phase boundary region reported by earlier workers. A comparison between the bond lengths for “B-site cations-oxygen anions” obtained after Rietveld refinement, with the bond length calculated using Shannon-Prewitt ionic radii, reveals the ionic nature of B-O (Ni/Ti-O) bonds for the cubic phase and partial covalent character for the other crystallographic phases.

  19. Aplicando recomendações da Escala de Braden e prevenindo úlceras por pressão: evidências do cuidar em enfermagem Aplicando las recomendaciones de la Escala de Braden y previniendo las úlceras por presión: evidencias en la atención de enfermería Applying recommendations of the Braden's Scale and preventing pressure ulcers: evidences for nursing care

    Directory of Open Access Journals (Sweden)

    Cristina Albuquerque de Sousa

    2006-06-01

    Full Text Available Questiona-se o risco de acometimento de úlcera de pressão (UP no cliente, e a validade do cuidado de enfermagem aplicando a escala de Braden para verificar as evidências desse cuidado na incidência da UP. Utilizou-se o método de medidas biofisiológicas em clientes de UTI. Encontrou-se 11 clientes com UP, numa incidência de 26,83%. A maioria (57,1% de úlcera encontra-se no estágio I. Clientes com UP têm escores menores que os sem UP mostrando sensibilidade para predizer o risco de UP. Concluiu-se que: a evidência dos cuidados de enfermagem foi demonstrada pela densidade de 47,12 % para os clientes sem UP; a incidência das UP foi menor que as encontradas em outras UTIs; os cuidados de enfermagem preventivos reduzem as UP.El riesgo del acometimento de la úlcera por presión en paciente es cuestionable así como la validez de la atención de enfermería al aplicar la escala de Braden para verificar las evidencias de este cuidado y la incidencia de UP. El método de las medidas biofisiológicas en pacientes de UTI fue utilizado. La UP fué encontrada en 11 pacientes en una incidencia de 26.83%. La mayoría (57.1% de las úlceras estavan en el estágio I. Los pacientes con UP tienen scores más bajos que los que no las tenían, demonstrando sensibilidad para predecir lo riesgo para UP. Se ha concluydo que: la evidencia de la atención de enfermería fue demonstrada por la densidad de 47,12% para los pacientes sin UP; la incidencia de la UP fue menor que las encontradas en otras UTIs; la atención preventiva de enfermería reducen las UP.The occurence risk of pressure ulcer (PU by the patient is questioned as well as the validity of nursing care applying the Braden's scale to verify the evidences of this care in the incidence of the PU. The method of biophysiologic measures in ICU patients was used. It was found 11 patients with PU, in a 26,83% incidence. The majority (57,1% of ulcer was in stage I. Patients with PU have lower scores than

  20. The formation and structure of mechano-synthesized nanocrystalline Sr{sub 3}Fe{sub 2}O{sub 6.4}: XRD Rietveld, Mössabuer and XPS analyses

    Energy Technology Data Exchange (ETDEWEB)

    Al-Rawas, A.D., E-mail: arawas@squ.edu.om [Department of Physics, Sultan Qaboos University, P.O. Box 36, 123 Al-Khoud, Muscat (Oman); Widatallah, H.M.; Al-Harthi, S.H. [Department of Physics, Sultan Qaboos University, P.O. Box 36, 123 Al-Khoud, Muscat (Oman); Johnson, C. [Chemistry Department, Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Gismelseed, A.M.; Elzain, M.E.; Yousif, A.A. [Department of Physics, Sultan Qaboos University, P.O. Box 36, 123 Al-Khoud, Muscat (Oman)

    2015-05-15

    Highlights: • The formation of mechano-synthesized nanocrystalline Sr{sub 3}Fe{sub 2}O{sub 7−δ} is investigated. • Pre-milling the reactants substantially lowers the formation temperature. • The core and surface structures were studied. • XRD and {sup 57}Fe Mössbauer spectroscopic analyses indicate the δ-value to be 0.60. • XPS shows a complex surface structure for the mechanosynthesized Sr{sub 3}Fe{sub 2}O{sub 7−δ} nanoparticles. - Abstract: The influence of ball milling and subsequent sintering of a 3:1 molar mixture of SrCO{sub 3} and α-Fe{sub 2}O{sub 3} on the formation of Sr{sub 3}Fe{sub 2}O{sub 7−δ} double perovskite is investigated with different analytical techniques. Milling the mixture for 110 h leads to the formation of SrCO{sub 3}-α-Fe{sub 2}O{sub 3} nanocomposites and the structural deformation of α-Fe{sub 2}O{sub 3} via the incorporation of Sr{sup 2+} ions. Subsequent sintering of the pre-milled reactants’ mixture has led to the partial formation of an SrFeO{sub 3} perovskite-related phase in the temperature range 400–600 °C. This was followed by the progressive development of an Sr{sub 3}Fe{sub 2}O{sub 7−δ} phase that continued to increase with increasing sintering temperature until a single-phased nanocrystalline Sr{sub 3}Fe{sub 2}O{sub 7−δ} phase was attained at 950 °C (12 h). This temperature is ∼350 °C lower than the temperature at which the material is prepared conventionally using the ceramic method. The evolution of different structural phases during the reaction process is discussed. Rietveld refinement of the X-ray diffraction data shows a value of 0.60 for the oxygen deficiency δ, in consistency with the Fe{sup 3+}/Fe{sup 4+} ratio derived from the {sup 57}Fe Mössbauer data recorded at both 300 K and 78 K. The Mössbauer data suggests that the Sr{sub 3}Fe{sub 2}O{sub 6.4} nanoparticles are superparamagnetic with blocking temperatures below 78 K. The surfaces of the Sr{sub 3}Fe{sub 2}O{sub 6

  1. Efeitos do período e volume de aplicação na segurança dos tratoristas aplicando herbicidas na cultura de cana-de-açúcar (Saccharum spp. Effects of herbicide spraying period and volume on the safety of tractor drivers spraying herbicides on sugarcane (Saccharum spp. crop

    Directory of Open Access Journals (Sweden)

    J.C. Momesso

    2003-12-01

    Full Text Available O objetivo deste trabalho foi avaliar os efeitos do período e volume de aplicação na segurança da atividade de tratoristas aplicando herbicidas na cultura de cana-de-açúcar com o pulverizador de barra montado em trator e a eficiência de equipamentos de proteção individual (EPIs e de uma cabina acoplada ao trator. As exposições dérmicas de 13 condições de trabalho foram avaliadas e analisadas estatisticamente por meio do delineamento inteiramente ao acaso e do esquema fatorial 3 x 2 x 2 + 1. O fator A foi a condição de exposição: 1 exposição dérmica potencial (EDP - sem nenhuma medida de segurança; 2 exposição com cabina no trator (Cabina; e 3 exposição com as vestimentas (EPI. O fator B foi o volume de aplicação: 1 200 L ha-1 e 2 100 L ha-1; e o fator C foi o período de aplicação: 1 diurno e 2 noturno. Como testemunha foi avaliada a EDP do tratorista aplicando na atividade usual de 300 L de calda ha-1, no período diurno. As exposições dérmicas (EDs aos herbicidas considerados nessas condições de trabalho foram estimadas por meio de dados substitutos das EDs avaliadas ao cátion Cu+2 adicionado como traçador nas caldas aplicadas. O pulverizador utilizado foi do modelo PJ 600, com barra de 12 m de comprimento e 24 bicos de jato plano TT 110 04 ou TT 110 02. As 13 condições de trabalho avaliadas foram classificadas como seguras (MS>1 para o tratorista aplicando os herbicidas glyphosate (48% i.a., MSMA (48%, diuron (46,8% + hexazinone (13,2%, clomazone (50%, sulfentrazone (50%, ametryne (50%, diuron (50%, isoxaflutole (75%, metribuzin (48%, 2,4-D (80,6%, ametryne (30% + clomazone (20%, ametryne (73,25% + trifloxysulfuron (1,85% e tebuthiuron (80 % e inseguras para o herbicida atrazine (50%, nos dois períodos e nos três volumes de aplicação, e ametryne (50%, na aplicação diurna e 100 L de calda ha-1. As aplicações noturnas e os volumes de aplicação reduzidos tornaram as condições de trabalho mais

  2. Rietveld refinement of the orthorhombic Pbca structures of Rb2CdSi5O12, Cs2MnSiO5O12, Cs2CoSi5O12 and Cs2NiSi5O12 leucites by synchrotron X-ray powder diffraction

    International Nuclear Information System (INIS)

    Bell, A.M.T.; Henderson, C.M.B.

    1996-01-01

    Analysis of high-resolution synchrotron X-ray powder diffraction patterns for hydrothermally synthesized Rb 2 CdSi 5 O 12 and Cs 2 MnSi 5 O 12 leucite analogues, and dry-synthesized Cs 2 CoSi 5 O 12 and Cs 2 NiSi 5 O 12 leucite analogues showed that they have an orthorhombic Pbca structure. The structures have been refined by the Rietveld method, showing that the tetrahedrally coordinated atoms (Si, Cd, Mn, Co and Ni) are ordered on separate sites. The Cs 2 MnSi 5 O 12 , Cs 2 CoSi 5 O 12 and Cs 2 NiSi 5 O 12 leucite samples are unusual in containing SiO 4 tetrahedra which are more distorted, on average, than the larger MnO 4 , CoO 4 and NiO 4 tetrahedra. The JCPDS file numbers for Rb 2 CdSi 5 O 12 , Cs 2 MnSi 5 O 12 and Cs 2 CoSi 5 O 12 are 46-1491, 46-1492 and 46-1493, respectively. (orig.)

  3. Rietveld refinement and dielectric properties of (Na{sub 0.5}Bi{sub 0.5}TiO{sub 3})-(Bi{sub 0.8}Ba{sub 0.2}FeO{sub 3}) ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Kaswan, Kavita, E-mail: kaswan.kavita@gmail.com; Agarwal, Ashish; Sanghi, Sujata; Singh, Ompal [Department of Applied Physics, Guru Jambheshwar University of Science and Technology, Hisar-125001 (India)

    2015-06-24

    (1-x)(Na{sub 0.5}Bi{sub 0.5}TiO{sub 3})-x(Bi{sub 0.8}Ba{sub 0.2}FeO{sub 3}) lead free ceramics (NBT, NBT-BBFO; x = 0.0, 0.1 respectively) have been synthesized by conventional solid state reaction method. Crystalline phase of sintered ceramics was investigated at room temperature using X-ray diffraction. Rietveld refinement of XRD data performed by FullProf revealed that both the samples exhibited rhombohedral structure with R3c space group. Dielectric properties of these ceramics were studied at different temperatures in a wide frequency range using impedance analyzer. Dielectric constant and dielectric loss were found to be increase with increase of BBFO content. The prepared ceramics exhibit a broad maximum in dielectric permittivity at 593K and dispersive permittivity at high temperatures. The NBT-BBFO sample shows a relaxor ferroelectric behavior at different frequencies.

  4. Prioridades de conservación aplicando información filogenética y endemicidad: un ejemplo basado en Carabidae (Coleoptera de América del Sur austral Conservation priorities using phylogenetic information and endemicity: an example based on Carabid beetles from Southern South America

    Directory of Open Access Journals (Sweden)

    Sergio Roig-Juñent

    2004-12-01

    Full Text Available Sobre la base de la información distribucional de las especies de Carabidae (Coleoptera de América del Sur austral, se reconocieron 17 áreas de endemismo. Para cada una de ellas se estimó la diversidad gamma, el porcentaje de endemismo, el valor filogenético y la complementariedad, exceptuando Juan Fernández del cual no se pudo obtener ningún valor filogenético. El cálculo del valor filogenético se realizó a través del uso de cuatro índices, el valor filogenético sin ninguna modificación (W, considerando la endemicidad (We, y sus respectivas estandarizaciones (Ws y Wes. Los resultados muestran que la estandarización del valor filogenético (Ws produce un sesgo cuando los cladogramas difieren en tamaño y que el complemento entre áreas es una herramienta secundaria de gran utilidad. Sin embargo, los resultados muestran que para determinar la importancia de las áreas, el complemento debe ser usado en conjunto con la diversidad específica y la endemicidad. Las comparaciones de los resultados obtenidos usando W, We y análisis de complementariedad estrictos y modificados muestran que el valor filogenético que admite endemicidad (We puede ser aplicado como único valor para determinar la importancia de cada área. Aplicando We, las seis primeras áreas seleccionadas acumulan el 72 % del valor filogenético y el 74 % de la diversidad gamma de los carábidos de América del Sur austral, mientras que ninguno de los otros parámetros usados acumula el 70 % de las especies antes de sumar la séptima área. Las seis áreas seleccionadas son la Selva valdiviana, las Sierras pampeanas, Coquimbo, Patagonia occidental, Chile central y La Araucanía. Es de hacer notar que las Sierras pampeanas y la Patagonia occidental son ambientes de pastizales, Coquimbo y Chile central son ambientes áridos y semiáridos, y solo la Selva valdiviana y Araucanía son típicos bosques australesBased on information of the Southern South American carabid

  5. Rietveld analysis, dielectric and impedance behaviour of Mn /Fe ion ...

    Indian Academy of Sciences (India)

    Figure 1 compares X-ray diffraction patterns of pow- ders calcined at temperature .... ground, absorption coefficient, atomic positions, two theta zero error, thermal ... attributed to segregation of Mn and Fe at grain boundaries. (Dai et al 1995).

  6. Rietveld refinement, impedance spectroscopy and magnetic properties of Bi{sub 0.8}Sr{sub 0.2}FeO{sub 3} substituted Na{sub 0.5}Bi{sub 0.5}TiO{sub 3} ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Kumari, Rekha [Department of Applied Physics, Guru Jambheshwar University of Science & Technology, Hisar 125001, Haryana (India); Ahlawat, Neetu, E-mail: neetugju@yahoo.co.in [Department of Applied Physics, Guru Jambheshwar University of Science & Technology, Hisar 125001, Haryana (India); Agarwal, Ashish; Sanghi, Sujata [Department of Applied Physics, Guru Jambheshwar University of Science & Technology, Hisar 125001, Haryana (India); Sindhu, Monica [Department of Physics, MKJK College, Rohtak 124001, Haryana (India); Ahlawat, Navneet [Matu Ram Institute of Engineering and Management, Rohtak 124001, Haryana (India)

    2016-09-15

    We herein presented the investigation on the structural, electrical and magnetic properties of (1−x)(Na{sub 0.5}Bi{sub 0.5}TiO{sub 3})–x(Bi{sub 0.8}Sr{sub 0.2}FeO{sub 3}) polycrystalline ceramic samples, with x=0.1, 0.3, 0.5 and 0.7. These samples were prepared by conventional solid state reaction method and the crystalline phase of prepared ceramics was identified with the help of X-ray diffraction pattern. Rietveld analysis of the obtained XRD data confirmed that all the synthesized samples adopt the rhombohedral crystal structure with R3c space group. Impedance spectroscopic measurements were performed on all the compositions in the frequency range 10 Hz–5 MHz to probe the electrical microstructure of polycrystalline (1−x)(Na{sub 0.5}Bi{sub 0.5}TiO{sub 3})–x(Bi{sub 0.8}Sr{sub 0.2}FeO{sub 3}) ceramics, which changes significantly as a function of x (content of BSFO). A significant increase in dielectric constant has been observed with increase in BSFO concentration, which was attributed to enhancement of oxygen vacancies. Detailed study of impedance complex plane plots revealed the presence of non-Debye type relaxation for all the prepared systems and enabled us to separate the contribution from grains and grain boundaries. Equivalent circuit model (R{sub g}CPE{sub g})(R{sub gb}CPE{sub gb})(R{sub e}CPE{sub e}) was employed to explain the impedance data for all the prepared samples. The activation energies obtained from electric modulus as well as dc conductivity increase with increase in BSFO content, which approaches the value 1 eV and indicates an Arrehenius type thermally activated process. Remnant magnetization (M{sub r}) and coercive field (H{sub c}) are found to be increase with BSFO concentration. - Highlights: • (1−x)NBT–xBSFO (x=0.1, 0.3, 0.5, 0.7) ceramics were prepared. • There is no change in crystal structure. • These can be used as data storage materials.

  7. Application of compartmental metabolic models for determination of retention and excretion functions; Aplicacao de modelos metabolicos para a determinacao de funcoes de excrecao e retencao

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Junior, O

    1994-07-01

    After an intake of radioactive material, its behaviour in the human body can be described by mathematical models, where organs, tissues or regions of the body are treated as a chain of linked compartments. The mathematical approach for such metabolic models is usually done through a system of differential equations of first order with constant coefficients. The solutions of this system of equations associates the radionuclide intake, with the fraction excreted or retained in the organ of interest. A computer program - called INCORP and for running in PC compatible microcomputers - was developed in order to find the solutions of such system of equations, using an analytical method based on expansion of series of exponential matrices. The metabolic model presented in the ICRP-30 publication was simulated using the INCORP program, in order to find the respective retention and excretion curves for selected radionuclides. (author)

  8. Anomalies in Ward identities revisited. Explicit calculation of the three point functions; Anomalias em identidades de Ward revisitadas. Calculo explicito das funcoes de tres pontos

    Energy Technology Data Exchange (ETDEWEB)

    Dalmolin, Fabricio Tronco

    2007-07-01

    The occurrence of unavoidable violations in symmetry properties of physical amplitudes is certainly one of the most intriguing problems in the context of Quantum Field Theory (QFT). These violations, which are called anomalies, play a crucial role in the construction of such theories due to the requirement of renormalizability. These phenomena can be established through very general mathematical arguments which are valid also for eventual exact solutions of the associated equations of motion. Exact exact solutions, however, are rarely possible, in this context. Given this limitation, the explicit verification of the violations in symmetry properties of physical amplitudes needs to be done within the context of perturbative solutions. The complication of this task is the occurrence of divergences in the perturbative physical amplitudes and all well known problems such as ambiguities associated to the internal momenta routing in loops, which, due to the divergence degree involved, invariably plague the anomalous amplitudes. Due to this fact, anomalies are commonly presented in the literature in a way associated to the referred ambiguities. This traditional association has been questioned in the light of a new strategy for manipulations and calculations involving divergent amplitudes in QFT. Within the context of the referred technique the mentioned ambiguities can be consistently eliminated and all the amplitudes of all the theories and models are dealt in an identical way. The symmetry properties, of non anomalous amplitudes, are simultaneously satisfied for the consistently regularized (ambiguities free) version of the amplitudes. It is also possible to obtain an adequate description of the anomalous amplitudes in a simultaneous way, i.e., by using absolutely the same prescription adopted for the treatment of those non anomalous, which we will show in details along the present work. The investigation which we will report here, in certain sense are complementary to others already performed within the same issue. In particular, in one of such investigation a pioneer and traditional reference has been revisited by using the alternative strategy mentioned above. In such study, a systematic treatment of purely fermionic one, two and three point functions, associated to scalar, pseudo-scalar, vector and axial-vector densities, has done. There, however, only the explicit expressions for one and two point functions were developed. The conclusions pointed out, in a very clear way, that the association between intrinsic ambiguities of the perturbative calculation and violations in symmetry properties is not consistent. At the same time, it was concluded that only in an investigation where the explicit forms for the three point functions involved are considered clean and sound conclusions can be extracted. This is due to the fact that, in the relevant symmetry properties, it is involved three ward identities and a low energy limit. This is precisely the main purpose of the present work: to promote a detailed investigation of the relations among green functions and ward identities, within the context of a model having only one specie of 1/2 spin fermionic field, that consider all the amplitudes having superficial degree of divergence higher than the logarithmic one, in a similar way as that made in the work of Gerstein and Jackiw, taking however the explicit form for the three point functions. This is one to get in the analysis, simultaneously, the ward identities and the low energy limits involved in the anomalous amplitudes as required by the Sutherland-Veltman theorem, in order to get an adequate understanding of the anomaly phenomena. We will show that our final results can be mapped in those found with the use of the Dimensional Regularization, in situation where this technique can be applied, or in those of Gerstein and Jackiw, however with conflicting interpretations. Finally, we will show that in the context of the adopted technique the desired results emerge, in a natural way, within the context of an universal interpretation for the amplitudes where the ambiguities are automatically eliminated. (author)

  9. Management functions for a distributed system applied in power plants and substations automation; Funcoes de gerenciamento para um sistema distribuido aplicado na automacao de usinas e subestacoes

    Energy Technology Data Exchange (ETDEWEB)

    Lemos, Rogerio Sergio Neves de

    1988-04-01

    This work presents the management functions for a distributed computer control system, which has been developed at Centro de Pesquisas de Energia Eletrica - CEPEL with the aim to automate hydroelectric power plants and extra high voltage power substations. The initial specifications developed are based on a architecture without redundancies which initially has the objective to get the effective knowledge of the system's behaviour. In the first part is given an introduction of dependability, with two aims: to present the basic concepts and terminology, and, to present a set of techniques in the area of computing systems fault tolerance. In control system is introduced, in terms of its architecture and functionality. The third part introduces the management activities for the distributed system are introduced together with a general model. Finally, the fault diagnosis in the distributed system is discussed, where is presented a new diagnosis algorithm. (author)

  10. Management functions for a distributed system applied in power plants and substations automation; Funcoes de gerenciamento para um sistema distribuido aplicado na automacao de usinas e subestacoes

    Energy Technology Data Exchange (ETDEWEB)

    Lemos, Rogerio Sergio Neves de

    1988-04-01

    This work presents the management functions for a distributed computer control system, which has been developed at Centro de Pesquisas de Energia Eletrica - CEPEL with the aim to automate hydroelectric power plants and extra high voltage power substations. The initial specifications developed are based on a architecture without redundancies which initially has the objective to get the effective knowledge of the system's behaviour. In the first part is given an introduction of dependability, with two aims: to present the basic concepts and terminology, and, to present a set of techniques in the area of computing systems fault tolerance. In control system is introduced, in terms of its architecture and functionality. The third part introduces the management activities for the distributed system are introduced together with a general model. Finally, the fault diagnosis in the distributed system is discussed, where is presented a new diagnosis algorithm. (author)

  11. Modelling of critical functions of nuclear reactors using Fild Programmable Gate Array; Modelagem de funcoes criticas de reatores nucleares utilizando Fild Programmable Gate Array

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, Pamela Iara Nolasco

    2016-07-01

    This paper proposes the development of a method using FPGA for critical security functions of a nuclear reactor. It was implemented two critical safety functions in VHDL, which is a way to describe, through a program, the behavior of a circuit or digital component. Two critical security functions, FCS Core Cooling, responsible for cooling the reactor core in the charts of the plant and also in the event of accidents involving loss of coolant and FCS Heat Transfer, responsible for cooling the reactor core in the event an accident with loss of coolant were implemented. In this Dissertation it was chosen the use of FPGA, because - due to the effects of aging, obsolescence issues, environmental degradation and mechanical failures - nuclear power plants need to replace their older systems by new ones based on digital technology. The technologies obtained using a system described in hardware language can be implemented in a programmable device, having the advantage of changing the code at any time. (author)

  12. Advanced functions using VBA for the Yacuiba Rio Grande (GASYRG) gas pipeline; Funcoes avancadas usando VBA no gasoduto Yacuiba Rio Grande

    Energy Technology Data Exchange (ETDEWEB)

    Torres Vega, Raul [TRANSIERRA S.A., Santa Cruz (Bolivia)

    2005-07-01

    The Yacuiba - Rio Grande Gas Pipeline is remote operated from the Supervision and Control Center (CSC) located in the offices of Transierra S.A. in Santa Cruz de la Sierra, Bolivia. This operation is made by means of a SCADA system based on satellite communication, it starts off at Yacuiba and finishes in Rio Grande, where it deliveries the export gas to Brazil. An Advanced Functions application was developed at the Transierra's CSC, This application runs under Intellution's iFix (HMI of the SCADA) in a Windows platform. It gathers transportation data in real time and by means of a mathematical process and a steady state simulation it makes the following on line calculations: Line Pack, Leak Detection, Transport Efficiency, Pressure Estimate in intermediate points and gas real velocity in the pipeline. The application was developed using Visual BASIC for Applications (VBA) (included in Intellution's iFix) and by means of an interphase to a historical server (iHistorian, Intellution) it is possible to store the obtained results, this integration also allows for the creation of graphs and trends with a great flexibility and to activate alarm points. With a practically null investment, this application replaces high cost specialized packages that are accessories to simulation or SCADA applications. (author)

  13. Analysis of the zirconia structure by `ab initio` and Rietveld methods; Analise da estrutura da zirconia por metodos `Ab initio` e de Rietveld

    Energy Technology Data Exchange (ETDEWEB)

    Bechepeche, A.P.; Nasar, R.S.; Longo, E. [Sao Carlos Univ., SP (Brazil). Dept. de Quimica; Treu Junior, O.; Varela, J.A. [UNESP, Araraquara, SP (Brazil). Inst. de Quimica

    1995-12-31

    The zirconia was doped with 0,113 mol of Mg O e 0,005 mol of Ti O{sub 2}, and it was calcined in 1550{sup d}eg C and it was analyzed by XRD. The results shows that pure zirconia contains 96,19% of monoclinic phase and 3,18% of cubic. However, the doping magnesia stabilizes the zirconia in 17,24 of monoclinic; 29,63 of tetragonal and 53,13% of cubic phase. The addition of titanium in zirconia gives 25,85% of tetragonal phase and 37,66% of cubic, and this shows the no stabilizing action of this transition metal. By the other side, the results with ab-initio calculating shows the same tendency resulting in the next values of total energy: pure zirconia - monoclinic -11.316,86ua; tetragonal -8742,09 ua and cubic -8742,80 ua and Zr O{sub 2} Ti O{sub 2} system - monoclinic -9463,02 ua, tetragonal -9459,39 ua and cubic -9459,97 ua (author) 3 figs., 2 tabs.

  14. Desarrollo de un sistema de recogida de datos en Facebook aplicando gamificación

    OpenAIRE

    Castaño Chillarón, Diego

    2015-01-01

    El surgimiento del Big Data unido al auge de las redes sociales en los últimos años ha propiciado que éstas almacenen cada vez más datos de los usuarios, en un intento de rentabilizar su modelo de negocio, explotándolos principalmente a través de la publicidad dirigida. Facebook se encuentra a la cabeza en esta carrera por los datos, almacenando información de 1.44 billones de usuarios (datos personales, gustos, relaciones, etc.). Con este creciente ecosistema surgen nuevas oportunidades p...

  15. Implementar Balanced Scorecard en una entidad financiera aplicando tecnologías Business Intelligence

    OpenAIRE

    Mendoza Villegas, María Milagros; Mendoza Villegas, María Milagros

    2008-01-01

    Hoy en día las organizaciones necesitan mantener la excelencia estratégica y operativa, para sobrevivir y enfrentar futuros desafíos. La presión de la competencia, las necesidades de obtener mejores resultados obligan a las organizaciones a asegurarse que las estrategias trazadas estén ejecutándose correctamente y que alcancen los niveles de eficiencia operativa para asegurar el éxito. Un aliado importante para lograr alcanzar el éxito es el Balanceé Scorecard (BSC), la herramienta de plan...

  16. Aplicando minería de datos para descubrir rutas de aprendizaje frecuentes en Moodle

    OpenAIRE

    Alejandro Bogarín Vega; Cristóbal Romero Morales; Rebeca Cerezo Menéndez

    2016-01-01

    En este artículo, aplicamos técnicas de minería de datos para descubrir rutas de aprendizaje frecuentes. Hemos utilizado datos de 84 estudiantes universitarios, seguidos en un curso online usando Moodle 2.0. Proponemos agrupar a los estudiantes, en primer lugar, a partir de los datos de una síntesis de uso de Moodle y/o las calificaciones finales de los alumnos en un curso. Luego, usamos los datos de los logs de Moodle sobre cada cluster/grupo de estudiantes separadamente con el fin de poder ...

  17. Mejoramiento de cimentaciones en suelos y rocas aplicando las técnicas de grouting

    OpenAIRE

    Ampuero Cayo, Salomón Edgard; Ampuero Cayo, Salomón Edgard

    2012-01-01

    Las técnicas de inyecciones de grouting, se conocen desde el año 1802 en Francia, desde entonces se ha recopilado información y se practica esta técnica mejorando cada vez. Los diseños, procedimientos de inyección, están orientados hacia los objetivos básicos, que son el control de agua subterránea y el tratamiento de los macizos rocosos fracturados y suelos sin cohesión. La aplicación de las técnicas de grouting en rocas; reducen el flujo de agua, refuerzan las rocas y mitigan la formaci...

  18. Aplicando minería de datos para descubrir rutas de aprendizaje frecuentes en Moodle

    Directory of Open Access Journals (Sweden)

    Alejandro Bogarín Vega

    2016-01-01

    Full Text Available En este artículo, aplicamos técnicas de minería de datos para descubrir rutas de aprendizaje frecuentes. Hemos utilizado datos de 84 estudiantes universitarios, seguidos en un curso online usando Moodle 2.0. Proponemos agrupar a los estudiantes, en primer lugar, a partir de los datos de una síntesis de uso de Moodle y/o las calificaciones finales de los alumnos en un curso. Luego, usamos los datos de los logs de Moodle sobre cada cluster/grupo de estudiantes separadamente con el fin de poder obtener más específicos y precisos modelos de procesos del comportamiento de los estudiantes.

  19. “Prototipo de control de riego tecnificado aplicando la tecnología del arduino”

    OpenAIRE

    CAYO CABRERA, GUIDO HUMBERTO; UNIVERSIDAD NACIONAL DEL ALTIPLANO

    2015-01-01

    El riego por aspersión se aplica el agua en suelo asperjado, o fraccionando el caudal en gotas las mismas que humedecen el terreno al tiempo que alcanzan la superficie del mismo. Se trata de un método de riego mecanizado, que asegura un preciso control de la lámina de agua aplicada en función de las condiciones edafo-climáticas y de cultivo y además permite una adecuada tecnificación de la práctica del riego. La metodología propuesta es mediante el riego automatizado y controlado vía web, que...

  20. Arquitectura software para robots móviles aplicando la metodología mdasr

    OpenAIRE

    Londoño Ospina, Nelson de J.

    2011-01-01

    Se aplica la Metodología de Desarrollo de Arquitecturas Software para Robots –MDASR, como herramienta de especificación, análisis y diseño de una Arquitectura de Control Reactiva. La metodología se apoya en métodos y lenguajes ampliamente adoptados como el P U (Proceso Unificado de Desarrollo de Software) y UML (Lenguaje Unificado de Modelado), apropiando conceptos y métodos empleados en Ingeniería Software

  1. INCLUSIÓN SOCIAL Y EL RECICLAJE EN LAS INSTITUCIONES EDUCATIVAS APLICANDO LAS TIC’S

    OpenAIRE

    Juan Calderón Cisneros; Ingrid León Baquerizo; Zoveida Zurita Murillo

    2013-01-01

    Se propone este trabajo investigativo de carácter ambiental y educativo, como una herramienta para disminuir el elevado volumen de basura que existe en los entornos de la Universidad de Guayaquil. Hay quienes desechan desperdicios, que sin embargo podrían ser de alguna manera recuperados, teniendo en cuenta que la  basura debe estar ubicada en sus respectivos recipientes, siendo separados, clasificados y distinguidos. Las necesidades educativas específicas que presentan los estudiantes con al...

  2. Tomada de Decisão Financeira: Aplicando o Processo Orçamentário

    Directory of Open Access Journals (Sweden)

    Filipe Prado Macedo da Silva

    2014-07-01

    Full Text Available Este artigo aborda a dinâmica da decisão financeira e o processo orçamentário no âmbito das empresas. Em vista da globalização e liberalização financeira, a tomada de decisão financeira ganhou importância dentro do processo de gestão empresarial, sobretudo quando afeta o fluxo de caixa e os relatórios contábeis. Algumas empresas – como a M&S Comercial – utilizam o processo orçamentário como ferramenta de apoio na gestão financeira. O orçamento serve de “guia” para os gestores da empresa. No estudo de caso, constatamos que a empresa melhorou seu desempenho econômico-financeiro ao integrar o processo orçamentário na dinâmica da tomada de decisão financeira.

  3. INCLUSIÓN SOCIAL Y EL RECICLAJE EN LAS INSTITUCIONES EDUCATIVAS APLICANDO LAS TIC’S

    Directory of Open Access Journals (Sweden)

    Juan Calderón Cisneros

    2013-12-01

    Full Text Available Se propone este trabajo investigativo de carácter ambiental y educativo, como una herramienta para disminuir el elevado volumen de basura que existe en los entornos de la Universidad de Guayaquil. Hay quienes desechan desperdicios, que sin embargo podrían ser de alguna manera recuperados, teniendo en cuenta que la  basura debe estar ubicada en sus respectivos recipientes, siendo separados, clasificados y distinguidos. Las necesidades educativas específicas que presentan los estudiantes con alguna discapacidad visual. Docentes, personal técnico y administrativo, ven en la implementación de una batería de reciclaje con tachos inteligentes, lograr una mejor clasificación, comenzando por difundir la importancia  de combinar  la tecnología con el reciclaje y por mantener el entorno universitario limpio, de tal manera que se proyecte a lo largo del tiempo y tenga un impacto en la conciencia de la comunidad, en relación al cuidado del medio ambiente. Esto generará que se tomen medidas y sistemas para manejar los desechos y sobre todo se motive a  utilizar los recursos necesarios para fomentar nuevas propuestas y generar alternativas para seguir con la cultura del reciclaje y su combinación con la tecnología.

  4. A new approach to texture measurements: Orientation distribution function (ODF) determination by Rietveld refinement

    International Nuclear Information System (INIS)

    Vondreele, R.; Larson, A.; Lawson, A.; Sheldon, R.; Wright, S.

    1996-01-01

    The preferred orientation of crystal grains within a manufactured part is described most fully by its orientation distribution function (ODF), which is a mapping of the probability of each of the possible grain orientations with respect to the exterior dimensions. Traditionally, an ODF is determined from pole figures for a relatively small number of reflections. These pole figures are measured with x-rays or neutrons using short detector scans over the center of an individual diffraction peak for a large number of different sample orientations. This is efficient if the selected diffraction peaks are reasonably strong (relative to background) and well separated, such as in pure fcc and bcc metals. It is also appropriate for constant wavelength sources where collection of individual diffraction peak intensities is a reasonably efficient use of the source. However, the traditional method is not very efficient for neutron diffraction at a spallation source such as LANSCE where the entire diffraction pattern is accessible for each sample setting. Moreover, a different approach is necessary for complicated diffraction patterns, such as from composite materials, intermetallic compounds, high T c ceramics, polyphasic minerals and polymers where there is expected to be heavy overlap of adjacent diffraction peaks. In addition, the large number of settings normally collected for an individual pole figure may not be necessary, since the entire pattern is obtained at each setting. Thus, a new method of ODF analysis needs to be developed to handle the more complex diffraction patterns obtained from modern technological materials as well as take advantage of the particular characteristics of spallation neutron sources. This project sought to develop the experimental procedures and the mathematical treatment needed to produce an orientation distribution function (ODF) directly from full diffraction patterns from a sample in a limited number of orientations

  5. Quantitative Mineralogical Analysis of Mars Analogues Using CHEMIN Data and Rietveld Refinement

    Science.gov (United States)

    Bish, D. L.; Sarrazin, P.; Chipera, S. J.; Vaniman, D. T.; Blake, D.

    2004-01-01

    Mineralogical analysis is a critical component of planetary surface exploration. Chemical data alone leave serious gaps in our understanding of the surfaces of planets where complex minerals may form in combination with H, S, and halogens. On such planets (e.g., Mars) a single chemical composition may represent a range of mineral assemblages. For example, Viking chemical analyses of excavated duricrust indicate that Mg and S are correlated and 10% MgSO4 (anhydrous weight) is a likely cementing agent. Pathfinder chemical data support a similar abundance of MgSO4 in the most altered materials. However, there are many possible Mg-sulfates with widely varying hydration states (including dehydrated and 1-, 2-, 3-, 4-, 5-, 6-, and 7-hydrates). In addition, other sulfate minerals such as gypsum (CaSO4 .2H2O) and other salts containing Cl may also exist. X-ray diffraction (XRD) has the ability to decipher mixtures of these phases that would be difficult, if not impossible to unravel using only chemical or spectral data.

  6. Analysis of the zirconia structure by 'ab initio' and Rietveld methods

    International Nuclear Information System (INIS)

    Bechepeche, A.P.; Nasar, R.S.; Longo, E.; Treu Junior, O.; Varela, J.A.

    1995-01-01

    The zirconia was doped with 0,113 mol of Mg O e 0,005 mol of Ti O 2 , and it was calcined in 1550 d eg C and it was analyzed by XRD. The results shows that pure zirconia contains 96,19% of monoclinic phase and 3,18% of cubic. However, the doping magnesia stabilizes the zirconia in 17,24 of monoclinic; 29,63 of tetragonal and 53,13% of cubic phase. The addition of titanium in zirconia gives 25,85% of tetragonal phase and 37,66% of cubic, and this shows the no stabilizing action of this transition metal. By the other side, the results with ab-initio calculating shows the same tendency resulting in the next values of total energy: pure zirconia - monoclinic -11.316,86ua; tetragonal -8742,09 ua and cubic -8742,80 ua and Zr O 2 Ti O 2 system - monoclinic -9463,02 ua, tetragonal -9459,39 ua and cubic -9459,97 ua (author)

  7. Rietveld refinement of KLaTiO4 from X-ray powder data

    Directory of Open Access Journals (Sweden)

    Bai-Chuan Zhu

    2011-04-01

    Full Text Available Potassium lanthanum titanate(IV, KLaTiO4, has been synthesized by conventional solid-state reaction. It crystallizes isotypically with the NaLnTiO4 (Ln = La, Pr, Nd, Sm, Eu, Gd, Y and Lu family. Five of the six atoms in the asymmetric unit (one K, one La, one Ti and two O atoms are situated on sites with 4mm symmetry, whereas one O atom has 2mm. site symmetry. The crystal structure can be described as being composed of single layers of distorted corner-sharing TiO6 octahedra extending parallel to (001. The layers are alternately separated by K+ and La3+ cations along [001]. The coordination number of both K+ and La3+ cations is nine, resulting in distorted KO9 and LaO9 polyhedra.

  8. Rietveld analysis of phase separation in annealed and leach tested Cm-doped perovskite

    International Nuclear Information System (INIS)

    White, T.J.

    1995-01-01

    A quantitative powder X-ray diffraction study was made of actinide doped perovskite of bulk composition Ca 0.98919 An 0.98919 Al 0.01081 O 3 where An corresponded to approximately equimolar proportions of Cm-244 and Pu-240. Sections of this sample accumulated irradiation doses up to 7.51 x 10 17 alpha decay events per gram (α/g). The damaged samples were treated in two ways. First, to establish the critical temperature for structural recovery under the reducing conditions of geological repositories, isochronal annealing was carried out at 600, 800, 1,000 and 1,100 C for 12 hours in graphite crucibles. Two groups of perovskites that had previously sustained doses of 4.5 x 10 17 and 7.4 x 10 17 α/g were tested in this way. For the former group, these conditions resulted in up to 9 weight percent (wt%) of available actinide separating as a fluorite-type dioxide near the perovskite surface. In the latter group, calcium was reduced to the metal which vaporized, leaving an excess of refractory titanium that crystallized as rutile. Second, material which has sustained doses of 1.6--4.0 x 10 17 alpha decays per gram was subjected to an MCC-1 leach test for two months at 90 C using a pH ∼ 2 solution. Under these conditions surficial perovskite dissolved congruently to release calcium into solution while the titanium reprecipitated as anatase. The implications of these results for the ultimate disposal of perovskite-bearing polyphase nuclear waste ceramics are considered

  9. Green's function for a neutral particle of spin 1/2 in a magnetic field; Funcoes de Green para uma particula neutra de spin 1/2 num campo magnetico

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Rafael de Lima [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Vaidya, Arvind Narayan [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Fisica

    2001-12-01

    Using the spectral theorema in context of Green's function in momentum space of neutrons in the magnetic field of a linear conductor with current the bound state energy spectrum and eigenfunctions are deduced. It's also pointed out that this problem present a new scenary of Green's function in non-relativistic quantum mechanics. (author)

  10. Real time stagger of electric network advanced analysis functions of a modern control center; Escalonamento em tempo real das funcoes avancadas de analise de rede eletrica de um moderno centro de controle

    Energy Technology Data Exchange (ETDEWEB)

    Zagari, Eduardo Nicola Ferraz

    1996-02-01

    This work presents two models for implementation of staggers for network analysis functions in real time for a control center. The methodology is described. Tests were performed in a electric power system of Campinas region, Sao Paulo sate - Southeast Brazil. Results are presented.

  11. Aplicando la Metodología PSP para el Desarrollo de un Sistema de Reconocimiento de Gestos

    Directory of Open Access Journals (Sweden)

    Erik Ramos Pérez

    2015-12-01

    Full Text Available MUDI es un sistema reconocedor de gestos, capaz de detectar el acercamiento, rotación y cambiar de pieza arqueológica modeladas en 3D existentes en el MureH. El sistema está contextualizado para un museo interactivo en el que los usuarios puedan descubrir las características de las piezas de una forma entretenida y divertida. Para desarrollar el sistema se utilizó PSP, el cual es una metodología encaminada al proceso personal, establecido y regido por etapas bien establecidas, una de ellas es el diseño que permite tener una buena estructura del sistema traduciéndose en una fácil implementación y control de los errores de codificación, así como el manejo de los requerimientos. Para medir la interacción, efectividad y facilidad de uso de MUDI se usaron técnicas de usabilidad, obteniendo resultados favorables, específicamente el acercamiento tuvo una calificación de 4.8, rotación de 4.0 y cambiar pieza de 4.4 en una escala del 0 al 5. Los usuarios manifestaron gran aceptación y buenos comentarios puesto que con MUDI se olvidaban de las visitas tradicionales.

  12. Optimización de la Gestión de Recursos Humanos (GRH) aplicando las soluciones SAP.

    OpenAIRE

    Arribas Martinez, Montserrat Ana

    2017-01-01

    Transformation of the HR function through technologies such as SAP HCM that facilitates the configuration of shared service centers (centralization) and which favors the digital transformation of their employees. Transformación de la Función de Recursos Humans mediante tecnología SAP HCM que facilita la configuración de centros de servicio compartidos (centralitzación) y que favorece la transformación digital de sus empleados. Transformació de la Funció de Recursos Humans mitjançant tec...

  13. HACIENDO EL BARRIO UN LUGAR MEJOR PARA VIVIR. UN ENFOQUE DE BIENESTAR SUBJETIVO APLICANDO LAS NECESIDADES HUMANAS FUNDAMENTALES

    OpenAIRE

    Papachristou, Ioanna Anna; Rosas Casals, Martí

    2015-01-01

    Los estudios del bienestar subjetivo (SWB han estado en el centro de atención scientífica en los últimos años. Con la mayoría de las personas viviendo ahora en ciudades, la necesidad de un enfoque más antropocéntrico para el estudio y la mejora de los entornos urbanos es cadavez mayor. En este sentido, definir y medir el bienestar subjetivo en contextos urbanos puede ser especialmente beneficioso en los procesos de diseño y planificación urbana. En este artículo, se presenta un método para me...

  14. Actividad física global de pacientes con factores de riesgo cardiovascular aplicando el "International Physical Activity Questionaire (IPAQ.

    Directory of Open Access Journals (Sweden)

    Angélica Zhang-Xu

    2011-07-01

    Full Text Available Objetivo: Determinar el nivel de actividad física global de los pacientes con factores de riesgo cardiovascular, mediante el cuestionario IPAQ. Material y métodos: Estudio tipo serie de casos. La población estuvo compuesta por pacientes con hipertensión arterial, obesidad y diabetes mellitus entre 35 y 69 años de edad. Se utilizó el IPAQ para medir el nivel de actividad física. Resultados: De 180 entrevistados, 122 (67,8% fueron del sexo femenino. La edad media fue 56,9 ± 8,8 años, el IMC promedio fue 29,0 ± 5,2 (18,6 - 48,5. Ciento nueve (60,5% pacientes tenían un solo factor de riesgo cardiovascular modificable por medio de actividad física, 59 (32,8% dos factores y 12 (6,7% tres factores. El tiempo promedio de diagnóstico en meses fue 34,6 (hipertensos y 51,1 (diabéticos. El nivel de actividad física fue trabajo en 30 (16,7% pacientes, en 80 (44,4% moderado y en 70 (38,9% alto. No hubo diferencias en el nivel de actividad física según la edad y sexo. Se encontró diferencia significativa en los pacientes con hipertensión quienes tenían actividad moderada (p=0,02 en los hipertensos obesos quienes tenían actividad físca alta (p=0,07. Conclusión: El nivel de actividad física global de los pacientes con factores de riesgo cardiovascular seleccionados fue predominantemente moderado y alto.(Rev Med Hered 2011;22:115-120.

  15. Eficiencia técnica y ambiental de la camaronicultura en Nayarit aplicando el índice de Malmquist

    Directory of Open Access Journals (Sweden)

    Francisco Javier Martínez-Cordero

    2015-01-01

    Full Text Available A partir de una base de datos no homogénea de 32 granjas de camarón en Nayarit para el periodo 2008-2011, el presente estudio aplica el índice de Malmquist para analizar su eficiencia técnica ET y ambientalmente ajustada EAA de una empresa o industria acuícola sostenible. Los resultados indican que los niveles de ET y EAA se han mantenido arriba de 0.80 y 0.75 en promedio, respectivamente. En general, los resultados confirman estudios regionales previos del cultivo de camarón, en función de que los rendimientos (kg/ha/año pueden ser decrecientes por causa de las enfermedades virales. Se recomienda aplicar estos indicadores de manera continua para asistir la planificación y toma de decisión tanto a nivel empresa como industria.

  16. Application of neural networks to the petroleum refining industry; Aplicando redes neurais a industria de refino de petroleo

    Energy Technology Data Exchange (ETDEWEB)

    Silva, R M.C.F. da [PETROBRAS, Rio de Janeiro, RJ (Brazil); Chaves, C. [Fundacao Gorceix, Belo Horizonte, MG (Brazil)

    2000-07-01

    Neural Network technology is an approach for describing behavior from process data, using mathematical algorithms and statistical techniques. The use of Neural Network in industrial process modeling and property estimation of feedstocks or products, is increasing in several kinds of chemical industries. This paper comments about critical successful factors, advantages and disadvantages of this methodology. Moreover, it presents some applications in Hydrotreating Process of the petroleum refining industry. In Hydrotreating of feedstocks, knowledge about characteristics of process regarding product property estimation, hydrogen consumption and removal of contaminants (sulfur, nitrogen, aromatics), are very important to process optimization, product specification and environment protection. The Neural Network technique has been used to model the behaviour of the chemical hydrogen consumption, the conversions of the hydrogenation of aromatic hydrocarbons, hydrodesulfurization and hydro denitrogenation reactions and the physical properties of product with operational conditions and feedstock properties. In addition, Neural Networks have been built to predict the cetane number of feedstocks. (author)

  17. Obtención de carmín de cochinilla aplicando hidrólisis enzimática

    OpenAIRE

    Inga Cueva, Tula Norma; Inga Cueva, Tula Norma

    2012-01-01

    El consumo de colorantes sintéticos como aditivos en la industria alimentaria, está siendo cada vez restringido, por las entidades reguladoras en aseguramiento, saneamiento en alimentos, debido a sus efectos toxicológicos, entre los que se encuentra el colorante rojo sintético azoico FD&C Red No. 2, conocido como Amaranto o E 123, (código alimentario según la Unión Europea), utilizados para dar color rojo a alimentos y cosméticos, siendo prohibido su consumo desde 1976 por la Administración d...

  18. Estudo de caso aplicando modelo para identificação de potenciais geradores de intangíveis

    Directory of Open Access Journals (Sweden)

    Rodney Wernke

    2003-12-01

    Full Text Available Relata estudo de caso em que foi aplicado o modelo Mapa para Identificação de Potenciais Geradores de Intangíveis. Após mencionar resumidamente a ferramenta utilizada, apresentam-se os procedimentos seguidos para implementar tal modelo numa empresa industrial, evidenciando os passos seguidos, as análises realizadas, os resultados alcançados e as limitações inerentes.This article reports on a case study which applied the model called Map for the Identification of Potential Intangible Asset Generators. After a summarized description of the applied tool, we present the procedures followed to implement such a model in an industrial company, disclosing the steps that were taken, the analyses carried out, obtained results and inherent limitations.

  19. INFLUENCIA DE LA COMPOSICION DE LA LECHE EN POLVO SOBRE LA ACTIVIDAD DE AGUA APLICANDO EL MODELO DE GAB

    Directory of Open Access Journals (Sweden)

    Julio Gil

    2016-01-01

    Full Text Available El presente trabajo, mediante el estudio de las isotermas de sorción a 25ºC, analiza la influencia sobre la actividad de agua (aw, de las diferentes composiciones de leche en polvo entera, descremada y reducida en lactosa. Justamente la incorporación de esta última a trabajos anteriores permite ampliar el comportamiento diferencial de los distintos componentes. E l trabajo permite establecer la relación entre el contenido de humedad de las leches en polvo estudiadas, con su actividad de agua (aw. Los resultados experimentales son evaluados con el modelo referencial de GAB , observando que el trazado de las isotermas y los parámetros del modelo se ajustan satisfactoriamente a los valores obtenidos . Se obser va la clara influencia de la presencia de los monosacáridos (glucosa y galactosa en la leche reducida en lactosa, que disminuyen la actividad a valores mayores a 0 . 4, debido a la mayor solubilidad de estos. El contenido graso en la leche entera, al no ser adsorbente se manifiesta en valores mayores para la actividad de agua.

  20. EFICIENCIA DEL TRATAMIENTO QUÍMICO EN LA PREVENCIÓN DEL TAPONAMIENTO DE GOTEROS APLICANDO AGUA RESIDUAL SANITARIA TRATADA

    Directory of Open Access Journals (Sweden)

    RAFAEL OLIVEIRA BATISTA

    2009-01-01

    Full Text Available El objetivo de este trabajo fue el de verificar la eficiencia del tratamiento químico en la prevención del taponamiento de los sistemas de goteo, cuando se usa aguas residuales sanitarias tratadas. Para la realización del ensayo experimental fue construida una plataforma de ensayos con la finalidad de abastecer cuatro unidades de irrigación por goteo con aguas residuales sanitarias, tratada y filtradas mediante un filtro de disco de 120 mesh. Fueron ensayados tres modelos de goteros (M1, M2 y M3 durante un período de 560 horas. En el tratamiento químico fueron ensayadas las concentraciones de cloro residual libre de 0; 0,4; 1,0 y 1,9 mg L-1. A partir de los resultados obtenidos se tienen las siguientes conclusiones: el agua residual sanitaria, tratada por aplicación vía sistema de irrigación por goteo propicio la formación de un biofilme en los goteros, resultante de la interacción entre colonias de bacterias y algas. La aplicación de cloro en el agua residual sanitaria tratada, minimizó el desarrollo del biofilme en el interior de los goteros y de las líneas laterales de irrigación; además, se encontró que los goteros con mayor diámetro en el laberinto y con mas de un filtro secundario (M2 y M3, son mas susceptibles al taponamiento cuando trabajan con aguas residuales tratadas. La concentración de cloro residual libre de 0,4 mg L-1 fue mas sustentable en la prevención de taponamiento por biofilme en sistemas de riego por goteo que operan con agua residual domestica tratada.

  1. Análisis sentimental de la polaridad de tweets en tiempo real aplicando algoritmos de clasificación

    OpenAIRE

    Campillos García, Eduardo

    2017-01-01

    El objetivo de este proyecto es el análisis, desarrollo y evaluación de un sistema de clasificación de polaridad sobre un producto determinado a través del contenido generado en Twitter en español. En primer lugar, se ha estudiado la situación actual en el campo del análisis sentimental (AS) y los avances más notables en esta área perteneciente al procesamiento del lenguaje natural. En segundo lugar, una vez estudiado el estado del arte, se pasará a desarrollar el código que implementarem...

  2. Conformación de equipos de proyectos de software aplicando algoritmos metaheurísticos de trayectoria multiobjetivo

    Directory of Open Access Journals (Sweden)

    Ana Lilian Infante

    2014-12-01

    Full Text Available La inadecuada conformación de equipos de proyecto de software es un problema que afecta a la industria de software a nivel mundial. Este proceso resulta complejo, teniendo en cuenta que debe considerar varios factores, como son, asignar a los roles del equipo las personas con las competencias apropiadas, considerar las incompatibilidades entre los miembros y la carga de trabajo, entre otros. Esta situación se torna más compleja en organizaciones medianas y grandes, debido a la gran cantidad de combinaciones de asignaciones posibles, por lo que esta etapa es prácticamente imposible de abordar de manera eficiente, sin la ayuda de modelos matemáticos que representen el problema a resolver lo más objetivamente posible. Este trabajo toma como antecedente un modelo que incluye tanto factores individuales como factores de equipo y plantea: maximizar las competencias de los trabajadores, minimizar las incompatibilidades entre los miembros del equipo y balancear la carga de trabajo. Incluye además, en una versión ampliada del modelo, minimizar el costo de desarrollar software a distancia. El modelo citado responde a un problema de optimización combinatorio multiobjetivo, por lo que para su solución se utilizaron algunas variantes multiobjetivo de los algoritmos metaheurísticos: Búsqueda Tabú, Recocido Simulado y Escalador de Colinas. El estudio experimental realizado ha llevado a identificar que las variantes multiobjetivo del Escalador de Colinas: Escalador de Colinas Estocático Multiobjetivo, Escalador de Colinas Multiobjetivo por mayor distancia y Escalador de Colinas Multiobjetivo con Reinicio, así como el algoritmo Recocido Simulado Multiobjetivo Multicaso son los que mejores resultados obtienen en este problema.

  3. Aplicando MDD al desarrollo de sistemas agropecuarios: Modelado de sistemas de control de calidad de granos almacenados en silobolsas

    OpenAIRE

    Martínez, Miguel; Lavié, Sebastián

    2010-01-01

    En esta tesis se aplicará una rama de la ingeniería de software denominada Desarrollo de Software Dirigido por Modelos (MDD por sus siglas en ingles: Model Driven software Development) El enfoque de Desarrollo Dirigido por Modelos (MDD), surge como un cambio del paradigma de desarrollo de software centrado en el código al desarrollo basado en modelos. Este enfoque promueve la sistematización y la automatización de la construcción de artefactos de software. Los modelos son considerados constru...

  4. Aplicando instrumentos metodológicos: alimentación en hogares urbanos de S. S. de Jujuy

    Directory of Open Access Journals (Sweden)

    Quintana, Sonia B.

    2005-01-01

    Full Text Available En el marco del proyecto "Auxología humana, nivel socioeconómico familiar y hábitos alimentarios en Jujuy (Argentina" y luego de estimar con técnicas antropométricas el estado nutricional de los alumnos concurrentes a la escuela Nº 430 del Barrio Norte de la capital jujeña, decidimos profundizar la investigación, buscando la interrelación con aspectos socioeconómicos y efectivas prácticas alimentarias. Para cumplir con este objetivo, recurrimos a instrumentos y técnicas de investigación que metodológicamente dieran cuenta de la complejidad del fenómeno. De este modo, se realizaron -en hogares seleccionados- entrevistas semiestructuradas dirigidas principalmente a aspectos sociodemográficos y socioeconómicos, y a continuación se aplicó anamnesis alimentaria a los/as encargados/as de la alimentación familiar. Luego del diseño, se efectuaron dos pruebas piloto, con la correspondiente adecuación de los instrumentos, surgiendo: a la conveniencia de aplicar primero la entrevista para facilitar el diálogo con el informante, y luego la encuesta al permitir repreguntar y corroborar respuestas antes dadas; y b la importancia de tener en cuenta la representación que el informante construye de su interlocutor y el rol que le asigna.

  5. Generación de un geoportal con análisis espacial aplicando operaciones geométricas

    OpenAIRE

    Torre Gordón, Nelson David de la

    2017-01-01

    The present project seeks to apply the acquired knowledge for the construction of a GeoPortal that allows basic geometric operations with spatial data stored in any previously loaded database. Selection of information is dynamic, allowing to assemble queries so finally encoded in GeoJSON format that can be copied or transmitted to another system in a light and fast way. In the first chapter is the theoretical framework necessary for understanding the construction of the GeoPortal. In...

  6. Application of the Wallingford Procedure to sewer network rehabilitation. Rehabilitacion de redes de alcantarillado. Aplicando el sistema de Wallingford

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, M. (Universidad Politecnica de de Cataluna. Barcelona (Spain)); Lopez, R. (Universitat de Lleida. Lleida (Spain))

    1999-01-01

    In this paper we present a summary of the Wallingford Procedure application to sewer network rehabilitation studies. After the methodology of the Procedure is revised, an application to a sewer network of Sant Boi de Llobregat is showed. Flow survey campaigns, calibration and validation processes and the alternative proposed to improve the initial situation are described. Finally, the benefits to apply such methodologies to the sewer network rehabilitation analysis are exposed. (Author) 3 refs.

  7. Application of the Wallingford Procedure to sewer network rehabilitation; Rehabilitacion de redes de alcantarillado. Aplicando el sistema de Wallingford

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, M. [Universidad Politecnica de de Cataluna. Barcelona (Spain); Lopez, R. [Universitat de Lleida. Lleida (Spain)

    1999-11-01

    In this paper we present a summary of the Wallingford Procedure application to sewer network rehabilitation studies. After the methodology of the Procedure is revised, an application to a sewer network of Sant Boi de Llobregat is showed. Flow survey campaigns, calibration and validation processes and the alternative proposed to improve the initial situation are described. Finally, the benefits to apply such methodologies to the sewer network rehabilitation analysis are exposed. (Author) 3 refs.

  8. Firework Madness: aplicando los métodos de un ingeniero de software al desarrollo de videojuegos

    OpenAIRE

    Pérez Alonso, Rubén

    2016-01-01

    Este trabajo se basa en la aplicación de métodos de desarrollo estructurado de software aprendidos durante la carrera en el ámbito del desarrollo de videojuegos, el cual por su juventud escasea de éstos. Idioma castellano.

  9. Rietveld refinement of the mixed boracite Fe1.59Zn1.41B7O13Br

    Directory of Open Access Journals (Sweden)

    Sandra Ulloa-Godínez

    2009-11-01

    Full Text Available The structural characterization of the new iron–zinc heptaborate bromide with composition Fe1.59Zn1.41B7O13Br, prepared by chemical transport is reported. A rigid-body model with constrained generalized coordinates was defined in order to hold the positions of the B atoms at reasonable interatomic distances that typically would reach unacceptable values because of the weak scattering power of boron. There are three independent sites for the B atoms of which two are tetrahedrally coordinated. The bond-valence sum around the third B atom, located on a threefold rotation axis, was calculated considering two cases of coordination of boron with oxygens: trigonal-planar and tetrahedral. The contribution of the fourth O atom to the bond-valence sum was found to be only 0.06 v.u., indicating the presence of a very weak bond in the right position to have a distorted tetrahedral coordination in favour of the trigonal-planar coordination for the third B atom. X-ray fluorescence (XRF was used to determinate the Fe/Zn ratio.

  10. Rietveld refinement of the mixed boracite Fe(1.59)Zn(1.41)B(7)O(13)Br.

    Science.gov (United States)

    Ulloa-Godínez, Sandra; Rosales, Ivonne; Bucio, Lauro; Farías, Mario H; Campa-Molina, Jorge

    2009-10-31

    The structural characterization of the new iron-zinc hepta-borate bromide with composition Fe(1.59)Zn(1.41)B(7)O(13)Br, prepared by chemical transport is reported. A rigid-body model with constrained generalized coordinates was defined in order to hold the positions of the B atoms at reasonable inter-atomic distances that typically would reach unacceptable values because of the weak scattering power of boron. There are three independent sites for the B atoms of which two are tetra-hedrally coordinated. The bond-valence sum around the third B atom, located on a threefold rotation axis, was calculated considering two cases of coordination of boron with oxygens: trigonal-planar and tetrahedral. The contribution of the fourth O atom to the bond-valence sum was found to be only 0.06 v.u., indicating the presence of a very weak bond in the right position to have a distorted tetra-hedral coordination in favour of the trigonal-planar coordination for the third B atom. X-ray fluorescence (XRF) was used to determinate the Fe/Zn ratio.

  11. Quantitative study of Portland cement hydration by X-Ray diffraction/Rietveld analysis and geochemical modeling

    Science.gov (United States)

    Coutelot, F.; Seaman, J. C.; Simner, S.

    2017-12-01

    In this study the hydration of Portland cements containing blast-furnace slag and type V fly ash were investigated during cement curing using X-ray diffraction, with geochemical modeling used to calculate the total volume of hydrates. The goal was to evaluate the relationship between the starting component levels and the hydrate assemblages that develop during the curing process. Blast furnace-slag levels of 60, 45 and 30 wt.% were studied in blends containing fly ash and Portland cement. Geochemical modelling described the dissolution of the clinker, and predicted quantitatively the amount of hydrates. In all cases the experiments showed the presence of C-S-H, portlandite and ettringite. The quantities of ettringite, portlandite and the amorphous phases as determined by XRD agreed well with the calculated amounts of these phases after different periods of time. These findings show that changes in the bulk composition of hydrating cements can be described by geochemical models. Such a comparison between experimental and modelled data helps to understand in more detail the active processes occurring during cement hydration.

  12. Strain and stress tensors of rolled uranium plate by Rietveld refinement of TOF neutron-diffraction data

    International Nuclear Information System (INIS)

    Balzar, D.; Popa, N.C.; Vogel, S.

    2010-01-01

    We report the complete macroscopic average strain and stress tensors for a cold-rolled uranium plate, based on the neutron TOF measurements. Both tensors were determined by the least-squares refinement of the interplanar spacings of 19 Bragg reflections. Based on the pole figures, as determined by GSAS, a triclinic sample symmetry of the uranium plate was assumed. Strain and stress are tensile in both the transverse and rolling directions and very small in the normal direction (through the thickness of the plate). Shear strain and stress components are compressive and of significant magnitude.

  13. Manual de revisoría fiscal con un enfoque de auditoría integral, aplicando estándares internacionales de auditoría (CW)

    OpenAIRE

    Villa-Mesa, Ronald José

    2015-01-01

    Este documento es el resultado del conocimiento adquirido tanto en la Academia como en el  ejercicio como profesional independiente y como docente de Contaduría Pública. Es de vital importancia para el ejercicio profesional del Contador-Auditor, reconocer la Revisoría Fiscal como una actividad propia de nuestra profesión, con funciones de fiscalización enmarcadas dentro de la legislación mercantil y la Ley 43 de 1990, Estatuto Orgánico de la Profesión Contable en Colombia. El Revisor Fiscal, ...

  14. E-Turismo aplicando tecnologías de geolocalización, visitas virtuales y realidad aumentada para dispositivos móviles

    OpenAIRE

    Rodríguez, Claudia Ivette

    2015-01-01

    Este documento se centra en el conocimiento de las diferentes herramientas para desarrollar un software basado en tecnologías móviles, el cual incorpora el uso de los sistemas de información geográfica, capaces de generar mapas interactivos que permiten la localización de los sitios de turismo, visitas virtuales a lugares ubica- dos en los mapas y la incorporación de tecnología de Realidad Aumentada para mejorar la información pro- porcionada a los visitantes que asisten a estos lugares; tamb...

  15. Aplicativos móveis para pessoas com deficiência aplicando-se técnicas de ciência de contexto

    Directory of Open Access Journals (Sweden)

    Elisângela de Souza Santos

    2015-12-01

    Full Text Available O presente artigo apresenta um aplicativo que fornece serviços baseados em localização – LBS – Location-Based Services. O Acessibility foi concebido utilizando Ciência de Contexto, levando em consideração o contexto no qual o usuário está inserido, para disponibilizar as informações corretas e necessárias que auxiliem o usuário portador de necessidades físicas. Além disso, auxilia o usuário portador de necessidades visuais a se localizar dentro da estrutura do IFPB, Campus Monteiro, por meio de dispositivos móveis com uso da tecnologia NFC de localização, através de ondas de curto alcance e com o auxílio de síntese de voz. Outros dois aplicativos foram desenvolvidos, com o intuito de complementar o Acessibility: o WhiteBoard e o Partitura. O primeiro é voltado a alunos cujas deficiências são auditivas e motoras. É uma espécie de tela na qual os usuários que não dominam a linguagem de sinais ou que possuem limitação física para escrever com caneta podem interagir melhor com o professor. O segundo aplicativo é voltado a alunos cuja deficiência é intelectual e/ou motora e tem por objetivo principal auxiliar alunos do Curso de Música a inserir as notas musicais napartitura. Para que fosse desenvolvido um aplicativo útil e promissor, foram feitos estudos do mercado atual,além do mapeamento dos alunos portadores de deficiências no IFPB, campus Monteiro.

  16. Análisis de la morosidad tributaria de las empresas aplicando técnicas borrosas y estadísticas. El caso de Mar del Plata

    OpenAIRE

    Mallo, Paulino E.; Artola, María Antonia; Zanfrillo, Alicia Inés; Morettini, Mariano; Galante, Marcelo Javier; Busetto, Adrián Raúl; Pascual, Mariano Enrique

    2006-01-01

    El propósito del presente trabajo es caracterizar el comportamiento de los indicadores contables de distintas empresas de pequeña y mediana envergadura del medio socioproductivo de la ciudad de Mar del Plata que puedan incidir en la determinación de la morosidad en el pago de tributos, sean nacionales, provinciales o municipales, a través de la aplicación de lógica difusa. Para ello se trabajó con una muestra de empresas representativas de distintos sectores productivos y comerciales de la ci...

  17. Desarrollo de un Sistema que Integra Componentes Biométricos Acoplado a un Esquema Transaccional Bancario Aplicando Reconocimiento de Huella Digital y Captura de Rostro

    OpenAIRE

    Fuentes Tamayo, Juan Francisco

    2008-01-01

    el presente documento contiene una solución práctica de un aplicativo el cual se encuentra actualmente en funcionamiento y permite a las instituciones bancarias reducir los fraudes utilizando el reconocimiento de huella dactilar y la captura del rostro del cliente.

  18. Aplicando Tolerancia a Fallas para la Implementación de Compensación de Saturación en Accionadores

    Directory of Open Access Journals (Sweden)

    Wilber Acuña-Bravo

    2008-07-01

    Full Text Available Resumen: En esta contribución se presenta un método para la implementación práctica de sistemas de control con compensación de saturación en los actuadores. La técnica se aplica en sistemas lineales, tomando como base un mecanismo de diagnóstico y detección de fallas. Para ello, la saturación en los actuadores es considerada como una falla en el sistema de control, la cual es detectada y aislada mediante un banco de filtros de diagnóstico de fallas, cuyos residuos son utilizados para efectuar la compensación de la saturación, proporcionando un esquema de control tolerante a esta falla particular. Así, el método exhibe ciertas propiedades de robustez frente a cambios en el funcionamiento de los actuadores. Para la síntesis de los filtros de detección de fallas se propone un método derivado de las técnicas de control óptimo robusto en H2/H∞, basado en desigualdades lineales matriciales. Para verificar las propiedades de la tećnica propuesta se presenta un ejemplo numeŕico. Palabras clave: Control tolerante a fallas, compensación anti-windup, filtros de detección defallas, desigualdades lineales matriciales

  19. APLICANDO TRAÇOS DE ACESSIBILIDADE E USABILIDADE WEB MÓVEL NA UNIVERSIDADE FEDERAL DE SERGIPE: RESPEITO À CIDADANIA E À INCLUSÃO DIGITAL

    Directory of Open Access Journals (Sweden)

    Christiano Santos Santana

    2012-12-01

    Full Text Available O crescente acesso às redes móveis expõe a UFS a uma necessidade vertente na atualização de seus padrões web anteriormente estabelecidos, remetendo às necessidades de reconfiguração de padrões objetivando favorecer a inclusão social e digital à comunidade sergipana. Essa pesquisa procurou analisar os problemas e aspectos que envolvem as questões de Acessibilidade e Usabilidade da web móvel relacionados ao site da Pós-Graduação da Universidade Federal de Sergipe (POSGRAP-UFS. Considerando-se a importância do uso desse portal para o meio acadêmico e comunitário, criou-se uma versão móvel considerando-se as normas e padrões do W3C (World Wide Web Consortium. Os resultados concretizaram melhorias na interface, layout e arquitetura na nova versão quando comparado à versão Desktop, reiterando, então, o respeito à cidadania, a inclusão digital e social. Em síntese, a presente pesquisa procurou estabelecer a equidade tecnológica, servindo de subsídio para o desenvolvimento futuro de outros sub-portais da UFS e em resposta, facilitando o acesso para os usuários do sistema, reduzindo os possíveis obstáculos nas interações pré-existentes via dispositivos móveis.

  20. Applying corpus linguistics methodology to psycholinguistics research Aplicando a metodologia da linguística de corpus à pesquisa psicolinguística

    Directory of Open Access Journals (Sweden)

    Luciane Corrêa Ferreira

    2010-01-01

    Full Text Available This study concerns the use of corpus linguistics methodology in psycholinguistics research. Ten linguistic metaphors were selected from English and American newspapers. After that, we identified the underlying conceptual metaphor based on the conceptual metaphor inventory by Lakoff and Johnson (1980, 1999. We seek to investigate what sort of knowledge EFL-learners use when trying to understand a linguistic metaphor. We examined how EFL-learners comprehend linguistic metaphors, firstly without using the context and then using the context. The sample comprised 221 Brazilian students and 16 American students at UCSC. We have also carried out an empirical research using WebCorp.Este estudo investiga o uso de metodologia de lingüística de corpus na pesquisa psicolingüística. Selecionaram-se dez metáforas em jornais ingleses e norte-americanos. Depois, identificou-se a metáfora conceptual subjacente com base no inventário de metáforas conceptuais apresentado por Lakoff e Johnson (1980, 1999. Buscou-se investigar que tipo de conhecimento os aprendizes de LE empregam ao tentar compreender metáforas. Analisou-se a maneira como os aprendizes de LE compreendem metáforas lingüísticas sem usar o contexto e, depois, utilizando o contexto. A amostra incluiu 221 estudantes brasileiros e 16 estudantes norte-americanos da UCSC.

  1. Una evaluación experimental para comparar la calidad de un software aplicando o no TDD dentro del modelo cascada

    OpenAIRE

    Goicochea Puertas, Antony Maykol

    2015-01-01

    El presente trabajo de investigación brinda un enfoque general de la aplicación de la técnica Test Driven Development (TDD), o Desarrollo Guiado por Pruebas, dentro de la metodología tradicional con enfoque Cascada, y cómo su implicancia proporciona resultados favorables durante el proceso de implementación y en consecuencia la mejora de la calidad del producto. La investigación se llevó a cabo mediante una evaluación experimental en donde se crearon cuatro (4) grupos de des...

  2. UWE en Sistema de Recomendación de Objetos de Aprendizaje. Aplicando Ingeniería Web: Un Método en Caso de Estudio

    Directory of Open Access Journals (Sweden)

    Citlali G. Nieves-Guerrero

    2014-06-01

    Full Text Available La Ingeniería Web propone nuevos métodos para el diseño de aplicaciones que se ejecutan en esta nueva plataforma que es la World Wide Web. Uno de estos métodos es UWE (UML Web Engineering, el cual aprovecha la notación estándar del UML e incorpora elementos que son propios del desarrollo Web. En este artículo se presenta un caso de estudio para el diseño de un Sistema de Recomendación de Objetos de Aprendizaje, donde el modelado básico se realiza mediante el UWE. Se modela una aplicación Web que permite a los usuarios realizar la composición de los Objetos de Aprendizaje que el mismo sistema le recomienda al usuario previo análisis de las características tanto del mismo como de los Objeto de Aprendizaje almacenados en un repositorio especializado llamado AGORA.

  3. COMPRENSIÓN DEL APRENDIZAJE DE LA PARÁBOLA EN UNDÉCIMO GRADO APLICANDO EL MODELO DE VAN HIELE

    Directory of Open Access Journals (Sweden)

    Marvin Alejandro Gaitán Hernández

    2015-04-01

    Full Text Available Esta investigación describe las dificultades de comprensión en el aprendizaje de la parábola en los estudiantes de undécimo grado y algunos aspectos de concepción del profesor de matemática desde el punto de vista de la evaluación educativa. Se trata de un estudio desde el paradigma cualitativo con un enfoque fenomenológico, donde los datos son el resultado de haber suministrado diferentes métodos de investigación como la encuestas, guías de observaciones a los estudiantes del undécimo grado y una entrevista al profesor de matemática; además de haber realizado una revisión de documentos en el currículo, programa y la planificación del profesor de matemática. El análisis por categorías se desarrolló utilizando el modelo de Van Hiele, los resultados muestran que las principales dificultades de la comprensión en el aprendizaje del contenido de la parábola, están vinculadas con las representaciones propias de los estudiantes con respecto al contenido, así como  de las dificultades de comunicación docente-discente durante el proceso de instrucción Matemática, con los cuales podemos caracterizar que los niveles del razonamiento de los estudiantes están vinculados a las diversas experiencias en el medio, permitiendo entrelazar imágenes como representaciones cognitivas o conceptuales a modelos del conocimiento matemático.SummaryThis research describes the difficulties of understanding learning the parable in junior’s school and some conception aspects of the mathematics professor from the point of view of educational assessment. This is a study from the qualitative paradigm with a phenomenological approach, where the data are a result of having provided different research methods such as surveys, observations guide to the eleventh grade students and an interview with mathematics professor; additionally, conducted a review of documents in the curriculum, program and planning of mathematics professor.The analysis by categories were developed using the Van Hiele model, the results show that the main difficulties of understanding in learning the content of the parable, are linked to the students own representation in regards to the content; as well as the difficulties in teaching-learning communication during mathematics instruction; which can be characterize; students levels reasoning are linked to the different experiences, allowing interlacing images as cognitive or conceptual representation to mathematical knowledge models.

  4. El relato de la experiencia depresiva: Aplicando los factores cuidativos de Jean Watson The expression of the depressive experience: the application of Jean Watson caring factors

    Directory of Open Access Journals (Sweden)

    Carme Ferré-Grau

    2008-03-01

    Full Text Available La elevada frecuencia de personas con trastornos depresivos en todos los niveles de atención y la complejidad de los cuidados, conlleva la necesidad, para la enfermera, de desarrollar nuevas habilidades y competencias en el abordaje integral de los pacientes y su familia. Para la comprensión de una persona con depresión es útil una mirada etnográfica que nos permita conocer la expresión subjetiva de la vivencia de la enfermedad. Un marco adecuado de referencia para ayudar en el cuidado de estos procesos es la teoría de Jean Watson sobre la Filosofía y Ciencia de los Cuidados Humanos, que a través de sus diez factores cuidativos enmarca el rol de la enfermera en "cómo tener cuidado de...". Este artículo trata de analizar, a través de los factores cuidativos de Watson, las vivencias subjetivas relacionadas con la transformación del cuerpo y la mente de las personas con depresión: el sufrimiento y el dolor, la autoimagen y el reconocimiento, la falta de energía, la pérdida de la esperanza. Se concluye que no es posible controlar el cuerpo sin controlar la mente y para ello nos puede ayudar el análisis subjetivo de la experiencia y la aplicación de los factores cuidativos.The high frequency of people with depressive disorders in Primary Health Care as well as in Hospital and the complexity of care, carry for nurses the need to develop new skills and competences to deal with complete care of patiens and families. To understand a person suffering depressive disorders may be useful an ethnographic look that let us know the subjective expression of the experience of being ill. An appropriate framework to help care is Jean Watson’s Philosophy and Science of Human Caring, trough 10 caring factors that frame the nursing role "to take care of…". This paper tries to analyze the subjective experience related to body and mind changes: suffering and pain, self-image and acceptance, lack of energy, loss of hope… in patients with depressive disorders. It is not possible to control body and not to control mind. To analyze the subjective experience trough Watson’s 10 caring factors, can be a good help.

  5. Monitoreo de los niveles de ruido ambiental en el barrio el Poblado aplicando la técnica geoestadística del kriging poligonal

    Directory of Open Access Journals (Sweden)

    Sánchez A. Luís Hernán

    2011-11-01

    Full Text Available Este artículo contiene los resultados del monitoreo del ruido ambiental (RA sobre la franja horaria diurna (LEQD en los barrios El Poblado (14 muestras y Lalinde (2 muestras, del área urbana del municipio de Medellín. El muestreo fue realizado durante 7 días en el mes de julio de 2008 y la información fue evaluada en el Centro de Geoestadística de la Universidad Nacional de Colombia. El análisis estructural de la variable ruido ambiental se basó en la regionalización de 417 datos tomados en el área urbana del municipio de Medellín, para el proyecto "Mapas acústicos y de concentración de monóxido de carbono de los municipios del área metropolitana del valle de Aburrá". La estructura variográfica fue acoplada a un modelo cúbico con rango de influencia de 780 metros y una desviación estándar real de 4.45 dB(A, la cual representa el 97% de la varianza teórica o estadística. Con base en estos resultados, se estimó para el barrio El Poblado utilizando la técnica del Kriging Poligonal, el nivel de RA entre 65 y 69 dB(A con un error relativo del 4%, que permite considerar geoestadísticamente este nivel de ruido en la categoría de probado. Por otro lado, el nivel de RA estimado para el barrio Lalinde podría variar en el intervalo 66 y 74 dB(A, con un error relativo del 38%, categorizado como un nivel de RA Posible; este último resultado indica que no es suficiente una muestra para categorizar el nivel acústico. El nivel de RA máximo estimado permite considerar el barrio El Poblado en el estándar de RA (decreto 0627/2006 adecuado para un Sector C y apropiado para zonas con usos permitidos comerciales, como centros comerciales, almacenes, locales o instalaciones de tipo comercial, talleres de mecánica automotriz e industrial, centros deportivos y recreativos, gimnasios, restaurantes, bares, tabernas, discotecas, bingos, casinos.

  6. Diseño óptimo de un sistema de distribución de agua (SDA aplicando el algoritmo Simulated Annealing (SA

    Directory of Open Access Journals (Sweden)

    Maikel Méndez-Morales

    2014-09-01

    Full Text Available En este artículo se presenta la aplicación del algoritmo Simulated Annealing (SA en el diseño óptimo de un sistema de distribución de agua (SDA. El SA es un algoritmo metaheurístico de búsqueda, basado en una analogía entre el proceso de recocido en metales (proceso controlado de enfriamiento de un cuerpo y la solución de problemas de optimización combinatorios. El algoritmo SA, junto con diversos modelos matemáticos, ha sido utilizado exitosamente en el óptimo diseño de SDA. Como caso de estudio se utilizó el SDA a escala real de la comunidad de Marsella, en San Carlos, Costa Rica. El algoritmo SA fue implementado mediante el conocido modelo EPANET, a través de la extensión WaterNetGen. Se compararon tres diferentes variaciones automatizadas del algoritmo SA con el diseño manual del SDA Marsella llevado a cabo a prueba y error, utilizando únicamente costos unitarios de tuberías. Los resultados muestran que los tres esquemas automatizados del SA arrojaron costos unitarios por debajo del 0.49 como fracción, respecto al costo original del esquema de diseño ejecutado a prueba y error. Esto demuestra que el algoritmo SA es capaz de optimizar problemas combinatorios ligados al diseño de mínimo costo de los sistemas de distribución de agua a escala real.

  7. DESARROLLO DE ESPUMANTE DE NARANJA - ESTUDIO DE LA FORMACIÓN DE BURBUJAS APLICANDO ANÁLISIS DE IMÁGENES

    OpenAIRE

    CAYETANO ARTEAGA, MARÍA CRISTINA

    2015-01-01

    [EN] Citrus production has had a great social, historic as well as economic impact in Salto Grande region. Many researches have been carried out on biotechnological transformations of orange juices. Thereby it has been developed the orange sparkling wine, obtained by second fermentation in bottle of a still orange wine, adjusting the traditional "champenoise" method. The main quality characteristic of this product is effervescence; bubbles form and ascend through the fluid mass when a bottl...

  8. DISEÑO Y CONSTRUCCIÓN DE PROTOTIPO PARA MEDICIÓN DE FLUJO DE CALOR APLICANDO CALORIMETRÍA DIRECTA: SENSADO POR FLUJO DE CALOR

    Directory of Open Access Journals (Sweden)

    OSCAR CADENA

    2008-01-01

    Full Text Available El presente artículo describe el diseño de un prototipo inalámbrico para la medición de flujo de calor, que permita a futuro aplicar el método de calorimetría directa por gradiente de flujo de calor en el área de la electrónica médica. Esta técnica se desarrolla gracias al avance y creación de sensores que permiten medir este tipo de variables, y se postula como una alternativa a las formas de medición utilizadas actualmente, presentando mejoras en su desempeño y costo. Los resultados obtenidos luego de efectuar la calibración del equipo permiten inferir que la técnica propuesta se adapta de forma eficiente y puede utilizarse como un sustituto significativamente más ventajoso comparado con los métodos existentes en la actualidad y aplicados en el seguimiento metabólico de personas.

  9. LA INFORMACIÓN DOCUMENTAL PARA LA IMPLEMENTACIÓN DE SISTEMAS DE GESTIÓN DE CALIDAD APLICANDO LA METODOLOGÍA DE SISTEMAS BLANDOS

    Directory of Open Access Journals (Sweden)

    Juan Miguel Castillo Fonseca

    2011-03-01

    Full Text Available Las necesidades de las organizaciones para conseguir eficacia, eficiencia y mejora continua en todas sus funciones y actividades que requieren el uso de documentos, conlleva a replantear las estrategias de acción e implementar sistemas de gestión de calidad que les ayuden a entender su comportamiento, su entorno y necesidades de información, tendientes a la calidad de sus procesos, productos y servicios. El presente trabajo plantea y describe, desde la concepción teórica de los sistemas y de la metodología de sistemas blandos (Soft Systems Methodology, SSM, las bases teóricas así como las ventajas y beneficios al utilizar este tipo de metodologías, que involucran a los archivos como la entidad vital que permite documentar y evidenciar todos los procesos de implementación, mantenimiento y evaluación de dichos sistemas.

  10. Aplicando o cenário de desenvolvimento de produtos em um caso prático de capacitação profissional

    Directory of Open Access Journals (Sweden)

    Mundim Ana Paula Freitas

    2002-01-01

    Full Text Available A vantagem competitiva de uma empresa de manufatura em uma economia globalizada está diretamente relacionada com sua capacidade de introduzir novos produtos no mercado, garantindo linhas de produtos atualizadas tecnologicamente e com características de desempenho, custo e distribuição condizentes com o atual nível de exigência dos consumidores. Contudo, uma grande dificuldade do gerenciamento integrado do processo de desenvolvimento de produtos é a existência de poucos profissionais capacitados a atuar eficientemente nesse processo de negócio caracterizado como multifuncional. Ou seja, profissionais possuidores de uma visão ampla e integrada deste processo. Uma forma de auxiliar esta capacitação profissional baseia-se na utilização de uma nova abordagem de aprendizagem caracterizada pela didática ativa, denominada cenário. Tal abordagem é suportada por modelos de referência, a partir dos quais se pode obter os conhecimentos necessários à execução do processo de negócio. Neste contexto, este artigo tem como objetivo abordar a questão da capacitação profissional relacionada ao desenvolvimento de produtos, empregando a abordagem de cenário. O artigo não só apresenta a caracterização do processo de desenvolvimento de produtos e seus requisitos para capacitação, como também descreve um caso prático de capacitação profissional realizado em uma empresa multinacional no Brasil, utilizando a abordagem de cenário e o método científico da pesquisa-ação.

  11. Eficiência do mercado de capitais após a adoção da IFRS no Brasil: aplicando o teste de Mishkin

    Directory of Open Access Journals (Sweden)

    Chrystian Tresman Zortea

    2017-08-01

    Full Text Available Este estudo investiga se a eficiência do mercado de capitais brasileiro com relação à incorporação das informações contábeis aos preços se alterou após a adoção das normas internacionais de contabilidade (IFRS. Para tanto, aplica-se o teste de Mishkin (1983 visando testar a hipótese de eficiência de mercado. Os resultados indicam que para o primeiro período de análise (pré-IFRS as variáveis explicativas, componentes do lucro em t tiveram um alto poder em inferir sobre os resultados do lucro futuro em t+1. Entretanto, com os resultados obtidos no teste não foi possível afirmar sobre alguma mudança no cenário da eficiência do mercado acerca das informações contábeis no mercado de capitais após a adoção dos IFRS.

  12. Aproximación a la medición del capital intelectual organizacional aplicando sistemas de lógica difusa

    OpenAIRE

    Medina, Santiago; Zuluaga, Esteban; López, Daniel; Granda, Fabián

    2010-01-01

    El capital intelectual es un componente inherente a toda empresa y lo conforma un grupo de variables que agrega valor; por lo tanto, su medición y direccionamiento estratégico son, con frecuencia, punto focal en las organizaciones del siglo XXI. Infortunadamente, por el carácter intangible y cualificativo de algunos de sus componentes, su medición y control presentan dificultades. Este trabajo propone, mediante el uso de herramientas basadas en la lógica difusa, una aproximación a la medición...

  13. Applying a new version of the Brazilian-Portuguese UPSIT smell test in Brazil Aplicando uma nova versão brasileira do UPSIT no Brasil

    Directory of Open Access Journals (Sweden)

    Laura Silveira-Moriyama

    2010-10-01

    Full Text Available Standardized olfactory tests are now available to quantitatively assess disorders of olfaction. A Brazilian-Portuguese version of the University of Pennsylvania Smell Identification Test (UPSIT is currently being developed specifically for the Brazilian population. The most recent Brazilian-Portuguese version of the UPSIT (UPSIT-Br2 was administered to 88 Brazilian subjects who had no history of neurological or otorhinolaryngological disease. UPSIT-Br2 scores decreased with age, were lower in men than in women, and were lower in subjects with lower income. The degree to which the poorer performance of subjects with lower socio-economic status reflects lack of familiarity with test items is not known. Although this version of the UPSIT provides a sensitive and useful test of smell function for the Brazilian population, a revision of some test items is needed to achieve comparable norms to those found using the North American UPSIT in the United States.Testes padronizados já estão disponíveis para testagem do olfato e uma versão em Português esta sendo desenvolvida para o University of Pennsylvania Smell Identification Test (UPSIT, especificamente para a população brasileira. A versão mais recente deste teste (chamada UPSIT-Br2 foi aplicada a 88 sujeitos brasileiros que não tinham história de qualquer problema neurológico ou otorrinolaringológico. Compatível com dados prévios da literatura, a performance no UPSIT-Br2 decaiu com a idade e foi inferior no genero masculino. Os resultados foram mais baixos em participantes de menor nível sócio-econômico e a relação deste achado com a falta de familiaridade para com os itens do teste não é conhecida. Apesar desta versão do UPSIT poder ser útil para o teste da função olfativa da população brasileira, a revisão de alguns itens se faz necessária para alcançar valores comparáveis aos dados normativos norte-americanos.

  14. GERENCIANDO INTANGIBLES EN EMPRESAS DE SOFTWARE APLICANDO EL PROCESO DE ANÁLISIS POR JERARQUÍAS Y EL CUADRO DE MANDO INTEGRAL

    Directory of Open Access Journals (Sweden)

    PATRICIA GONZÁLEZ GONZÁLEZ

    2011-01-01

    Full Text Available El objetivo de este artículo es presentar una metodología que a partir de la integración de dos herramientas como son el Analytic Hierarchy Process (AHP y el Balanced Scorecard (BSC, permita gerenciar los intangibles en empresas basadas en el conocimiento como es el caso de las empresas de software. Se efectuó un estudio de caso, cuyos resultados permitieron identificar los intangibles que son prioritarios para este tipo de empresas. Por otro lado, se observó coherencia entre los intangibles prioritarios y la especificidad que cada una de las empresas presenta en cuanto a su razón de ser: diseño, mantenimiento y comercialización. Se concluye que la integración del AHP y el BSC da origen a una metodología que facilita la gestión de los intangibles, a partir de la jerarquización y monitoreo de desempeño y logro de los mismos expresados en objetivos estratégicos e indicadores en empresas de software.

  15. Categorización automática de tweets sobre el tema político electoral aplicando algoritmos de clasificación supervisada

    OpenAIRE

    Cumbicus Pineda, Oscar Miguel

    2017-01-01

    Actualmente el incremento del uso de redes sociales para compartir contenidos y opiniones de diferentes índoles permite tener un gran volumen de información. Twitter, es una de las redes sociales más utilizadas por su fácil acceso y manejo. Los usuarios de esta red se convierten no solamente en actores pasivos de recepción y consumo de información, sino también en generadores de contenidos. El análisis de tweets requiere de un proceso sistemático para su recolección, transforma...

  16. Aplicando un Algoritmo Genético para Balancear Carga Dinámicamente en Ambientes Distribuidos Orientados a Objetos (CORBA)

    OpenAIRE

    Fco. Javier Luna Rosas; Rene Tristán Ávila; J. de Jesús Martínez Pedroza

    2003-01-01

    Balancear Carga significa como distribuir procesos entre procesadores conectados por una red, para equilibrar la carga de trabajo entre ellos. Los algoritmos de planeación distribuida global pueden ser divididos en dos grandes grupos: algoritmos de balanceo de carga dinámica y algoritmos de balanceo de carga estática. Los algoritmos de balanceo de carga estática, también referenciados como planeación de tareas obtienen la localización de todos sus requerimientos antes de comenzar su ...

  17. Aplicando Scrum y Prácticas de Ingeniería de Software para la Mejora Continua del Desarrollo de un Sistema Ciber-Físico

    Directory of Open Access Journals (Sweden)

    Gabriela Sobrevilla

    2017-05-01

    Full Text Available En la actualidad, presiones competitivas fuerzan a las compañías a desarrollar productos y servicios en el menor tiempo posible. Una alternativa para lograrlo es el uso de métodos de desarrollo ágiles como Scrum. A pesar de que Scrum ha sido usado exitosamente en muchos dominios de aplicación, no existe un claro entendimiento sobre cómo aspectos específicos del desarrollo de Sistemas Ciber-Físicos deben ser tratados cuando se utiliza este método sin que afectar la agilidad. En este artículo se describen algunos problemas técnicos y organizacionales que surgieron durante el desarrollo de un Sistema Ciber-Físico y cómo se resolvieron incorporando algunas prácticas de ingeniería de software. Compartiendo esta experiencia se pretende ayudar a otros equipos de desarrollo a ganar un mejor entendimiento sobre algunos de los problemas relacionados a este tipo de sistemas y cómo enfrentarlos con las prácticas descritas.

  18. Diseño e implementación de un sistema de inventarios, aplicando simulación Montecarlo, en una empresa de Servicios Petroleros

    OpenAIRE

    Montenegro López, Roberto Rodrigo

    2011-01-01

    184 hojas : ilustraciones, 29 x 21 cm + CD-ROM 3478 En el capítulo I, se concentra el marco teórico, donde se habla de los inventarios como: tipos de inventarios, gestión de inventarios, modelos de inventarios, medidas de desempeño y pronósticos. Entre los tipos de inventarios, más comunes están los inventarios de materias primas, productos en proceso y producto terminado. La gestión de inventarios, da a conocer el análisis ABC que permite clasificar los productos de acuerdo al consumo mo...

  19. Un Estudio del Comportamiento de los Ingresos Tributarios de la Provincia de Tucumán Aplicando un Análisis de Serie de tiempo

    Directory of Open Access Journals (Sweden)

    María Cristina Leguizamón

    2003-06-01

    Full Text Available Muchos tipos de datos en economía son un conjunto de observaciones respecto a una misma variable, realizadas en momentos equidistantes de tiempo, que se los presenta como una "serie de tiempo". Las series de tiempo se analizan para poder hacer predicciones respecto a la marcha de la economía, resultando la utilidad de dichas predicciones, en función de la precisión lograda. El objetivo de este trabajo es analizar la serie correspondiente a la recaudación impositiva mensual total de la provincia de Tucumán durante el período comprendido entre enero de 1988 y julio de 2002 a fin de visualizar si dicha recaudación se ha visto afectada por la situación económica financiera de la Argentina en la última década, a través de un análisis de series de tiempo. El análisis está enfocado en la introducción de una tendencia estocástica en el modelo, de modo de considerar los cambios estructurales de la economía en los últimos años. Desde el punto de vista estadístico, el mecanismo para modelar una tendencia estocástica es la forma de espacio de estado. Este enfoque permite (1 estimar los parámetros desconocidos a través de la descomposición del error de predicción y (2 que las predicciones sean calculadas extendiendo el filtro de Kalman. Además el algoritmo de suavizado basado en el enfoque de Kalman proporciona un estimador óptimo de la tendencia en cada punto del período muestral.

  20. Estimación de Armónicos sobre FPGA Aplicando Estadística de Orden Superior y Convolución

    OpenAIRE

    Miguel Enrique Iglesias Martínez; Bárbaro Maykel López-Portilla Vigil; Fidel Ernesto Hernández Montero

    2013-01-01

    En este trabajo se propone la implementación sobre FPGA de un modelo conjunto que aplica las características estadísticas (cumulantes) de orden superior, combinadas a un proceso de convolución, lo cual permite obtener las componentes espectrales con su amplitud, frecuencia y fase originales, contaminadas por un proceso de ruido de distribución normal, aún desconociendo la señal de entrada. El aporte fundamental del mismo radica en la implementación del modelo propuesto sobre una arquitectura ...

  1. Application of powder X-ray diffraction and the Rietveld method to the analysis of oxidation processes and products in sulphidic mine tailings

    DEFF Research Database (Denmark)

    Balic Zunic, Tonci; Katerinopoulou, Anna; Edsberg, Anders

    2011-01-01

    silica were applied as proper models. The procedures developed on test mixtures result in estimated errors of determination typically lower than 2 wt%. The approach was applied to the analysis of the complex problem of estimating mass balance in oxidized mine tailings from the Nanisivik Mine, Nunavut......, Canada revealing an oxidized proportion of 9 % of total pyrite content in the well drained tailings during a period of 8 years and a negligible oxidation in the water-covered tailings....

  2. Rietveld refinement of the langbeinite-type mixed-metal phosphate K2Ni0.5Zr1.5(PO43

    Directory of Open Access Journals (Sweden)

    Igor V. Zatovsky

    2014-07-01

    Full Text Available Dipotassium [nickel(II zirconium(IV] tris(orthophosphate was prepared from a self-flux in the system K2O–P2O5–NiO–K2ZrF6. The title compound belongs to the langbeinite family and is built up from two [MO6] octahedra [M = Ni:Zr with mixed occupancy in ratios of 0.21 (4:0.79 (4 and 0.29 (4:0.71 (4, respectively] and [PO4] tetrahedra interlinked via vertices into a 3∞[M2(PO43] framework. Two independent K+ cations are located in large cavities of the framework, with coordination numbers to O2− anions of nine and twelve. The K, Ni, and Zr sites are located on threefold rotation axes.

  3. Valoración ecosistémica a partir del uso de métricas de paisaje aplicando sistemas de información geográfica en cultivos de palma africana

    Directory of Open Access Journals (Sweden)

    Claudia Mayelly Ramírez Cano

    2016-12-01

    Full Text Available La valoración del paisaje es una herramienta que contribuye en los procesos de gestión y planificación mediante la generación de indicadores que permiten caracterizar las condiciones del territorio. En esta investigación se analizaron las métricas de paisaje a partir de: área de la clase (CA, área total del paisaje (TA, porcentaje del área total del paisaje (PLAND, número de parches de la clase (NP y densidad de parches (PD, relación área-perímetro promedio (MPAR, índice de diversidad de Shannon (SDI e índice de equitatividad de Shannon  (SEI y la valoración se realizó con la adaptación metodológica de los autores Paula Másmela y Alejandro Gómez, dicha adaptación permitió discernir sobre las características y calidad del paisaje en el municipio de Puerto Wilches, Santander, Colombia, durante el periodo entre 1987 y 2015.  La valoración paisajística se realizó a partir de imágenes de satélite mediante análisis multitemporal de las coberturas para cuantificar y caracterizar las transformaciones paisajísticas dadas en el territorio. Los resultados obtenidos muestran que en el año 1987 el paisaje era más dinámico, constituido por variedad de coberturas y ecosistemas; mientras en 2015 existe una implementación a gran escala del monocultivo de palma africana que rompe con la estructura paisajística, sin embargo, el resultado de calidad visual arrojó clasificación media, que evidencia la importancia de realizar una revisión a fondo sobre las actuales políticas de ordenación del territorio.

  4. Determinación de peligros volcánicos aplicando técnicas de evaluación multicriterio y SIG en el área del Nevado de Toluca, centro de México

    OpenAIRE

    Aceves-Quesada, Fernando; López-Blanco, Jorge; Martin del Pozzo, Ana Lillian

    2006-01-01

    Los estudios de peligros volcánicos a corto y largo plazo mediante la utilización de tecnologías geográficas generan un conocimiento útil para el análisis, planeación y manejo de las crisis volcánicas. El Nevado de Toluca es un estratovolcán que a lo largo de su historia geológica ha tenido erupciones violentas acompañadas de flujos piroclásticos, lahares, avalanchas, caída de cenizas y pómez. Durante los últimos 50,000 años, este volcán ha presentado al menos ocho erupciones vesuvianas, cuat...

  5. Evaluación de los anuncios de alimentos procesados y ultraprocesados en la televisión en España aplicando el modelo de Semáforo Nutricional de Reino Unido

    Directory of Open Access Journals (Sweden)

    Félix Alexis Morales Rodríguez

    2017-10-01

    Full Text Available Introducción: dado el interés en disminuir el consumo de alimentos de bajo valor nutricional, el propósito del presente estudio fue evaluar la calidad nutricional de los anuncios de alimentos procesados y ultraprocesados en la televisión en España. Material y métodos: estudio transversal, observacional y descriptivo de los anuncios televisivos de alimentos procesados y ultraprocesados en los cuatros canales generalistas y el canal infantil con publicidad y mayores audiencias. Se analizó un día entre semana y otro de fin de semana, en las dos franjas horarias de mayor audiencia media. Para la evaluación se consideró la frecuencia de repetición de los anuncios de cada producto registrado y se utilizó la versión vigente del Semáforo Nutricional (SN de Reino Unido, estableciéndose el perfil de SN mayoritario de cada canal y del conjunto. Resultados: el 19,6% de los anuncios emitidos se correspondió con alimentos procesados y ultraprocesados. El canal infantil Boing presentó una presión de este tipo de publicidad elevada (36,8%, duplicando a la media de los canales generalistas (17,4%. El SN mayoritario del conjunto de canales fue rojo para grasas y grasas saturadas, y verde para azúcares y sal. El canal infantil Boing presentó el peor perfil nutricional, siendo rojo para todos los nutrientes analizados, excepto para la sal, que fue ámbar, mientras que Telecinco presentó el mejor, siendo verde para todos los nutrientes analizados. Conclusiones: la publicidad de los alimentos procesados y ultraprocesados en la televisión en España presenta una calidad nutricional general mejorable, especialmente en el canal infantil analizado, lo que aconsejaría adoptar políticas más eficaces que limiten la exposición de los niños a los anuncios de productos poco saludables.

  6. Análisis de la morosidad tributaria de las empresas aplicando técnicas borrosas y estadísticas. El caso de Mar del Plata. Segunda parte

    OpenAIRE

    Mallo, Paulino E.; Artola, María Antonia; Zanfrillo, Alicia Inés; Morettini, Mariano; Galante, Marcelo Javier; Busetto, Adrián Raúl; Pascual, Mariano Enrique

    2007-01-01

    Continuando con el objetivo buscado en el trabajo presentado en el Coloquio de Estadística del año 2006, en esta oportunidad aportamos una nueva ponencia que amplía las metodologías utilizadas en aquella oportunidad, a la vez que profundiza las conclusiones a las que se había arribado entonces. El propósito es caracterizar el comportamiento de los indicadores contables de distintas empresas de pequeña y mediana envergadura del medio socio-productivo de la ciudad de Mar del Plata que puedan in...

  7. Evaluación energética industrial de las instalaciones textiles de Delltex Industrial S.A. planta Cumbayá aplicando la norma NTE INEN-ISO 50001:2012

    OpenAIRE

    Taipe Vilaña, Walter Edwin

    2016-01-01

    Este proyecto presenta la aplicación de la norma NTE INEN-ISO 50001:2012, en la realización de la evaluación energética de las instalaciones de Delltex Industrial S.A. ubicada en Cumbayá; la cual inicia con la esquematización del proceso productivo de la planta para construir los diagramas de flujo de proceso, insumos y energéticos; descrito el proceso de la planta, se realiza el balance global de energía mediante la caracterización del consumo con la identificación de los principales usuario...

  8. Diseño y elaboración de un prototipo de monitor de signos vitales aplicando métodos no invasivos con comunicación de datos a dispositivos móviles

    OpenAIRE

    Tintín Durán, Edisson Ismael

    2015-01-01

    El documento consiste en el diseño y desarrollo de un prototipo de monitor de signos vitales que se comunique con dispositivos móviles Android, con el fin de proponer un método automatizado de la adquisición de datos sin la necesidad de la presencia de un personal de salud. The document consists of the design and development of a prototype Vital Signs Monitor to communicate with Android mobile devices, in order to propose an automated method of data acquisition without requiring the presen...

  9. Estudio de factibilidad para la creación de una Escuela de cocina en el Valle de Tumbaco, aplicando las nuevas tendencias de la administración, enfocadas en el cliente

    OpenAIRE

    Pérez Herrera, Jenny Gabriela

    2008-01-01

    La creación de una escuela de cocina se decidió después de realizar una encuesta piloto, la recopilación hecha a un gran grupo de personas del Valle de Tumbaco, preguntando cuáles las necesidades básicas y destacadas. Las mujeres que en su gran mayoría son profesionales o estudiantes universitarias plantearon que les gustaría aprender a cocinar, pero no de una forma tradicional sino dinámica. El tema propuesto ha sido planteado considerando que el estudio de pre factibilidad enfoca to...

  10. Predictive analysis on the electric energy distribution systems reliability: applying the synerGEE system; Analisis predictivo de la confiabilidad en los sistemas de distribucion de energia electrica: aplicando el sistema synerGEE

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez Andrade, Carlos

    2008-12-15

    Electrical distribution systems ought to deliver electric power as economical as possible with an acceptable degree of service quality and continuity. Nevertheless, their faults represent one of the main causes of customer's unavailability. At the moment, a wide range of determinist criteria in the improvement of systems reliability based on past behavior are used, but they do not respond to the stochastic nature of system behavior, and are applied without an adequate balance between reliability and economy. In order to obtain this balance a minimum cost planning methodology that considers the predictive analysis of different investment alternatives in addition to the past behavior of the system is required, which guarantees that the economic resource available and limited will be used to gather the greater possible reliability degree. In this work this problem is approached with the fundamentals and methodologies needed to assess the design effects and operative criteria over the main reliability indexes used by the main utilities around the world, with emphasis on the need to optimize economical resources. The use of the system SynerGEETM, is investigated, probing it as a useful tool for the predictive reliability analysis. Due to the lack of experience that exists in Mexico with this type of analysis, distribution engineers has to become familiar with the concepts of the reliability engineering, their application to establish distribution systems models, and acquiring the ability to use the modern simulation tools, allowing them to evaluate the behavior of these systems with enough analytical rigor. In this sense a serial of well known study cases are presented to help them in this labor. [Spanish] Los sistemas de distribucion de energia electrica deben satisfacer la demanda de energia electrica de la forma mas economica posible, con un grado de calidad y continuidad aceptable. Sin embargo, sus fallas son una de las principales causas de indisponibilidad en el suministro de esta fuente de energia a los usuarios. Las mejoras a la confiabilidad, que se practican actualmente en Mexico, se basan en criterios deterministas, que no responden a la naturaleza estocastica del comportamiento de los sistemas, y se aplican sin que exista un balance adecuado entre confiabilidad y economia. Lograr este equilibrio requiere aplicar una metodologia de planeacion de costo minimo que considere, ademas del comportamiento historico del sistema, una evaluacion ante diferentes alternativas de inversion, garantizando que los recursos economicos disponibles y limitados, se utilicen de manera optima para lograr el mayor grado de confiabilidad posible. En este trabajo se presentan los fundamentos y las metodologias requeridas para evaluar los efectos del diseno y de los criterios operativos sobre la confiabilidad de los puntos de carga del sistema de distribucion y su relacion con los principales indices de confiabilidad utilizados por las empresas electricas en el mundo, haciendo enfasis en la necesidad de evaluar el costo de reforzar estos indicadores. Se investiga el uso del sistema de analisis de sistemas de distribucion SynerGEE, como una herramienta de simulacion util para evaluar la confiabilidad de los sistemas de distribucion de manera predictiva. La falta de experiencia que se tiene en Mexico con este tipo de analisis, requiere que los ingenieros de distribucion se familiaricen con estos conceptos, para aplicarlos en el diseno de sus sistemas de distribucion, con la habilidad para utilizar las herramientas de simulacion modernas. Con este proposito se plantean una serie casos de estudio sencillos, con los cuales se sentiran comodos para introducirse en la exploracion y aprendizaje de este tema.

  11. EL GOBIERNO CORPORATIVO EN LA NUEVA EMPRESA DE BASE TECNOLÓGICA APLICANDO LAS CONCLUSIONES DE UNA REVISIÓN SISTEMÁTICA DE LA LITERATURA A LAS EMPRESAS SPIN-OFF DE LA UNIVERSIDAD POLITÉCNICA DE VALENCIA

    OpenAIRE

    HERNÁNDEZ GUILLAMÓN, IRENE

    2015-01-01

    En el contexto económico actual de crisis – postcrisis y tras haber quedado patente las limitaciones e ineficiencias que muchas veces han afectado a los órgano de Gobierno de las empresas, se ha incrementado la presión sobre el estudio de dichas estructuras y mecanismos. De forma paralela, durante los últimos años se ha promovido como motor de recuperación económica el emprendimiento, especialmente aquel dentro de sectores con un alto valor añadido. El presente trabajo propone aunar estas ...

  12. Los centros de incubación de negocios y la gestión de redes: exploración empírica aplicando el análisis de redes sociales

    Directory of Open Access Journals (Sweden)

    Noel M. Muñiz

    2013-11-01

    Full Text Available Las incubadoras de negocios consideran la gestión de redes como un elementocrítico para generar capacidades competitivas; el modelo más evolucionadoactualmente es conocido como «incubación en red». Sin embargo, diversos investigadoresaducen la necesidad de relacionar estos dos constructos positivamente. El estudioexplora la aplicación de la «teoría de redes» al campo del emprendimiento a travésde las interconexiones, entre incubados y grupos de interés, y las magnitudes propiasde dicha teoría. La muestra comprende 18 empresas asistidas bajo la modalidad de«acompañamiento externo». Su originalidad radica en explorar las claves del éxito dela gestión de incubación desde la perspectiva del análisis de redes. Por último, se aportauna serie de recomendaciones para futuros estudios.

  13. Evaluación del nivel de madurez y capacidad del sistema integrado de control hidrocarburífero (SICOHI) del Ministerio de Minas y Petróleos aplicando el marco de referencia Cobit.

    OpenAIRE

    Jiménez Amoroso, María Belén; Pallo Navas, Carlos Andrés

    2010-01-01

    Conceptualización del sistema integrado de control hidrocarburífero (Secohi). Descripción del proceso de gestión tecnológica y soporte al sistema integrado de control hidrocarburífero. Descripción de los procesos usuarios. Marco teórico. Modelo de madurez. Requerimientos del negocio. Nivel de madurez del sistema. Manejo de metodología COBIT. Evaluación del sistema integrado de control hidrocarburífero (SICOHI).

  14. EFICIÊNCIA DOS MERCADOS FUTUROS DE COMMODITIES AGRÍCOLAS APLICANDO-SE O TESTE DE COINTEGRAÇÃO./ EFFICIENCY OF THE AGRICULTURAL COMMODITY FUTURES MARKET BY APPLYING THE COINTEGRATION TEST.

    Directory of Open Access Journals (Sweden)

    Jorge Harry Harzer

    2012-08-01

    Full Text Available Este artigo tem o objetivo de testar a forma fraca de eficiência do mercado futuro brasileiro dacommoditie agrícola café arábica, usando a técnica de cointegração a fim de verificar se os preços futuroscorrentes são estimadores não viesados dos preços à vista esperados para o futuro. Para isso, utiliza asséries históricas de janeiro de 2005 a maio de 2011 dos preços futuros, que foram coletados na Bolsa deMercadorias e Futuros – BM&F, e os preços à vista calculados pelo CEPEA/ESALQ/USP. As métricas utilizadassão os testes ADF de Dickey e Fuller para detectar a presença de raiz unitária e o teste de cointegraçãode Johansen para verificar a existência de um relacionamento de longo prazo. Os resultados indicaram anão estacionariedade das séries de preços e a presença de cointegração. Porém, o teste dos parâmetrosα = 0 e β = 1 da regressão que comprovam a eficiência fraca e não viés encontraram indícios estatísticosde não eficiência de mercado, bem como da presença de um viés indicando a existência de um prêmioassociado ao risco./ This article aims at testing the weak form of efficiency of the commodity futures market in Arabicacoffee farming using the cointegration technique in order to check if the current futures prices arebiased estimators of spot prices expected for the future. Thereto it uses the futures prices time seriesfrom January 2005 to May 2011, which were collected in the Commodities and Futures Exchange - BM &F and spot prices, calculated by CEPEA / ESALQ / USP. Dickey and Fuller’s ADF tests are the metrics usedto detect the presence of unit root and Johansen’s cointegration test is used to verify the existence ofa long term relationship. The results indicated the non-stationarity of price series besides the presenceof cointegration. However, regression parameters testing α = 0 e β = 1 proves that weak efficiency andnon-biased found statistical evidence of non-market efficiency. Moreover, the presence of a bias indicatingthe existence of a premium associated with risk was also found.

  15. System for calibration of instruments of x-ray measurement (CIR-X) applying the PGCS; Sistema para calibracion de instrumentos de medicion de rayos X (CIR-X) aplicando el PGCS

    Energy Technology Data Exchange (ETDEWEB)

    Gaytan G, E.; Rivero G, T.; Cruz E, P.; Tovar M, V.M.; Vergara M, F.J. [ININ, 52750 La Marquesa, Estado de Mexico (Mexico)]. e-mail: egg@nuclear.inin.mx

    2007-07-01

    The Department of Metrology of Ionizing Radiations of the ININ carries out calibration of instruments for X-ray measurement that determine the operation parameters in X-ray diagnostic machines of the health and private sectors. To facilitate this task, the Department of Automation and Instrumentation developed a system for acquisition and signals processing coming from a reference voltage divider with traceability at NIST that is connected directly to the X-rays tube. The system is integrated by the X-ray unit, the X-ray measurement equipment Dynalizer IIIU of RADCAL, a data acquisition card, a personal computer and the acquisition software and signals processing. (Author)

  16. Metodología de planificación de cadenas de suministro de productos de consumo masivo de alimentos envasados, aplicando los conceptos lean y agile, en el Perú

    OpenAIRE

    Hernández Bazo, Carlos Alberto

    2011-01-01

    En la presente tesis doctoral, se desarrolla y se valida una metodología de planificación de la red de distribución de cadenas de suministro de la industria de consumo masivo de alimentos envasados, que se ha estructurado tomando como base los conceptos lean y agile, desarrollados por diferentes autores en los últimos veinte años. Se define, también, las ventajas y limitaciones al aplicar esta metodología y compararla con la metodología de planificación tradicional, a fin de determinar si...

  17. Metodología de planificación de cadenas de suministro de productos de consumo masivo de alimentos envasados, aplicando los conceptos Lean y Agile (Parte II)

    OpenAIRE

    Hernández Bazo, Carlos

    2014-01-01

    El presente trabajo muestra un segundo avance de la Investigación Doctoral que desarrolla la metodología de planificación que utiliza los conceptos Lean y Agile en la industria de Consumo masivo de alimentos envasados .Este trabajo presenta los resultados logrados luego de un estudio de investigación del tipo exploratorio descriptivo, con diseño del tipo mixto que muestra; una evaluación previa cuantitativa experimental de laboratorio y una evaluación posterior cualitativa.

  18. Deshidratación Osmótica de Láminas de Mango cv. Tommy Atkins Aplicando Metodología de Superficies de Respuesta Osmotic Dehydration of Mango Pieces cv. Tommy Atkins Applying Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    José Edgar Zapata Montoya

    2012-06-01

    Full Text Available Resumen. Se aplicó el método de superficies de respuesta para estudiar el efecto de la temperatura y la concentración de ácido cítrico sobre la deshidratación osmótica de láminas de mango cv. Tommy Atkins. La deshidratación osmótica se evaluó en términos del porcentaje de pérdida de peso (%PP, ganancia de sólidos (%GS, pérdida de humedad (%PH, y pérdida de actividad acuosa (%PAw. Los resultados indicaron que tanto la temperatura como la concentración de ácido cítrico, tuvieron efectos significativos sobre el %PP, %PH, y %PAw, en el rango de condiciones evaluado (25 ºC - 45 ºC y (1% - 3% respectivamente. La adición de ácido cítrico en la solución osmodeshidratante redujo de forma significativa los recuentos de microorganismos, sin afectar las características sensoriales del producto. Los niveles máximos de los parámetros cinéticos se consiguen después de 4 h de proceso, con temperaturas de 45 ºC y concentraciones de ácido cítrico de 3% p/p, siendo 47,62%, 53,07% y 6,04%, los valores óptimos para %PP, %PH y %PAw respectivamente, con aceptación sensorial del 100 % y reducciones en los recuentos microbianos de más de dos ciclos logarítmicos.Abstract. The response surface methodology was applied to study the effect of temperature and concentration of citric acid in osmotic dehydration of cv. Tommy Atkins mango pieces. Osmotic dehydration was evaluated in terms of the percentage of weight reduction (%WR, solid gain (%SG, water loss (%WL and reduction of water activity (%RWA. The results indicated that the temperature and the concentration of citric acid had significant effects on the (%WR, (%WL and (%RWA in the range of conditions evaluated (25 °C- 45 ºC and (1% - 3% respectively. The addition of citric acid in the osmodehydrating solution significantly reduced the microorganism recount without affecting the sensory characteristics of the product. The maximum values of kinetic parameter are reached after 4 h of processing, with temperature of 45 ºC and concentration of 3%. The optimum values for %WR, %WL y %RWA, were 47.62%, 53.7% y 6.04%, respectively. The sensory acceptance was of 100% and reductions in the microbial recount of more than two logarithmic cycles.

  19. Comparative analysis of the use of biomass with conventional generation technologies by applying eco-efficiency; Analise comparativa da utilizacao da biomassa com tecnologias convencionais de geracao aplicando eficiencia ecologica

    Energy Technology Data Exchange (ETDEWEB)

    Lora, Electo Eduardo Silva [Universidade Federal de Itajuba (UNIFEI), MG (Brazil)], e-mail: electo@unifei.eu.br; Salomon, Karina Ribeiro [Universidade Federal de Itajuba (UNIFEI), MG (Brazil). Nucleo de Estudos em Sistemas Termicos], e-mail: karinas@unifei.edu.br

    2004-07-01

    The world's concern regarding the reduction atmospheric emissions, due to the global warming, it is a subject that is being quite discussed. A parameter that evaluates the environmental impact considering the emissions of CO{sub 2}, SO{sub x}, NO{sub x} and PM in an integral way and comparing to the international air quality standards that are in force is called ecological efficiency ({epsilon}). This paper intends to compare environmental impacts of the atmospheric pollution due to technologies that use the biomass as fuel with conventional and advanced technologies of electricity generation. It is also evaluated the advantages of the use of the cogeneration starting from the biomass. The most important results that were obtained are comparative graphs confirming that the use of the biomass as energy source is a good option from the ecological point of view, when pollution control methods are used. (author)

  20. Comparación del contenido de licopeno, β-caroteno y fenoles en tomate aplicando un manejo hortícola convencional y ecológico y hongos formadores de micorrizas arbusculares (HFMA

    Directory of Open Access Journals (Sweden)

    Christian Ulrichs

    2008-04-01

    Full Text Available Los frutos de tomate son ricos en compuestos antioxidantes que han sido reconocidos como benéficos para la salud humana y los manejos hortícolas pueden influir la concentración de estos metabolitos secundarios. Los hongos formadores de micorrizas arbusculares (HFMA pueden influir en la absorción de nutrientes y agua por la planta. El estudio, llevado a cabo en invernadero, examinó si tomates ‘Vitella F1’, cultivados orgánicamente, se diferencian en su contenido de licopeno, β-caroteno y fenoles totales en los frutos de tomates manejados convencionalmente. Los tratamientos fueron los métodos de cultivo: convencional, orgánico, convencional+HFMA y orgánico+HFMA. Comparando los métodos de cultivo, no se encontró ninguna diferencia significativa para los parámetros nutritivos analizados; solamente tomates manejados orgánicamente tuvieron un contenido de fenoles totales un poco menor. En los dos métodos de cultivo, las plantas inoculadas con HFMA (Glomus sp. formaron contenidos más altos de licopeno en los frutos que los sin inoculación. Los tomates manejados orgánicamente aumentaron su concentración de β-caroteno y de los fenoles totales a consecuencia del tratamiento con HFMA. La aplicación de HFMA aumentó el peso fresco del fruto pero no el del tallo. El aumento del crecimiento y la adquisición de los nutrientes en tomate demostraron el potencial de la colonización con HFMA para incrementar la concentración de compuestos antioxidantes en el fruto. La mosca blanca (Trialeurodes vaporariorum fue controlada exitosamente con la aplicación de la tierra diatomaceous Fossil Shield® 90 en los tratamientos orgánicos y con Applaud® en el cultivo convencional.

  1. The Study of Mining Activities and their Influences in the Almaden Region Applying Remote Sensing Techniques; Estudio de la Influencia de las Actividades Mineras de Mercurio en la Comarca de Almaden Aplicando Tecnicas de Teledeteccion

    Energy Technology Data Exchange (ETDEWEB)

    Rico, C; Schmid, T; Millan, R; Gumuzzio, J

    2010-11-17

    This scientific-technical report is a part of an ongoing research work carried out by Celia Rico Fraile in order to obtain the Diploma of Advanced Studies as part of her PhD studies. This work has been developed in collaboration with the Faculty of Science at The Universidad Autonoma de Madrid and the Department of Environment at CIEMAT. The main objective of this work was the characterization and classification of land use in Almaden (Ciudad Real) during cinnabar mineral exploitation and after mining activities ceased in 2002, developing a methodology focused on the integration of remote sensing techniques applying multispectral and hyper spectral satellite data. By means of preprocessing and processing of data from the satellite images as well as data obtained from field campaigns, a spectral library was compiled in order to obtain representative land surfaces within the study area. Monitoring results show that the distribution of areas affected by mining activities is rapidly diminishing in recent years. (Author) 130 refs.

  2. EVALUACIÓN DEL SECADO DE PEREJIL APLICANDO TÉCNICAS DE DESHIDRATACIÓN OSMÓTICA COMO PRETRATAMIENTO EVALUATION OF PARSLEY DRYING APPLYING OSMOTIC DEHYDRATION TECHNIQUES AS PRETREATMENT

    Directory of Open Access Journals (Sweden)

    Maribel García Mahecha

    2010-12-01

    Full Text Available En este estudio se evaluó el efecto de la temperatura de secado (50 y 60 °C y los diferentes tipos de pretratamientos (sin pretratamiento, deshidratación osmótica y deshidratación osmótica al vacío sobre las características fisicoquímicas y nutricionales del perejil deshidratado, midiendo la actividad de agua, densidad, rehidratación, color, contenido de vitamina C y carotenos. Los resultados mostraron que el secado de perejil a una temperatura de 60 °C sin pretratamiento es el más adecuado, presentando un menor tiempo de proceso (68 min, una mayor reducción en la humedad (4,3% y un menor efecto en los contenidos de vitamina C (8,7 mg de vitamina C/100 g de muestra y carotenos (36,9 mg de carotenos/100 g de muestra. Los procesos de secado con osmodeshidratación como pretratamiento son más lentos, debido a la formación de una capa de jarabe en la superficie de las muestras, la cual dificulta la salida de la humedad del interior de las hojas. El contenido de vitamina C disminuye en todos los procesos, pero es mayor en aquellos con pretratamiento por la solubilidad de la vitamina en el agua. Los carotenos se reducen en una mayor proporción en los procesos que toman mayor tiempo en llegar a la humedad de equilibrio debido a su termosensibilidad.The influence of the drying temperature (50 and 60 °C and the different pretreatments (without pretreatment, osmotic dehydration and vacuum osmotic dehydration were evaluated on the physical, chemical and nutritional characteristics of dried parsley, such as water activity, density, rehydration, color, vitamin C content, and carotene content. The results showed that drying at 60 °C without pretreatment is the best process for drying parsley because the process time (68 min and the moisture content (4,3% are lower and the vitamin C (8,7 mg vitamin C/100 g sample and carotene contents (36,9 mg carotene/100 g sample are less affected. The drying processes with osmodehydration as pretreatment are slower due to the formation of a syrup coating on the sample surface, making the movement of moisture within the parsley leaves more difficult. The vitamin C content decreases in all processes, but the decrease is higher in the process with pretreatment due to the solubility of the vitamin in the water. The carotene content decreases at a higher rate in the process that takes more time to reach equilibrium moisture content due to its thermosensitivity

  3. Factores de elección de licenciaturas en la División Académica de Informática y Sistemas (DAIS aplicando minería de datos

    Directory of Open Access Journals (Sweden)

    Manuel Villanueva

    2014-04-01

    Full Text Available El objetivo de la investigación permite identificar los factores que influyen en los estudiantes, al momento de seleccionar una de las cuatro Licenciaturas que ofrecela División Académicade Informática y Sistemas (DAIS dela Universidad JuárezAutónoma de Tabasco, México. Su desarrollo se realizó en seis Subsistemas de Instituciones de Educación Media Superior de carácter público estatal y federal del estado de Tabasco. El enfoque metodológico se fundamento mediante la aplicación del proceso de KDD “Knowledge Discovery in Databases” conocido como Descubrimiento de Conocimiento en Bases de Datos, el cual es interpretado como “El proceso no trivial de identificar patrones válidos, nuevos, potencialmente útiles y en última instancia comprensible en los datos”, utilizando la técnica de Predicción de Regresión Lineal dela Herramienta Weka.Para la obtención de información y respectivo análisis, se diseñó un cuestionario aplicado a los seis Subsistemas, cuyos resultados informacionales fueron almacenados en una base de datos y se depuró para aplicarle la técnica de minería de datos. Los resultados obtenidos porla Herramienta Weka, muestran los motivos y factores que influyen en la toma de decisiones de los alumnos al momento de la selección de una carrera. Se prevé que los resultados han de ser considerados por las autoridades académicas para la toma de decisiones y definición de estrategias que les permitan promocionar sus licenciaturas.

  4. Enseñanza de la primera ley de la termodinámica aplicando la metodología de problema resuelto y estrategias de resolución de problemas para mejorar el rendimiento de los estudiantes

    OpenAIRE

    Espol; Cano Bravo, Rosa Alexandra

    2017-01-01

    El principal problema que enfrentamos los profesores en el aula de clases, sin duda alguna es el nivel de rendimiento de los estudiantes, por lo que continuamente se utilizan diferentes técnicas, con el fin de que nuestros alumnos asimilen los conocimientos que se imparten; sin embargo es conocido que en el rendimiento de los alumnos, no solo influye el profesor, parte importante de la ecuación son los individuos, y como ellos receptan y asimilan la información. Guayaquil MAGISTER...

  5. Reducción del miedo escénico y mejora del afecto positivo, la autoeficacia y el desempeño ante la actuación en público: un cuasi=experimento aplicando PNL

    OpenAIRE

    Serrano Leiva, Damaris

    2015-01-01

    Treball final de Grau en Psicologia. Codi: PS1048. Curs acadèmic 2014-2015 En este estudio, se llevó a cabo un cuasi-experimento con el fin de evaluar la eficacia de dos técnicas en Programación Neuro Linguística (PNL): anclas y submodalidades en la mejora del afecto positivo, autoeficacia y desempeño, y la reducción del miedo escénico y del afecto negativo en alumnos de teatro de la Escuela Municipal de Villarreal. Para ello, se establecieron dos condiciones: Un grupo experime...

  6. Determination of dissolved oxygen in saline waters applying mathematical methods and as a membrane electrode sensor; Determinacion de oxigeno disuelto en aguas salinas aplicando modelos matematicos y como sensor electrodo de membrana

    Energy Technology Data Exchange (ETDEWEB)

    Mayari, R.; Espinosa, M. C.; Ruiz, M. [Centro Nacional de Investigaciones Ceintificas. La Habana (Cuba); Romero, E. [Universidad de Huelva (Spain)

    2000-07-01

    This work shows as specific methodology for the determination of dissolved oxygen in saline waters that allows to consider the variations of temperature and of concentration of salts. Both factors influence the solubility of the gases in water, making possible in place measurements, in bodies of water with content of salts unto of the concentration of sea water, with greater dependability. The mathematical models obtained are shown, the errors due to equipment, as well as the results obtained when applying this methodology in saline waters with diverse levels of contamination this allows to discern when the decrease of dissolved oxygen levels is due to an increase in the salinity or to an increase in the contamination of the water body. (Author) 7 refs.

  7. Análisis y diseño de un sistema en ambiente Web para control de inventarios en negocios de comida gourmet, aplicando bases de datos distribuidas

    OpenAIRE

    Albuja Espinoza, Marcelo Patricio

    2010-01-01

    El programa SIF, creado mediante la implementación de herramientas como : Visual Studio 2005, Ajax e Infragestic, permite el manejo y control de las existencias de productos y materias primas de una empresa orientada al servicio de preparación de alimentos. Gracias a la tecnología web, el usuario puede acceder al aplicativo desde cualquier ubicación, menteniendo la información actualizada, entre las bases de datos que se pueden encontrar en el mismo o en diferentes servidores, permitiendo un ...

  8. ALGORITMO ETAPA A ETAPA PARA LA SIMULACIÓN DE CASCADAS DE EXTRACCIÓN EN FASE LÍQUIDA APLICANDO EL MODELO DE EQUILIBRIO ALGORITMO ETAPA A ETAPA PARA A SIMULAÇÃO DE CASCATAS DE EXTRAÇÃO EM FASE LÍQUIDA APLICANDO O MODELO DE EQUILÍBRIO STAGE-BY-STAGE ALGORITHM FOR SIMULATION OF LIQUID PHASE EXTRACTION CASCADES APPLYING THE EQUILIBRIUM MODEL

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    César A Sánchez

    2009-12-01

    Full Text Available Se presenta un método de solución etapa a etapa para el conjunto de ecuaciones de balance de masa, relaciones de equilibrio, suma de composiciones y entalpía (MESH, mass equilibrium sum enthalpy que representan el modelo de equilibrio para un arreglo a contracorriente de etapas de extracción en fase líquida. El fundamento teórico se encuentra en la termodinámica: equilibrio líquido-líquido, flash isotérmico y flash adiabático. El algoritmo supera los alcances de los métodos gráficos e isotérmicos típicos en el estudio de los procesos de extracción y es aplicable a situaciones adicionales muy comunes: transferencia de calor en las etapas, etapas adiabáticas, temperaturas diferentes para los flujos de alimentación y solvente. El algoritmo se ilustra en tres ejemplos, los dos primeros en operación isotérmica con tres componentes (agua, ácido acético y acetato de butilo y diez etapas, y un tercero más elaborado que involucra transferencia de calor con cuatro componentes (agua, ácido acético, butanol y acetato de butilo y quince etapas.Apresenta-se um método de solução etapa a etapa para o conjunto de equações de balanço de massa, relações de equilíbrio, soma de composições e entalpia (MESH mass equilibrium sum enthalpy que representam o modelo de equilíbrio para um arranjo en contracorrente de períodos de extração em fase líquida. O fundamento teórico se encontra na termodinâmica: equilíbrio líquido-líquido, flash isotérmico e flash adiabático. O algoritmo supera os alcances dos métodos gráficos e isotérmicos típicos no estudo dos processos de extração e é aplicável a situações adicionais muito comuns: transferência de calor nas etapas, etapas adiabáticas, temperaturas diferentes para os fluxos de alimentação e solvente. O algoritmo se ilustra em três exemplos, os dois primeiros em operação isotérmica com três componentes (água, ácido acético e acetato de butila e dez etapas, e um terceiro mais elaborado que envolve transferência de calor com quatro componentes (água, ácido acético, butanol e acetato de butila e quinze etapas.It is shown a stage-by-stage solution method for the group of mass balances, equilibrium relationships, sum of compositions and enthalpy equations (MESH equations that represents the equilibrium model for a countercurrent multistage liquid-liquid extraction arrangement. The theoretical foundation is in thermodynamics: liquid-liquid equilibrium, isothermal flash, and adiabatic flash. The algorithm exceeds the scope of graphics and isothermal methods used in the study of extraction processes, which is applicable to very common typical situations: heat transfer by stage, adiabatic stages, and different temperatures in feed and solvent streams. The algorithm is illustrated in three examples, the first two in isothermal operation with three components (water, acetic acid and butyl acetate and ten stages, and a third one more elaborated involving heat transfer with four components (water, acetic acid, butanol, butyl acetate and fifteen stages.

  9. Determinación del contenido de alúmina reactiva de las adiciones puzolánicas naturales y artificiales, por termogravimetría y por el método de Rietveld

    OpenAIRE

    Trusilewicz, Lidia Natalia

    2014-01-01

    Tanto el tema de esta investigación, como sus objetivos, fundamentos, materiales seleccionados y parte experimental para alcanzarlos, han sido promovidos por la situación y el estado de las construcciones de hormigón armado que se comenzaron a realizar en España a partir del año 1975, con hormigones y morteros de cemento que contenían cenizas volantes hasta un 20 %, en principio, y hasta un 35 %, más tarde, de su dosificación de cemento Portland (CP), los cuales y en contra de lo esperado, ha...

  10. Desarrollo de un protocolo para la aplicación del método de Rietveld y del estándar interno en la caracterización de materiales cerámicos con contenido de amorfos

    OpenAIRE

    Jaramillo Raquejo, Daniela

    2015-01-01

    La técnica de difracción de rayos X de muestras en polvo se ha convertido en una de las herramientas más útiles en el ámbito internacional para el análisis mineralógico cuantitativo de materiales -- Con base en esta técnica se han desarrollado diversos métodos con los cuales no solo es posible obtener información cualitativa y cuantitativa de las fases cristalinas en un material, sino también del contenido de amorfos si el material es semicristalino -- Los métodos de este tipo más difundidos ...

  11. Extraction of toxic and valuable metals from wastewater sludge and ash arising from RECICLAGUA, a treatment plant for residual waters applying the leaching technique; Extraccion de metales toxicos y valiosos de los desechos de lodos y cenizas provenientes de la planta tratadora de aguas residuales RECICLAGUA aplicando la tecnica de lixiviado

    Energy Technology Data Exchange (ETDEWEB)

    Guerrero D, J J

    2004-07-01

    Presently work, the technique is applied of having leached using coupled thermostatted columns, the X-ray diffraction for the identification of the atomic and molecular structure of the metals toxic that are present in the residual muds of a treatment plant of water located in the municipality of the Estado de Mexico, RECICLAGUA, likewise the techniques is used of Inductively Coupled Plasma Mass Spectroscopy and X-ray fluorescence analysis for the qualitative analysis. We took samples of residual sludge and incinerated ash of a treatment plant waste water from the industrial corridor Toluca-Lerma RECICLAGUA, located in Lerma, Estado de Mexico. For this study 100 g. of residual of sludge mixed with a solution to 10% of mineral acid or sodium hydroxide according to the case, to adjust the one p H at 2, 5, 7 and 10, bisulfite was added, of 0.3-1.5 g of dodecyl sulfate of sodium and 3.93 g of DTPA (triple V). Diethylene triamine penta acetate. These sludges and ashes were extracted from toxic and valuable metals by means of the leaching technique using coupled thermostated columns that which were designed by Dr. Jaime Vite Torres, it is necessary to make mention that so much the process as the apparatus with those that one worked was patented by him same. With the extraction of these metals, benefits are obtained, mainly of economic type, achieving the decrease of the volume of those wastes that have been generated; as well as the so much use of those residuals, once the metals have been eliminated, as of those residuals, once the metals have been eliminated, as of those liquors, the heavy metals were extracted. It was carried out a quantitative analysis using Icp mass spectroscopy, this way to be able to know the one content of the present metals in the samples before and after of leaching them, these results reported a great quantity of elements. Another of the techniques employees was the analysis by X-ray diffraction that provides an elementary content of the samples, identifying elements that are present in concentrations greater to 0.5% in weight, as long as the spectroscopy analysis of emission for plasma very low concentrations are identified already that this method causes the destruction of the sample achieving the identification of all the present elements. With the obtained results we are able to compare the concentrations of the metals before and after the leaching. We calculate by this way the percentage of efficiency for each one of the variables that we managed in the development of the study, achieving the extraction of those toxic and valuable metals, present in the sludge and ashes until of 100%. Based on the results we can mention that the workers who are exposed to aerosols and powders of these toxic residuals those which they contain heavy metals. (Author)

  12. Estrategia de intervención para la monitorización y reducción de las crisis de asma bronquial aplicando un sistema de alerta temprana Intervention strategy for monitoring and reduction of bronchial asthma crises applying an early alert system

    Directory of Open Access Journals (Sweden)

    Tatiana de la Vega Pazitková

    2011-06-01

    Full Text Available Introducción: el asma es una enfermedad psicosomática que constituye un importante problema de salud mundial. El clima y el tiempo influyen sobre la salud humana. Es conocida la influencia de los factores ambientales en la aparición de las crisis agudas de asma bronquial. Objetivo: diseñar una estrategia de intervención comunitaria, sobre la base de la asociación del asma con los cambios meteorotrópicos, con el fin de alertar, tempranamente, de la posibilidad de desencadenamiento de las manifestaciones clínicas, mitigarlas y reducir las crisis de asma. Métodos: se diseñó un plan de acción que incluye a médicos, los pacientes y sus tutores que acudieron al servicio de urgencia del policlínico "Ana Betancourt", y sus consultorios médicos, durante el año 2010. Todos se adiestraron en la interpretación y procesamiento del modelo de pronóstico biometeorológico, cuyos resultados alertará sobre su accionar diario ante los riesgos meteorotrópicos. Resultados: se propone una estrategia de intervención comunitaria, con el fin de reducir, en al menos 20 %, el número de pacientes con crisis de asma, y su gravedad. Conclusiones: los factores ambientales influyen en la aparición de las crisis agudas de asma bronquial. Las condiciones de hiperoxia o aumento de la densidad parcial de oxígeno en el aire son predecibles, y se puede alertar, oportunamente, a las autoridades de salud sobre su ocurrencia, lo que permite ejecutar planes de acción y medidas profiláctico preventivas que minimicen los impactos desfavorables de los cambios de tiempo anunciados.Introduction: asthma is a psychosomatic disease becomes important health problem at world scale. The climate and time influenced on the human health. It is known the influence of environmental factors on the appearance of acute crises of bronchial asthma. Objective: to design a community intervention strategy based on the association of asthma with the meteorotropic changes to alert early on the possibility of triggering clinical manifestations, to alleviate and to reduce the asthma crises. Methods: an action plan was designed including physicians, patients and their custodians came to emergence service of "Ana Betancourt" polyclinic and its consulting rooms over 2010. All them were trained in the interpretation and processing of the bio-metereological prognosis form, whose results will alert on its daily action in face of metereotropic risks. Results: authors propose a community intervention strategy to reduce in at least a 20 % the number of patients with asthma crises and its severity. Conclusions: environmental factors influenced on the appearance of acute crises of bronchial asthma. The hyperoxia conditions or the increase in partial density of oxygen in the air are predicable, allowing to alert at time to health authorities on its occurrence to carry out actions plans and prophylactic-preventive measures to minimize the unfavourable impacts of the climatic changes reported.

  13. MODELACIÓN DE UNA ESTRUCTURA DE PAVIMENTO UTILIZANDO LOS MÓDULOS DINÁMICOS OBTENIDOS EN LABORATORIO APLICANDO LAS METODOLOGÍAS MARSHALL Y SUPERPAVE MODELING OF A PAVEMENT STRUCTURE USING DYNAMIC MODULES OBTAINED IN A LABORATORY APPLYING MARSHALL AND SUPERPAVE METHODOLOGIES

    Directory of Open Access Journals (Sweden)

    Carlos Rodolfo Marín Uribe

    2007-07-01

    Full Text Available El programa SHRP (Strategic Higway Research Program a través del nuevo método de diseño de mezclas asfálticas en caliente 'Superpave', ha impulsado el desarrollo de investigaciones con el fin de obtener mezclas asfálticas más durables, resistentes y en general, que muestren un comportamiento superior como su nombre lo indica. Entonces, es importante conocer los estados de esfuerzos y deformaciones que se producen al modelar una estructura de pavimento con capas de rodadura, compuestas con mezclas asfálticas diseñadas por métodos distintos (Marshall y Superpave y, por supuesto, con una caracterización dinámica diferente (leyes de fatiga, módulos dinámicos y respuesta al ahuellamiento. Esta modelación permite tener una idea general de la capacidad estructural para soportar el tránsito durante su vida útil representada en el valor de N (Número de ejes equivalentes de carga y quizá obtener algunos indicios de posibles ahorros en costos de conservación de los pavimentos, razones fundamentales para apoyar e incentivar la implementación del método Superpave como nuevo diseño de las mezclas asfálticas en caliente.The SHRP (Strategic Highway Research Program through the new design method of hot asphalt mixtures 'Superpave' has promoted the development of researches in order to get more durable and resistant asphalt mixtures that show a superior performance. Then, it is important to know the effort and deformation condition that are produced when modeling a pavement structure with asphalt layers made up of asphalt mixtures designed with different methods (Marshall and Superpave and therefore, with a different dynamic characterization (fatigue laws, dynamic modules, and deterioration answers. This modeling allows us to have a general idea of the structural capacity to endure traffic throughout its life cycle represented by N value (Number of equivalent loads axis and perhaps to obtain some hints of possible savings in pavement preservation costs which are basic reasons to support and stimulate the implementation of the Superpave Method as a new design of the hot asphalt mixtures.

  14. Análisis y diseño de la información del Departamento de Subtransmisiones y Subestaciones de la Empresa Eléctrica Regional Centrosur C.A. para la elaboración de prototipos aplicando la metodología RUP

    OpenAIRE

    Calle Ortiz, Andrés Arturo; Duchi Pesántez, Patricia Maribel; Luna Bacuilima, Gladys Catalina

    2008-01-01

    Este Plan de Desarrollo del Software es una versión didáctica para la obtención del título de Ingeniería en Sistemas de la Universidad Politécnica Salesiana se encuentra preparada como propuesta para la elaboración de un software que permita la administración de información del departamento de subestaciones de la Empresa Eléctrica Regional CentroSur C.A. Este documento provee una visión global del enfoque de desarrollo propuesto. El proyecto ha sido ofertado por los estudiantes de la UPS e...

  15. Diseño e implementación de una red inalámbrica, aplicando el estándar de comunicaciones ZIGBEE, para el monitoreo de los sistemas: antiheladas, regadío y ventilación de un prototipo de invernadero inteligente para el cultivo de rosas

    OpenAIRE

    Erazo Rodas, Mayra Johanna

    2012-01-01

    Máster en Redes de Telecomunicación para Países en Desarrollo. Universidad Rey Juan Carlos. Tutor: Juan Antonio Hernández Tamames PhD. Co-tutor: Susana Borromeo López PhD. La producción de flores es una de las actividades más importantes que sustenta la economía del Ecuador, siendo la rosa una de las especies más cotizadas a nivel mundial. Sin embargo en la actualidad existe muy poca investigación orientada al monitoreo de los sistemas de ventilación, regadío y anti-heladas, que c...

  16. Study of the dependence of resolution temporal activity for a Philips gemini TF PET/CT scanner by applying a statistical analysis of time series; Estudio de la dependencia de la resolucion temporal con la actividad para un escaner PET-TAC philips gemini TF aplicando un analisis estadistico de series temporales

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez Merino, G.; Cortes Rpdicio, J.; Lope Lope, R.; Martin Gonzalez, T.; Garcia Fidalgo, M. A.

    2013-07-01

    The aim of the present work is to study the dependence of temporal resolution with the activity using statistical techniques applied to the series of values time series measurements of temporal resolution during daily equipment checks. (Author)

  17. Evaluación de MDE para la estimación de volúmenes por procesos de erosión aplicando análisis de autocorrelación espacial en una cuenca de los andes venezolanos. Caso de estudio: microcuenca torrencial La Machirí

    Directory of Open Access Journals (Sweden)

    Cristopher Camargo Roa

    2014-06-01

    Full Text Available Los modelos digitales de elevación (MDE, como representación visual de las formas del relieve y de los valores de altura, han sido muy útiles para estudiar los aspectos relacionados con la topografía de un área. Esta investigación se realizó en un área de 3.39 km2 de la microcuenca torrencial La Machirí (estado Táchira, Venezuela. Tuvo por objetivo evaluar un MDE obtenido por un proceso de fotogrametría digital cotejado a su vez con un MDE elaborado a partir de la edición de curvas de nivel existentes en cartas topográficas. Para ello se aplicaron métodos como el análisis exploratorio de datos espaciales (ESDA y la geoestadística de puntos (análisis de mínima distancia, análisis de patrones espaciales, variograma y superficie variográfica. Se pudo determinar una diferencia existente entre ambos modelos, resultado de la sumatoria de los errores generados, en primer lugar, por la distribución espacial de los puntos de control señalados para el proceso fotogramétrico (número de puntos menores al valor de una distribución normal, posible sesgo espacial entre los puntos y manifestación de fenómenos de dependencia espacial, seguido del error generado a partir del método de interpolación aplicado durante el mismo y el error resultante originado por el comportamiento local de los procesos de erosión en el área. La primera valoración arrojó una diferencia en la superficie de área de 0.57 ha y en volumen de 9.41 hm3 en ambos MDE. Un análisis sectorizado permitió determinar la falta de al menos 3 puntos de control para obtener un MDE más satisfactorio.

  18. LA VACUNACIÓN ANTI-NEUMOCÓCICA CON LA VACUNA CONJUGADA 13-VALENTE EN POBLACIÓN INMUNOCOMPETENTE DE 65 AÑOS: ANALISIS DEL IMPACTO PRESUPUESTARIO EN ESPAÑA APLICANDO UN MODELO DE TRANSMISIÓN DINÁMICA

    Directory of Open Access Journals (Sweden)

    Reyes Lorente Antoñanzas

    2016-01-01

    Full Text Available Fundamentos: Las infecciones causadas por el Streptococcus pneumoniae en el adulto tienen repercusiones importantes en la salud. El objetivo fue analizar el impacto económico y sanitario en 5 años de la vacunación de la cohorte española de 65 años inmunocompetente con la vacuna antineumocócica conjugada 13-valente.Métodos: Mediante un modelo de transmisión dinámica basado en ecuaciones diferenciales se analizó la carga de la enfermedad neumocócica (EN en sujetos de 65 años en 5 años, siendo vacunada anualmente el 36,5% de la cohorte. Se aplicó la eficacia de la vacuna del 52,5% observada en el estudio CAPITA en pacientes de 65 años inmunocompetentes, cobertura de serotipos vacunales del 63,4% (estudio CAPA, incidencia de infección neumocócica de 162,2/100.000 casos año (CMBD 2010-2013 y proporción de vacunados previamente al arranque del modelo del 0,99%. La perspectiva fue la del Sistema Nacional de Salud (SNS. Costes de casos de EN según CMBD y precio de venta de laboratorio de la vacuna conjugada.Resultados: En 5 años la vacunación con vacuna conjugada 13-valente espera evitar 10.360 casos de EN (7.411 hospitalizaciones por neumonías y 699 muertes (14.736 años de vida ganados -AVG-, en una cohorte de 65 a 69 años de edad. El coste de vacunación esperado de 36,5 millones de euros se compensaría completamente por la reducción de 41,5 millones de costes médicos evitados, con un ahorro neto acumulado de 3,8 millones de euros a precios constantes (4,9 a precios corrientes.Conclusión: La vacunación con vacuna conjugada 13-valente en adultos de 65 años inmunocompetentes resulta eficiente para el Sistema Nacional de Salud, reduciendo la carga de enfermedad y evitando un número importante de muertes.

  19. Analysis of the relationship between relative abundance of mature, impregnated females of Pleoticus muelleri (Bate, 1888 (Crustacea, Decapoda and environmental variables through statistical models Análisis de la relación entre la abundancia relativa de las hembras maduras e impregnadas de Pleoticus muelleri (Bate, 1888 (Crustácea, Decapoda y las variables ambientales aplicando modelos estadísticos

    Directory of Open Access Journals (Sweden)

    Mónica Fernández

    2011-01-01

    Full Text Available The relationship between the relative abundance of mature and impregnated females of the Argentine red shrimp Pleoticus muelleri (Bate 1888 and environmental variables was analyzed using statistical methods. Analyzed data carne from the research cruises of the Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP carned out durmg January 2000, 2001, 2005, and 2007; March 2006; and November 2004, 2005, and 2006 in San Jorge Gulf (Argentina. The biological variables considered were the relative abundances of mature and impregnated female shrimp, whereas the environmental variables corresponded to depth, bottom water temperature and salinity, and the difference between surface and bottom water temperature and salinity. Generalized additive models were used as an exploratory tool for the numerical data and the general linear models as a confirmatory tool. The results showed that the distributions and abundances of mature and impregnated females were related to the bottom water temperature and salinity and to depth. The relationship increased along with temperature; with salinity, however, it decreased for mature females and increased for impregnated females. An optimal depth range was evidenced, where the largest concentrations of these individuáis were located.Se presenta el análisis de la relación entre la abundancia relativa de las hembras maduras e impregnadas del langostino Pleoticus muelleri (Bate, 1888 y las variables ambientales, mediante la aplicación de modelos estadísticos. Los datos analizados provienen de las campañas de investigación del Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP realizadas en enero de 2000, 2001, 2005 y 2007, marzo de 2006 y noviembre de 2004, 2005 y 2006 en el Golfo San Jorge (Argentina. Se consideraron las variables biológicas: abundancia relativa de hembras maduras y de hembras impregnadas de langostino y las variables ambientales: profundidad, temperatura y salinidad del agua de fondo así como, la diferencia de temperatura y de salinidad entre el agua de superficie y de fondo. Para el tratamiento numérico de los datos se aplicaron Modelos Aditivos Generalizados como herramienta exploratoria y Modelos Lineales Generales como herramienta confirmatoria. Los resultados indican que la distribución y abundancia de las hembras maduras e impregnadas se relacionan con la temperatura y la salinidad del agua de fondo, y con la profundidad. Con la temperatura se destaca una relación creciente; mientras que con la salinidad, una relación decreciente con las hembras maduras y una relación creciente con las hembras impregnadas. Considerando la profundidad, se evidenció un rango óptimo donde se localizaron las mayores concentraciones de estos individuos.

  20. Diseño de un sistema de control de gestión aplicando una reingeniería de procesos al área de abastecimiento (compras e importaciones) en una empresa que se dedica al desarrollo, producción y comercialización de vinos, licores y demás productos afines

    OpenAIRE

    Albán Del Salto, Shirley Juliana; Eugenio Gonzalez, Melissa Tamara

    2013-01-01

    Este proyecto fue aplicado a una compañía dedicada al desarrollo, producción y comercialización de vinos, licores y demás productos afines. En vista de su constante crecimiento, esta empresa decidió realizar un cambio sustancial en el sistema de compras que utilizaba para una mejora en el uso de los recursos materiales y financieros. Motivo por el cual optó valerse de un Sistema de Control de Gestión basado en indicadores de Gestión y desempeño para el proceso de compras, el mismo que básicam...

  1. SFMEA: análise do efeito e modo da falha em serviços - aplicando técnicas de prevenção na melhoria de serviços SFMEA: service failure mode and effect analysis

    Directory of Open Access Journals (Sweden)

    Roberto Gilioli Rotondaro

    2002-01-01

    Full Text Available De acordo com a definição de serviços, uma das características é a proximidade com o cliente durante o processo de elaboração e entrega do serviço, por isso, se alguma coisa der errada, isto acontecerá na sua frente. Este artigo mostra como, a partir dos conceitos da técnica FMEA, é desenvolvida uma ferramenta de prevenção, a SFMEA, que é adequada para prevenir a ocorrência de falhas durante a produção dos serviços, de modo que estes sempre atendam às expectativas dos clientes. Um grupo de pessoas envolvidas com a tarefa desenha o fluxo do serviço identificando os momentos da verdade, aqueles momentos em que o cliente entra em contato com a organização prestadora do serviço. Estes pontos serão a base para a aplicação da técnica de SFMEA, de modo a eliminar a possibilidade de falhas durante a entrega do serviço. São apresentados dois exemplos de aplicação da ferramenta, de modo a comprovar a sua eficácia.According to Service definition, the customer is frequently present during the processes and delivery of the service. If something goes wrong it will happen in front of the customer. This article shows that the use of SFMEA as a prevention tool in the service's business is a very powerful technique. A group of employees were trained in prevention tools, designed the process map, found the critical points and applied the SFMEA method in order do prevent any failure during services operation. The first results indicated that all the actions implemented were really effective and SFMEA is a good tool for preventing errors.

  2. Análise da perspetiva adequada para garantia da prevenção de acidentes numa máquina complexa, aplicando os requisitos mínimos de segurança ou os duma norma tipo ‘C’

    OpenAIRE

    Gomes, Horácio Filipe Arsénio

    2016-01-01

    Dissertação apresentada para cumprimento dos requisitos necessários à obtenção do grau de Mestre em Segurança e Higiene no Trabalho A presente dissertação tem como objetivo avaliar até que ponto uma máquina complexa na área de produção de aço líquido, se considera segura, cumprindo os requisitos mínimos da legislação nacional em vigor. Analisou-se a evolução do estado da arte na segurança das máquinas para a produção de aço e a aplicação do código de boas práticas existente para esta...

  3. Data base structure and Management for Automatic Calculation of ''210 Pb Dating Methods Applying Different Models; Estructura de la Base de Datos y Modo de Operacion para Realizar el Calculo Automatizado de Datacion mediante ''210 Pb Aplicando Diversos Modelos

    Energy Technology Data Exchange (ETDEWEB)

    Gasco, C.; Anton, M. P.; Ampudia, J.

    2003-07-01

    The introduction of macros in trie calculation sheets allows the automatic application of various dating models using unsupported ''210 Pb data from a data base. The calculation books the contain the models have been modified to permit the implementation of these macros. The Marine and Aquatic Radioecology group of CIEMAT (MARG) will be involved in new European Projects, thus new models have been developed. This report contains a detailed description of: a) the new implement macros b) the design of a dating Menu in the calculation sheet and c) organization and structure of the data base. (Author) 4 refs.

  4. Estudio de la configuración productiva de una planta de pre-montaje de unidades aplicando parámetros de presencia máxima de opciones (Study of the configuration of a pre-assembly plant using maximum fill levels of units’ options

    Directory of Open Access Journals (Sweden)

    Julien Maheut

    2015-07-01

    Full Text Available En este artículo, se define un sistema Pull para resolver el problema de secuenciación de unidades homogéneas. La literatura y la práctica abordan habitualmente este problema de un modo Push en el que un sistema inteligente calcula la siguiente unidad que el sistema debe producir en función de lo que tiene disponible. El método propuesto plantea que se alimente la planta con órdenes de fabricación (unidad a unidad en función de las que permanecen en la planta (o más bien de las que faltan. Se plantea el caso de una planta de montaje en la que existe una planta de pre-montaje previa a la línea de montaje con líneas en paralelo y ruteos alternativos así como operaciones que se realizan en estaciones ubicadas fuera de la línea. Se estudiará el impacto de restringir la cantidad de unidades que reciben operaciones de alto tiempo de ciclo en el sistema considerando diferentes indicadores. Se propone analizar los niveles de manera teórica considerando tanto los espacios físicos existentes y considerando los tiempos existentes en el sistema. Por último, se propone un análisis a través de una simulación basada en eventos discretos con Simio Simulation Software®.In this paper, a " pull " system to solve the problem of sequencing homogeneous units is defined. The literature and practice usually address this problem of " Push" mode in which an intelligent system calculates the next unit that the system must produce according to what is available . The proposed method suggests that the plant is fed with production orders (unit by unit versus those that remain in the plant ( or rather those than miss. The case study of an assembly factory in which a new pre-assembly plant with parallel lines and alternate routings and pull off tables prior to the final assembly plant is introduced. The impact of restricting the number of units that receive high operating cycle time in the system consid-ering different indicators are studied. It is proposed to analyze the levels, theoretically con-sidering both physical space as existing times in the system. Finally , an analysis through a simulation based on discrete events with Simio Simulation Software® is proposed.

  5. Desarrollo del módulo para administración de proyectos utilizando la plataforma libre ODOO, aplicando el método cadena crítica basado en la teoría de restricciones del Dr. Eliyahu Goldratt.

    OpenAIRE

    Mogrovejo Baque, Mercedes; Ormaza Acosta, Christopher

    2015-01-01

    En la presente investigación se desarrolló sistema de administración de proyectos basado en cadena crítica del Dr Eliyahu Goldratt fundamentado en la teoría de restricciones, sobre la plataforma de código abierto Odoo, esta teoría permite identificar y gestionar puntualmente 3 problemas que se dan en la administración de proyectos, estos son: el síndrome del estudiante, la ley de parkinson, y el contexto de multitareas. In this research was developed a project management system based on cr...

  6. Optimization of methodology for the assessing of bioaccumulation factors of periphyton metals applying the X-ray fluorescence technique; Optimizacion de la metodologia para la evaluacion de los factores de bioacumulacion de metales en perifiton aplicando la tecnica de fluorescencia de rayos X

    Energy Technology Data Exchange (ETDEWEB)

    Merced Ch, D.

    2015-07-01

    The Lerma River is one of the most polluted at Mexico, has a high pollutant load and low biodiversity, this aquatic plants and species zoo perifiton presented adaptations to environmental conditions that exist due to dumping of wastewater are developed. In this paper bioaccumulation factors (BAF) of Cr, Mn, Fe, Ni, Cu, Zn and Pb metal on Hydrocotyle ranunculoides zoo perifiton associated with the upper reaches of the Lerma River applying the technique of fluorescence X-rays were evaluated in the form of Total Reflection. The BAF were higher compared to the soluble fraction to the total fraction this because the metal in the soluble phase are in solution and are therefore more available to join aquatic organisms, moreover respect to the BAF sediment were ≤ 1.5 indicate that these organisms have little affinity for incorporating metals from the sediment. Considering the sum of the FBA of all metals in each agency notes that the leech was the biggest bio accumulated metals (42468) followed by the worm to (27958), the arthropod with (10757) and finally the snail with (8421). Overall for this study agencies according to the BAF reported to bio accumulate metals are the following behavior Fe > Zn > Cu > Cr > Ni > Mn > Pb. (Author)

  7. Da pesquisa à prática de enfermagem aplicando o modelo de adaptação de Roy De la investigación a la práctica de enfermería mediante la aplicación del modelo de adaptación de Roy From research to nursing practice applying the Roy adaptation model

    Directory of Open Access Journals (Sweden)

    Sónia Margarida Santos Coelho

    2011-12-01

    Full Text Available Os modelos e as teorias de enfermagem contribuem para o desenvolvimento do conhecimento em enfermagem, guiando as investigações no sentido do desenvolvimento da disciplina e, consequentemente, da prática. De acordo como o Modelo de Adaptação de Roy, a pessoa é vista como um ser adaptável com mecanismos que permitem a adaptação de comportamentos em resposta aos estímulos ambientais. De fato, a pessoa é o enfoque central dos cuidados de enfermagem, visando-se sempre a melhoria dos cuidados prestados baseados em investigação. A metodologia do Modelo de Adaptação de Roy baseia-se na aplicabilidade do processo de enfermagem, facilitando aos enfermeiros a coleta de dados, estabelecimento de objetivos e diagnósticos de enfermagem, a determinação de intervenções de enfermagem e a posterior avaliação do processo. Assim o objetivo desta pesquisa é realizar uma revisão crítica da aplicação do Modelo Adaptação de Roy aplicado à prática e à pesquisa em Enfermagem.Los modelos y teorías de enfermería contribuyen para el desarrollo del conocimiento en Enfermería, guiando las investigaciones para el desarrollo de la disciplina y, consecuentemente, de la práctica. De acuerdo con el Modelo de Adaptación de Roy se ve la persona como un mecanismo de adaptación que permite el ajuste del comportamiento en respuesta a estímulos ambientales. De hecho, la persona es el foco central de la atención de enfermería, buscando siempre el mejoramiento de la atención basada en la investigación. La metodología del Modelo de Adaptación de Roy se basa en la aplicación del proceso de enfermería, lo que facilita a las enfermeras para recopilar datos, establecer metas y diagnósticos de enfermería, la determinación de las intervenciones de enfermería y el proceso de evaluación posterior. Así, el objetivo de esta investigación es una revisión crítica de la aplicación del Modelo de Adaptación de Roy empleado para la práctica y la investigación en enfermería.The models and theories of nursing contribute to the development of nursing knowledge, guiding the research towards the development of the discipline and practice accordingly. According to the Roy Adaptation Model, the person has to be seen as an adaptive mechanism that allows the adaptation of behavior in response to environmental stimuli. In fact, the person is the central focus of nursing care, always aiming at the improvement of care based on research. The methodology of the Roy Adaptation Model is based on the applicability of the nursing process, making it easier for nurses to collect data, establish goals and nursing diagnoses, the determination of nursing interventions and the subsequent evaluation process. Thus the objective of this research is to critically review the application of the Roy Adaptation Model applied into the practice and nursing research.

  8. Estudio experimental de minimización de la contaminación de efluentes de la industria de curtidos aplicando reutilización de baños residuales y tratamientos con procesos de membrana y biológicos

    OpenAIRE

    Galiana Aleixandre, María Vicenta

    2010-01-01

    En la presente Tesis Doctoral se ha estudiado la reducción de la contaminación en el agua residual de una empresa de curtidos. Para ello, se ha realizado una caracterización de las aguas residuales de tenería, con el fin de detectar las fases del proceso que producen mayor cantidad de contaminación. Tras ello, se han realizado ensayos de reutilización de agua residual de pelambre en la fase de remojo y las reutilizaciones directas de los baños de píquel, curtición y recurtición, tintura y eng...

  9. Estimativas de parâmetros genéticos para produção de leite e persistência da lactação em vacas Gir, aplicando modelos de regressão aleatória Estimates of genetic parameters for milk yield and persistency of lactation of Gyr cows, applying random regression models

    Directory of Open Access Journals (Sweden)

    Luis Gabriel González Herrera

    2008-09-01

    Full Text Available Com o objetivo de estimar parâmetros genéticos para a produção de leite no dia do controle (PLDC, foram usadas as 2.440 primeiras lactações de vacas da raça Gir leiteira, com partos registrados entre 1990 e 2005. As PLDC foram consideradas em dez classes mensais e analisadas por meio de modelo de regressão aleatória (MRA utilizando-se como efeitos aleatórios o genético-aditivo, o de ambiente permanente e o residual e, como efeitos fixos, o grupo de contemporâneos (GC, a co-variável idade da vaca ao parto (efeito linear e quadrático e a curva média de lactação da população. Os efeitos genético-aditivos e de ambiente permanente foram modelados utilizando-se as funções de Wilmink (WIL e Ali e Schaeffer (AS. As variâncias residuais foram modeladas utilizando-se 1, 4, 6 ou 10 classes. Os grupos de contemporâneos foram definidos como rebanho-ano-estação do controle contendo no mínimo três animais. Os testes indicaram que o modelo com quatro classes de variâncias usando a função paramétrica AS foi o que melhor se ajustou aos dados. As estimativas de herdabilidade variaram de 0,21 a 0,33 para a função AS e de 0,17 a 0,30 para WIL e foram maiores na primeira metade da lactação. As correlações genéticas entre as PLDC foram positivas e elevadas entre os controles adjacentes e diminuiram quando a distância entre os controles aumentou. Para o melhor modelo, foram estimados os valores genéticos para a produção de leite acumulada até os 305 dias e, para períodos parciais da lactação, foram obtidas como médias dos valores genéticos preditos naquele período. Os valores genéticos foram comparados, por meio da correlação de posto, ao valor genético predito para a produção acumulada até os 305 dias, pelo método tradicional. As correlações entre os valores genéticos indicaram que podem ocorrer divergências na classificação dos animais pelos critérios estudados.Data consisting of 2,440 first lactations of Gyr cows calving between 1990 and 2005 were used to estimate genetic parameters of monthly test-day milk yield (TDMY. Records were analyzed by random regression models (MRA that included the additive genetic and permanent environmental random effects and the contemporary group, age of cow at calving (linear and quadratic components and the average trend of the population as fixed effects. Random trajectories were fitted by Wilmink's (WIL and Ali & Schaeffer's (AS parametric functions. Residual variances were fitted by step functions with 1, 4, 6 or 10 classes. The contemporary group was defined by herd-year-season of test-day and included at least three animals. Models were compared by Akaike's and Schwarz's Bayesian (BIC information criterion. The AS function used for modeling the additive genetic and permanent environmental effects with heterogeneous residual variances adjusted with a step function with four classes was the best fitted model. Heritability estimates ranged from 0.21 to 0.33 for the AS function and from 0.17 to 0.30 for WIL function and were larger in the first half of the lactation period. Genetic correlations between TDMY were high and positive for adjacent test-days and decreased as days between records increased. Predicted breeding values for total 305-day milk yield (MRA305 and specific periods of lactation (obtained by the mean of all breeding values in the periods using the AS function were compared with that predicted by a standard model using accumulated 305-day milk yield (PTA305 by rank correlation. The magnitude of correlations suggested differences may be observed in ranking animals by using the different criteria which were compared in this study.

  10. Detection of the high vibration origin in the body of an electrical generator driven by steam turbine applying diagnostic techniques; Deteccion del origen de alta vibracion en el cuerpo de un generador electrico accionado por turbinas de vapor aplicando tecnicas de diagnostico

    Energy Technology Data Exchange (ETDEWEB)

    Martinez Bravo, Fernando (Mexico)

    2007-11-15

    One of the problems that electric generators present is the high vibration due to causes that can go from simple mechanical unbalance, misalignment, mechanical relaxation, resonance or some other interaction that can influence in the system. In this document is presented the vibration analysis of an electric generator with a capacity of 350 MW, driven by a steam turbine composed of three stages (high pressure, intermediate pressure and low pressure) connected to the electric generator through a rigid connection. [Spanish] Uno de los problemas que se presentan en los generadores electricos es la alta vibracion debida a causas que pueden ir desde un simple desbalance mecanico, desalineamiento, aflojamiento mecanico, resonancia o alguna otra interaccion que pueda influir en el sistema. Se presenta en este documento el analisis de vibracion de un generador electrico con una capacidad de 350 MW, impulsado por una turbina de vapor compuesta de tres etapas (alta presion, presion intermedia y baja presion) acopladas al generador electrico a traves de un acoplamiento rigido.

  11. Long-term energy demand forecasting for the Sao Paulo state, Brazil, applying the structural decomposition model for three alternative growth sceneries of the state economy; Projecao da demanda setorial de energia do Estado de Sao Paulo no longo prazo, aplicando o modelo de desagregacao estrutural em tres cenarios alternativos de crescimento da economia do estado

    Energy Technology Data Exchange (ETDEWEB)

    Laite, Alvaro Afonso Furtado; Bajay, Sergio Valdir; Pereira, Andre Flavio Soares [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia Mecanica. Dept. de Energia]|[Universidade Estadual de Campinas, SP (Brazil). Nucleo Interdisciplinar de Planejamento Energetico (NIPE)]. E-mails: afurtado@fem.unicamp.br; bajay@fem.unicamp.br; apereira@fem.unicamp.br

    2006-07-01

    Long-term demand forecasts (up to 2025) are presented in this paper for the main energy forms consumed in the residential, trade and services, rural, transport, and industrial sectors in the State of Sao Paulo. They were obtained with the help of a flexible forecasting model based on the structural decomposition of the demand, for three alternative scenarios concerning the growth of the state economy. These three state-wise scenarios are related to initially nation-wide defined scenarios, through assumptions concerning the evolution on the ratio between the state GDP and the national GDP. (author)

  12. Evaluación del comportamiento productivo de cultivares de caña de azúcar (Saccharum spp. a través de diferentes ambientes en Tucumán, aplicando la técnica estadística "GGE biplot" Assessment of sugarcane cultivars (Saccharum spp. productive behaviour through different environments in Tucumán by means of "GGE biplot" technique

    Directory of Open Access Journals (Sweden)

    Ernesto R. Chavanne

    2007-12-01

    Full Text Available En el presente trabajo, se utilizó la técnica estadística "GGE biplot" como herramienta de análisis para explorar el efecto combinado del genotipo y de la interacción genotipo-ambiente en dos grupos de cultivares de caña de azúcar evaluados en seis localidades del área cañera de Tucumán entre 2002 y 2006. Los ensayos fueron implantados de acuerdo a un diseño en bloques completos al azar con tres repeticiones. En este estudio se analizaron los datos de rendimiento de azúcar/ha determinados en el mes de mayo. El análisis "GGE biplot" permitió discriminar a los genotipos de acuerdo a su producción de azúcar/ha y a su estabilidad relativa a través de ambientes. Los genotipos más destacados fueron identificados como aquellos que mostraron mayores valores de CP1 y valores de CP2 próximos a cero. La aplicación de este método de análisis permitió además, detectar genotipos adaptados a ambientes específicos. Los análisis "GGE biplot" explicaron el 58% y 64% de los efectos combinados de genotipo y de interacción genotipo-ambiente en los grupos 1 y 2 de cultivares de caña de azúcar, respectivamente. Se destaca en general la simplicidad del gráfico de "GGE biplot" para la identificación de genotipos superiores de caña de azúcar, cuando estos son evaluados a través de diferentes ambientes."GGE biplot" technique was used in this work to analyze the effects of genotype and genotype-environment interaction on sugarcane yield per ha during May, considering two sugarcane genotype groups evaluated from 2002 to 2006 on six different sites in the sugarcane growing area in Tucumán. The trials were conducted using a randomized complete block design with three replications. Data concerning sugar yield during May were analyzed. The "GGE biplot" technique allowed identifying genotypes with higher sugar yield per ha in May and their relative stability through environments. The outstanding genotypes were identified as those that showed higher PC1 values and PC2 values close to zero. This method also allowed detecting the adaptability of genotypes to specific enviroments. The "GGE biplot" analysis accounted for 58% and 64% of the combined effects of genotype and genoype-environment interaction in groups 1 and 2, respectively. The simplicity of the "GGE biplot" display for identifying outstanding sugarcane genotypes evaluated through different environments is remarkable.

  13. Bioestadística como apoyo a la praxis pedagógica de la Zoología de invertebrados en la determinación de Rotíferos de hábitat planctónico en el ecosistema de la laguna del Parque Recreacional de la ciudad de Cúcuta, aplicando las claves dicotómicas para su clasificación.

    Directory of Open Access Journals (Sweden)

    María Eugenia Muñoz-Peñaloza

    2012-01-01

    Full Text Available The study involved the identification and classification of phylum specimens rotifers from planktonic habitat in the recreational lagoon park ecosystem in Cucuta City. Was made a topographic uprising to the lagoon, was distributed in eight areas and physicochemical water analyses were performed. Rotifers were collected and identified in two ways, first, using representative schemes of the most common genera, according to Barnes (1995, Gardiner (1978, Hickman (1995, Arteaga, Herrera (2005, Strebler and Krauter (1987 Iafrancesco (1997 and second, the systematic identification through the application of the dichotomous key to genera, according to James G. Needham And Paul R. Needham (1982. To characterize the presence of rotifers according to zones, we used the frequency distribution, at the rates: Jaccard (presence or absence, Raup-Crick index (similarity in relation to the areas and Margalef index (for diversity. The lagoon water according to the physicochemical parameters and bioindication was classified as beta mesosapria, being secondary contact for recreational purposes. We found six families of rotifers: Brachionidae, Philodinidae, Notommatidae, Synchaetidae, Collotheidae, Lecanidae and ten genera Brachionus, Lepadella, Colurella, Philodina, Rotary, Cephalodella, Trichocerca, Polyartha, Collotheca and Lecane and through the application of biostatistics rotifers were distributed according to areas. The procedures and photographic records developed in the study are a support material, for pedagogical praxis in rotifer phylum topic in invertebrate zoology.

  14. La técnica origami en la enseñanza de los conceptos de perímetro, diferencia entre cuadrado y rectángulo, y de área del cuadrado, aplicando el modelo de van hiele y la teoría de Piaget en alumnos de segundo y tercer grado de la sede Santa Fé del Centro Educativo Ciató de Pueblo Rico Risaralda

    OpenAIRE

    Sanchez Giraldo, Heber Antonio

    2017-01-01

    La investigación muestra la efectividad lograda en el aprendizaje de los conceptos de perímetro, diferencia entre cuadrado y rectángulo, y de área del cuadrado, utilizando para la generación de los dos primeros conceptos la técnica Origami y los principios constructivistas basados en la teoría de Jean Piaget para el caso del área del cuadrado. La idea de los niveles y de las fases del modelo Van Hiele para la enseñanza de la geometría; y los principios pedagógicos formulados por Jean Piage...

  15. The analysis of powder diffraction data

    International Nuclear Information System (INIS)

    David, W.I.F.; Harrison, W.T.A.

    1986-01-01

    The paper reviews neutron powder diffraction data analysis, with emphasis on the structural aspects of powder diffraction and the future possibilities afforded by the latest generation of very high resolution neutron and x-ray powder diffractometers. Traditional x-ray powder diffraction techniques are outlined. Structural studies by powder diffraction are discussed with respect to the Rietveld method, and a case study in the Rietveld refinement method and developments of the Rietveld method are described. Finally studies using high resolution powder diffraction at the Spallation Neutron Source, ISIS at the Rutherford Appleton Laboratory are summarized. (U.K.)

  16. On the use of a composite moderator at the IBR-2 reactor: Advantages for the neutron-diffraction texture analysis of rocks

    Czech Academy of Sciences Publication Activity Database

    Bulavin, M. V.; Vasin, R.N.; Kulikov, S.A.; Lokajíček, Tomáš; Levin, D.M.

    2016-01-01

    Roč. 10, č. 4 (2016), s. 677-686 ISSN 1027-4510 Institutional support: RVO:67985831 Keywords : cold moderator * neutron-diffraction texture analysis * phase analysis * Rietveld method Subject RIV: DB - Geology ; Mineralogy

  17. Kunst voorbij identiteit en differentiatie

    NARCIS (Netherlands)

    F.D.R. Maet (Frank)

    2005-01-01

    textabstractFrank Maet heeft opleidingen gevolgd in theater (Kleine Academie Brussel) en beeldende kunst (Rietveld Academie Amsterdam) en vervolgens filosofie gestudeerd (V.U.Brussel). Zijn eindverhandeling zocht naar invloeden van de esthetica op de wetenschapsfilosofie (met voornamelijk aandacht

  18. Microstructural studies on variation of defect parameters in Zr–Sn

    Indian Academy of Sciences (India)

    ... modified Rietveld method and Warren–Averbach method taking silicon as standard. ... This analysis confirms that the growth fault, , is totally absent or negligibly ... faulting tendency abruptly drops to a level of negligible presence or zero.

  19. The study of disorder and nanocrystallinity in C–S–H, supplementary cementitious materials and geopolymers using pair distribution function analysis

    KAUST Repository

    Meral, Cagla; Benmore, C.J.; Monteiro, Paulo J.M.

    2011-01-01

    Significant progress was achieved with the application of Rietveld method to characterize the crystalline phases in portland cement paste. However, to obtain detailed information on the amorphous or poorly crystalline phases, it is necessary

  20. Žena jako tvůrkyně

    Czech Academy of Sciences Publication Activity Database

    Hnídková, Vendula

    2012-01-01

    Roč. 91, č. 9 (2012), s. 542-544 ISSN 0042-4544 Institutional support: RVO:68378033 Keywords : Dutch architecture * modern architecture * Gerrit Rietveld Subject RIV: AL - Art, Architecture, Cultural Heritage

  1. Preferred orientation of ettringite in concrete fractures

    KAUST Repository

    Wenk, Hans-Rudolf; Monteiro, Paulo J. M.; Kunz, Martin; Chen, Kai; Tamura, Nobumichi; Lutterotti, Luca; Del Arroz, John

    2009-01-01

    distribution of ettringite crystals. Diffraction images are analyzed using the Rietveld method to obtain information on textures. The analysis reveals that the c axes of the trigonal crystallites are preferentially oriented perpendicular to the fracture

  2. Aplicación de técnicas de minería de datos a los log generados por CATEDU

    OpenAIRE

    Buera Corchón, Ricardo

    2012-01-01

    Extracción de conocimiento de los log generados por un servidor web aplicando técnicas de minería de datos. Extracció de coneixement dels log generats per un servidor web aplicant tècniques de mineria de dades.

  3. Vulnerabilidad y riesgo por inundación en San Cristóbal de las Casas, Chiapas

    Directory of Open Access Journals (Sweden)

    Guillermo Montoya Gómez

    2008-01-01

    en las colonias localizadas en los márgenes de los ríos utilizando un modelo digital de elevación y aplicando encuestas. Se determinaron las características de las viviendas, el nivel de ingresos de sus pobladores y los grados de vulnerabilidad y riesgo a que están expuestos.

  4. Implementación del proceso de canal verde en la aduana marítima de Guayaquil

    OpenAIRE

    Celi Chamba, Johanna Paola

    2008-01-01

    propone un nuevo proceso para facilitar el comercio exterior y de manera en especial las actividades de importación; este proceso denominado Canal Verde o Aforo Automático está siendo aplicando en la mayoría de las aduanas del mundo logrando crear aduanas eficientes

  5. El deporte y la podología: tendencias actuales en ortopodología (primera parte)

    OpenAIRE

    Dorca Coll, Adelina; Céspedes Céspedes, Tomás; Cuevas Gómez, Rafael; Sacristán Valero, Sergi

    1993-01-01

    Se pretende revisar los conceptos y criterios que se venían aplicando en ortopodología y exponer las tendencias actuales tanto en la valoración de los parámetros previos al diseño ortopodológico como en la confección del tratamiento.

  6. Biofunctionality and immunocompatibility of starch-based biomaterials

    Science.gov (United States)

    Marques, Alexandra Margarida Pinto

    A procura de novos biomateriais que desempenhem funcoes especificas sem, no entanto, desencadearem respostas negativas nos hospedeiros constitui um desafio permanente e actual nesta area. Biomateriais degradaveis foram uma das solucoes propostas e actualmente em aplicacao mas, embora possuam vantagens inegaveis, tambem apresentam alguns problemas nomeadamente no que diz respeito aos seus produtos de degradacao e respectivos efeitos negativos consequentes. Outros biomateriais, entre os quais polimeros de origem natural, foram propostos considerando que os seus produtos de degradacao poderao ser incorporados nas vias metabolicas normais evitando efeitos secundarios no hospedeiro. Ate ao momento, e apesar de todos os esforcos e do grande numero de dispositivos biomedicos desenvolvidos, o biomaterial ideal para uma aplicacao especifica ainda nao foi encontrado. Estudos com polimeros biodegradaveis a base de amido demonstraram que estes materiais possuem propriedades promissoras abrindo novas perspectivas para a sua possivel aplicacao numa variedade de aplicacoes biomedicas. Assim, de modo a demonstrar que estes materiais tem de facto potencial para serem utilizados em, por exemplo, substituicao ossea, sistemas de libertacao controlada, cimentos osseos e engenharia de tecidos, seria imperativo avaliar com maior profundidade a resposta biologica desencadeada pelos mesmos. Para tal foi delineado um plano de trabalhos com tres objectivos principais: i) avaliar a citocompatibilidade dos polimeros e compositos a base de amido com monitorizacao da citotoxicidade e analise da adesao e proliferacao celulares nas suas superficies. Foi dada particular atencao a osteoblastos considerando uma possivel aplicacao ortopedica para estes materiais; ii) estabelecer modelos in vitro para analisar e prever, tanto quanto possivel, uma situacao real de resposta inflamatoria; iii) validar os resultados in vitro com um modelo in vivo ja estabelecido em outros trabalhos de analise da resposta

  7. Application of the {beta}-Decay of Te{sup 132} for the Preparation of I{sup 132} -Labelled Molecules; Application de la Desintegration {sup 132}Te {beta}{sup -} -> {sup 132}I a la preparation de Molecules Marquees; ИСПОЛЬЗОВАНИЕ {beta}-РАСПАДА Te{sup 132} - J{sup 132} ДЛЯ ПОЛУЧЕНИЯ МЕЧЕНЫХ МОЛЕКУЛ; Preparacion de Moleculas Marcadas Aplicando la Desintegracion {sup 132}Te {beta}{sup -} {sup 132}I

    Energy Technology Data Exchange (ETDEWEB)

    Adloff, J. -P.; Adloff-Bacher, M. [Departement de Chimie Nucleaire, Centre de Recherches Nucleaires, Strasbourg (France)

    1963-03-15

    The principal advantage of iodine-132 in biological and medical applications, and in uses as a radioactive tracer, lies in its short half-life (T{sub 1/2} = 2.30 h) which, however, represents a serious drawback for the synthesis of labelled molecules. The paper shows that it is possible to take advantage of the chemical reactivity of 'nascent' iodine, formed during {beta}-decay of tellurium-132, for rapidly preparing labelled species with a high specific activity. This reactivity comes partly from the sudden change of the atomic number during the decay, which in turn releases a highly excited iodine atom, and partly from the internal conversion of the {gamma}-ray following the {beta}-emission. Iodine-132 has to be formed within the medium to be labelled: the most convenient chemical form for the parent compound is tellurium-132 tetrachloride, which is soluble in a number of organic liquids. Several systems have been studied (aromatic hydrocarbons and derivatives, alcohols, etc.)- After a few hours of contact, the organic solution is analysed by gaseous phase radiochromatography, and the separation of the various labelled species formed by radiosynthesis can be effected by distillation after addition of carriers. The labelled products may be the results of isotopic exchange or hydrogen abstraction and fragmentation reactions. Near-specific labelling can be achieved in some cases by the use of a suitable organic medium. (author) [French] La courte periode de l'iode-132 (T{sub 1/2} = 2,30h)qui justifie son interet en biologie, en medecine et comme indicateur radioactif, represente cependant un inconvenient majeur lorsqu'il s'agit de realiser la synthese de molecules marquees. On montre qu'il est possible de tirer profit de la reactivite chimique de l'iode 'naissant ' forme par la desintegration de tellure-132, en vue de preparer rapidement des molecules marquees avec une activite specifique elevee. Cette reactivite provient de l'energie d'excitation de l'iode, due a la brusque variation de la charge nucleaire au cours de la desintegration,ainsi que de la conversion interne du rayonnement y succedant l'emission {beta}. L'iode-132 doit se former au sein du systeme a marquer: la forme chimique la plus appropriee du compose parent est le tetrachlorure de tellure-132, soluble dans un certain nombre de liquides organiques. Plusieurs systemes ont ainsi ete etudies (hydrocarbures aromatiques et derives, alcools, etc.). Apres un contactdequelques heures, la solution organique est analysee par chromatographie en phase gazeuse et les differents composes, marques par radiosynthese, sont separes par distillation en presenced'entraineurs. Les produits marques peuvent etre le resultat de reactions d'echanges isotopiques ou de substitution et fragmentation. L'emploi d'un milieu organique convenable permet dans certains cas un marquage pratiquement specifique. (author) [Spanish] El corlo periodo de semidesintegracion del yodo-132 (T{sub 1/2} = 2,30 h), que justifica su interes en biologia, medicina y como indicador radiactivo entrana no obstante un inconveniente grave cuando se trata de sintetizar moleculas marcadas. Los autores demuestran que es posible sacar provecho de la reactividad quimica del yodo 'naciente' formado por desintegracion del teluro-132 para preparar rapidamente moleculas marcadas de elevada actividad especifica. Esta reactividad se debe a la energia de excitacion del yodo, causada por la brusca variacion de la carga nuclear durante la desintegracion, asi como por la conversion interna de las radiaciones y que suceden a la emision {beta}. El yodo-132 tiene que formarse dentro del sistema que se desea marcar; la forma quimica mas adecuada del compuesto madre es el tetracloruro de teluro-132, soluble en algunos liquidos organicos. De este modo se han estudiado varios sistemas (hidrocarburos aromaticos y sus derivados, alcoholes, etc. ...). Despues de un contacto de algunas horas, la solucion organica se analiza por cromatografia de gases y los diversos compuestos, marcados por radiosintesis, se separan por destilacion en presencia de portadores. Los productos marcados pueden resultar de reacciones de intercambio isotopico o de sustitucion y fragmentacion. En ciertos casos, el empleo de un medio organico conveniente permite lograr una marcacion practicamente especifica. (author) [Russian] Korotkij period poluraspada izotopa J{sup 132} (T{sub 1/2} = 2,3 chasa), kotoryj opravdyvaet Interes, projavljaemyj k nemu v biologii i: medicine, i kotoryj javljaetsja svoego roda radioaktivnym indikatorom, predstavljaet vmeste s tem samoe bol'shoe neudobstvo, kogda idet rech' o provedenii sinteza mechenyh molekul. Otmechaetsja vozmozhnost' ispol'zovanija himicheskoj reaktivnosti 'dochernego' izotopa joda, obrazujushhegosja v rezul'tate raspada Te{sup 1}'3{sup 2} dlja bystrogo poluchenija mechenyh molekul s bol'shoj udel'noj aktivnost'ju. Jeta reaktivnost' voznikaet iz jenergii vozbuzhdenija joda, poduchaemoj v rezul'tate rezkogo izmenenija zarjada jadra v processe raspada, a takzhe vnutrennej konversii, soprovozhdajushhejsja {beta}-izlucheniem, sledujushhej za Je-raspadom. Jod-132 obrazuetsja v sisteme, prednaznachennoj dlja mechenija; naibolee podhodjashhej himicheskoj formoj ishodnogo komponenta javljaetsja chetyrehhloristyj Te{sup 132} v opredelennom organichjoskom rastvo rntele. V svjazi o jetim issledovanijam podvergalis' neskol'ko sistem (aromaticheskie uglevodorody i proizvodnye, spirty i pr.), Posde obluchenija v techenie neskol'kih chasov organicheskij rastvor analizirovalsja metodom gazovoj hromatografii. Razlichnye mechenye komponenty otdeljalis' putem distilljacii s nositelem. Mechenye produkty mogut byt' polucheny v rezul'tate reakcij izotopnogo obmena, zameshhenija i razlozhenija. Ispol'zovanie podhodjashhej organicheskoj sredy pozvoljaet v opredelennyh sluchajah proizvodit' na praktike specificheskoe mechenie. (author)

  8. Phase quantification of mullite-zirconia and zircon commercial powders using PAC and XRD techniques

    Energy Technology Data Exchange (ETDEWEB)

    Rendtorff, Nicolas M.; Conconi, Maria S.; Aglietti, Esteban F. [Centro de Tecnologia de Recursos Minerales y Ceramica (CETMIC: CONICET-CIC) (Argentina); Chain, Cecilia Y.; Pasquevich, Alberto F. [Universidad Nacional de La Plata, Departamento de Fisica, IFLP, Facultad de Ciencias Exactas (Argentina); Rivas, Patricia C. [CONICET (Argentina); Martinez, Jorge A., E-mail: toto@fisica.unlp.edu.ar; Caracoche, Maria C. [Universidad Nacional de La Plata, Departamento de Fisica, IFLP, Facultad de Ciencias Exactas (Argentina)

    2010-06-15

    The short range technique of the Perturbed Angular Correlation (PAC) and x-ray diffraction (Rietveld) methods have been employed to determine the phase content in commercial mullite-zirconia and zircon raw materials that are ordinarily used to produce ceramic materials. The PAC technique, which probes zirconium-containing compounds at nanoscopic level, showed that zircon contains crystalline ZrSiO{sub 4} and an important amount of a structurally distorted zircon, which is also observed accompanying monoclinic zirconia in mullite-zirconia. This particular zircon phase was not detected by the long range x-ray diffraction-Rietveld technique. After an annealing treatment, important changes in crystalline contents of the powders allow confirming, by the x-ray diffraction-Rietveld method, the preexistence of this particular zircon phase. This fact must be taken into account when preparing multicomposites based on the present raw materials.

  9. Crystallite Size and Microstrain Measurement of Cathode Material after Mechanical Milling using Neutron Diffraction Technique

    Directory of Open Access Journals (Sweden)

    A. Fajar

    2010-12-01

    Full Text Available The measurements of neutron diffraction patterns of commercially product and 10 hour mechanically milled cathode material lithium cobaltites (LiCoO2 have been performed. Rietveld analysis using FullProf does not show the change of crystal structure due to milling process, but the diffraction pattern has a lower intensity and the diffraction-line was broadening. The results of line-broadening study on milled sample using Rietveld methods detected that the microstrain was occurred in the sample with value 0.127080(35 % and the average crystallite size was 424.78(20 Å.

  10. Tin-Platinum catalysts interactions on titania and silica

    International Nuclear Information System (INIS)

    Nava, N.; Del Angel, P.; Salmones, J.; Baggio-Saitovitch, E.; Santiago, P.

    2007-01-01

    Pt-Sn was supported on titania and silica, and the resulting interactions between the components in prepared samples and the resulting interactions between the components before and after treatment with hydrogen were characterized by Moessbauer spectroscopy, X-ray diffraction, Rietveld refinement, high-resolution transmission electron microscopy (HRTEM) and catalytic tests data. Results show the presence of Pt and SnO 2 after calcinations, and Pt 3 Sn, PtSn and PtSn 3 after reduction. Rietveld analysis shows that some Ti 4+ are replaced by Sn 4+ atoms in the titania structure. Finally, HRTEM and the practically absence of activity observed confirms that metallic platinum is encapsulated

  11. Sistema Kaizen en la administracion

    Directory of Open Access Journals (Sweden)

    Gallegos, H.

    2007-01-01

    Full Text Available En este artículo presentaremos la importancia que tiene el área de administración como factor de reducción de costos para la empresa aplicando el sistema kaizen. Analizaremos en forma general la administración de las empresas, enfocándonos en las áreas de oportunidad que pueden existir, así como la posible solución a esto, utilizando el sistema kaizen, obteniendo como resultado una reducción de costos, tiempos o mejoras en los procesos administrativos. También se anexa un caso practico en el cual se muestra como aplicando la metodología kaizen en las actividades administrativas podemos lograr una reducción de tiempos y/o costos todo esto causado por la reingeniería de los procesos.

  12. Análisis de la estabilidad actual de la ermita sur en la Hidroeléctrica Mazar

    OpenAIRE

    Almache Sánchez, Luis Mario

    2014-01-01

    La Hidroeléctrica Mazar presenta varios problemas relacionados con taludes inestables que afectan su normal funcionamiento y representan un riesgo para la represa construida. El presente trabajo analiza la estabilidad de la ladera La Ermita Sur ubicado aguas arriba de la presa en el que diferentes factores desencadenaron un movimiento de esta masa. Se realizó una modelación por medios computacionales del talud, analizando como factor primordial desencadenante el agua. Aplicando el mét...

  13. Estudio del riesgo de los suelos contaminados con metales pesados para las infraestructuras de hormigón y valorización de dichos suelos mediante fabricación de morteros con aditivos calizos : aplicación en la Bahía de Portman

    OpenAIRE

    Meseguer Serrano, Fernando

    2016-01-01

    El potente desarrollo experimentado por los paises a nivel mundial durante el siglo pasado, ha generado una fuerte competencia por los recursos naturales que ha hecho insostenible el uso actual del suelo. A nivel europeo se pretende aliviar estas tensiones reintroduciendo en el proceso productivo los residuos susceptibles de ser valorizados, aplicando políticas que tienden a buscar un equilibrio entre prevenir la contaminación actual y recuperar la pasada, y están basadas en los principio...

  14. Estudio y desarrollo de procesos de soporte de negocio en una empresa española perteneciente al sector de las infraestructuras, servicios, ingeniería y sistemas.

    OpenAIRE

    Porcar Tremps, Víctor

    2010-01-01

    El presente proyecto tiene como objetivo principal estudiar y desarrollar procesos de soporte de negocio de una multinacional española, cuya actividad principal es el negocio de las infraestructuras. Las empresas llevan tiempo trabajando para alcanzar la máxima excelencia en la gestión de sus procesos, y para ello han ido aplicando progresivamente los diferentes avances tecnológicos que han ido surgiendo. En este caso la herramienta utilizada es un sistema BPM (Business Process...

  15. Eficacia de la acupuntura en la espasticidad del paciente que ha padecido un ictus. Revisión sistemática

    Directory of Open Access Journals (Sweden)

    Juan Rodríguez-Mansilla

    2016-04-01

    Conclusión: Aunque se muestran mejoras respecto a la reducción de la espasticidad, la eficacia de la técnica no ha podido demostrarse para esta enfermedad. Son necesarios estudios que calculen el tamaño de los efectos reportados, aplicando procedimientos homogéneos en el diseño así como en la duración, frecuencia e instrumentos de medida utilizados.

  16. Análisis, diseño, desarrollo e implementación de políticas y procedimientos para la gestión de los servidores. Caso de estudio: Centro de Investigación IDE-GEOCA.

    OpenAIRE

    Jiménez Erazo, Darwin Ramiro; Osorio Duque, Marcelo Paúl

    2016-01-01

    This project is a case study, where we do an analysis of security by opensource tools, applying OSSTMM and ethical hacking methodology, allowing to identify vulnerabilities in the infrastructure and showing corresponding to each mitigations, defining a scheme basis for the implementation of security policies for the IDE-IA-GEOCA..research..center. El presente proyecto, es un caso de estudio, donde realizamos un análisis de seguridad informática mediante herramientas opensource, aplicando m...

  17. Plan de mercadeo para una promotora de eventos corporativos

    OpenAIRE

    Burbano Zhindon, Andrea Cristina; Chavez Lopez, Maria Cecilia; Orlando Haro, Sofia Pierina; Miranda, Jorge Luis

    2009-01-01

    Este proyecto presenta una alternativa para todas aquellas empresas que realizan eventos frecuentemente, ofreciéndoles un servicio personalizado para la coordinación de cada uno de los detalles que conlleva la organización de un evento. El objetivo fundamental de este estudio es desarrollar un plan de mercadeo para el servicio antes mencionado, aplicando los principios del marketing para su correcta implementación.

  18. Aproximación a un modelo de indicadores de alerta temprana considerando la función de pérdida del Banco Central

    OpenAIRE

    Armagno, Daniel; García Fronti, Javier; Rey, Sebastián

    2004-01-01

    Nuestro interés en este trabajo es estudiar las causas que llevan al debilitamiento de las entidades bancarias. Para ello incluiremos en el análisis, al responsable de la toma de decisiones del Banco Central que tiene en consideración una función de pérdida del tipo desarrollada en Dermirgüç–Kunt, A. and E. Detragiache (1999). Aplicando un modelo logit y evaluamos los resultados obtenidos.

  19. Control borroso para la valoración del impacto ambiental generado por contaminantes emergentes en aguas residuales hospitalarias

    OpenAIRE

    Leadina Sánchez Barboza

    2015-01-01

    La valoración de impactos ambientales está sujeta a imprecisión, vaguedad y subjetividad. Estas características son extensivas al impacto generado por la presencia de contaminantes emergentes -fármacos- en aguas residuales hospitalarias, por lo que este trabajo propone valorar el impacto de dichos contaminantes mediante un sistema de inferencia borrosa, utilizando el toolbox fuzzy logic de MATLAB®, aplicando el sistema experto Mamdani. Los conjuntos borrosos de entrada se establecieron a part...

  20. Bulletin of Materials Science | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    We have studied for the first time the effect of Ag addition (0–15 wt%) to the superconducting system, Nd 1.85 Ce 0.15 CuO 4 , on its crystal structure and local structural features, using synchrotron X-ray diffraction(SXRD) and Raman spectroscopy, respectively. SXRD and subsequent Rietveld refinement studies on powders ...

  1. The iron member of the CPO-27 coordination polymer series: Synthesis, characterization, and intriguing redox properties

    DEFF Research Database (Denmark)

    Märcz, Matthias; Johnsen, Rune; Dietzel, Pascal D.C.

    2012-01-01

    The microporous coordination polymer CPO-27-Fe was synthesized from iron salts and 2,5-dihydroxyterephthalic acid by microwave assisted solvothermal synthesis. The crystal structures of the as-synthesized compounds were determined by Rietveld refinement from powder X-ray diffraction data using...

  2. Magnetic phase transitions in strongly chained semiconductor compounds TIFeS2 and TIFeSe2

    International Nuclear Information System (INIS)

    Asgerov, E.B.; Madadzada, A.I.; Beskropvniy, A.I.; Asgerov, E.B.; Mehdiyeva, R.N.; Madadzada, A.I.; Ismayilov, D.I.; Kerimova, E.M.

    2014-01-01

    Full text: The analysis of diffraction data was carried out by the Rietveld method using the programs VMRIA and FullProf, using as a starting model for the calculations of neutron diffraction profile of X-ray data. The neutron data showed that over the entire temperature range of these compounds have a monoclinic crystal structure symmetry

  3. Direct observations of the MOF (UiO-66) structure by transmission electron microscopy

    KAUST Repository

    Zhu, Liangkui

    2013-01-01

    As a demonstration of ab initio structure characterizations of nano metal organic framework (MOF) crystals by high resolution transmission electron microscopy (HRTEM) and electron diffraction tomography methods, a Zr-MOF (UiO-66) structure was determined and further confirmed by Rietveld refinements of powder X-ray diffraction. HRTEM gave direct imaging of the channels. © 2013 The Royal Society of Chemistry.

  4. Structural and electrical properties of Nd.sub.1.7./sub.Ba.sub.0.3./sub.Ni.sub.0.9./sub.Cr.sub.0.1./sub.O.sub.4+δ./sub. compound

    Czech Academy of Sciences Publication Activity Database

    Jammali, M.; Hassen, R.B.; Rohlíček, Jan

    2012-01-01

    Roč. 27, č. 3 (2012), s. 184-188 ISSN 0885-7156 Institutional research plan: CEZ:AV0Z10100521 Keywords : X-ray diffraction * sol-gel * Rietveld refinement * adiabatic small polaron hopping model * semi-conductive behaviour Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.544, year: 2012

  5. Synthesis, structural and ferromagnetic properties of La1–x Kx ...

    Indian Academy of Sciences (India)

    2016-08-26

    Aug 26, 2016 ... Synthesis, structural and ferromagnetic properties of La1–KMnO3 (0.0≤ 0.25) phases by solution combustion method ... Structural parameters were determined by the Rietveld refinement method using powder XRD data. Parent ... The ratio of the Mn3+/Mn4+ was determined by the iodometric titration.

  6. Quantitative X-ray diffraction analysis of development of Z phase in 12%Cr–Nb–V–N steel

    DEFF Research Database (Denmark)

    Di Nunzio, P. E.; Cipolla, L.; Vipraio, S. Tiberi

    2010-01-01

    . A quantitative determination of the volume fractions of the extracted nitrides that had formed after aging treatments at 650uC for up to 10 000 h was carried out by an X-ray diffraction procedure, based on the Rietveld approach. The investigation of the Z phase evolution by the Johnson...

  7. Magnetic ordering in the rare earth iron germanates HoFeGe2O7 and ErFeGe2O7

    DEFF Research Database (Denmark)

    Cascales, C.; Puebla, E.G.; Klimin, S.

    1999-01-01

    RFeGe2O7 (R = Ho, Er) have been prepared in polycrystalline form, and their crystal structures have been refined from room-temperature high-resolution neutron diffraction data by the Rietveld method. Both materials are isostructural, space group P2(1)/m (no. 11), Z = 4. The most interesting feature...

  8. Structural and compositional stability of the mechanically alloyed (Fe,Mo)-Al at elevated temperatures

    Czech Academy of Sciences Publication Activity Database

    Jirásková, Yvonna; Buršík, Jiří; Roupcová, Pavla; Jančík, D.; Čížek, J.

    2015-01-01

    Roč. 168, NOV (2015), s. 108-116 ISSN 0254-0584 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0068 Institutional support: RVO:68081723 Keywords : Magnetic properties * Electron microscopy * Rietveld analysis * Phase transitions Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.101, year: 2015

  9. Incident spectrum determination for time-of-flight neutron powder diffraction data analysis

    International Nuclear Information System (INIS)

    Hodges, J. P.

    1998-01-01

    Accurate characterization of the incident neutron spectrum is an important requirement for precise Rietveld analysis of time-of-flight powder neutron diffraction data. Without an accurate incident spectrum the calculated model for the measured relative intensities of individual Bragg reflections will possess systematic errors. We describe a method for obtaining an accurate numerical incident spectrum using data from a transmitted beam monitor

  10. 'The End of Sitting' : An Empirical Study on Working in an Office of the Future

    NARCIS (Netherlands)

    Withagen, Rob; Caljouw, Simone R.

    Background Inspired by recent findings that prolonged sitting has detrimental health effects, Rietveld Architecture Art Affordances (RAAAF) and visual artist Barbara Visser designed a working environment without chairs and desks. This environment, which they called The End of Sitting, is a sculpture

  11. Magnetic and ferroelectric characteristics of Gd 3 + and Ti 4 + co ...

    Indian Academy of Sciences (India)

    The crystallographicsite occupancies of Gd and Ti were confirmed by Rietveld refinement of XRD data,Mössbauer spectroscopy and magnetization measurements. An enhancement in ferromagnetic properties along with moderate ferroelectricproperties have been observed after co-doping. There was an increasing trend in ...

  12. Neutron diffraction studies on Ca1− xBaxZr4P6O24 solid solutions

    Indian Academy of Sciences (India)

    P6O24 compositions from combined Rietveld refinements of powder X-ray and neutron diffraction data. All the studied compositions crystallize in rhombohedral lattice (space group R-3 No. 148). A continuous solid solution is concluded from ...

  13. Chemical and structural characterization of natural phosphate of ...

    African Journals Online (AJOL)

    Powder X-ray diffraction fitting results confirm that compound belongs to the apatite family crystallising in the hexagonal system, space group P63/m. The cell parameters are: a = 9.3547(5) Å; c = 6.8929(4) Å. KEY WORDS: Natural phosphate, Fluoroapatite, Infrared, X-Ray diffraction, Rietveld structure refinement. Bull. Chem ...

  14. Synthesis, structural and electrical characterizations of DySr.sub.5./sub.Ni.sub.2.4./sub.Cu.sub.0.6./sub.O.sub.12-δ./sub..

    Czech Academy of Sciences Publication Activity Database

    Hamdi, S.; Ouni, S.; Chaker, H.; Rohlíček, Jan; Ben Hassen, R.

    2011-01-01

    Roč. 184, č. 11 (2011), s. 2897-2901 ISSN 0022-4596 Institutional research plan: CEZ:AV0Z10100521 Keywords : Rietveld refinement * K 2 NiF 4 -type structure * electrical resistivity * oxygen vacancies * iodometric titration Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.159, year: 2011

  15. RAAAF's office landscape The End of Sitting : Energy expenditure and temporary comfort when working in non-sitting postures

    NARCIS (Netherlands)

    Caljouw, Simone R.; de Vries, Rutger; Withagen, Rob

    2017-01-01

    An earlier study suggested that the activity-inviting office landscape called "The End of Sitting", designed by Rietveld Architecture Art Affordances (RAAAF), should be considered as an alternative working environment to prevent sedentary behavior. The End of Sitting lacks chairs and tables but

  16. HgO-added YBa2Cu3O7− δ superconductors

    Indian Academy of Sciences (India)

    The structural studies were carried out by neutron scattering and Rietveld analysis. The neutron scattering revealed that Hg is not incorporated in the Y-123 system and has shown optimum oxygen concentration. The significant role played by the HgO is to provide oxygen ambient through its decomposition, thus changing ...

  17. Quantitative analysis of retained austenite in laser melted martensitic stainless steel

    CSIR Research Space (South Africa)

    Seleka, T

    2007-11-01

    Full Text Available of this study was to determine if X-ray diffraction (XRD) was sufficient for quantifying the volume percentage of retained austenite. After a preliminary qualitative analysis, a Rietveld full pattern refinement program was used to quantify the volume percentage...

  18. Neutron scattering study of combustion-synthesized Ce1− xCuxO2− x

    Indian Academy of Sciences (India)

    Powder neutron diffraction and Hi- neutron diffraction data have been recorded and analysed in order to obtain the local and long range order of Cu in Cu-doped CeO2 with three doping levels of Cu. Rietveld method and MCGR techniques of data analysis for the two types of data reveal that the Cu ion is in the 2+ ...

  19. Computation of X-ray powder diffractograms of cement components ...

    Indian Academy of Sciences (India)

    Computation of X-ray powder diffractograms of cement components and its application to phase analysis and hydration performance of OPC cement. Rohan Jadhav N C Debnath. Volume 34 Issue 5 August 2011 pp 1137- ... Keywords. Portland cement; X-ray diffraction; crystal structure; characterization; Rietveld method.

  20. Minimization of absorption contrast for accurate amorphous phase quantification: application to ZrO.sub.2./sub. nanoparticles

    Czech Academy of Sciences Publication Activity Database

    Suzuki-Muresan, T.; Deniard, P.; Gautron, E.; Petříček, Václav; Jobic, S.; Grambow, B.

    2010-01-01

    Roč. 43, Part 5 (2010), 1092-1099 ISSN 0021-8898 Institutional research plan: CEZ:AV0Z10100521 Keywords : x-ray diffraction * Rietveld refinement * nanoparticles Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.794, year: 2010

  1. Structural behaviour of AgNO3 at low temperatures by neutron ...

    Indian Academy of Sciences (India)

    [4] F El-Kabbany, Y Badr, G Said and S Taha, Appl. Phys. A43, 65 (1987). [5] Z Shen, W F Sherman and G R Wilkinson, J. Mol. Struct. 175, 395 (1988). [6] R Rodriguez-Carvajal, FULLPROF: A Program for Rietveld Refinement, profile matching and integrated intensity, version 3.1 (LLB, France) (1995). [7] R Feyerherm, M F ...

  2. Assessment of the potential hazard represented by natural raw materials containing mineral fibres -The case of the feldspar from Orani, Sardinia (Italy)

    Czech Academy of Sciences Publication Activity Database

    Gualtieri, A. F.; Gandolfi, N. B.; Pollastri, S.; Rinaldi, R.; Sala, O.; Martinelli, G.; Bacci, T.; Paoli, F.; Viani, Alberto; Vigliaturo, R.

    2018-01-01

    Roč. 350, May (2018), s. 76-87 ISSN 0304-3894 R&D Projects: GA MŠk(CZ) LO1219 Keywords : feldspar * tremolite * Rietveld * SEM * EMPA Subject RIV: DB - Geology ; Mineralogy OBOR OECD: Mineralogy Impact factor: 6.065, year: 2016 https://www.sciencedirect.com/science/article/pii/S0304389418300888

  3. Multiscale Biological Materials

    DEFF Research Database (Denmark)

    Frølich, Simon

    of multiscale biological systems have been investigated and new research methods for automated Rietveld refinement and diffraction scattering computed tomography developed. The composite nature of biological materials was investigated at the atomic scale by looking at the consequences of interactions between...

  4. Methane storage mechanism in the metal-organic framework Cu3(btc)2: An in situ neutron diffraction study

    NARCIS (Netherlands)

    Getzschmann, J.; Senkovska, I.; Wallacher, D.; Tovar, M.; Fairen-Jimenez, D.; Düren, T.; van Baten, J.M.; Krishna, R.; Kaskel, S.

    2010-01-01

    The adsorption of deutero-methane (CD4) in Cu3(btc)2 (HKUST-1) was investigated at 77 K using high-resolution neutron powder diffraction. Rietveld refinement of the neutron data revealed a sequential filling of the rigid framework at distinct preferred adsorption sites, and showed the importance of

  5. Bulletin of Materials Science | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Finally microstructural defect parameters such as domain size (), r.m.s. microstrain 〈 2 〉1/2, twin fault ('), spacing fault () and deformation stacking fault () were evaluated in these alloys by Fourier line shape analysis using Rietveld method in which the X-ray diffraction profiles of these alloys were described by the ...

  6. On the Stress-Induced Formation of R-Phase in Ultra-Fine-Grained Ni-Rich NiTi Shape Memory Alloys

    Czech Academy of Sciences Publication Activity Database

    Olbricht, J.; Yawny, A.; Pelegrina, J.L.; Dlouhý, Antonín

    42A, č. 9 (2011), s. 2556-2574 ISSN 1073-5623 R&D Projects: GA ČR GA106/09/1913 Institutional research plan: CEZ:AV0Z20410507 Keywords : martensitic transformations * rietveld method * single-crystals Subject RIV: JG - Metallurgy Impact factor: 1.545, year: 2011

  7. Thermoelastic and structural properties of ionically conducting cerate perovskites: (II) SrCeO3 between 1273 K and 1723 K

    DEFF Research Database (Denmark)

    Knight, Kevin S.; Haynes, Richard; Bonanos, Nikolaos

    2015-01-01

    The temperature dependence of the crystal structure and the thermoelastic properties of SrCeO3 have been determined from Rietveld refinement of high resolution, neutron time-of-flight powder diffraction data collected in 5 K intervals between 1273 K and 1723 K. No evidence was found for critical ...

  8. Synthesis, structure and thermoelectric properties of La1 ...

    Indian Academy of Sciences (India)

    Structural parameters for all the compounds were confirmed by the Rietveld refinement method usingpowder X-ray diffraction (XRD) data and exhibit the rhombhohedral crystal structure with space group R-3c (No. 167). Thescanning electron microscopy study reveals that the particles are spherical in shape and sizes, in the ...

  9. Aplicación de diversos métodos químicos para determinar actividad antioxidante en pulpa de frutos Aplicação de diversos métodos químicos para determinar atividade antioxidante em polpa de frutas

    Directory of Open Access Journals (Sweden)

    E. Marta Kuskoski

    2005-12-01

    Full Text Available El Brazil es considerado un de los principales países productores de zumos de frutos, ocupando en concreto la tercera posición respecto a esto. La diversidad de frutos en el mercado es cada vez mayor, introduciéndose diariamente nuevos frutos tropicales cuyas propiedades y actividades no están aún totalmente determinadas. El gobierno brasileño apoya el comercio exterior de frutos, invirtiendo fondos en exposiciones que promueven y sitúan a los nuevos productos en los países de la Unión Europea, tal como la "Brazilian Fruit Festival" que promociona frutos in natura, pulpas congeladas y zumos procesados. Se publican cada vez en mayor número nuevas investigaciones que asocian el consumo de frutas con efectos beneficiosos para la salud humana. Este trabajo tiene por objeto la determinación del índice de fenoles totales (FT, antocianos totales (AT y la capacidad antioxidante de las pulpas de frutos comerciales congelados, aplicando los métodos espectrofotométrico químicos mas en boga para la determinación de la actividad antioxidante (ABTS, DPPH y DMPD. Se ha determinado la capacidad antioxidante de las pulpas de los frutos tropicales de mayor consumo en el mercado del sur de Brazil (mora, uva, açaí, guayaba, fresa, acerola, piña, mango, graviola, cupuaçu y maracuyá aplicando el método ABTS con medidas a dos tiempos (1 y 7 minutos, DPPH (30 y 60 minutos y DMPD (10 minutos. Los valores TEAC (capacidad antioxidante equivalente al Trolox obtenidos de las pulpas oscilan entre mínimos y máximos de 2,0 y 67,2 µmol/g aplicando el ensayo ABTS, 1,02 y 67,0 µmol/g aplicando DPPH y 4,2 y 46,6 µmol/g aplicando DMPD. La capacidad antioxidante obtenida por los métodos ABTS y DPPH se encuentra correlacionada con el contenido de compuestos fenólicos y antocianos.Considerado um dos principais paises produtores de sucos de frutas, o Brasil é o terceiro maior produtor de frutas tropicais. A diversidade de frutas no mercado é cada vez

  10. Tin-Platinum catalysts interactions on titania and silica

    Energy Technology Data Exchange (ETDEWEB)

    Nava, N. [Instituto Mexicano del Petroleo Lazaro Cardenas 152, 07730 Mexico, D.F. (Mexico)], E-mail: tnava@imp.mx; Del Angel, P. [Instituto Mexicano del Petroleo Lazaro Cardenas 152, 07730 Mexico, D.F. (Mexico); Salmones, J. [Instituto Politecnico Nacional-ESIQIE UPALM, 07738 Mexico, D.F. (Mexico); Baggio-Saitovitch, E. [Centro Brasileiro de Pesquisas Fisicas, Rua Dr. Xavier Sigaud 150, 22290-180 Rio de Janeiro, Brasil (Brazil); Santiago, P. [Instituto de Fisica, UNAM, Mexico, D. F., 04510 Mexico (Mexico)

    2007-09-30

    Pt-Sn was supported on titania and silica, and the resulting interactions between the components in prepared samples and the resulting interactions between the components before and after treatment with hydrogen were characterized by Moessbauer spectroscopy, X-ray diffraction, Rietveld refinement, high-resolution transmission electron microscopy (HRTEM) and catalytic tests data. Results show the presence of Pt and SnO{sub 2} after calcinations, and Pt{sub 3}Sn, PtSn and PtSn{sub 3} after reduction. Rietveld analysis shows that some Ti{sup 4+} are replaced by Sn{sup 4+} atoms in the titania structure. Finally, HRTEM and the practically absence of activity observed confirms that metallic platinum is encapsulated.

  11. Temperature-Induced Desorption of Methyl tert-Butyl Ether Confined on ZSM-5: An In Situ Synchrotron XRD Powder Diffraction Study

    Directory of Open Access Journals (Sweden)

    Elisa Rodeghero

    2017-02-01

    Full Text Available The temperature-induced desorption of methyl tert-butyl ether (MTBE from aqueous solutions onto hydrophobic ZSM-5 was studied by in situ synchrotron powder diffraction and chromatographic techniques. This kind of information is crucial for designing and optimizing the regeneration treatment of such zeolite. The evolution of the structural features monitored by full profile Rietveld refinements revealed that a monoclinic (P21/n to orthorhombic (Pnma phase transition occurred at about 100 °C. The MTBE desorption process caused a remarkable change in the unit-cell parameters. Complete MTBE desorption was achieved upon heating at about 250 °C. Rietveld analysis demonstrated that the desorption process occurred without any significant zeolite crystallinity loss, but with slight deformations in the channel apertures.

  12. Expanding the structural landscape of niclosamide: a high Z ' polymorph, two new solvates and monohydrate HA

    DEFF Research Database (Denmark)

    Sovago, Ioana; Bond, Andrew D.

    2015-01-01

    to be twinned by twofold rotation around that axis. The acetonitrile molecules occupy channels in the structure. A complete structure is provided for niclosamide monohydrate, C13H8Cl2N2O4·H2O, polymorph HA, obtained by Rietveld refinement against laboratory powder X-ray diffraction data. It has been suggested...... that this compound is related to the methanol solvate of niclosamide [Harriss, Wilson & Radosevljevic Evans (2014). Acta Cryst. C70, 758-763], but it is found that the two are not fully isostructural: they contain isostructural two-dimensional layers, but the layers are arranged differently in the two structures....... This suggests that HA may have the potential for polytypism, and features in the Rietveld difference curve indicate that a polytype fully isostructural with the methanol solvate might be present....

  13. High-pressure studies of a ThMn sub 1 sub 2 -type actinide compound: UFe sub 5 Al sub 7

    CERN Document Server

    Halevy, I; Kimmel, G; Atzmony, U; Pereira, L C J; Goncalves, A P; Schäfer, W

    2002-01-01

    The ternary inter-metallic compound, UFe sub 5 Al sub 7 , crystallize in a tetragonal ThMn sub 1 sub 2 type structure. In the as-cast samples a residual phase of FeAl (approx 2% wt) was identified in the grain boundaries. The amount of the residual cubic phase of FeAl was determined by Rietveld analysis and reduced by the annealing process. UFe sub 5 Al sub 7 maintains the tetragonal symmetry as a function of pressure, while FeAl keeps the cubic structure as was determined by the Rietveld analysis. The volume-pressure curve calculated from the x-ray analysis is V/V sub 0 = 0.87 for UFe sub 5 Al sub 7 at 26.0 GPa.

  14. Synthesis and crystal structure of the quaternary compound AgFe{sub 2}GaTe{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Delgado, Gerzon E., E-mail: gerzon@ula.ve [Laboratorio de Cristalografía, Departamento de Química, Facultad de Ciencias, Universidad de Los Andes, Mérida 5101 (Venezuela, Bolivarian Republic of); Quintero, Eugenio; Tovar, Rafael; Grima-Gallardo, Pedro; Quintero, Miguel [Centro de Estudio de Semiconductores, Departamento de Física, Facultad de Ciencias, Universidad de Los Andes, Mérida 5101 (Venezuela, Bolivarian Republic of)

    2014-11-15

    Highlights: • New quaternary compound. • Synthesis from solid state reaction. • Crystal structure. • Rietveld refinement. - Abstract: The crystal structure of the quaternary compound AgFe{sub 2}GaTe{sub 4}, belonging to the system I–II{sub 2}–III–VI{sub 4}, was characterized by Rietveld refinement using X-ray powder diffraction data. The powder pattern was composed by 84.5% of the principal phase AgFe{sub 2}GaTe{sub 4} and 15.5% of the secondary phase FeTe. This material crystallizes with stannite structure in the tetragonal space group I-42m (N° 121), Z = 2, unit cell parameters a = 6.3409(2) Å, c = 12.0233(4) Å, V = 483.42(3) Å{sup 3}, and is isostructural with CuFe{sub 2}InSe{sub 4}.

  15. Applicability of empirical correlations for estimating global solar radiation

    International Nuclear Information System (INIS)

    Gopinathan, K.K.; Baholo, M.

    1987-01-01

    Three empirical models suggested by different investigators, for estimating monthly mean daily global radiation on a horizontal surface, are compared statistically to test their universal applicability. The models thus compared are those suggested by Rietveld, Glover and McCulloch and Gopinathan. The models are compared by calculating the root mean square error, mean bias error and mean relative percentage error values. The model suggested by Gopinathan yields the best results in terms of root mean square, mean bias and mean percentage errors. The model by Rietveld is the second best and the model by Glover and McCulloch comes at third place. However, the differences in the magnitude of errors among the three models are very small and all the three models can be considered to be accurate for global radiation estimation for any location in the world

  16. Transformation of Goethite to Hematite Nanocrystallines by High Energy Ball Milling

    Directory of Open Access Journals (Sweden)

    O. M. Lemine

    2014-01-01

    Full Text Available α-Fe2O3 nanocrystallines were prepared by direct transformation via high energy ball milling treatment for α-FeOOH powder. X-ray diffraction, Rietveld analysis, TEM, and vibrating sample magnetometer (VSM are used to characterize the samples obtained after several milling times. Phase identification using Rietveld analysis showed that the goethite is transformed to hematite nanocrystalline after 40 hours of milling. HRTEM confirm that the obtained phase is mostly a single-crystal structure. This result suggested that the mechanochemical reaction is an efficient way to prepare some iron oxides nanocrystallines from raw materials which are abundant in the nature. The mechanism of the formation of hematite is discussed in text.

  17. Synthesis, magnetic properties and Moessbauer spectroscopy for the pyrochlore family Bi{sub 2}BB Prime O{sub 7} with B=Cr and Fe and B Prime =Nb, Ta and Sb

    Energy Technology Data Exchange (ETDEWEB)

    Blanco, Maria C. [INFIQC (CONICET), Dpto. de Fisicoquimica, Fac. de Ciencias Quimicas, U.N.C., Cordoba (X5000HUA) (Argentina); Franco, Diego G. [INFIQC (CONICET), Dpto. de Fisicoquimica, Fac. de Ciencias Quimicas, U.N.C., Cordoba (X5000HUA) (Argentina); Centro Atomico Bariloche - CNEA, Av. E. Bustillo 9500, S.C. de Bariloche (8500), R.N. (Argentina); Jalit, Yamile; Pannunzio Miner, Elisa V. [INFIQC (CONICET), Dpto. de Fisicoquimica, Fac. de Ciencias Quimicas, U.N.C., Cordoba (X5000HUA) (Argentina); Berndt, Graciele; Paesano, Andrea [Departamento de Fisica, Universidade Estadual de Maringa, Parana (Brazil); Nieva, Gladys [Centro Atomico Bariloche - CNEA, Av. E. Bustillo 9500, S.C. de Bariloche (8500), R.N. (Argentina); Carbonio, Raul E., E-mail: carbonio@mail.fcq.unc.edu.ar [INFIQC (CONICET), Dpto. de Fisicoquimica, Fac. de Ciencias Quimicas, U.N.C., Cordoba (X5000HUA) (Argentina)

    2012-08-15

    The samples Bi{sub 2}BB Prime O{sub 7}, with B=Cr and Fe and B Prime =Nb, Ta and Sb were prepared by solid state method. The crystallographic structure was investigated on the basis of X-ray powder diffraction data. Rietveld refinements show that the crystal structure is cubic, space group Fd-3m. The Bi{sup 3+} cation on the eight-coordinate pyrochlore A-site shows displacive disorder, as a consequence of its lone pair electron configuration. There is also a considerable A-site disorder shown by Rietveld Analysis and confirmed in the case of the iron containing samples with Moessbauer spectroscopy. The magnetic measurements show paramagnetic behavior at all temperatures for the Cr oxides. The Fe pyrochlores show antiferromagnetic order around 10 K.

  18. Interstitial positions of tin ions in alpha-(FerichSn)(2)O-3 solid solutions prepared by mechanical alloying

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Lin, Rong; Nielsen, Kurt

    1997-01-01

    The microstructure of samples of 91, 85, and 71 mol % alpha-Fe-2-O-3-SnO2. prepared by mechanical alloying, has been studied by x-ray diffraction with Rietveld structure refinements, On the basis of the structure refinements to the whole x-ray diffraction patterns for the four as-milled samples, ......, it is found that tin ions do not substitute iron ions in the solid solution, although this model is generally assumed in the literature. The Sn4+ ions occupy the empty octahedral holes in the lattice of the alpha-Fe2O3 phase.......The microstructure of samples of 91, 85, and 71 mol % alpha-Fe-2-O-3-SnO2. prepared by mechanical alloying, has been studied by x-ray diffraction with Rietveld structure refinements, On the basis of the structure refinements to the whole x-ray diffraction patterns for the four as-milled samples...

  19. Applying the X-ray diffraction analysis for estimating the height and width of nanorods in low symmetry crystal multiphase materials

    Science.gov (United States)

    Mokhtari, Ali; Soleimanian, Vishtasb; Dehkordi, Hamed Aleebrahim; Dastafkan, Kamran

    2017-11-01

    In this work the potential of Rietveld refinement procedure is used to study the shape and size of non-spherical nanocrystallites. The main advantages of this approach are that not only it can successfully extend to all nanomaterials with different crystal symmetries but also it can evaluate the various phases of multiple materials comparing to electron microscopy methods. Therefore, between seven crystal systems, the formulation of monoclinic and hexagonal crystals is developed. This procedure is applied for the mixture of sodium carbonate and zinc oxide nanocrystallites at different fractions of doped gadolinium oxide. It is found that the crystallites of sodium carbonate and zinc oxide have the rod and ellipsoidal shapes, respectively. The microstructure results are compared with the results of scanning electron microscopy imaging. Good agreement is achieved between the results of scanning electron microscopy and Rietveld methods.

  20. The peak in neutron powder diffraction

    International Nuclear Information System (INIS)

    Laar, B. van; Yelon, W.B.

    1984-01-01

    For the application of Rietveld profile analysis to neutron powder diffraction data a precise knowledge of the peak profile, in both shape and position, is required. The method now in use employs a Gaussian shaped profile with a semi-empirical asymmetry correction for low-angle peaks. The integrated intensity is taken to be proportional to the classical Lorentz factor calculated for the X-ray case. In this paper an exact expression is given for the peak profile based upon the geometrical dimensions of the diffractometer. It is shown that the asymmetry of observed peaks is well reproduced by this expression. The angular displacement of the experimental profile with respect to the nominal Bragg angle value is larger than expected. Values for the correction to the classical Lorentz factor for the integrated intensity are given. The exact peak profile expression has been incorporated into a Rietveld profile analysis refinement program. (Auth.)

  1. Local and average structures of 0.7Pb(Mg1/3Nb2/3)O3 - 0.3PbZrO3

    International Nuclear Information System (INIS)

    Krishna, P.S.R.; Shinde, A.B.; Narasimhan, S.L.; Tiwari, V.S.; Singh, G.

    2005-01-01

    The local and average structure of 0.7Pb(Mg 1/3 Nb 2/3 )O 3 - 0.3PbZrO 3 (PMN-PZ) was studied by neutron diffraction. The Rietveld refinement was carried out to determine the average, long-range crystallographic structure, while the pair density function (PDF) analysis was used in studying the local atomic structure. The local atomic structure determined by the PDF analysis, was found to be significantly different from the average crystallographic structure determined by the Rietveld analysis. These results show that the conflict between the local structural preference and the average structure is not limited to relax or ferroelectric oxides, but may be widely prevalent in mixed-ion ferroelectrics. (author)

  2. X-ray and electron diffraction studies of the structures of pseudo-perovskite compounds Pb2(Sc,Ta)O6 and Pb2(Mg,W)O6

    International Nuclear Information System (INIS)

    Baba-Kishi, K.Z.; Cernik, R.J.

    1992-01-01

    Electron diffraction patterns, X-ray precession patterns and synchrotron Rietveld powder diffraction profiles were used to study the crystal structure of the pseudo-perovskite compound Pb 2 (Sc, Ta)O 6 (PST). The results of a Rietveld refinement and single-crystal X-ray precession studies showed that PST has a lower symmetry than the cubic Fm3m in the paraelectric state. The remarkable similarities between the crystal structures of the antiferroelectric Pb 2 (Mg, W)O 6 (PMW) and ferroelectric PST are studied in detail by electron diffraction and it is suggested that PST is a weak or frustrated antiferroelectric oxide. The influence of the degree of structural long-range order on the existence of an antiferroelectric phase transition in PST and PMW is discussed. (orig.)

  3. In Situ High Resolution Synchrotron X-Ray Powder Diffraction Studies of Lithium Batteries

    DEFF Research Database (Denmark)

    Amri, Mahrez; Fitch, Andy; Norby, Poul

    2015-01-01

    allowing diffraction information to be obtained from only the active material during battery operation [2]. High resolution synchrotron x-ray powder diffraction technique has been undertaken to obtain detailed structural and compositional information during lithiation/delithiation of commercial LiFePO4...... materials [3]. We report results from the first in situ time resolved high resolution powder diffraction experiments at beamline ID22/31 at the European Synchrotron Radiation Facility, ESRF. We follow the structural changes during charge of commercial LiFePO4 based battery materials using the Rietveld...... method. Conscientious Rietveld analysis shows slight but continuous deviation of lattice parameters from those of the fully stoichiometric end members LiFePO4 and FePO4 indicating a subsequent variation of stoichiometry during cathode delithiation. The application of an intermittent current pulses during...

  4. Effect of titania on the characteristics of a Tin-Platinum catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Morales-Gil, P., E-mail: moralesp@imp.mx; Nava, N. [Instituto Mexicano del Petróleo (Mexico); Baggio-Saitovitch, E. [Centro Brasileiro de Pesquisas Físicas (Brazil)

    2015-06-15

    Pt-Sn bimetallic catalysts dispersed on alumina are commonly used for reforming and dehydrogenation reactions. In this research work, Pt and Sn were supported on titania. The resulting interactions between the components in the prepared samples, before and after treatment with hydrogen, were studied by Mössbauer spectroscopy, X-ray diffraction and Rietveld refinement. The results show the presence of Pt and SnO{sub 2} after calcinations. After the reduction process, metallic Pt, PtSn, and Pt{sub 3}Sn alloys were identified. The Rietveld refinement analysis shows that some Ti{sup 4+} atoms were replaced by Sn{sup 4+} atoms in the titania structure. Finally, the Mössbauer spectroscopy and X-ray diffraction results indicate that metallic platinum and SnO{sub 2} are encapsulated by a TiOx layer.

  5. Characterization of vaterite synthesized at various temperatures and stirring velocities without use of additives

    Czech Academy of Sciences Publication Activity Database

    Ševčík, Radek; Pérez-Estébanez, Marta; Viani, Alberto; Šašek, Petr; Mácová, Petra

    2015-01-01

    Roč. 284, November (2015), s. 265-271 ISSN 0032-5910 R&D Projects: GA ČR(CZ) GP14-20374P; GA MŠk(CZ) LO1219 Keywords : synthesis * vaterite * Rietveld method * morphology * nanoindentation Subject RIV: AL - Art, Architecture, Cultural Heritage Impact factor: 2.759, year: 2015 http://www.sciencedirect.com/science/article/pii/S0032591015005239

  6. Analysis and interpretation of diffraction data from complex, anisotropic materials

    Science.gov (United States)

    Tutuncu, Goknur

    Most materials are elastically anisotropic and exhibit additional anisotropy beyond elastic deformation. For instance, in ferroelectric materials the main inelastic deformation mode is via domains, which are highly anisotropic crystallographic features. To quantify this anisotropy of ferroelectrics, advanced X-ray and neutron diffraction methods were employed. Extensive sets of data were collected from tetragonal BaTiO3, PZT and other ferroelectric ceramics. Data analysis was challenging due to the complex constitutive behavior of these materials. To quantify the elastic strain and texture evolution in ferroelectrics under loading, a number of data analysis techniques such as the single peak and Rietveld methods were used and their advantages and disadvantages compared. It was observed that the single peak analysis fails at low peak intensities especially after domain switching while the Rietveld method does not account for lattice strain anisotropy although it overcomes the low intensity problem via whole pattern analysis. To better account for strain anisotropy the constant stress (Reuss) approximation was employed within the Rietveld method and new formulations to estimate lattice strain were proposed. Along the way, new approaches for handling highly anisotropic lattice strain data were also developed and applied. All of the ceramics studied exhibited significant changes in their crystallographic texture after loading indicating non-180° domain switching. For a full interpretation of domain switching the spherical harmonics method was employed in Rietveld. A procedure for simultaneous refinement of multiple data sets was established for a complete texture analysis. To further interpret diffraction data, a solid mechanics model based on the self-consistent approach was used in calculating lattice strain and texture evolution during the loading of a polycrystalline ferroelectric. The model estimates both the macroscopic average response of a specimen and its hkl

  7. Neutron powder diffraction studies of Hydrogen and Denterium in Palladium Phosphides

    International Nuclear Information System (INIS)

    Andersson, Y.

    1986-01-01

    The use of the Rietveld-type profile refinements on neutron powder diffraction intensity data for determining crystallographic positions of hydrogen and deuterium in metal hydrides is illustrated by results obtained on some hydrogenated and deuterated palladium phosphides. The structural features of the solid solutions of hydrogen and deuterium in Pd/sb15/P/sb2/ Pd/sb6/P and Pd/sb3/P/sb1-u/ (0< u<0.28) are briefly presented and discussed

  8. Characterisation and development of fine porosity in magnesium potassium phosphate ceramics

    Czech Academy of Sciences Publication Activity Database

    Viani, Alberto; Radulescu, A.; Pérez-Estébanez, Marta

    2015-01-01

    Roč. 161, December (2015), s. 628-630 ISSN 0167-577X R&D Projects: GA MŠk(CZ) LO1219 Keywords : amorphous materials * chemically-bonded ceramics * microstructure * Rietveld-RIR method * small-angle neutron scattering * specific surface area Subject RIV: AL - Art, Architecture, Cultural Heritage Impact factor: 2.437, year: 2015 https://juser.fz-juelich.de/record/255737

  9. Determination of the stoichiometric rate in UO2 samples

    International Nuclear Information System (INIS)

    Moura, Sergio C.; Lima, Nelson B. de; Sassine, Andre; Bustillos, Jose Oscar Vega

    2000-01-01

    The gravimetric and voltammetric methods for determination of non-stoichiometric O/U ratio in uranium dioxide used as nuclear fuel are discussed in this work. The oxidation of uranium oxide is very complex due to many phase changes. Gravimetric and voltammetric methods do not detect phase changes. The results of this work shown that, to evaluate both methods is requiring to be done Rietveld methods by X-ray diffraction data to identify the uranium oxide phase changes. (author)

  10. Study of non stoichiometric uranium dioxide samples (UO2)

    International Nuclear Information System (INIS)

    Moura, Sergio C.; Lima, Nelson B. de; Bustillos, Jose O.V.

    1999-01-01

    The gravimetric and voltammetric methods for determination of non-stoichiometric O/U ratio in uranium dioxide used as nuclear fuel are discussed in this work. The oxidation of uranium oxide is very complex due to many phase changes. gravimetric and voltammetric methods do not detect phase changes. The results of this work shown that, to evaluate both methods is requiring to be done Rietveld methods by x-ray diffraction data to identify the uranium oxide phase changes. (author)

  11. Solvothermal growth of a ruthenium metal-organic framework featuring HKUST-1 structure type as thin films on oxide surfaces.

    Science.gov (United States)

    Kozachuk, Olesia; Yusenko, Kirill; Noei, Heshmat; Wang, Yuemin; Walleck, Stephan; Glaser, Thorsten; Fischer, Roland A

    2011-08-14

    Phase-pure crystalline thin films of a mixed-valence Ru(2)(II,III) metal-organic framework with 1,3,5-benzenetricarboxylate (btc) as a linker were solvothermally grown on amorphous alumina and silica surfaces. Based on the Rietveld refinement, the structure of Ru-MOF was assigned to be analogous to [Cu(3)(btc)(2)] (HKUST-1). This journal is © The Royal Society of Chemistry 2011

  12. Structural and spectroscopic investigation of lanthanum-substituted ...

    Indian Academy of Sciences (India)

    Administrator

    and one Y atom form two alternated equilateral triangles at level 1/4 and 3/4 centred on ..... Carpena et al observed that the localization of Nd. 3+ ions in the cationic sites depended ... Atomic coordinates, occupancy factors and thermal parameters after Rietveld refinement of Sr10–xLax(PO4)6–x. (SiO4)xO samples. Wyckoff.

  13. Accurate quantitative XRD phase analysis of cement clinkers

    International Nuclear Information System (INIS)

    Kern, A.

    2002-01-01

    Full text: Knowledge about the absolute phase abundance in cement clinkers is a requirement for both, research and quality control. Traditionally, quantitative analysis of cement clinkers has been carried out by theoretical normative calculation from chemical analysis using the so-called Bogue method or by optical microscopy. Therefore chemical analysis, mostly performed by X-ray fluorescence (XRF), forms the basis of cement plan control by providing information for proportioning raw materials, adjusting kiln and burning conditions, as well as cement mill feed proportioning. In addition, XRF is of highest importance with respect to the environmentally relevant control of waste recovery raw materials and alternative fuels, as well as filters, plants and sewage. However, the performance of clinkers and cements is governed by the mineralogy and not the elemental composition, and the deficiencies and inherent errors of Bogue as well as microscopic point counting are well known. With XRD and Rietveld analysis a full quantitative analysis of cement clinkers can be performed providing detailed mineralogical information about the product. Until recently several disadvantages prevented the frequent application of the Rietveld method in the cement industry. As the measurement of a full pattern is required, extended measurement times made an integration of this method into existing automation environments difficult. In addition, several drawbacks of existing Rietveld software such as complexity, low performance and severe numerical instability were prohibitive for automated use. The latest developments of on-line instrumentation, as well as dedicated Rietveld software for quantitative phase analysis (TOPAS), now make a decisive breakthrough possible. TOPAS not only allows the analysis of extremely complex phase mixtures in the shortest time possible, but also a fully automated online phase analysis for production control and quality management, free of any human interaction

  14. Los Mapas Contables de Gestión de las Empresas Cotizadas Chilenas: Análisis Cualitativo

    OpenAIRE

    Pérez-Benedito, Miguel A; Porcuna-Enguix, Luis; Porcuna-Enguix, Rubén

    2017-01-01

    El artículo analiza las clases de gestión realizadas por las empresas cotizadas chilenas localizadas en los espacios administrativos de Chile. La orientación del análisis realizado considera que el factor cultural de la región donde están localizadas las empresas chilenas condiciona la clase de gestión desarrollada por dichas empresas. El desarrollo de esta hipótesis se realiza aplicando la metodología contable de los gráficos radiales. Las tensiones existentes entre los periodos medios de ma...

  15. Sistema agropecuario integrado usando labranza cero

    OpenAIRE

    Pedro Paneque Rondón

    2003-01-01

    En el trabajo se muestra una tecnología de punta con vistas a desarrollar la explotación de las actividades agrícolas y pecuarias en una misma finca, para la producción de granos, cahe y leche, simultáneamente de forma programada, aplicando la tecnología denominada "Integración Agricultura-Pecuaria", con el propósito de obtener mejor apro v echamiento de los bienes de producción, mano de obra, maquinaria, instalaciones y principalmente el suelo

  16. Direct piezoelectric effect d33 non-linearity in PZT ceramics

    OpenAIRE

    Pérez Pérez, Rafael; Albareda Tiana, Alfonso; Pérez Codina, Estel; García García, José Eduardo; Tiana Alsina, Jordi; Gorri Ochoa, José Antonio

    2006-01-01

    Se ha implementado una nueva técnica de medida aplicando un esfuerzo uniaxial sobre la muestra y midiendo la carga generada. Se aplica un esfuerzo suficientemente intenso para producir efectos no lineales, y se analiza la respuesta no sólo en función de la amplitud del esfuerzo sino de su valor instantáneo. Se ha observado que el coeficiente d33 aumenta siempre linealmente con la amplitud, tanto en las cerámicas PZT comerciales blandas como en las duras, en este último caso al revés de lo qu...

  17. Progreso Técnico y Poder de Mercado en la Industria Textil: Evidencia Empírica para Colombia, 1975-2006

    OpenAIRE

    José B. Gallego-Alzate; Jaime A. Osorio-Usuga; Juan D. Lora-Restrepo

    2011-01-01

    Este trabajo presenta los resultados de un estudio relacionado con la existencia de poder de mercado en la industria textil colombiana desde 1975 hasta 2006. Se utiliza como indicador de poder de mercado el índice de Lerner, obtenido a partir de la generalización del residuo de Solow. La estimación se realiza utilizando series de tiempo obtenidas de la Encuesta Anual Manufacturera y aplicando el método de los mínimos cuadrados ordinarios. La conclusión fundamental es la confirmación de la exi...

  18. RESPUESTA DE 12 VARIEDADES DE TRIGO A LA SALINIDAD EN LAS ETAPAS INICIALES DEL CRECIMIENTO

    OpenAIRE

    L. Argentel; L. M. González; R. Plana

    2006-01-01

    Con el objetivo de analizar la respuesta varietal del cultivo de trigo a la salinidad en las etapas iniciales del crecimiento de las plántulas, se montó un experimento con 12 variedades, aplicando dos niveles de NaCl en la solución. Las variables evaluadas fueron la absorción de agua por las semillas, altura de las plantas y longitud de la raíz, y la acumulación de biomasas fresca y seca. Mediante un análisis de componentes principales, se establecieron los indicadores de mayor contribución a...

  19. Estudio de los Tweens y las Redes Sociales, Tacna, 2016.

    OpenAIRE

    Mamani Mamani, Deysi Gaby; Gonzalo Jara, Gustavo Richard; Yufra Tozo, Wilfredo Renato

    2016-01-01

    La tesis propuesta en las siguientes páginas: “Estudio de los Tweens y las Redes Sociales, Tacna, 2016”, busca poner en evidencia las preferencias, razones de uso, y uso, de las redes sociales por parte del grupo etario conformado por los tweens o pre adolescentes (Niños entre 8 y 12 años). La investigación presentada es de carácter descriptivo, de diseño no experimental y transversal, y se llevó a cabo aplicando un cuestionario (Asistido), conformado por 11 preguntas, a 146 niños entre la...

  20. Análisis estructural de la gestión de la convivencia escolar en centros de buenas prácticas de Andalucía (España)

    OpenAIRE

    Tirado Morueta, Ramón; Conde Vélez, Sara

    2016-01-01

    Este artículo presenta un estudio cuyo objetivo es comprobar desde una perspectiva estructural la influencia de un conjunto de medidas en la reducción de problemas de convivencia. Se toma una muestra de centros con amplia experiencia en la gestión de la convivencia en Andalucía (España), aplicando escalas de medida sometidas a análisis de fiabilidad y validez de constructo. Los resultados permiten corroborar la influencia del liderazgo, la educación en el conflicto, la elabo...

  1. TELECONTROL DE GESTIÓN DE ALARMAS EXTERNAS EN UNA RADIO BASE

    OpenAIRE

    Lizano Bravo, Xavier Gonzalo

    2015-01-01

    El “Telecontrol de Gestión de alarmas externas en una radio base” permite administrar y controlar de maneraremota la posición del mástil telescópico de una radio base móvil de telecomunicaciones, además el sistema de la radio base provee la seguridad necesaria de los equipos dentro la misma, aplicando hardware y software libre lo que permitirá disminuir el coste para las empresas de telecomunicaciones. Para poder administrar la posición del mástil telescópico de la radio base móvil...

  2. COMPETITIVIDAD DE LA PEQUEÑA EMPRESA DEL SECTOR ORNAMENTALES EN ATLIXCO, MÉXICO

    OpenAIRE

    Vlashskiv Mosquera Aldana

    2010-01-01

    El objetivo principal de esta investigación es presentar el perfil competitivo de las pymes del sector ornamentales. Para este análisis se hizo una evaluación de once pymes, aplicando el modelo porteriano. Con las tablas que se presentan en los resultados, es posible realizar una comparación de los factores con los ideales del modelo de medición; dicha comparación permite a los empresarios percatarse de su posición competitiva. Derivado del análisis y la evaluación de la muestra se concluye q...

  3. ANÁLISIS COMPARATIVO DE FRAMEWORKS PARA EL DESARROLLO DE APLICACIONES WEB EN JAVA

    OpenAIRE

    Sánchez Acosta, Carlos; Universidad Señor de Sipán; Tuesta Monteza, Victor; Universidad Señor de Sipán; Mejía Cabrera, Iván

    2015-01-01

    En éste documento se presenta un análisis comparativo de frameworks en Java para el desarrollo de aplicaciones web, aplicando una matriz de un modelo de evaluación. Para analizar los frameworks y seleccionarlos se realizó en base a criterios de madurez y documentación, obteniendo como resultado los Frameworks Spring, Struts, JSF, Angular JS para su evaluación.  Asimismo para el análisis teórico de frameworks se formuló un método QSOS, concebido para definir características comparativas del so...

  4. Efecto de la adición de carragenina kappa i.ii y goma tara sobre características de calidad del jamón de cerdo picado y cocido.

    OpenAIRE

    Restrepo Molina, Diego Alonso; Molina Cote, Fabio Alexander; Cabrera Torres, Kenneth Roy

    2011-01-01

    Se evaluaron sinéresis, color y dureza instrumental y, sensorialmente las características de olor, sabor, color y dureza en jamones inyectados, cocidos y picados de cerdo, los cuales se habían elaborado aplicando en la salmuera de inyección una mezcla de hidrocoloides compuesta por carragenina kappa I.II y goma tara en una proporción de 79:21, en niveles del 1% y 1,2%, usando tres repeticiones para el estudio. Los jamones así elaborados se compararon contra un jamón testigo, elaborado sin el ...

  5. EFECTO DE LA ADICIÓN DE CARRAGENINA KAPPA I.II Y GOMA TARA SOBRE CARACTERÍSTICAS DE CALIDAD DEL JAMÓN DE CERDO PICADO Y COCIDO EFFECT OF THE ADDITION OF KAPPA I.II CARRAGEENAN AND TARA GUM ON QUALITY CHARACTERISTICS OF COOKED AND CHOPPED PORK HAMS

    OpenAIRE

    Diego Alonso Restrepo Molina; Fabio Alexander Molina Cote; Kenneth Roy Cabrera Torres

    2010-01-01

    Se evaluaron sinéresis, color y dureza instrumental y, sensorialmente las características de olor, sabor, color y dureza en jamones inyectados, cocidos y picados de cerdo, los cuales se habían elaborado aplicando en la salmuera de inyección una mezcla de hidrocoloides compuesta por carragenina kappa I.II y goma tara en una proporción de 79:21, en niveles del 1% y 1,2%, usando tres repeticiones para el estudio. Los jamones así elaborados se compararon contra un jamón testigo, elaborado sin el ...

  6. An exploratory study regarding the hypothetical human embryo donation in Peru

    OpenAIRE

    Álvarez Díaz, Jorge Alberto

    2013-01-01

    Objetivo: Explorar opiniones de pacientes que han acudido a técnicas de reproducción asistida (TRA) complejas, respecto a la donación de gametos y embriones, así como las razones para hacerlo o no. Diseño: Estudio transversal de bioética descriptiva, con metodología cualitativa etnográfica, mediante entrevista semiestructurada, aplicando análisis del discurso al texto resultante. Lugar: Clínica privada, en Lima, Perú. Participantes: Veinte mujeres y 12 hombres, quienes habían acudido por lo m...

  7. Influencia de la asimetría de información de mercado en el nivel de ventas de los productores de aguaymanto distrito, Bambamarca, 2013 - 2015

    OpenAIRE

    Vásquez Montenegro, Ellard Eric

    2017-01-01

    La presente investigación desarrollada trata de determinar ¿Cuál es la Influencia de la asimetría de información de mercado en el nivel de ventas del aguaymanto (Phisalis peruviana L.) en productores? del Distrito de Bambamarca, específicamente en los caseríos de Lucmacucho, Cashapampa Bajo y Alto, Nogalpampa y Hualanga pertenecientes al Centro Poblado de Llaucan. El método que se utilizó para resolverlo es el método científico, aplicando la encuesta por tratarse de una ciencia social, con la...

  8. Aumento do Acesso à Internet em Banda Larga no Brasil e Sua Possível Relação com o Crescimento Econômico: Uma Análise de Dados em Painel

    OpenAIRE

    Hildebrando Rodrigues Macedo; Alexandre Xavier Ywata de Carvalho

    2010-01-01

    Aplicando-se modelos econométricos sobre dados em painel, analisou-se o possível relacionamento entre aumento da densidade de acessos de banda larga por habitantes no Brasil e o crescimento do Produto Interno Bruto (PIB) e PIB per capita. Utilizaram-se dados, desagregados por Unidades da Federação (UFs), das densidades de acessos de banda larga, PIB, PIB per capita e escolaridade da população, e dados agregados nacionalmente dos investimentos em telecomunicações. Os dados de densidade de aces...

  9. Violencia de género y procesos de empobrecimiento: estudio de la violencia contra las mujeres por parte de su pareja o ex-pareja sentimental

    OpenAIRE

    Espinar-Ruiz, Eva

    2003-01-01

    El objetivo de esta investigación ha sido analizar las posibles relaciones entre la violencia de la que puede ser objeto una mujer por parte de su pareja o ex-pareja sentimental y diferentes procesos de empobrecimiento. Para ello, aplicando un enfoque de género, se atiende a dos perspectivas: los procesos de empobrecimiento como contexto en el que pueden tener lugar situaciones de violencia y la propia violencia como factor de empobrecimiento. La estrategia metodológica seguida es básic...

  10. Aplicación de la metodología de intervención psicosocial de la Asociación de Expertos en Psicosociología Aplicada - AEPA en una empresa siderometalúrgica

    OpenAIRE

    López-Barón, Francisco; Carrión García, M. Ángeles

    2014-01-01

    Peer-reviewed Estudio de caso de la intervención psicosocial en una empresa siderometalúrgica aplicando la metodología de intervención psicosocial de la Asociación de Expertos enb Psicosociología Aplicada - AEPA. A case study of psycho-social intervention in an iron and steel company applying the methodology of psychosocial intervention of the Association of Applied Psychology Experts - AEPA. Estudi de cas de la intervenció psicosocial en una empresa siderometal·lúrgica aplicant la m...

  11. Aplicación de la Teoría de Restricciones y su Incidencia en los Costos de Producción en la Empresa MIVIRN, de la ciudad de Riobamba provincia de Chimborazo.

    OpenAIRE

    Guananga Díaz, Freddy Román

    2017-01-01

    El presente proyecto de investigación tuvo como objetivo la elaboración una propuesta de mejora para la empresa MIVIRN aplicando la Metodología de la Teoría de Restricciones (TOC), para minimizar los costos de producción. En el desarrollo de la investigación se logra establecer la demanda histórica y en base a esta se proyecta la demanda futura, que permite evaluar y determinar los tiempos estándar, se costea los centros de producción mediante el costeo directo, con estos ...

  12. Protocol synchronization of estrus and ovulation in sheep

    OpenAIRE

    Almeida, Marcelo Ferreira de

    2009-01-01

    Objetivou-se testar o protocolo hormonal para IATF (inseminação artificial em tempo fixo) com progesterona por 6 dias aplicando-se eCG (gonadotrofina Coriônica Eqüina) ou BE (Benzoato de Estradiol) e indução de estros utilizando-se: esponjas vaginais impregnadas com MAP (acetato de medroxiprogesterona) por 6, 9 e 14 dias ou dose única de PGF2a ou efeito macho. Experimento 1: No D0 cada ovelha (n=31) recebeu CIDR sendo divididas aleatoriamente em 3 grupos: G-C (controle) CIDR por 9 dias e na r...

  13. Responsabilidad civil por accidentes en espectáculos taurinos

    OpenAIRE

    Caballero Moreno, María Araceli

    2016-01-01

    El trabajo versa sobre la responsabilidad civil aplicada al campo de los espectáculos taurinos, explicando el régimen de responsabilidad aplicable, regulado en el art. 1.902 de nuestro Código Civil, centrándose especialmente en quién debe asumir la responsabilidad en caso de producirse daños a los espectadores del festejo por los propios animales, si la propia víctima por haber llevado a cabo una conducta imprudente aplicando la teoría de la asunción del riesgo o los organizadores del festejo...

  14. El nexo entre cambio climático y energía renovable en el Mercosur. Un análisis comparativo de las legislaciones de Argentina y Brasil

    OpenAIRE

    Casola, Laura; Freier, Alexander

    2017-01-01

    El sector energético es uno de los principales contribuyentes al cambio climático debido a la combustión de hidrocarburos, por lo que la energía renovable se presenta como una alternativa para promover el desarrollo sustentable. En ese sentido, aplicando una metodología comparativa, este artículo analiza las regulaciones sobre cambio climático y energía renovable en Argentina y Brasil, considerados los dos Estados política y económicamente más fuertes del Mercosur, los cuales están especialme...

  15. Diseño y Construcción de un Electroimán Tipo Solenoide

    OpenAIRE

    Raúl Vargas Alba; Pedro Juárez Molina

    2013-01-01

    Se presenta el desarrollo de un p rototipo experimental aplicando los principios básicos de ele ctromagnetismo mediante la conceptualización de un electroimán simple con su correspondiente diseño, con éste se pretende propiciar que el estudiante de ingeniería en sistemas computacionales del Instituto Tecnológico de Querétaro que cursa el 2º semestre visualice los diversos orígenes de física clásica y una de sus aplicaciones.

  16. Diseño de un modelo de descripción, valoración, clasificación y remuneración de puestos para la empresa Novacero S.A., planta Lasso

    OpenAIRE

    Cajas Garzón, Alexandra Maribel

    2012-01-01

    208 hojas : ilustraciones, 29 x 21 cm El presente proyecto de titulación tiene por objetivo diseñar un Modelo de Descripción, Valoración, Clasificación y Remuneración de Puestos, aplicando la Metodología HAY de Valoración de Cargos por Perfiles y Escalas, para la Empresa NOVACERO S.A. Planta Lasso. Se definió un Mapa de Procesos, considerando los que están orientados a satisfacer las necesidades del cliente interno y externo lo cual es un insumo básico para proceder con la identificación ...

  17. Hacia el establecimiento de un nuevo ethos de la actividad física

    OpenAIRE

    Andrade Patarroyo, Johny Leandro

    2013-01-01

    Tesis (Magister en Educación). Universidad Católica de Manizales, Facultad de Educación, 2013 Esta obra de conocimiento da cuenta de una experiencia de vida, en conjunción con la realidad de los formadores que han puesto en escena su desinterés por los paradigmas contemporáneos de la Actividad Física, en lo referente a su desarrollo formativo. Es decir, aplicando las nuevas tendencias de actividad física como las clases grupales a través de juegos lúdicos, rumba terapia o danza aeróbica;si...

  18. Análisis cuantitativo de cuarzo-alfa en mezclas de cemento portland anhidro y calcita sintética por difracción de rayos X con equipo Philips PW-1700

    Directory of Open Access Journals (Sweden)

    Sagrera-Moreno, J. L.

    1985-09-01

    Full Text Available In this article there are explained the necessary steps to make up a quantitative analysis of alpha-quartz applying the technique of rays X diffraction, in artificial mixtures of anhydrous portland cement and synthetic calcite, which contents are known.

    En el presente artículo se explican los pasos necesarios para realizar un análisis cuantitativo de cuarzo-alfa aplicando la técnica de difracción de rayos X en mezclas artificiales de cemento portland anhidro y calcita sintética, cuyos contenidos son conocidos.

  19. Ambientes de aprendizaje para el desarrollo de habilidades metacognitivas durante la resolución de problemas: estudio longitudinal en estudiantes de los últimos semestres de ingeniería química de la UDLAP

    OpenAIRE

    Ramírez Apud López, Zaira

    2013-01-01

    En la actualidad, se ha demostrado que los profesionistas del área de las ingenierías, son contratados, retenidos y remunerados por la capacidad que muestran en la resolución de problemas del área laboral (Jonassen et al, 2006) Con base en lo anterior, el presente trabajo propone el desarrollo de Ambientes de Aprendizaje Basados en la Solución de Problemas, en estudiantes1 de la Licenciatura en Ingeniería Química durante sus últimos tres semestres de la Carrera, aplicando los procesos de s...

  20. Análisis del Método Leader (2007-2013) en Extremadura mediante técnicas SIG y Análisis Multivariado

    OpenAIRE

    Ana Nieto Masot; Gema Cárdenas Alonso

    2017-01-01

    Durante los últimos 25 años se vienen aplicando en las zonas rurales europeas, y más concretamente en Extremadura, unas estrategias territoriales con la que activar el desarrollo económico de las mismas y disminuir, en lo posible, sus diferencias respecto a las urbanas mediante la diversificación económica del territorio de actuación a través de la puesta en marcha de proyectos cofinanciados por los fondos europeos, las administraciones nacionales y la población local a través del denominado ...

  1. EVALUACIÓN DE ALTERNATIVAS PARA CLIMATIZACIÓN DE ESTANQUES CON ENERGÍA SOLAR PARA CULTIVO DE TILAPIA ROJA (Oreochromis sp), LOCALIZADOS EN LA ZONA FRÍA DEL VALLE DEL CAUCA, COLOMBIA EVALUATION OF ALTERNATIVES FOR AIR CONDITIONING OF PONDS WITH SOLAR ENERGY FOR CULTIVATION OF RED TILAPIA (Oreochromis sp), LOCATED IN THE COLD AREA OF THE CAUCA VALLEY, COLOMBIA

    OpenAIRE

    Francisco Javier Borja Gallardo; Luis Octavio González Salcedo; Victoria Eugenia Quintero de Vallejo

    2006-01-01

    La investigación fue desarrollada para que la tilapia roja (Oreochromis sp), especie de pez mÁs producida en Colombia, pueda ser explotada en lugares donde las condiciones óptimas para su normal desarrollo no son las adecuadas, como son las regiones altas con temperaturas por debajo de los 24 °C, aplicando metodologías relacionadas con el aprovechamiento de la energía solar. Las técnicas evaluadas fueron: climatización por medio de colectores solares, climatización por medio de manta térmica,...

  2. Optimización de un nuevo proceso electroquímico para descontaminación de residuos finos de escombrera de mina

    OpenAIRE

    Nogueira Henriques-Rosa, Manuel Alberto

    2016-01-01

    [ES]La falta de un proceso de descontaminación de residuos de escombreras de mina fue el problema a superar en este trabajo conducente a la obtención del título de doctor. Los estudios iniciales se basaron en la caracterización física y química de los residuos de la mina de wolframio de Barruecopardo (provincia de Salamanca) y sirvieron como base para el posterior estudio sobre la eliminación del arsénico, el hierro y el manganeso presentes en esos residuos aplicando el nuevo método de tr...

  3. Estudio para un Modelo de Gestión de un Acuífero Costero, mediante Metodologías Participativas y Análisis Geoestadístico en el marco del Desarrollo Local. Manglaralto, Ecuador

    OpenAIRE

    Herrera Franco, Gricelda América

    2016-01-01

    El presente estudio se fundamenta en la investigación-acción-participativa (IAP), para buscar alternativas que tiendan al desarrollo local de un territorio. Se centra en la cuenca hidrográfica del rio Manglaralto-Santa Elena-Ecuador, aplicando un sistema metodológico participativo que considera las características peculiares del territorio, que se analizan geoespacialmente reconociendo la influencia de la dinámica de sus cambios y observando los móviles que la propiciaban. A través de mecani...

  4. Las nuevas tecnologías : un enfoque real sobre su aplicación en la creación de comunidades virtuales basadas en la fidelización de clientes a través de estrategias de venta personalizada

    OpenAIRE

    Cutropía Fernández, Carlo

    2002-01-01

    Esta tesis doctoral tiene una finalidad no sólo teórica, de investigación relativa a estrategias de venta personalizada mediante la creación de comunidades virtuales aplicando para ello nuevas tecnologías, sino también práctica, puesto que los resultados de la citada investigación se han desarrollado de hecho y están funcionando con éxito en una comunidad virtual de aproximadamente dieciséis mil personas y el presente trabajose ocupa de presentar y analizar dichos resultados. Este doble enfoq...

  5. Sucesos estresantes y sus impactos en mujeres y jóvenes de la comunidad de cuitzeo, Michoacán: El ciclo de la migración México-EUA en sus familias

    Directory of Open Access Journals (Sweden)

    Nydia Obregón-Velasco

    Full Text Available El presente trabajo describe algunos sucesos de vida estresantes y los impactos que tienen en la salud de las mujeres y sus hijos jóvenes, a partir de la migración hacia EUA de algunos de sus familiares directos, lo cual favorece el ciclo de migración en la familia. Se utilizó la metodología cualitativa con un enfoque de participación-acción, aplicando grupos focales, entrevistas y observación participante durante diferentes actividades realizadas en la comunidad de Cuitzeo, Michoacán, tales como conferencias y talleres.

  6. Determinantes para la estructura de financiamiento de las empresas no financieras: un análisis con datos de panel para Ecuador 2004 y 2006

    OpenAIRE

    Ulloa Mendez, Carmen Isabel; Barrios Villon, Raquel Delcarmen

    2008-01-01

    La presente tesis hace referencia al análisis de los Determinantes para la Estructura de Financiamiento de las empresas ecuatorianas no financieras que cotizan en el mercado bursátil, aplicando la metodología de datos de panel para el periodo comprendido entre 2004 y 2006, para determinar, mediante un recorrido por la literatura teórica, empírica y la posterior aplicación descriptiva y econometrica, los factores explicativos del nivel de endeudamiento, los cuales manifestarán de forma impo...

  7. ABSTRACT IMPLEMENTATION OF A KIND TO MANAGE DATA SETS USING PROGRAMMING LANGUAGE C + +

    OpenAIRE

    Ruiz L., Edgar; Hinojosa L., Hilmar

    2014-01-01

    This article presents the implementation of a data abstract type to represent the Set Theory Mathematical Concept, The program has been written in C++ Program Language applying the Object Oriented Programming Paradigm through a Dev C++ v.4.1 Compiler, a GNU compiler with GPL licence. El artículo presenta la implementación de un tipo abstracto de datos para representar el concepto matemático de la teoría de conjuntos. El programa ha sido escrito en lenguaje de programación C++ aplicando el ...

  8. Política Social Comparada entre países de la Alianza del Pacífico y de la Unión Europea: México, Finlandia y España

    OpenAIRE

    Vidal Figueroa, Carla

    2014-01-01

    En la actualidad no existen estudios comparativos que midan de forma global la política social como input de los gobiernos. Una alternativa es la inclusión de diversos indicadores relevantes para la política social en un solo índice, que permita realizar un análisis estadístico y comparativo de diferentes países. El objetivo de este estudio es conocer la factibilidad de medir la política social basándonos en sus input y aplicando el Social Policy Index (SPI) en tres países de diferente régime...

  9. Modelo de simulación dinámica para la evaluación de la viabilidad financiera de un negocio y la estimación de su probabilidad de éxito

    OpenAIRE

    Robert Hernández Martínez

    2013-01-01

    Un problema típico que enfrentan los pequeños negocios es estimar - con razonable probabilidad – si su empresa tendrá éxito o no. El presente modelo computacional permite evaluar el riesgo de invertir en un proyecto de negocio; aplicando herramientas financieras, estadísticas y de simulación, para responder a preguntas de interés para el futuro emprendedor de un negocio.El modelo está diseñado para solicitar algunos datos de entrada (INPUTS), información clave para procesar el análisis de via...

  10. Arquitectura para sistemas de memoria organizacional en instituciones de educación superior

    OpenAIRE

    Quilca Condori, Alexander Edwin

    2014-01-01

    El presente trabajo de investigación tiene como objetivo definir una arquitectura para sistemas de Memoria Organizacional en Instituciones de Educación Superior. El objetivo surge del problema identificado, en el cual la construcción de sistemas de gestión del conocimiento es tratada como construcción de sistemas típicos, aplicando métodos iterativos que si bien proporcionan versiones tempranas del sistema, no permiten predecir y gestionar adecuadamente el desarrollo del sistema. Además, d...

  11. Evaluación de la modificación del contenido de nitrógeno en una fórmula de fertirriego usada en el cultivo de miniclavel variedad Rony cultivado en sustrato

    OpenAIRE

    Casas Ortiz, Nathalia Rocío

    2015-01-01

    El sector floricultor ocupa un lugar privilegiado en la economía colombiana. En la Sabana de Bogotá se encuentra aproximadamente el 85% del total del área cultivada por flores en nuestro país. El nivel de producción de flores se caracteriza por presentar altos consumos de agua. Esta actividad tiene un gran impacto sobre el ambiente y los costos de producción del cultivo, en especial, cuando las labores de fertirriego se realizan de manera convencional, aplicando dosis de fertirriego uniformes...

  12. Important stages in the development of Romanian accounting profession (from 1800 up to now

    Directory of Open Access Journals (Sweden)

    Adriana Tiron Tudor

    2007-07-01

    contables quedaron destruidos; en el último período, desde 1990 hasta nuestro días, Rumania comenzó a mejorar la convergencia de su sistema contable, aplicando en una primera etapa el modelo francés, para continuar luego en nuestros días con su aproximación a los IFRS. El papel jugado por la profesión contable en las últimas décadas es crucial, debido a su motivación y los deseos de implantar “el mejor” sistema contable, así como su actividad diaria, desarrollada en provecho de sus miembros.

  13. APLICACIÓN DE INGENIERÍA DIRIGIDA POR MODELOS (MDA, PARA LA CONSTRUCCIÓN DE UNA HERRAMIENTA DE MODELADO DE DOMINIO ESPECÍFICO (DSM Y LA CREACIÓN DE MÓDULOS EN SISTEMAS DE GESTIÓN DE APRENDIZAJE (LMS INDEPENDIENTES DE LA PLATAFORMA

    Directory of Open Access Journals (Sweden)

    CARLOS ENRIQUE MONTENEGRO MARÍN

    2011-01-01

    Full Text Available El objetivo general es realizar un modelado específico de dominio para la construcción de módulos en sistemas de gestión del aprendizaje (LMS independientes de la plataforma. Para esto, el punto de partida es un metamodelo para la construcción de un lenguaje específico de dominio (DSL que con ingeniería dirigida por modelos (MDE y aplicando las debidas transformaciones se consiga de un modelo independiente de la plataforma, el despliegue de este modelo se realizara en varias plataformas LMSs.

  14. Identificación y caracterización sindromológica desde la medicina tradicional china (MTC) del cuadro clínico de mujeres ingresadas al Hospital Gíneco-Obstétrico Isidro Ayora (HGOIA) y al Hospital Carlos Andrade Marín (HCAM) con diagnóstico biomédico de preeclampsia CIE10 O14

    OpenAIRE

    Mena Echeverría, Fabián Eduardo

    2017-01-01

    Se estudiaron 30 casos de mujeres ingresadas con diagnóstico de preeclampsia en los hospitales Gíneco Obstétrico Isidro Ayora (HGOIA) y Carlos Andrade Marín (HCAM) de Quito, entre los meses de junio y septiembre de 2016, aplicando la historia clínica de medicina tradicional china ACUMOX, con el fin de identificar los síndromes de la medicina tradicional china (MTC) en estas 30 mujeres. El cuadro clínico de estas mujeres corresponde a 12 síndromes diferentes, desde la óptica de la MTC, de los ...

  15. Causas Jurídicas de la Contaminación Sonora por Ruido, en las principales zonas de la Ciudad de Arequipa, entre los años 2009 al 2013

    OpenAIRE

    Villagómez Riveros, Álvaro Jesús

    2017-01-01

    RESÚMEN El presente trabajo de investigación sobre las Causas Jurídicas de la Contaminación Sonora o también conocido como Ruido Ambiental, parte de la hipótesis por la cual la población arequipeña percibe un gran malestar debido a que siente que no se está aplicando de manera adecuada las correspondientes leyes y normativas para atenuar esta, planteándose como objetivos en el presente trabajo, el explicar las causas jurídicas que tiene la contaminación sonora en la ciudad de Arequipa, det...

  16. Biblioteca 2.0, nuevas estrategias de comunicación y marketing : el caso de la Biblioteca Universitaria de Huelva

    OpenAIRE

    Carvajal Cantero, María de los Ángeles; Escribano Loza, Juan Manuel; Gómez Boullosa, Juan José; González Parra, Inmaculada; Lara Díaz, Isabel; Moyar Godino, Lourdes; Ruiz Fernández, Mar; Yuste Álvarez, José Manuel

    2013-01-01

    La Biblioteca Universitaria de Huelva apuesta por ser una biblioteca 2.0. Aplica sus herramientas y filosofía para mejorar la comunicación con sus usuarios, conocer sus necesidades de información, difundir sus servicios y recursos y mejorar su visibilidad aplicando técnicas de marketing y branding. La BUH está presente en Facebook, Twitter, Tuenti y Flickr, además de tener dos blogs, uno interno (Oberón), y otro abierto (La Buhardilla). Se describen las pautas del grupo de trab...

  17. Deficiencia de Vitamina A y Estado Nutricional Antropométrico en niños MarginalesUrbanos y Rurales en el Estado Zulia, Venezuela

    OpenAIRE

    Amaya-Castellanos, Daisy; Viloria-Castejón, Haydée; Ortega, Pablo; Gómez, Gisela; Urrieta, Jesús R; Lobo, Pablo; Estévez, Jesús

    2002-01-01

    El presente estudio transversal fue realizado para estimar la prevalencia de deficiencia de vitamina A (DVA) y desnutrición proteico-energética en una población infantil (24 a 85 meses) de tres barrios marginales urbanos de Maracaibo Estado Zulia, Venezuela (n=173) y de una zona rural (n=34), vecina a Maracaibo, por medio del análisis del retinol sérico y mediciones antropométricas, aplicando puntuación Z a los indicadores Talla//Edad (ZT//E); Peso//Edad (ZP//E) y Peso//Talla (ZP//T), compara...

  18. Tipos de redes personales de los inmigrantes y adaptación psicológica

    OpenAIRE

    Maya Jariego, Isidro

    2002-01-01

    Elaboramos una tipología de redes de apoyo en un colectivo de inmigrantes marroquíes (n=81), filipinos (n=69) y senegaleses (n=23) residentes en Marbella, aplicando la entrevista Mannheim de apoyo social (MISS) (Veiel, 1990, 1993). Primero realizamos tres análisis de conglomerados exploratorios utilizando como variables-criterio indicadores de (1) composición familiar y étnica, (2) funciones de apoyo, y (3) tamaño y estructura de la red. Los análisis de chi-cuadrado entre las tres clasificaci...

  19. Prevención primaria

    OpenAIRE

    Henao Gaviria, Luis Fernando

    1989-01-01

    Pretende este trabajo sobre "Prevención primaria" brindar en forma general una seria de conceptos sobre la salud y la enfermedad, las diferentes barreras que se pueden interponer para que esta no se presente o si se presenta sea lo menos virulenta posible, si deja secuelas buscar que el paciente las trate de superar y evitar la muerte, se logra lo anterior aplicando los niveles de prevención de Leavell y Clark, se hará enfasis en el 1° y 2° nivel que corresponden al fomento o promoción de la ...

  20. Análisis de nuevas perspectivas de innovación en el sector de la automoción. Reducción de peso en elementos móviles con bajo coste

    OpenAIRE

    Morón Morte, Juan Carlos

    2011-01-01

    El aumento del precio del petróleo, y las nuevas normativas de contaminación, así como la necesidad de crear un vehículo eléctrico de mayor autonomía, ha provocado que las firmas que desarrollan y fabrican automóviles hayan tenido que intensificar sus esfuerzos en reducir el peso de los mismos. Y las puertas de los automóviles, son unos de los elementos en los que se trabaja con empeño para reducir su peso, garantizando siempre su resistencia mecánica y estética, aplicando dife...

  1. ¡Te lo creíste! Sobre cómo la información falsa se introduce en nuestra memoria

    Directory of Open Access Journals (Sweden)

    Malen Migueles

    2008-11-01

    Full Text Available La incorporación de información falsa en la memoria de un suceso delictivo puede alterar el subsiguiente testimonio. Para estudiar la aceptación de tres tipos diferentes de información falsa se realizaron tres experimentos aplicando el paradigma de la información engañosa. Los resultados señalan que los detalles (vs. acciones, los contenidos periféricos (vs. centrales y la información de tipicidad alta (vs. baja se aceptan con mayor facilidad.

  2. Articulación de la participación ciudadana y de las autoridades del cantón Puebloviejo (Prov. De los Ríos) en la gestión del manejo integral de los residuos sólidos, en función del desarrollo local.

    OpenAIRE

    Quinaloa Sisa, Darwin Michael

    2015-01-01

    La presente investigación cuyo enfoque orienta a demostrar mediante una adecuada gestión de residuos, aplicando como herramienta de acción el reciclaje. La problemática medio-ambiental en lo relacionado a los RSU en las comunidades pequeñas tiene varios grados de complejidad articular con la comunidad. Otro aspecto importante es el mejoramiento de la calidad de vida mediante la generación de puestos de trabajo y por consiguiente obtención de beneficios económicos. This research approach...

  3. Preparación Física con niños y jóvenes. Una perspectiva metodológica

    OpenAIRE

    Los Santos i Poquet, Carles

    2000-01-01

    La gran mayoría de los profesionales y no profesionales del entrenamiento deportivo nos movemos o trabajamos sobre todo con niños y niñas de diversas edades y no tanto con categorías de adultos. La infancia y la adolescencia son unas etapas muy delicadas en la vida de la persona y esto me hace pensar si trabajamos con ellos correctamente desde un punto de vista pedagógico, aplicando una metodología adecuada para ellos y si buscamos lo que les corresponde para su edad, a nivel físico y deporti...

  4. Riesgo psicosocial de los trabajadores inmigrantes en España

    OpenAIRE

    Sanchis-Ruiz, A.; Varela-Hall, C.; Martins-Muñoz, G.; Díaz-Sotero, M.

    2013-01-01

    Introducción: España en las últimas décadas ha sido un receptor de un intenso flujo migratorio, sin embargo, por la crisis financiera actual, se está evidenciando un gran descenso. La inmigración está ligada al trabajo y búsqueda de mejores condiciones de vida. El trabajador inmigrante presenta una serie de riesgos psicosociales. Metodología: Se realiza búsqueda en principales bases de datos bibliográficas mediante palabras clave y se descriptores, aplicando posteriormente criterios de pertin...

  5. Interface Móvil para el Sitio Web de la UACO

    Directory of Open Access Journals (Sweden)

    Agustin Moyano

    2016-04-01

    En este trabajo nos enfocamos en desarrollar un prototipo para el sitio Web móvil de la Unidad Académica Caleta Olivia (UACO de la Universidad Nacional de la Patagonia Austral (UNPA considerando al usuario como el centro del diseño y desarrollo. Con esta filosofía en mente, se define un marco de trabajo para el desarrollo del prototipo incorporando recomendaciones de Usabilidad y Accesibilidad Web de referentes internacionales y aplicando herramientas para el diseño inclusivo dirigido a dispositivos móviles.

  6. Factores de éxito de las alianzas estratégicas: el caso de las empresas integradoras mexicanas

    Directory of Open Access Journals (Sweden)

    Francisco Camargo Mireles, Ph.D

    2011-07-01

    Full Text Available El propósito de este trabajo fue explorar los factores de desempeño en las empresas integradoras mexicanas (una forma de alianza estratégica, aplicando un modelo teórico integral derivado de una revisión exhaustiva de la literatura del periodo 1985-2010. Los resultados obtenidos muestran que el desempeño de las alianzas está en función de dos actores: el socio y la alianza, y que cada uno de ellos tiene sus propios factores determinantes.

  7. Optimización del desempeño de un sistema de recomendación de documentos de texto basado en la configuración de los servidores.

    OpenAIRE

    Rodrigo Vences Nava; Víctor Hugo Menéndez Domínguez; Alfredo Zapata González

    2016-01-01

    Cuando se habla de sistemas informáticos en la Web, una de las configuraciones más utilizadas por los desarrolladores es la combinación de Apache y MySql, independientemente del sistema operativo sobre el cuál se desarrolle. En este trabajo se muestra cómo optimizar los tiempos de procesamiento y despliegue de información en el navegador Web de un Sistema de Recomendación de trabajos de titulación, aplicando sencillas configuraciones en el servidor Apache y siguiendo algunas buenas prácticas ...

  8. ¡Te lo creíste! Sobre cómo la información falsa se introduce en nuestra memoria

    OpenAIRE

    Malen Migueles; Karlos Luna

    2008-01-01

    La incorporación de información falsa en la memoria de un suceso delictivo puede alterar el subsiguiente testimonio. Para estudiar la aceptación de tres tipos diferentes de información falsa se realizaron tres experimentos aplicando el paradigma de la información engañosa. Los resultados señalan que los detalles (vs. acciones), los contenidos periféricos (vs. centrales) y la información de tipicidad alta (vs. baja) se aceptan con mayor facilidad.

  9. Eficacia de programas de intervención para el desarrollo de habilidades psicológicas en jóvenes con discapacidad mental

    Directory of Open Access Journals (Sweden)

    Dalia Ma. Aguirre Pérez

    2002-01-01

    Full Text Available Se muestra el desempeño de personas adolescentes y adultas con daño cerebral, después de haber participado en programas de intervención para el desarrollo de habilidades psicológicas, que permitan promover su integración social e independencia personal. El estudio se llevó acabo aplicando la escala de Rogers y D?Eugenio, la evaluación psicológica breve en español (neuropsi y el test guestáltico visomotor de Bender.

  10. Implementación de miniproyectos de investigación: una forma no convencional en los trabajos prácticos de práctica profesional bioquímica

    OpenAIRE

    Pawluk, Diana Beatriz

    2013-01-01

    En la presente tesis, se implementó y evaluó un trabajo práctico innovador, no estructurado, mediante el desarrollo de pequeños proyectos de investigación o “miniproyectos” con finales abiertos, aplicando técnicas de Biología Molecular. Se evaluó el impacto sobre las actitudes que experimentaron los alumnos al realizar una actividad práctica tradicional (Grupo Control), en comparación con la de aquellos que hicieron una actividad práctica no estructurada (Grupo Ensayo), de la Sección Parasi...

  11. Efecto de la fisioterapia en un paciente con cuadriplejia por ependimoma medular

    Directory of Open Access Journals (Sweden)

    Julio César Granados-Carrera

    2014-07-01

    Full Text Available La fisioterapia en pacientes con problemas neurológicos, mejora la capacidad funcional identificando limitaciones provocadas por la lesión aplicando técnicas kinésicas. Se describe los efectos de la fisioterapia en un paciente con cuadriplejía secundaria a ependimoma medular que no recibió tratamiento quirúrgico. La regulación del tono postural favoreció el control postural y el equilibrio en actividades en sedente y en cama. Se obtuvo independencia funcional en actividades básicas de la vida diaria.

  12. Diseño de un prototipo de volante para un vehículo tipo formula SAE mediante técnicas de optimización estructural

    OpenAIRE

    Picón Mejía, Jaime Andrés

    2016-01-01

    En este proyecto técnico se presenta una metodología para el diseño y construcción de un prototipo de volante de dirección para un vehículo tipo formula SAE, aplicando técnicas de optimización estructural considerando procesos de manufactura aditiva. In this technical project, a methodology is presented for the design and construction of a prototype steering wheel for a Formula SAE vehicle, using structural optimization techniques considering additive manufacturing processes.

  13. Perfil psicosocial de la persona emprendedora

    OpenAIRE

    Trejo López, Enrique Alberto

    2015-01-01

    El objeto de la tesis es estudiar el perfil psicosocial de la persona emprendedora y de la emprendedora que continúa a pesar de la crisis, constatando las diferencias respecto al resto de los grupos laborales. Se realiza un estudio multidimensional, psicosocial, de nivel descriptivo y analítico, con un carácter longitudinal, aplicando instrumentos y metodologías cualitativas y cuantitativas y aportando datos disgregado por sexo En el marco teórico recogemos los estudios e investigacion...

  14. Un modelo para la valuación de intangibles. Aplicación a las franquicias de la industria restaurantera en México

    OpenAIRE

    RODRÍGUEZ BATRES, AXEL

    2010-01-01

    La presente Tesis Doctoral se enmarca dentro del campo de la valoración de empresas, aplicando la metodología de valoración analógica a las empresas franquiciadas en el sector de la hostelería en México. El principal objetivo es el desarrollo de un modelo de valoración para el conjunto de las empresas franquiciadas restauranteras que operan en todo el país, con el fin de brindar a los empresarios de este modelo de negocios, una herramienta para la estimación del valor comercial y facilit...

  15. Lean Six Sigma Startup Methodology (L6SSM): una metodología general de innovación de la calidad aplicada a los sectores de la producción y servicios

    OpenAIRE

    García Camús, Juan Manuel

    2015-01-01

    Tesis Doctoral leída en la Universidad Rey Juan Carlos de Madrid en 2015. Director de la Tesis: Javier Martínez Moguerza La calidad, eficiencia, flexibilidad y rapidez en la entrega de un determinado producto o servicio se ha vuelto prioridad en la gestión, lo que ha provocado la necesidad de implementar las llamadas metodologías ágiles. Desde hace pocos años, surge Lean Startup como una nueva tecnología conjunto de éstas y de otras que tradicionalmente se venían aplicando. Las principa...

  16. Investigação sobre a satisfação do usuário dos serviços prestados pelo Metrô de São Paulo: um estudo exploratório, descritivo e ilustrativo com a utilização do modelo de equações estruturais User satisfaction with the Metro of Sao Paulo: an exploratory, descriptive and illustrative study using structural equation modeling

    OpenAIRE

    André Castilho Ferreira da Costa; Saulo Soares de Souza; Letticia Caruso Thomaz da Silva

    2008-01-01

    O objetivo desta pesquisa foi discutir a aplicabilidade da metodologia do American Customer Satisfaction Index (ACSI) a situações da realidade brasileira, com base no modelo de equações estruturais. Para tanto, foi realizada uma verificação empírica do comportamento do modelo, aplicando-o à amostra de dados colhida entre usuários dos serviços prestados pela Companhia do Metropolitano de São Paulo - Metrô. Os resultados confirmaram apenas em parte as relações do modelo, sugerindo, principalmen...

  17. Aceptabilidad a suplementos nutricios en mujeres embarazadas o lactando y niños menores de cinco años

    OpenAIRE

    Martínez Homero; Campero Lourdes; Rodríguez Guadalupe; Rivera Juan

    1999-01-01

    OBJETIVO. Se llevó a cabo un estudio exploratorio para profundizar en aspectos relativos a la aceptabilidad y el apego al consumo de suplementos nutricios que forman parte de un programa gubernamental de apoyo a la nutrición, dirigido a grupos vulnerables. MATERIAL Y MÉTODOS. Se entrevistó a mujeres embarazadas o en lactancia, así como a madres de niños lactantes, niños destetados y niños menores de dos años con desnutrición. Los datos se recolectaron mediante visitas al hogar, aplicando una ...

  18. Propuesta de implementación de una guía de procedimientos para mejorar la eficiencia en los procesos de la Central de Esterilización del Hospital "Dr. Teodoro Maldonado Carbo" de la ciudad de Guayaquil.

    OpenAIRE

    Payez Freire, Eva Cristina

    2015-01-01

    La presente investigación se desarrolló en la central de esterilización del Hospital Teodoro Maldonado Carbo de la ciudad de Guayaquil, perteneciente al Instituto Ecuatoriano de Seguridad Social, con la finalidad de evaluar el nivel de aplicación de los procedimientos obligatorios de esterilización y su relación con el nivel de eficiencia en los resultados obtenidos. Para el logro de los objetivos planteados se desarrolló una investigación de campo aplicando encuestas y entrevistas al...

  19. Estudio de viabilidad de financiamiento a través de un contrato forward de tasas de interés en Empresas del Sector Industrial - metálico en el Ecuador

    OpenAIRE

    Aguayo Yépez, Andrés Gustavo

    2007-01-01

    El presente estudio; orientado a determinar la viabilidad de obtener financiamiento utilizando un mecanismo alterno de endeudamiento a través de contratos derivados, y específicamente aplicando y suscribiendo un “Contrato forward de tasas de interés” (FRA). En cada uno de los fundamentos planteados en el estudio de investigación se ha enfatizado en aspectos tanto de forma como de fondo, esto es, determinando claramente el sector al cual esta dirigido, los participantes en el mercado, las c...

  20. Estrategias para la competitividad en la agroexportación de alcachofa

    OpenAIRE

    Fernández J., Leoncio; Facultad de Economía y Planificación, Universidad Nacional Agraria La Molina (Perú).

    2009-01-01

    Esta investigación tuvo como objetivo definir la estrategias para la competitividad en la agroexportación de alcachofa, aplicando para ello el modelo de Michael porter referida a las estrategias genéricas o generales; pero complementando el análisis con el modelo de Cliff Bowman, que sitúa mas apropiadamente en el entorno la definición de la estrategia. El resultado fue definir el “liderazgo en costos” como estrategia para la competitividad, complementado con una estrategia de diferenciación....

  1. Equilibrio entre fases para la aplicación de solventes verdes en tecnología de alimentos

    OpenAIRE

    Hernández, Elvis J.

    2010-01-01

    [ES]: En este trabajo se presentan los resultados obtenidos del estudio (experimental y teórico) del equilibrio entre fases de compuestos alimentarios y solventes verdes, aportando nuevos resultados a los fundamentos de los procesos de separación por contacto en equilibrio de la tecnología de alimentos. Se obtuvieron nuevos datos de equilibrio entre fases, aplicando métodos experimentales a altas presiones (equilibrio líquido – fluido supercrítico, para el disolvente dióxido de carbono) y ...

  2. La vegetación del peñón de Gibraltar

    OpenAIRE

    Sánchez García, Iñigo; Galán de Mera, Antonio; Cortés, John E.

    2000-01-01

    La vegetación del Peñón de Gibraltar. En el presente trabajo, presentamos un estudio de la vegetación de Gibraltar según la metodología de Braun-Blanquet. Como resultado, proponemos los nuevos sintáxones que aparecen en el resumen en inglés. La principal característica del paisaje vegetal de Gibraltar es que la vegetación natural está muy alterada con la presencia de comunidades fragmentarias. Estas son comentadas aplicando los conceptos de 'comunidad basal' (BC), 'comunidad derivada' (DC) y ...

  3. Aplicación de la nueva plataforma virtual (Moodle) en el proceso de enseñanza/aprendizaje del Análisis de estados financieros en la UCM

    OpenAIRE

    Rodríguez Paredes, Mercedes; Rodríguez López, Ángel; Fidalgo Cerviño, Esther

    2011-01-01

    El objetivo principal de este proyecto es el diseño y desarrollo de metodologías en la enseñanza/aprendizaje universitaria del Análisis de estados financieros, aplicando la filosofía y utilizando las herramientas de la nueva plataforma (Moodle), con el objetivo de contrastar la hipótesis de que la enseñanza a través de la plataforma virtual motivará mucho más a los discentes, de forma que los conocimientos y competencias en el área de referencia se verán ampliamente potenciados. Así, el desar...

  4. Estandarización de la PCR para el diagnóstico del virus de la Hepatitis B en el Perú

    OpenAIRE

    Hijar, G; Carrillo, C; Padilla, C; Cabezas, C; Suárez, M; Romero, G; Montoya, Y

    1998-01-01

    La detección del ADN del virus de la Hepatitis B, (VHB) es el marcador más sensible para determinar la replicación activa e infectividad del virus circulante. Por esta razón la Reacción en Cadena de la Polimerasa (PCR) fue aplicada satisfactoriamente usando primers específicos para gen del antígeno de superficie (HBsAg). Un fragmento de 260 bp fue amplificado in vitro a partir de 200 µl. de sueros de pacientes aplicando PCR. La tecnología de PCR está siendo aplicada en el diagnóstico de pacie...

  5. Seguridad y salud ocupacional en una empresa maderera peruana: 2007-2008

    OpenAIRE

    Fartolino Ushinahua, Gabriela

    2010-01-01

    Objetivo: Conocer la situación de la seguridad y salud ocupacional en una empresa maderera ubicada en la provincia de Loreto, Amazonía peruana, a fin de generar información para tomar medidas correctivas. Método: Para conocer la percepción de los trabajadores se utilizó la técnica de la en-cuesta, aplicando 157 cuestionarios al personal de planta. La información de casos de accidentes y enfermedades fue tomada de las fichas de accidentes de trabajo y los descansos médicos de la oficina de per...

  6. Criminología biológica: Una mirada desde la genética forense/Biological criminology: a view from the forensic genetics

    OpenAIRE

    Rosa Elizabeth Carrera Palao

    2017-01-01

    El presente artículo tiene como objeto establecer el estado del arte en neurobiología en torno a la predisposición genética que determina la conducta agresiva, en el ámbito de las neurociencias, y etiopatogenia de la anatomía patológica en los trastornos de personalidad antisocial, que caracteriza la conducta violenta del comportamiento delictivo, de interés a la criminología biológica. Aplicando el método de búsqueda selectiva no sistemática de información relevante de investigaciones ci...

  7. Burnout y problemas de salud mental en docentes: diferencias segun características demográficas y sociolaborales

    OpenAIRE

    Marenco-Escuderos, Alled Damela; Ávila-Toscano, José Hernando

    2016-01-01

    Resumen A través de este estudio se evaluó la existencia de diferencias entre las manifestaciones de burnout y los problemas de salud mental en docentes de acuerdo con sus características demográficas y sociolaborales. La evaluación se cumplió con 235 docentes del nivel medio académico de cuatro instituciones oficiales en Colombia, aplicando el MBI-Ed y el GHQ-28 a través de un estudio empírico de diseño comparativo. Se observó mayor agotamiento y baja realización profesional entre las mujere...

  8. Aplicación de la metodología de solución de problemas para aumentar la productividad en una empresa textil

    OpenAIRE

    Paredes Sánchez, Luis Carlos; Paredes Sánchez, Luis Carlos

    2014-01-01

    El objetivo del presente informe de suficiencia profesional es presentar la mejora de la productividad en una empresa textil dedicada a la fabricación de cierres aplicando los conceptos de mejora continúa representados en la metodología de solución de problemas los cuales son utilizados en los círculos de calidad. Se inició con un diagnostico funcional de la empresa para conocer sus principales clientes, proveedores y procesos. Después se continuó con la descripción de su pensamiento estra...

  9. Absorción de soluciones preservantes de nueve especies de maderas, mediante procesos de impregnación a vacío - presión e inmersión

    OpenAIRE

    R. Machuca-Velasco; M. Fuentes-Salinas; A. Borja-de la Rosa

    2006-01-01

    El presente trabajo se realizó con la finalidad de conocer la capacidad de absorción de preservadores de las maderas de Pinus arizonica (pino blanco), Pinus engelmanni (pino real), Pinus patula (pino colorado), Ceiba pentandra (ceiba), Manilkara zapota (chicozapote), Spondias mombin (jobo), Quercus insignis (chicalaba), Quercus laurina (laurelillo) y Quercus oleoides (tesmol), aplicando los procesos de impregnación vacío-presión e inmersión con sales CCA (cobre, cromo, arsénico) tipo...

  10. Autoría de aplicaciones móviles para el análisis de datos

    OpenAIRE

    Person Montero, Tatiana

    2018-01-01

    La incorporación de aplicaciones móviles en diversos entornos genera una gran cantidad de información resultante de la interacción de los usuarios con estas aplicaciones. El análisis de esta información puede ser de gran utilidad para el profesional, ya que le puede facilitar la toma de decisiones o la valoración del proceso que esté aplicando, permitiendo mejorar los resultados o detectar determinados patrones. La información recogida se puede definir siguiendo una serie de características: ...

  11. Marketing relacional en el sistema financiero español

    OpenAIRE

    Casariego Mogo, Diego

    2013-01-01

    Por lo tanto, nos planteamos en este trabajo conocer cómo un entorno de crisis económica ha afectado a las empresas bancarias en cuanto a sus políticas de marketing de relaciones, tratando de relacionar la situación económica de la entidad con sus estrategias de marketing relacional a través de análisis de casos concretos. Además, presentaremos una aproximación empírica que nos permita determinar aquellas entidades que están aplicando un mayor enfoque relacional.

  12. Un marco de trabajo para la Integración de Arquitecturas de Software con Metodologías Ágiles de Desarrollo

    OpenAIRE

    Vivas, Luis; Cambarieri, Mauro; García Martínez, Nicolás; Petroff, Marcelo; Muñoz Abbate, Horacio

    2013-01-01

    La construcción de software dentro de un marco metodológico ágil ofrece la posibilidad de contar con procesos livianos y simples, aplicando técnicas de programación que permiten expresar el concepto de agilidad, garantizando código de calidad desde el inicio del proceso de desarrollo. Algunas técnicas que han sido probadas en metodologías tradicionales de desarrollo de software son usualmente utilizadas en metodologías ágiles, como por ejemplo las pruebas de unidad. En este trabajo propone...

  13. Factores de contaminación ambiental por el desarrollo de proyectos petroleros en el Caño el Ingeniero, municipio de Puerto Gaitán Meta

    OpenAIRE

    Martínez Gómez, Sonia Janneth

    2017-01-01

    Tesis (Maestría en Desarrollo Sostenible y Medio Ambiente). Universidad de Manizales. Facultad de Ciencias Contables, Económicas y Administrativas. CIMAD, 2016 Con esta investigación se quiere realizar un estudio en el caño el ingeniero para determinar los principales factores y causas de contaminación, aplicando métodos de recolección de muestras para análisis y/o determinación de los valores de las fuentes de agua y posteriormente obtener unos resultados para realizar un análisis de lo q...

  14. Videojuegos en redes sociales: aprender desde experiencias óptimas

    OpenAIRE

    Esnaola Horacek, Graciela; Levis, Diego

    2009-01-01

    Desarrollaremos conceptos de interés académico acerca de las posibilidades educativas que actualmente ofrecen los entornos lúdicos en la Web 2.0, capturando el interés generalizado de los estudiantes. Destacaremos una definición particular de videojuego aplicando determinadas categorías de análisis a las propuestas lúdicas que ofrecen las redes sociales, en especial el caso Facebook. La línea que destacamos durante nuestra trayectoria de investigación se ubica en los entrecruzamientos que ...

  15. Análisis multivariado y QFD como herramientas para escuchar la voz del cliente y mejorar la calidad del servicio

    OpenAIRE

    Gutiérrez Pulido,Humberto; Gutiérrez González,Porfirio; Garibay López,Cecilia; Díaz Caldera,Lizbeth

    2014-01-01

    Las organizaciones del sector servicios contribuyen con un alto porcentaje del producto interno bruto de las principales economías del mundo, esto genera la necesidad de buscar alternativas para mejorar los procesos de este sector. Es reconocido que escuchar la voz del cliente es un buen punto de partida para evaluar la calidad de un servicio. Es frecuente que se busque escuchar al cliente aplicando algún cuestionario o encuestas. Sin embargo, debido a los múltiples ítems de las encuestas, es...

  16. MODELOS REALISTAS EN LA VERIFICACIÓN DEL ESFUERZO CORTANTE EN ELEMENTOS DE HORMIGÓN ARMADO

    Directory of Open Access Journals (Sweden)

    Francisco Aguirre

    2015-07-01

    En este artículo se proponen modelos basados en la TCCM y TCCMS y se muestra resultados de ejemplos aplicando estos modelos comparándolos con las normas ACI 318-11 y CAN23.3-04. En el cálculo de la armadura transversal, la variación entre la TCCM y las normas ACI 318-11 y CAN23.3-04 fue de 33% y 64% respectivamente y la variación entre la TCCMS y las normas ACI 318-11 y CAN23.3-04 fue de 2% y 25% respectivamente.

  17. PROGRAMA DE INTERVENCION PARA ELEVAR LOS NIVELES DE AUTOESTIMA EN ALUMNAS DE SEXTO AÑO BASICO

    OpenAIRE

    Valdés G, Lídice

    2001-01-01

    Este trabajo corresponde a un estudio de medición de los Niveles de Autoestima en las escalas General, Social, Escolar y Hogar, a través del Inventario de Autoestima de Coopersmith (1984), en niñas de sexto año básico, Escuela México de Valdivia, con rasgos de inmadurez en la interacción social. Se realizaron dos mediciones, aplicando el diseño preexperimental de pretest y postest al mismo grupo-curso. Los resultados de las mediciones, efectuadas el primer semestre de los años 1999 y 2000, mu...

  18. Gobierno y modelado de la seguridad de la información en las organizaciones

    OpenAIRE

    Ontoria Gonzalo, Sandra

    2011-01-01

    En este proyecto se estudia el entorno de Gobierno de Seguridad de la Información, con la finalidad de establecer un análisis y diseño de un Sistema de Gobierno de Seguridad de la Información. El entorno de Gobierno se centra en la normativa ISO 27000, aplicando modelos de procesos como Cobit e ITIL, modelos de madurez y métricas para garantizar la Seguridad de la Información a alto nivel, bajo la normativa legal vigente. Asimismo, se van a analizar las herramientas de mercado orientada...

  19. Evaluación de destinos turísticos mediante la tecnología de la ciencia de datos

    OpenAIRE

    Amaya Molinar, Carlos Mario; Magaña Espinoza, Pedro; Ochoa Llamas, Ileana

    2017-01-01

    Se presentan resultados de un estudio exploratorio aplicando una metodología de Big Data a dos destinos turísticos mexicanos, utilizando la modalidad de análisis de sentimientos y opiniones en comentarios publicados en línea sobre cuatro modalidades de servicios turísticos: atractivos turísticos, hospedaje, alimentos y bebidas y transporte. La metodología emite evaluaciones positivas, negativas y neutrales sobre cada uno de los establecimientos y servicios analizados; los datos se tomaron de ...

  20. Aplicación de dos pruebas estadísticas de bondad de ajuste en muestras complejas: un caso práctico en el campo forestal

    OpenAIRE

    Quintero-Méndez, María A.; Durán-Núñez, Mariano J.

    2008-01-01

    En esta investigación se comparan dos pruebas de bondad de ajuste en términos de su error tipo I: ji-cuadrada de Pearson y Rao-Scott con corrección de segundo orden, aplicadas a datos recolectados mediante técnicas de muestreo que no cumplen los supuestos de independencia e igual probabilidad de inclusión de las observaciones, llamadas muestras complejas. Ambas pruebas se usaron para ajustar categorías diamétricas en una plantación de gmelina (Gmelina arborea), aplicando muestreo sistemático ...

  1. Evaluación de riesgos ergonómicos del puesto de auxiliar de topografía en las empresas de construcción

    OpenAIRE

    Gros, Joaquín

    2012-01-01

    El Fundamento Básico objeto del trabajo, es adquirir la destreza suficiente en el manejo de los métodos de evaluación de riesgos ergonómicos, aplicando y desarrollando de manera práctica los conocimientos teóricos vistos en la fase anterior del máster. Para ello, en el desarrollo de este trabajo se va a proceder a realizar la evaluación de los riesgos ergonómicos a los que está expuestos los trabajadores que ocupan el puesto de Auxiliar de Topografía en las obras de construcción.

  2. The element of leadership in the validation of a model of quality management for schools

    OpenAIRE

    Alfaro, Pablo López

    2010-01-01

    A medida que el país alcanza mejor estado de desarrollo, las organizaciones no educacionales han incorporado paulatinamente a su quehacer, elementos de liderazgo, planificación estratégica, de desarrollo organizacional y evaluaciones de la calidad de su gestión, aplicando planes sistemáticos de mejoramiento. Este acento en la gestión también se ha manifestado en el ámbito de las instituciones educativas, siendo el liderazgo uno de los factores de mayor incidencia en la gestión de estas organi...

  3. El componente liderazgo en la validación de un modelo de gestión escolar hacia la calidad

    OpenAIRE

    Alfaro,Pablo López

    2010-01-01

    A medida que el país alcanza mejor estado de desarrollo, las organizaciones no educacionales han incorporado paulatinamente a su quehacer, elementos de liderazgo, planificación estratégica, de desarrollo organizacional y evaluaciones de la calidad de su gestión, aplicando planes sistemáticos de mejoramiento. Este acento en la gestión también se ha manifestado en el ámbito de las instituciones educativas, siendo el liderazgo uno de los factores de mayor incidencia en la gestión de estas organi...

  4. DETECCION Y RECONOCIMIENTO DE ROSTROS

    OpenAIRE

    Tinoco Martínez, Sergio Rogelio

    2012-01-01

    En el presente trabajo se revisa el algoritmo propuesto por Moghaddam et al. en [Moghaddam95a] para la detección automática de rostros y para el proceso complementario de reconocimiento facial en [Moghaddam96]. Aunque no se proporciona una aportación nueva se pudo comprobar en una implementación propia, aplicando varias simplificaciones al desarrollo original de Moghaddam, el desempeño reportado en cuanto al reconocimiento facial se trata. Sin embargo, en cuanto a la combinación de detecci...

  5. COSTES SANITARIOS DIRECTOS DE LAS NEOPLASIAS DE PULMÓN Y VEJIGA DE ORIGEN LABORAL EN ESPAÑA EN 2008

    OpenAIRE

    Montserrat García Gómez; Rosa Urbanos Garrido; Rosario Castañeda López; Patricia López Menduiña

    2012-01-01

    Fundamentos: La falta de reconocimiento del origen laboral de algunos tumores malignos conlleva que el coste de su asistencia sanitaria recaiga sobre el Sistema Nacional de Salud. El objetivo de nuestro estudio es conocer el número de procesos atendidos por cáncer de pulmón y vejiga atribuibles al trabajo en España en el Sistema Nacional de Salud (SNS) en 2008, así como los costes sanitarios derivados de su atención. Métodos: El número de procesos se estimó aplicando las fracciones atribuible...

  6. Generación de políticas para la gestión de riesgos de seguridad en el desarrollo de software.

    OpenAIRE

    Montalvo Armijos, Renny Geovanny

    2017-01-01

    El objetivo fue generar políticas para la gestión de riesgos de seguridad en el desarrollo de software en el Consejo de la Judicatura, la investigación empieza al generar un ambiente de pruebas en el que se encuentran configurados en el mismo servidor dos aplicaciones prototipo, los mismos que se configuran, una aplicando las políticas generadas, y otra sin aplicar las políticas. Como resultado de la investigación, al aplicar las políticas y utilizarlas durante la etapa de desa...

  7. Demostraciones algebraicas de las ecuaciones cuadráticas en SHARḤ AL-URJŪZA AL-YĀSMĪNIYYA de IBN AL-HĀ'IM

    OpenAIRE

    Fadil, Abdelaziz; Puig, Luis

    2014-01-01

    El álgebra árabe es operar con cantidades desconocidas aplicando las mismas reglas aritméticas que operan con los números conocidos. Esta conceptualización, junto con la definición de las especies de números, ha facilitado el desarrollo del cálculo algebraico de las expresiones algebraicas. En particular, ha permitido la denominación, enunciación, clasificación y formulación de seis ecuaciones cuadráticas. Se han propuesto demostraciones ingenuas, geométricas y algebraicas de lo...

  8. Efecto de extractos vegetales de polygonum hydropiperoides, solanum nigrum y calliandra pittieri sobre el gusano cogollero (spodoptera frugiperda)

    OpenAIRE

    Lizarazo H., Karol; Mendoza F., Cristina; Carrero S., Rocío

    2009-01-01

    El gusano cogollero Spodoptera frugiperda es una de las plagas que más afectan los cultivos en la región de Sumapaz (Cundinamarca, Colombia). En la actualidad se controla principalmente aplicando productos de síntesis química, sin embargo la aplicación de extractos vegetales surge como una alternativa de menor impacto sobre el ambiente. Este control se emplea debido a que las plantas contienen metabolitos secundarios que pueden inhibir el desarrollo de los insectos. Por tal motivo, la present...

  9. Guía de Aplicación de la Técnica de Calidad Seis Sigma en el Proceso de Desarrollo de Software

    OpenAIRE

    Hinojosa, C.; Monge, D.; Mosquera, V.

    2016-01-01

    El objetivo del presente proyecto, ha sido desarrollar una guía que permita mejorar el nivel de eficiencia en el control de calidad del proceso de desarrollo de software, aplicando la técnica Seis Sigma, en base a un análisis situacional que evidencie la realidad de las prácticas de calidad en la industria del software ecuatoriano. Los fundamentos sobre el proceso de desarrollo de software, certificaciones de calidad, y Seis Sigma, fueron obtenidos mediante una metodología de investigación ti...

  10. Amor y enamoramiento en personas con discapacidad intelectual. Un campo por explorar

    OpenAIRE

    Morentin, R.; Arias, B.; Verdugo Alonso, Miguel Ángel; Rodríguez Mayoral, José Manuel

    2006-01-01

    El amor es considerado uno de los fenómenos interpersonales más importantes, relacionándose además con la salud, la felicidad y el bienestar general. Sin embargo, el acercamiento científico al amor como objeto de estudio no se ha ampliado a las personas con discapacidad intelectual, aun cuando sí se estén desarrollando programas y actuaciones centradas en la educación afectivo-sexual. En este estudio, se pretende iniciar este camino (aún desconocido), aplicando la conocida Escala Triangular d...

  11. Dificultades conceptuales para predecir equilibrios químicos homogéneos y heterogéneos

    OpenAIRE

    López González, W.

    2009-01-01

    En este trabajo quedan evidenciados los errores conceptuales en una muestra a la que se aplicó un instrumento, en el que se le planteó distintas situaciones para predecir el desplazamiento de un sistema en equilibrio. Se presentaron dificultades aplicando el principio de LeChatelier en cuanto a: comparaciones masa-concentración, inyección de un gas inerte al sistema, a volumen (V) y temperatura (T) constantes, inyección de uno de los gases intervinientes en el equilibrio a presión (P) y T con...

  12. Evaluación de los contenidos de información de medicamentos en un grupo de agencias reguladoras de medicamentos

    OpenAIRE

    Gil Rojas, Yaneth

    2016-01-01

    OBJETIVO: Evaluar las diferencias de información publicada por el Invima y otras Autoridades Reguladoras de Medicamentos en relación a un grupo de variables seleccionadas y analizar las diferencias aplicando estrategias de visualización de datos. METODOLOGÍA: Estudio descriptivo de corte transversal, en el cual se comparan las diferencias en la información de medicamentos publicada en las agencias reguladoras de medicamentos. Para la definición de los criterios de comparación, más relevantes ...

  13. Exploración de la violencia sexual en la ciudad de Bogotá: una aplicación de técnicas de minería de datos

    OpenAIRE

    Nelson J. Garnica; Ángela Marcela Olaya Murillo

    2011-01-01

    Este estudio ofrece una aproximación a la violencia sexual utilizando datos de fuente secundaria y aplicando algunas técnicas de minería de datos. La fuente de datos utilizada es el Instituto Nacional de Medicina Legal y Ciencias Forenses, y los algoritmos aplicados son Selección por Características, C5.0 y K-Means. Antes de la aplicación de dichas técnicas se hace una aproximación teórica a la violencia sexual, para apreciar la forma como se ha abordado este tipo de violencia y la manera com...

  14. Atividade residual de diuron, oxyfluorfen e prometryne no controle de Euphorbia heterophylla Residual activity of diuron, oxyfluorfen, and prometryne for Euphorbia heterophylla control

    OpenAIRE

    R.S. Oliveira Jr.; J.C. Carneiro; J. Constantin; G. Santos; A.C. Francischini; A.M. Oliveira Neto

    2012-01-01

    As aplicações de herbicidas em pré-emergência têm por finalidade a obtenção da atividade residual no início do ciclo das culturas. Assim, o objetivo deste trabalho foi avaliar a atividade residual dos herbicidas diuron, oxyfluorfen e prometryne, aplicados isoladamente ou em misturas, no controle de Euphorbia heterophylla. Oito experimentos foram conduzidos em casa de vegetação, aplicando-se doses dos herbicidas ou das misturas aos 30, 20, 10 e 0 dias antes da semeadura da planta daninha (DAS)...

  15. La comunicación de las emociones

    OpenAIRE

    García Fernández, José-Lorenzo

    1991-01-01

    Revisión histórica de las aportaciones más significativas de la filosofía, antropología, etología, psicología, etc. acerca de la emoción en sus aspectos expresivo y comunicativo. Identifica, asimismo, las estructuras y regiones del cerebro relacionadas con las emociones e investiga en profundidad el lenguaje del rostro humano. En la segunda parte, la tesis realiza un análisis de algunas obras cinematográficas aplicando las categorías del "análisis transaccional" y de las disciplinas que estud...

  16. Alterações do desenvolvimento de crianças prematuras nascidas de mães com malária no periodo gestacional

    OpenAIRE

    Simões, Maria da Conceição Ribeiro

    2012-01-01

    Objetivo : O estudo buscou avaliar as alterações no desenvolvimento de crianças prematuras nascidas de mães com malária no periodo gestacional, em Porto Velho, Rondônia. O objetivo principal é descrever as alterações encontradas nessas crianças aplicando um teste preditivo para alterações no desenvolvimento e compará-las à um grupo controle de crianças prematuras nascidas de mães que não apresentaram malária no periodo gestacional. Métodos : Por ser um estudo do tipo transvers...

  17. Utilidad de la relación estratégica comunitaria y el marketing en el sector de bebidas alcohólicas

    OpenAIRE

    Mendieta Pinzón, Waldo Alejandro; Navarro Duque, Francisco José; Romero Sierra, Edisson Alejandro

    2014-01-01

    El estudio busca demostrar la utilidad que tiene la relación estratégica comunitaria en el sector de bebidas alcohólicas en Colombia y cómo la utilizan a través del marketing. Cómo estas funcionan en el sector y si las organizaciones las están aplicando; si lo hacen qué tipo de estrategias emplean para adentrarse y relacionarse con su entorno. Se identifica la efectividad de estas estrategias; si en realidad están promoviendo el desarrollo de la comunidad como el de la organización y paso a s...

  18. A vueltas con la alfabetización visual: lenguaje y significado en las películas de Wes Anderson

    OpenAIRE

    Ferreras Rodríguez, José Gabriel; Leite, Lucimeire Virgilio

    2008-01-01

    El presente artículo tiene por objetivo discutir algunos elementos del concepto de la alfabetización visual, aplicando, luego, las herramientas de análisis de imágenes a las películas de Wes Anderson, como ejemplos del manejo intencional de las imágenes para transmitir determinados significados. The present article aims to discuss, firstly, some elements encompassed in the definition of visual literary and, secondly, to apply some image analysis tools to Wes Anderson’s movies, as examples ...

  19. A vueltas con la alfabetización visual: lenguaje y significado en las películas de Wes Anderson

    OpenAIRE

    José Gabriel Ferreras Rodríguez; Lucimeire Vergilio Leite

    2008-01-01

    El presente artículo tiene por objetivo discutir algunos elementos del concepto de la alfabetización visual, aplicando, luego, las herramientas de análisis de imágenes a las películas de Wes Anderson, como ejemplos del manejo intencional de las imágenes para transmitir determinados significados. The present article aims to discuss, firstly, some elements encompassed in the definition of visual literary and, secondly, to apply some image analysis tools to Wes Anderson’s movies, as examples of...

  20. A vueltas con la alfabetización visual: lenguaje y significado en las películas de Wes Anderson

    Directory of Open Access Journals (Sweden)

    José Gabriel Ferreras Rodríguez

    2008-01-01

    Full Text Available El presente artículo tiene por objetivo discutir algunos elementos del concepto de la alfabetización visual, aplicando, luego, las herramientas de análisis de imágenes a las películas de Wes Anderson, como ejemplos del manejo intencional de las imágenes para transmitir determinados significados. The present article aims to discuss, firstly, some elements encompassed in the definition of visual literary and, secondly, to apply some image analysis tools to Wes Anderson’s movies, as examples of intentional pictorial organization so as to convey specific meanings.

  1. La mortalidad feto-infantil y de menores de 5 años en Cuba: período 2000-2010. The fetal- infant mortality and under 5 years in Cuba: 2000-2010

    OpenAIRE

    Lorenzo I. Herrera León

    2015-01-01

    La etapa fetal es vital para el desarrollo y bienestar del futuro ser humano, de ahí que el presente trabajo se haya propuesto como objetivo analizar la evolución de la mortalidad feto-infantil y de menores de 5 años durante el decenio 2000-2010, en Cuba. Para el logro de este se realizaron estimaciones de los eventos vitales que acompañan al proceso del embarazo (abortos e interrupciones, embarazos, mortinatos y nacimiento). A raíz de dichas estimaciones y aplicando técnicas estadísticas de ...

  2. La mortalidad feto-infantil y de menores de 5 años en Cuba: período 2000-2010

    OpenAIRE

    Herrera León, Lorenzo I.

    2015-01-01

    La etapa fetal es vital para el desarrollo y bienestar del futuro ser humano, de ahí que el presente trabajo se haya propuesto como objetivo analizar la evolución de la mortalidad feto-infantil y de menores de 5 años durante el decenio 2000-2010, en Cuba. Para el logro de este se realizaron estimaciones de los eventos vitales que acompañan al proceso del embarazo (abortos e interrupciones, embarazos, mortinatos y nacimiento). A raíz de dichas estimaciones y aplicando técnicas estadísticas de ...

  3. Epidemiología y caracterización de los factores de riesgo de diarrea viral bovina y neosporosis en bovinos del valle del Mantaro – región Junín

    OpenAIRE

    Arauco Villar, Fernando

    2015-01-01

    Se realizó un estudio epidemiológico de Diarrea viral bovina (DVB) y neosporosis en 425 vacas en producción de 37 hatos del Valle del Mantaro-Región Junín, Perú, mediante ELISA e identificando sus factores de riesgo aplicando una encuesta. Para DVB se encontraron prevalencias: muestral 66.33%, predial 97.3% (36/37) y promedio/hato 64.78%, Concepción tuvo las prevalencias promedio/hato y muestral más altas, luego Jauja, Chupaca y Huancayo; la prevalencia de animales persistentement...

  4. Selección de materiales para la fabricación de equipamiento en plantas productoras de ácido fosfórico.

    OpenAIRE

    SCHORR, MICHAEL; VALDEZ, BENJAMíN; OCAMPO, JUAN DE DIOS

    2011-01-01

    El ácido fosfórico (AF) es un importante ácido industrial utilizado en la industria química, agroquímica, incluyendo fertilizantes, agua. energia, bioingenierla. aceros, alimentos, bebidas, etc. Se produce de roca fosfórica (RF) aplicando dos procesos: Via húmeda, por ataque con ácido sulfürico y por reacción con ácido clorhídrico y posterior extracción con solventes orgánicos. Estas plantas muestran un alto riesgo de corrosión puesto que manejan y procesan ácidos corrosivos, operan bajo seve...

  5. LA GIMNASIA CEREBRAL Y LA CREATIVIDAD DE LOS NIÑOS Y LAS NIÑAS DE 4 A 5 AÑOS DE EDAD DE LA UNIDAD EDUCATIVA LUIS A MARTINEZ DEL CANTÓN AMBATO PROVINCIA DEL TUNGURAHUA

    OpenAIRE

    Salazar Garcés, María Cristina

    2016-01-01

    El mundo actual requiere seres humanos con formación integral que fusione conocimientos, habilidades, destrezas, valores, la presente investigación sobre la gimnasia cerebral y la creatividad de los niños y las niñas de 4 a 5 años de edad de la Unidad Educativa Luis A. Martínez del Cantón Ambato, Provincia de Tungurahua, tiene como finalidad investigar el nivel de desarrollo de la creatividad de los niños mencionados, aplicando para ello encuestas dirigidas a los docentes, entrevistas a las a...

  6. Diferencias comportamentales en gallinas ponedoras con y sin el "Método Llovera" durante el período primaveral.

    OpenAIRE

    Mentzel, Rubén

    2009-01-01

    Recibido: Dic.2008 | Aceptado: Abr.2009 En trabajos anteriores se demostraron las ventajas del control de moscas en galpones de gallinas ponedoras, aplicando el “Método Llovera”. El mismo consiste en colocar gallinas de descarte en el piso, sin alimentación propia, en una cantidad correspondiente al 10% de los animales del galpón.1 De esta forma se logra disminuir la cantidad de moscas, y aumentar la producción de huevos mejorando la calidad y la rentabilidad. Un ambiente sin moscas es mu...

  7. Medidas preventivas, correctoras y compensatorias del impacto ecológico de carreteras

    OpenAIRE

    Aizpurúa Giráldez, Nerea

    2011-01-01

    Las medidas preventivas, correctoras y compensatorias empleadas en los proyectos de carretera son uno de los elementos clave para conseguir la integración ambiental de estas infraestructuras. De ellas dependerá que los posibles impactos ambientales generados durante su construcción y explotación no supongan un detrimento inadmisible de la calidad ambiental. La tipología de medidas que se vienen aplicando desde hace más de veinte años en durante el proceso de Evaluación de Impacto Ambiental (E...

  8. Amortización de Intangibles con cargos variables y gradiente aritmético predeterminado

    OpenAIRE

    Zans Arimana, Walter

    2014-01-01

    En este trabajo el objetivo general de la investigación ha sido construir un método que permita amortizar un activo intangible con un procedimiento nuevo, basado en cargos anuales que varían con un gradiente aritmético previamente establecido por la gerencia. La metodología ha sido numérica, aplicando las propiedades de las progresiones aritméticas. Los resultados han llevado a la construcción del mencionado método, concluyendo dicho procedimiento cumple con la definición de amortización que ...

  9. Aplicación de la filosofía lean management a Merkamueble

    OpenAIRE

    López Díez, Javier

    2015-01-01

    RESUMEN: El objetivo de este trabajo es analizar los procesos clave de Merkamueble aplicando los principios de la filosofía Lean Management, los cuales están orientados a la mejora de la gestión actual de la empresa. Para conseguir el objetivo, en primer lugar, se ha realizado la representación de un mapa de procesos de la empresa clasificando los procesos en estratégicos, clave y de apoyo. Posteriormente, se han analizado en mayor profundidad los procesos clave (recepción del cliente, tr...

  10. Aplicación del Software MAT6 y su influencia en el rendimiento académico en el área de matemática del sexto grado de la I.E. 6020 Villa María del Triunfo, 2012

    OpenAIRE

    Rojas Vargas, Jesús Luis Alberto; Chuquihuamaní Aguilar, Wilder José

    2015-01-01

    El bajo rendimiento académico en matemática de los escolares es un problema que muchos docentes tratan de superar aplicando variadas estrategias en la enseñanza de matemática. En ese sentido, esta investigación busca responder el problema general: ¿Cómo influye la aplicación del software Mat6 en el rendimiento académico en el área de matemática de los estudiantes de sexto grado de primaria de la I.E. 6020. Villa maría del Triunfo, 2012? y como objetivo general: Explicar la i...

  11. Riscos ocupacionais autorreferidos por trabalhadores de uma indústria de produção de fertilizantes – RS – Brasil

    OpenAIRE

    Liane Silveira da Rosa; Leticia Machado Pereira; Leticia Silveira Cardoso; Marta Regina Cezar-Vaz; Valdecir Zavarese da Costa

    2016-01-01

    Objetivo: descrever a exposição a riscos ocupacionais autorreferida por trabalhadores de uma indústria de fertilizantes sólido e líquido no Extremo Sul do Rio Grande do Sul – Brasil. Método: estudo descritivo, realizado com 78 trabalhadores, dos quais 49 atuavam no setor de produção e 29 no de movimentação e ensaque. Produziu-se uma análise quantitativa, aplicando-se a estatística descritiva para apresentar as características dos trabalhadores e a exposição aos riscos ocupacionais autorreferi...

  12. Cálculo de secciones de cable en baja tensión en una planta de oil & gas

    OpenAIRE

    Cabeza Sánchez, Álvaro

    2014-01-01

    Frecuentemente, cuando se afronta el problema del cálculo de las secciones mínimas de cable en baja tensión mediante el criterio de la intensidad máxima admisible y de la caída de tensión, resulta complicado encontrar alguna herramienta que, de una forma sencilla y rápida, proporcione una estimación realista de los diferentes tipos de cable y sus secciones para confeccionar la lista de cables. En este Proyecto Fin de Carrera se desarrolla una hoja de cálculo que, aplicando normati...

  13. Estudio bioquímico-clínico en personas ocupacionalmente expuestas a la acción de Agroquímicos y efectos de su uso frecuente sobre la salud

    OpenAIRE

    Sarabia Nuñez, Consuelo; Negrón Ballarte, Luisa; Meléndez Serrano, María del Carmen; Pérez González, Rocío Milagros

    2014-01-01

    Con el fin de evaluar las alteraciones con riesgo para la salud que parecen ocasionar algunos compuestos químicos usados en la agricultura, se ha investigado a 68 agricultores ocupacionalmente expuestos de la zona de Huando - Huaral (Lima).Se determinó importantes enzimas de función hepática: la Colinesterasa plasmática (CHE), aplicando el método cinético adaptado por Wierner, la Glutamil transpeptidasa (yGT), según el método de Szasz y las transaminasas (GOT y GPT) mediante el método UV opti...

  14. Clima y compromiso organizacional en una mediana empresa manufacturera de San Luis Potosí, S.L.P.

    OpenAIRE

    Crespo Bravo, Carolina

    2016-01-01

    Este trabajo tiene como objetivo principal analizar la relación que existe entre clima y compromiso organizacional y de estos con las características personales. La muestra se integró con 80 trabajadores de una mediana empresa manufacturera ubicada en la ciudad de San Luis Potosí. Se realizó un estudio empírico transversal aplicando cuestionarios para clima organizacional de Araujo et al. (2011), el cual se construyó con características inherentes a las dimensiones: a) estilo de geren...

  15. Resultados do Grupo de Trabalho de Tecnologias Avançadas IDE do Projecto OTALEX C

    OpenAIRE

    Vivas, Pedro; Álvarez, Rafael; Mateus, Júlio; Pavo, Marcos; Rubio, J.M.; González, Julián; Soriano, Marcos; Caballero, Carmen; Aparício, Alberto; Batista, T.; Carriço, Cristina; Cabezas, José; Fernández, Luis; Jiménez, Alberto; Gamero, Ulises

    2013-01-01

    Apresentam-se os resultado do Grupo de Trabalho de Tecnologias Avançadas IDE do projeto OTALEX-C, sendo estes: a geração de dados interligados de elementos geográficos do território OTALEX-C para a publicação de uma Web Semântica, e a captura e publicação de dados ambientais através de serviços padronizados de registo de observações com recurso a sensores, aplicando a standard SOS definida pela OGC. POCTEP 2007-2013

  16. Análisis de los convertidores electrónicos de potencia necesarios para un sistema de iluminación fotovoltaico semi-autónomo.

    OpenAIRE

    ZAMBRANO PARRA, BRAYAN LEONARDO

    2018-01-01

    [EN] In this project is expected to analize the main conversors to be used on a solar energy panel converter, this is focused in theorical analysis and a simulation of them applying knowledge accuired all along the degree. [ES] En el presente proyecto se espera realizar el conjunto de convertidores necesario para el funcionamiento de un sistema fotovoltáico, se concentra en el análisis teórico y una simulación de los mismos, aplicando así los conocimientos adquiridos a lo largo de la titul...

  17. Localización probabilística del humanoide Nao en el campo de la RoboCup

    OpenAIRE

    García Sierra, Juan Felipe; Fernández Llamas, Camino; Matellán Olivera, Vicente; Rodríguez Lera, Francisco Javier

    2010-01-01

    Una de las habilidades fundamentales que debe poseer un robot para definirse como autónomo es la de autolocalizarse en un entorno dado. En este artículo abordaremos el problema de la localización aplicando técnicas probabilísticas combinando representaciones topológicas y métricas sobre un terreno acotado como es el campo de fútbol de la RoboCup. El artículo presenta también el funcionamiento y resultados obtenidos sobre un conjunto de pruebas simuladas y reales utilizando el humanoide Nao...

  18. Investigación de microorganismos promotores del crecimiento vegetal en cultivos de interés agronómico mediante análisis metagenómico y microbiológico

    OpenAIRE

    Ramos Cabrera, Efrén Venancio

    2018-01-01

    La ocurrencia de una amplia diversidad de microorganismos endófitos diazotróficos asociados a cultivares de importancia agronómica ha sido descripta en varias publicaciones aplicando técnicas de secuenciación masiva, huella dactilar y cultivo dependientes. El análisis de las secuencias nifH sugiere que una importante proporción de estos endófitos se corresponden con microorganismos aún sin identificación taxonómica y/o no han sido cultivados in vitro. En estos estudios se encuentra rasgos int...

  19. Structure of Pigment Yellow 181 dimethylsulfoxide N-methyl-2-pyrrolidone (1:1:1) solvate from XRPD + DFT-D

    International Nuclear Information System (INIS)

    Streek, Jacco van de

    2015-01-01

    The relatively complex structure of a triclinic disolvate was solved from low-resolution laboratory powder diffraction data through the intermediate use of dummy atoms and the combination with quantum-mechanical calculations. With only a 2.6 Å resolution laboratory powder diffraction pattern of the θ phase of Pigment Yellow 181 (P.Y. 181) available, crystal-structure solution and Rietveld refinement proved challenging; especially when the crystal structure was shown to be a triclinic dimethylsulfoxide N-methyl-2-pyrrolidone (1:1:1) solvate. The crystal structure, which in principle has 28 possible degrees of freedom, was determined in three stages by a combination of simulated annealing, partial Rietveld refinement with dummy atoms replacing the solvent molecules and further simulated annealing. The θ phase not being of commercial interest, additional experiments were not economically feasible and additional dispersion-corrected density functional theory (DFT-D) calculations were employed to confirm the correctness of the crystal structure. After the correctness of the structure had been ascertained, the bond lengths and valence angles from the DFT-D minimized crystal structure were fed back into the Rietveld refinement as geometrical restraints (‘polymorph-dependent restraints’) to further improve the details of the crystal structure; the positions of the H atoms were also taken from the DFT-D calculations. The final crystal structure is a layered structure with an elaborate network of hydrogen bonds

  20. Structural refinement, photoluminescence and Raman spectroscopy of wurtzite Mn-doped Zn O pellets

    Energy Technology Data Exchange (ETDEWEB)

    Marquina, J.; Martin, J.; Luengo, J.; Vera, F.; Roa, L. [Centro de Estudios Avanzados en Optica, Universidad de los Andes, Merida 5101 (Venezuela, Bolivarian Republic of); Gonzalez, J. [Centro de Estudios de Semiconductores, Universidad de los Andes, Merida 5101 (Venezuela, Bolivarian Republic of); Rodriguez, F.; Renero L, C.; Valiente, R. [Malta-Consolider Team, CITIMAC, Facultad de Ciencias, Universidad de Cantabria, Santander 69005 (Spain); Delgado, G. E., E-mail: marquinajesus@gmail.com [Laboratorio de Cristalografia, Facultad de Ciencias, Universidad de los Andes, Merida 5101 (Venezuela, Bolivarian Republic of)

    2017-11-01

    We report the results of the Rietveld refinement, photoluminescence and Raman spectroscopy of Mn-doped Zn O ceramic pellets. Rietveld refinement shows that samples crystallize in the wurtzite structure and for the Mn-doped sample indicated that the Mn atoms substitute the Zn tetrahedral crystallographic sites in the Zn O host lattice. The emission and absorption spectra of Mn-doped Zn O have been investigated in the visible-UV region and the data have been interpreted in terms of the wurtzite Zn O electronic structure. Two broad bands, one due to superposition between donor bound excitons (DX) and free excitons (FX) and other due free-to bond excitonic recombination (FB) dominates the low-temperature photoluminescence spectra of Mn-doped Zn O bulk. In the Raman spectrum, an extra mode at ∼520 cm{sup -1} has been observed in agreement with earlier works, and it is an indicator for the incorporation of Mn{sup +2} ions into the Zn O host matrix since it is not is observed in Zn O pristine. Rietveld refinement of the X-ray diffraction patterns, energy-dispersive X-ray spectroscopy (EDS) technique, and Raman spectroscopies were performed to study these effects. (Author)

  1. Grain size dependent phase stabilities and presence of a monoclinic (Pm) phase in the MPB region of (1-x)Bi(Mg_1_/_2Ti_1_/_2)O_3_-_xPbTiO_3

    International Nuclear Information System (INIS)

    Upadhyay, A.; Singh, A.K.

    2016-01-01

    The results of the room temperature structural studies on (1-x)Bi(Mg_1_/_2Ti_1_/_2)O_3_-_xPbTiO_3 ceramics using Rietveld analysis of the powder X-ray diffraction data in the composition range 0.28≤x≤0.45 are presented. The morphotropic phase boundary region exhibits coexistence of monoclinic (space group Pm) and tetragonal (space group P4mm) phases in the composition range 0.33≤x≤0.40. The structure is nearly single phase monoclinic (space group Pm) in the composition range 0.28≤x≤0.32. The structure for the compositions with x≥0.45 is found to be predominantly tetragonal with space group P4mm. Rietveld refinement of the structure rules out the coexistence of rhombohedral and tetragonal phases in the morphotropic phase boundary region reported by earlier authors. The Rietveld structure analysis for the sample x=0.35 calcined at various temperatures reveals that phase fraction of the coexisting phases in the morphotropic phase boundary region varies with grain size. The structural parameters of the two coexisting phases also change slightly with changing grain size. (author)

  2. Grain size dependent phase stabilities and presence of a monoclinic (Pm) phase in the morphotropic phase boundary region of (1−x)Bi(Mg{sub 1/2}Ti{sub 1/2})O{sub 3}-xPbTiO{sub 3} piezoceramics

    Energy Technology Data Exchange (ETDEWEB)

    Upadhyay, Ashutosh; Singh, Akhilesh Kumar, E-mail: akhilesh-bhu@yahoo.com, E-mail: aksingh.mst@itbhu.ac.in [School of Materials Science and Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005 (India)

    2015-04-14

    Results of the room temperature structural studies on (1−x)Bi(Mg{sub 1/2}Ti{sub 1/2})O{sub 3}-xPbTiO{sub 3} ceramics using Rietveld analysis of the powder x-ray diffraction data in the composition range 0.28 ≤ x ≤ 0.45 are presented. The morphotropic phase boundary region exhibits coexistence of monoclinic (space group Pm) and tetragonal (space group P4 mm) phases in the composition range 0.33 ≤ x ≤ 0.40. The structure is nearly single phase monoclinic (space group Pm) in the composition range 0.28 ≤ x ≤ 0.32. The structure for the compositions with x ≥ 0.45 is found to be predominantly tetragonal with space group P4 mm. Rietveld refinement of the structure rules out the coexistence of rhombohedral and tetragonal phases in the morphotropic phase boundary region reported by earlier authors. The Rietveld structure analysis for the sample x = .35 calcined at various temperatures reveals that phase fraction of the coexisting phases in the morphotropic phase boundary region varies with grain size. The structural parameters of the two coexisting phases also change slightly with changing grain size.

  3. Layered B-site cation ordering: A key factor in ferrimagnetism of Y{sub 2}MnCrO{sub 6}

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Lin [Department of Physics, University of Science and Technology of China, Hefei, Anhui (China); Yang, Lei [Collaborative Innovation Center for Magnetoelectric Industry, China Three Gorges University, Yichang, Hubei (China); Lee, Ming-Hsien; Lin, Tseh-Hsing [Department of Physics, Tamkang University, Taipei, Taiwan (China); Zhang, ZhongFeng; Xie, XiangNan [Department of Physics, University of Science and Technology of China, Hefei, Anhui (China); Zhu, Hong, E-mail: zhuh@ustc.edu.cn [Department of Physics, University of Science and Technology of China, Hefei, Anhui (China)

    2014-07-15

    Highlights: • Rietveld refinement and first-principles calculations are performed for Y{sub 2}MnCrO{sub 6}. • The layered B-site cation ordering is a more reliable structure for Y{sub 2}MnCrO{sub 6}. • Y{sub 2}MnCrO{sub 6} has an insulating ferrimagnetism (0 0 1)-ordered ground state. • The layered ordered pattern plays a key role for the ferrimagnetism in Y{sub 2}MnCrO{sub 6}. - Abstract: We report the Rietveld refinement of powder X-ray diffraction (XRD) pattern and first-principles calculations for the half-Cr{sup 3+} doped YMnO{sub 3} compound. The Rietveld refinement results suggest that the compound has a monoclinic structure with the Mn{sup 3+}/Cr{sup 3+} layers alternately stacking along the [0 0 1] direction. The first-principles calculations show that the structure with layered B-site cation ordering has the lowest total energy; meanwhile, the insulating ferrimagnetic state is more favored compared to the ferromagnetic state, which is in agreement with the reported experimental results. Based upon Goodenough’s model of semi-covalent exchange, we argue that the anisotropic magnetic couplings between the Mn{sup 3+}/Cr{sup 3+} cations ordered in layered pattern play an important role for the ferrimagnetism in the compound.

  4. Effect of an electrolyte flow on electrochemical hydrogen permeation

    Directory of Open Access Journals (Sweden)

    Ana María Pérez-Ceballos

    2014-01-01

    Full Text Available Se ha estudiado el efecto de la aplicación de un flujo de elect rolito sobre la superficie de detección de una membrana de hier ro puro en ensayos de permeación electroquímica de hidrógeno. Para la real ización de los ensayos se usó una celda del tipo Devanathan mod ificada, de tal manera que un flujo de electrolito fue inyectado directa mente sobre la superficie de salida de hidrógeno. La generación de hidrógeno se realizó aplicando una corriente catódica de 2,85mA y se usó una solución de NaOH 0,1M + 2mgL-1 As2O3. La celda de detección fue mantenida bajo control potenciostático y se usó u na solución buffer de borato de sodio (pH=8,4. No se observó u na variación significativa de la corriente de permeación en los en sayos realizados aplicando flujo de electrolito.

  5. El marketing político

    Directory of Open Access Journals (Sweden)

    Alvaro H. Cifuentes G.

    2015-04-01

    Full Text Available RESUMEN Si un candidato desea ser elegido, las técnicas de marketing aplicadas a la política, le son imprescindibles. El marketing político (Politing es el análisis  metódico de los diferentes segmentos que integran el ámbito político de una sociedad y de los factores que puedan modificarlos. Se aplican al candidato, a los votantes, al análisis de la publicidad política, a los simpatizantes, a desconocedores  del partido y a los indecisos. Los candidatos colombianos lo están aplicando, y compañías nuestras exportan servicios  de asesoría de países suramericanos.Promocionar  un candidato implica estructurar una compañía tal como una empresa, aplicando técnicas de ventas, de fijación de cuotas y de planeación estratégica.

  6. Estructura de autocorrelación espacial de la actividad comercial en los municipios de la Región de Murcia.

    Directory of Open Access Journals (Sweden)

    Juana María Vivo Molina

    2004-01-01

    Full Text Available En este trabajo, se realiza una aproximación al estudio de la dependencia entre variable económica y localización espacial aplicando la metodología de la Teoría de las Variables Regionalizadas (TVR. En particular, nos centraremos en la localización de actividades económico-comerciales de los municipios de la Comunidad Autónoma de la Región de Murcia (CARM. Aplicando métodos estadísticos para la reducción de datos que nos permiten eliminar información redundante, detectamos estructuras latentes en el desarrollo económico-comercial dentro de los municipios de la CARM. La metodología TVR nos permite constatar la presencia de correlación espacial, considerando los municipios de la Región de Murcia georeferenciados dentro del plano topográfico, en las estructuras latentes detectadas.

  7. Facile synthesis of B-type carbonated nanoapatite with tailored microstructure

    Energy Technology Data Exchange (ETDEWEB)

    Gualtieri, Magdalena Lassinantti, E-mail: magdalena.gualtieri@unimore.it [Dipartimento Ingegneria “Enzo Ferrari”, Università degli studi di Modena e Reggio Emilia, I-41125 Modena (Italy); Romagnoli, Marcello, E-mail: marcello.romagnoli@unimore.it [Dipartimento Ingegneria “Enzo Ferrari”, Università degli studi di Modena e Reggio Emilia, I-41125 Modena (Italy); Hanuskova, Miriam, E-mail: Miriam.hanuskova@unimore.it [Dipartimento Ingegneria “Enzo Ferrari”, Università degli studi di Modena e Reggio Emilia, I-41125 Modena (Italy); Fabbri, Elena, E-mail: Elena.fabbri@unimore.it [Dipartimento Ingegneria “Enzo Ferrari”, Università degli studi di Modena e Reggio Emilia, I-41125 Modena (Italy); Gualtieri, Alessandro F., E-mail: Alessandro.gualtieri@unimore.it [Dipartimento di Scienze Chimiche e Geologiche, Università degli studi di Modena e Reggio Emilia, I-41121 Modena (Italy)

    2014-12-15

    Nanolime and a phosphate-based chelating agent were used to synthesize B-type carbonated apatite. Developed Rietveld refinement strategies allowed one to determine process yield, product crystallinity as well as structural (unit cell) and microstructural (size, strain) parameters. The effect of synthesis temperature (20–60 °C) as well as Ca/P ratio (1.5–2.5) and solid content (10–30 wt%) of the starting batch on these properties were investigated. FTIR, TEM and gas adsorption data provided supporting evidence. The process yield was 42–60 wt% and found to be governed by the Ca/P ratio. The purified products had high specific surface area (107–186 m{sup 2}/g) and crystallinity (76–97%). The unit cell parameters, correlated to the degree of structural carbonate, were sensitive to the Ca/P ratio. Instead, temperature governed the microstructural parameters. Less strained and larger crystals were obtained at higher temperatures. Long-term aging up to 6 months at 20 °C compensated for higher crystal growth kinetics at higher temperature. - Graphical abstract: Controlled synthesis of carbonated apatite at moderate temperatures using nanolime and sodiumhexametaphosphate as starting reagent. - Highlights: • Chemical synthesis of nano-sized apatite with tailored microstructure was performed. • Colloidal Ca(OH){sub 2} and a phosphorus-based chelating agents were used as reagents. • The method is simple and reproducible which facilitate industrial process scale-up. • Rietveld refinement strategies for product characterization were developed. • Rietveld analyses provided yield, microstructural and structure information.

  8. The Embodied Brain: Towards a Radical Embodied Cognitive Neuroscience

    Directory of Open Access Journals (Sweden)

    Julian eKiverstein

    2015-05-01

    Full Text Available In this programmatic paper we explain why a radical embodied cognitive neuroscience is needed. We argue for such a claim based on problems that have arisen in cognitive neuroscience for the project of localizing function to specific brain structures. The problems come from research concerned with functional and structural connectivity that strongly suggests that the function a brain region serves is dynamic, and changes over time. We argue that in order to determine the function of a specific brain area, neuroscientists need to zoom out and look at the larger organism-environment system. We therefore argue that instead of looking to cognitive psychology for an analysis of psychological functions, cognitive neuroscience should look to an ecological dynamical psychology. A second aim of our paper is to develop an account of embodied cognition based on the inseparability of cognitive and emotional processing in the brain. We argue that emotions are best understood in terms of action readiness (Frijda 1986, 2007 in the context of the organism’s ongoing skillful engagement with the environment (Rietveld 2008; Bruineberg & Rietveld 2014; Kiverstein & Rietveld 2015. States of action readiness involve the whole living body of the organism, and are elicited by possibilities for action in the environment that matter to the organism. Since emotion and cognition are inseparable processes in the brain it follows that what is true of emotion is also true of cognition. Cognitive processes are likewise processes taking place in the whole living body of an organism as it engages with relevant possibilities for action.

  9. Facile synthesis of B-type carbonated nanoapatite with tailored microstructure

    International Nuclear Information System (INIS)

    Gualtieri, Magdalena Lassinantti; Romagnoli, Marcello; Hanuskova, Miriam; Fabbri, Elena; Gualtieri, Alessandro F.

    2014-01-01

    Nanolime and a phosphate-based chelating agent were used to synthesize B-type carbonated apatite. Developed Rietveld refinement strategies allowed one to determine process yield, product crystallinity as well as structural (unit cell) and microstructural (size, strain) parameters. The effect of synthesis temperature (20–60 °C) as well as Ca/P ratio (1.5–2.5) and solid content (10–30 wt%) of the starting batch on these properties were investigated. FTIR, TEM and gas adsorption data provided supporting evidence. The process yield was 42–60 wt% and found to be governed by the Ca/P ratio. The purified products had high specific surface area (107–186 m 2 /g) and crystallinity (76–97%). The unit cell parameters, correlated to the degree of structural carbonate, were sensitive to the Ca/P ratio. Instead, temperature governed the microstructural parameters. Less strained and larger crystals were obtained at higher temperatures. Long-term aging up to 6 months at 20 °C compensated for higher crystal growth kinetics at higher temperature. - Graphical abstract: Controlled synthesis of carbonated apatite at moderate temperatures using nanolime and sodiumhexametaphosphate as starting reagent. - Highlights: • Chemical synthesis of nano-sized apatite with tailored microstructure was performed. • Colloidal Ca(OH) 2 and a phosphorus-based chelating agents were used as reagents. • The method is simple and reproducible which facilitate industrial process scale-up. • Rietveld refinement strategies for product characterization were developed. • Rietveld analyses provided yield, microstructural and structure information

  10. Investigation on the formation of Cu-Fe nano crystalline super-saturated solid solution developed by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Mojtahedi, M., E-mail: m.mojtahedi@gmail.com [School of Materials Science and Engineering, Iran University of Science and Technology, Narmak, Tehran 16846-13114 (Iran, Islamic Republic of); Goodarzi, M.; Aboutalebi, M.R. [School of Materials Science and Engineering, Iran University of Science and Technology, Narmak, Tehran 16846-13114 (Iran, Islamic Republic of); Ghaffari, M. [Department of Electrical and Electronics Engineering, UNAM-Institute of Materials Science and Nanotechnology, Bilkent University, Ankara 06800 (Turkey); Soleimanian, V. [Department of Physics, Faculty of Science, Shahrekord University, P.O. Box 115, Shahrekord (Iran, Islamic Republic of)

    2013-02-15

    Highlights: Black-Right-Pointing-Pointer The deformation of the mechanically alloyed Cu-Fe powder is anisotropic. Black-Right-Pointing-Pointer The Rietveld method is more proper and results in smaller crystallite size than the Scherer and Williamson-Hall methods. Black-Right-Pointing-Pointer A dual phase super saturated solid solution achieved after 96 h of milling of the mixtures with 30, 50 and 70 wt.% of Iron. Black-Right-Pointing-Pointer A final proportion of approximately 85% FCC and 15% BCC structure obtained in all of the applied compositions. - Abstract: In this study, the formation of super saturated solid solution in the binary Cu-Fe system was investigated. Three powder blends with 30, 50 and 70 wt.% of Fe were milled for different times to 96 h. The variations of lattice parameter and inter-planar spacing were calculated and analyzed using X-ray diffraction analysis (XDA). The anisotropy of lattice deformation in the FCC phase was studied and the obtained results were compared to milled pure Cu powder. Furthermore, crystallite size was calculated using Scherer formula in comparison with Rietveld full profile refinement method. Considering the previous studies about the formation of non-equilibrium FCC and BCC phases, the phase evolution has been discussed and the proportion of each phase was calculated using Rietveld refinement method. Supplementary studies on the evolution of microstructure and formation of solid solution were carried out using high resolution transmission electron microscopy (HRTEM). Finally, high angle annular dark field (HAADF) imaging was utilized to find out the level of homogeneity in the resulting phases. While true alloying takes place in each phase, the final structure consists of both FCC and BCC nano-crystallites.

  11. Effect of Cu{sup 2+} and Ni{sup 2+} substitution at the Mn site in (La{sub 0.63}Ca{sub 0.37})MnO{sub 3}: A neutron powder diffraction investigation

    Energy Technology Data Exchange (ETDEWEB)

    Martinelli, A., E-mail: alberto.martinelli@spin.cnr.it [CNR-SPIN, C.so Perrone 24, 16152 Genova (Italy); Ferretti, M. [CNR-SPIN, C.so Perrone 24, 16152 Genova (Italy); Dipartimento di Chimica e Chimica Industriale, Università di Genova, Via Dodecaneso 31, 16146 Genova (Italy); Castellano, C. [Università degli Studi di Milano, Dipartimento di Chimica Strutturale e Stereochimica Inorganica, Via G. Venezian 21, 20133 Milano (Italy); Cimberle, M.R. [IMEM-CNR, Via Dodecaneso 33, 16146 Genova (Italy); Ritter, C. [Institute Laue—Langevin, 6 rue Jules Horowitz, 38042 Grenoble Cedex 9 (France)

    2013-04-15

    The crystal and magnetic structures of the (La{sub 0.63}Ca{sub 0.37})(Mn{sub 1−x}TM{sub x})O{sub 3} compounds (x=0.00, 0.03, 0.08; TM=Cu{sup 2+}, Ni{sup 2+}) were investigated between 5 K and 300 K by means of dc magnetic measurements and neutron powder diffraction analysis followed by Rietveld refinement. Both substituting cations lead to a reduction of the long range ferromagnetic ordering temperature; ferromagnetism is strongly suppressed in the 8% Cu-substituted sample, where long- and short-range FM magnetic orders coexist together with short-range A-type AFM order. This particular feature can be related to the Jahn–Teller character of Cu{sup 2+}, absent in Ni{sup 2+}, and suggests the occurrence of a quantum critical point in the (La{sub 0.63}Ca{sub 0.37})(Mn{sub 1−x}Cu{sub x})O{sub 3} system. - Graphical abstract: Rietveld refinement plot of (La{sub 0.63}Ca{sub 0.37})(Mn{sub 0.92}Cu{sub 0.08})O{sub 3} showing in the inset the coexistence of broad A-type AFM peaks with FM ones. Highlights: ► (La{sub 0.63}Ca{sub 0.37})MnO{sub 3} was substituted with Ni and Cu. ► Neutron powder diffraction and Rietveld refinement were carried out. ► A quantum critical point possibly occurs in the (La{sub 0.63}Ca{sub 0.37})(Mn{sub 1−x}Cu{sub x})O{sub 3} system.

  12. Local structure and disorder in crystalline Pb9Al8O21

    International Nuclear Information System (INIS)

    Hannon, Alex C.; Barney, Emma R.; Holland, Diane; Knight, Kevin S.

    2008-01-01

    Crystalline Pb 9 Al 8 O 21 is a model compound for the structure of non-linear optical glasses containing lone-pair ions, and its structure has been investigated by neutron powder diffraction and total scattering, and 27 Al magic angle spinning NMR. Rietveld analysis (space group Pa3-bar (No. 205), a=13.25221(4) A) shows that some of the Pb and O sites have partial occupancies, due to lead volatilisation during sample preparation, and the non-stoichiometric sample composition is Pb 9-δ Al 8 O 21-δ with δ=0.54. The NMR measurements show evidence for a correlation between the chemical shift and the variance of the bond angles at the aluminium sites. The neutron total correlation function shows that the true average Al-O bond length is 0.8% longer than the apparent bond length determined by Rietveld refinement. The thermal variation in bond length is much smaller than the thermal variation in longer interatomic distances determined by Rietveld refinement. The total correlation function is consistent with an interpretation in which AlO 3 groups with an Al-O bond length of 1.651 A occur as a result of the oxygen vacancies in the structure. The width of the tetrahedral Al-O peak in the correlation function for the crystal is very similar to that for lead aluminate glass, indicating that the extent of static disorder is very similar in the two phases. - Graphical abstract: Combined neutron powder diffraction and total scattering, and 27 Al NMR on crystalline Pb 9 Al 8 O 21 shows it to be a non-stoichiometric compound with vacancies due to PbO volatilisation. A detailed consideration of the thermal and static disorder is given, showing that glass and crystal phases have very similar disorder at short range

  13. Characteristic length scale dependence on conductivity for La2-xErxMo2O9 (0.05 ≤ x ≤ 0.3) oxide ion conductors

    Science.gov (United States)

    Paul, T.; Ghosh, A.

    2016-05-01

    Structural property of polycrystalline La2-xErxMo2O9 has been investigated. Rietveld refinements at room temperature of the materials suggest a single phase nature with cubic symmetry (space group P213). The electron density contour plot confirms the nature of different cation-oxygen bonds. Time dependent mean square displacement (√) and the spatial extent of the sub-diffusive motion (√) are evaluated using the linear response theory. The localized hop at O2 and O3 sites is found to be favorable for oxygen ion migration for these systems.

  14. Correlação entre dados estruturais e bandas de vibração no infravermelho para a fase espinélio Zn7-xNi xSb2O12 Correlation between structural data and infraved vibrational bands of the Zn7-xNi xSb2O12 spinel phase

    Directory of Open Access Journals (Sweden)

    L. Gama

    2000-12-01

    Full Text Available A fase espinélio Zn7-xNi xSb2O12 tem apresentado propriedades magnéticas importantes, comportando-se como spin-glass. Desde que estas propriedades são fortemente dependentes da configuração precisa dos átomos nesta estrutura, foram utilizados neste trabalho, com o intuito de clarificar essa configuração, a espectroscopia de infravermelho, aliada ao refinamento de estruturas pelo método de Rietveld. O espectro de infravermelho mostra nas condições de contorno estudadas a presença de três das quatro bandas ativas comuns aos espinélios. Conforme resultados do refinamento pelo método de Rietveld, o níquel substitui o zinco primeiramente no sítio octaédrico e, em altas concentrações (x > ou = 3, migra para o sítio tetraédrico. Essa migração é indicada pelo "splitting", em torno de 520 cm-1, para (x > ou = 3, apresentado no espectro de infravermelho quando a banda n2 é afetada pela mudança do cátion bivalente.The Zn7-xNi xSb2O12 spinel phase shows important magnetic properties with a spin-glass behavior. As these properties are strongly dependent on the atomic configuration in the spinel structure, infrared spectroscopy and the structure refining by the Rietveld analysis have been studied. The infrared spectrum presents three to four of the common spinel active modes. The Rietveld analysis shows that Ni firstly substitutes for Zn in the octahedral site and, for large (x > or = 3 concentrations, migrates to the tetrahedral site. The indication of that migration is the splitting at approximately 520 cm-1, shown in the infrared spectrum when the nu 2 band is modified by the substitution of the divalent cation.

  15. Synthesis and crystal structure of the γ-modifications of US2 and USe2

    International Nuclear Information System (INIS)

    Kohlmann, H.; Beck, H.P.

    1997-01-01

    We report on γ-US 2 and γ-USe 2 which may be synthesized by a presumably topotactic reaction from the corresponding U 3 X 5 compounds and elementary chalcogen. γ-USe 2 can also be prepared by a high pressure transformation of α-USe 2 at 4 GPa and 773 K. The structure of the γ phases could be determined and refined by a Rietveld procedure from powder date. They crystallize in an anti-Fe 2 P-type arrangement. Unusual features of these structures and a possible reaction mechanism for the formation of the compounds are discussed. (orig.)

  16. Nano and micro reoriented domains and their relation with the crystal structure in the new ferroelectric boracite Zn3B7O13Br

    International Nuclear Information System (INIS)

    Campa-Molina, J; Ulloa-Godinez, S; Barrera, A; Bucio, L; Mata, J

    2006-01-01

    A new zinc brome boracite Zn 3 B 7 O 13 Br has been grown by a chemical transport reaction in closed quartz ampoules at 920 K. The crystal structure was characterized by Rietveld refinement. Ferroelectric nano and micro reorientable domains were found in this material using polarizing optical microscopy (PLM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Chemical analysis was performed with x-ray energy dispersive spectroscopy (EDX). In the crystal, a new structure transition at 586 K from orthorhombic (Pca 2 1 ) to cubic cell (F4-bar3c) has been found. This transition was corroborated by differential scanning calorimetry (DSC)

  17. Structural characterization of two new quaternary chalcogenides: CuCo{sub 2}InTe{sub 4} and CuNi{sub 2}InTe{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Delgado, Gerzon E.; Grima-Gallardo, Pedro; Nieves, Luis, E-mail: gerzon@ula.ve [Universidad de Los Andes, Merida (Venezuela, Bolivarian Republic of); Cabrera, Humberto [Centro Multidisciplinario de Ciencias, Instituto Venezolano de Investigaciones Cientificas (IVIC), Merida (Venezuela, Bolivarian Republic of); Glenn, Jennifer R.; Aitken, Jennifer A. [Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, PA (United States)

    2016-11-15

    The crystal structure of the chalcogenide compounds CuCo{sub 2}InTe{sub 4} and CuNi{sub 2}InTe{sub 4} , two new members of the I-II{sub 2}-III-VI{sub 4} family, were characterized by Rietveld refinement using X-ray powder diffraction data. Both materials crystallize in the tetragonal space group I4-bar 2m (No. 121), Z = 2, with a stannite-type structure, with the binaries CoTe and NiTe as secondary phases. (author)

  18. Synthesis, crystal structure, and transport properties of Fe substituted rhombohedral skutterudite derivatives Co4−xFexGe6Se6

    KAUST Repository

    Wei, Kaya

    2014-11-01

    We report on the synthesis and low temperature transport properties of rhombohedral derivatives of the cubic skutterudite CoSb3, namely Co4-xFexGe6Se6 with x = 0, 1, 1.5. Rietveld refinement and elemental analyses were used to identify the structure and stoichiometry of the compositions. The thermal conductivity was investigated by employing the Debye model with different phonon-scattering parameters. This investigation demonstrates that Fe substitution is feasible in these skutterudite derivatives and can significantly affect the transport properties as compared with Co4Ge6Se6. © 2014 Elsevier B.V. All rights reserved.

  19. Solid-state structural properties of 2,4,6-trimethoxybenzene derivatives, determined directly from powder X-ray diffraction data in conjunction with other techniques

    International Nuclear Information System (INIS)

    Pan Zhigang; Xu Mingcan; Cheung, Eugene Y.; Platts, James A.; Harris, Kenneth D.M.; Constable, Edwin C.; Housecroft, Catherine E.

    2006-01-01

    Structural properties of 2,4,6-trimethoxybenzaldehyde, 2,4,6-trimethoxybenzyl alcohol and 2,4,6-trimethoxyacetophenone have been determined directly from powder X-ray diffraction data, using the direct-space Genetic Algorithm (GA) technique for structure solution followed by Rietveld refinement. Structural similarities and contrasts within this family of materials are elucidated. The work illustrates the value of utilizing information from other sources, including spectroscopic data and computational techniques, as a means of augmenting the structural knowledge established from the powder X-ray diffraction data

  20. Barium strontium titanate powders prepared by spray pyrolysis

    International Nuclear Information System (INIS)

    Brankovic, G.; Brankovic, Z.; Goes, M.S.; Paiva-Santos, C.O.; Cilense, M.; Varela, J.A.; Longo, E.

    2005-01-01

    Ultasonic spray pyrolysis (SP) has been investigated for the production of the barium strontium titanate (BST) powders from the polymeric precursors. The processing parameters, such as flux of aerosol and temperature profile inside the furnace, were optimized to obtain single phase BST. The powders were characterized by the methods of X-ray diffraction analysis, SEM, EDS and TEM. The obtained powders were submicronic, consisting of spherical, polycrystalline particles, with internal nanocrystalline structure. Crystallite size of 10 nm, calculated using Rietveld refinement, is in a good agreement with results of HRTEM