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structural refinement » structural reinforcement (Expander búsqueda), structural elements (Expander búsqueda)
structural different » estructurales diferentes (Expander búsqueda), structural diversity (Expander búsqueda)
structural refinement » structural reinforcement (Expander búsqueda), structural elements (Expander búsqueda)
structural different » estructurales diferentes (Expander búsqueda), structural diversity (Expander búsqueda)
1
artículo
Publicado 2000
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[Y1-xCax]SrBaCu2.80(PO4)0.20Oy samples with 0.10 ≤ x ≤ 0.40 were syntherized using the solid state reaction technique. X-ray diffraction patterns show that all the compounds crystallized into a 123 tetragonal structure. The analysis of the structure with Rietveld refinement were made using a model that contains one Cu(2) in four coordination and not in five coordination as in the other 123 tetragonal structures. This fact allows that Tc increase with Ca concentration. All samples are superconductors as reported in a previous paper.
2
artículo
Publicado 2000
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(PO4)3- doped [Y0.75Ca0.25]SrBaCu3-x(PO4)xOy compounds with 0.00 ≤ x ≤ 0.30 were synthesized using the solid state reaction technique at normal pressure and temperture conditions. The X-ray diffraction patterns show that for x= 0.0 the samples crystallize into an orthorhombic phase, and for other x values the samples presented a tetragonal structure. The Rietveld method was used to refine the lattice constants. The analysis of structure with Rietveld refinement was done using a model that contains one Cu(2) in a four coordination and not in five coordination in the other 123 tetragonal structures. All samples are superconductors as reported previously [1].
3
artículo
Publicado 2021
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This main objective of this study is the use of free and open source software to identify structural lineaments and enhancement of geological structures, without the need to use commercial software. In this study, a digital elevation model (DEM) with a resolution of 12.5 m ALOS PALSAR was used on which the different relief visualization techniques were performed, obtaining structural guidelines and enhancement of geological structures (possible faults), in addition graphs were made of rosettes and histograms, with the help of free and open source software such as SAGA GIS, QGIS 3.4.12, Stereonet and OpenStereo. The lineaments were analyzed by azimuth frequency, using different methods; Multidirectional shading, Shading with light variation every 30°, Combined shadows, Red Relief Image Map (RRIM); and finally the obtaining and processing of structural guidelines was carried out with each...
4
artículo
Publicado 2017
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In this study, magnetic nanocomposites were developed and used as adsorbents for lead and copper from aqueous media. Structural, surface, magnetic and textural properties of functionalized maghemite nanoparticles synthesized by alkaline co-precipitation were studied. The surfaces of the iron oxide nanoparticles (Nps) were modified with different chemical agents such as fatty and amino acids, silica (SiO2), mesoporous silica (SBA-15), hydroxyapatite, multiwall carbon nanotubes (MWCNTs) and ethylenediaminetetraacetic acid (EDTA), obtaining NPs with mean particle sizes ranging from 7 to 16 nm according to Rietveld refinement and TEM images analysis. The physicochemical surface properties of the functionalized materials were studied via zeta potential (z) and Fourier transform infrared (FTIR) spectroscopy. Mossbauer spectroscopy (MS) as a function of temperature and DC magnetometry were ¨ u...
5
artículo
Publicado 2017
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Purpose. This paper aims to analyse the capital structure determining factors of Latin American and US corporations after the crisis of 2008, as a means of comparing theoretical assumptions and empirical results in markets of different efficiency levels. Design/methodology/approach. The study sample comprises 1,091 companies belonging to the six largest economies in Latin America plus the USA, in the years 2009 to 2013. The authors performed a regression with data from a balanced overview, which were obtained by using the criterion of minimum weighted square. Findings. The results demonstrated differences in determining factors of capital structure between companies from Latin America and from the USA. The pecking order theory was mostly observed in Latin American companies and the trade-off theory greater was closely aligned with US firms. Originality/value. This research brings new con...
6
artículo
Publicado 2017
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Purpose – This paper aims to analyse the capital structure determining factors of Latin American and US corporations after the crisis of 2008, as a means of comparing theoretical assumptions and empirical results in markets of different efficiency levels. Design/methodology/approach – The study sample comprises 1,091 companies belonging to the six largest economies in Latin America plus the USA, in the years 2009 to 2013. The authors performed a regression with data from a balanced overview, which were obtained by using the criterion of minimum weighted square. Findings – The results demonstrated differences in determining factors of capital structure between companies from Latin America and from the USA. The pecking order theory was mostly observed in Latin American companies and the trade-off theory greater was closely aligned with US firms. Originality/value – This research br...
7
artículo
Publicado 2020
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ABSTRACT Cassava, corn and potato starches were subjected to ozone processing under the same conditions, in order to allow comparisons. The molecular structure was evaluated using two chromatographic analyses: high-performance size-exclusion chromatography (HPSEC) coupled to multiangle laser light scattering (MALLS) and differential refractive index (RI) detectors, and gel permeation chromatography (GPC). Both proved the molecular depolymerization caused by ozonation, as well as illustrated the different behavior of each starch source – in special in relation to their molar mass dispersity. The granular morphology was not affected by ozone processing. On the other hand, the starch properties were affected by ozonation. In general, the apparent viscosity decreased during pasting, as well as the complex modulus (G*) of the immediately formed gels. After cooling and storage, however, the ...
8
artículo
Publicado 2016
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Este estudio tuvo como objetivo investigar los criterios diagnósticos y propuestas de intervención relacionados al TDAH de diferentes categorías profesionales en la ciudad de Natal – RN, Brasil. Participaron 34 profesionales seleccionados por conveniencia y a quienes se les realizó una entrevista semi-estructurada. Luego de la categorización de las informaciones se procedió al análisis descriptivo multidimensional de tipo Clusters. Se hizo evidente la división de la muestra total en otros dos grupos en relación a las tres variables de mayor relevancia: educación, número de sesiones utilizadas en el diagnóstico y uso de instrumentos formales. El Grupo 1, formado por médicos, se caracterizó por la utilización de dos o tres sesiones y por el uso de instrumentos y escalas formales. En el grupo 2, el número promedio de sesiones fue superior a tres y todos los psicólogos y l...
9
capítulo de libro
Publicado 2018
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The application of different diagnostic techniques in a historical construction allows the obtained information to complement each other, which contributes to a detailed and complete data of the conservation state of a building. This paper provides a structural diagnosis of the church “Virgen de la Asunción” of Sacsamarca village in Ayacucho, Peru. Due to exposure to weathering, torrential rains, and past seismic activity, the Sacsamarca church has a poor conservation state. Hence, it is necessary to identify properly the structural pathologies and their extension in the church. A first part of the research was the development of a three-dimensional geometrical model using aerial and terrestrial photogrammetry, aiming to characterize the general damage state of the building, including inaccessible zones. The data generated from the aerial and terrestrial acquisition allowed a detail...
10
tesis de maestría
Publicado 2019
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I would like to thank the National Council of Science, Technology and Technological Innovation (Concytec) from Peru for the award of a scholarship which made it possible to do this research work.
11
tesis de maestría
Publicado 2019
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Semiconductor-insulator interfaces play an important role in the performance of many different electronic and optoelectronic devices such as transistors, LEDs, lasers and solar cells. Particularly, the recombination of photo-generated charge carriers at interfaces in crystalline silicon solar cells causes a dramatic efficiency reduction. Therefore, during the fabrication process, the crystalline silicon must be subjected to prior superficial passivation; typically through an insulating layer such as SiO2, SiNx or AlOx. The function of this passivating layer is to reduce electrical recombination losses in interfacial defect states originating from dangling bonds. The associated passivation parameters are, on the one hand, stable charges within the insulating layer (Qox) that by repelling a certain type of charge carrier from the crystalline silicon surface, reduces its recombination effec...
12
tesis de maestría
Publicado 2019
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Semiconductor-insulator interfaces play an important role in the performance of many different electronic and optoelectronic devices such as transistors, LEDs, lasers and solar cells. Particularly, the recombination of photo-generated charge carriers at interfaces in crystalline silicon solar cells causes a dramatic efficiency reduction. Therefore, during the fabrication process, the crystalline silicon must be subjected to prior superficial passivation; typically through an insulating layer such as SiO2, SiNx or AlOx. The function of this passivating layer is to reduce electrical recombination losses in interfacial defect states originating from dangling bonds. The associated passivation parameters are, on the one hand, stable charges within the insulating layer (Qox) that by repelling a certain type of charge carrier from the crystalline silicon surface, reduces its recombination effec...
13
artículo
Publicado 2021
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In this investigation, the elasto-plastic behavior and the seismic performance of concrete reinforced frame structures reinforced are evaluated by applying the Pushover method. This evaluation is done on several cases: with high ductility steel (Grade 40), conventional steel (Grade 60) and high strength steel (Grade 75). For the previous, the capacity curve graph obtained from the displacement coefficient method was used to measure the capacity of the structure. In addition, the performance of the structure for different levels of seismic design are evaluated with the resulting values of ductility and rigidity of each case. The results showed that reinforcing a structure with a Grade 40 reinforcing steel increases the energy dissipation capacity, and if reinforced with a Grade 75 reinforcing steel increases the strength capacity in the structure. Finally, the comparative result of the va...
14
artículo
Publicado 2021
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The authors are grateful to the Sao Paulo Research Foundation (FAPESP, Brazil) for funding the project n? 2019/05043-6; this study was financed in part by the ?Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - Brazil (CAPES)? ? for the JS Guedes (88882.378356/2019-01) and KC Santos (88882.378385/2019-01) M.Sc. scholarships; to the National Council for Scientific and Technological Development (CNPq, Brazil) for the JS Guedes M.Sc. scholarship (131235/2020-6) and the productivity grant of PED Augusto (306557/2017-7); and to the Fondo Nacional de Desarrollo Científico, Tecnológico y de Innovación Tecnológica (FONDECYT, Peru) from the ?Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica? (CONCYTEC, Peru) for funding the project n° 409-2019-FONDECYT.
15
tesis de grado
Publicado 2023
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Wild potato species hold important genes related to disease resistance, tolerance to abiotic stress, and other traits of agronomic interest; however, they remain being the least explored. This study aimed to develop an accessible and replicable R analysis workflow to explore the genetic diversity and population structure of the International Potato Center’s (CIP) wild potato germplasm collection through nonparametric approaches. We worked with single nucleotide polymorphism (SNP) data from 1248 wild potato accessions, most of which had been genotyped for the first time. Genetic diversity parameters were calculated prior to structure analysis. Population structure was analyzed through parametric methods such as variational Bayesian inference, and nonparametric methods, such as dimensionalityreduction and distance-based techniques. Distance-based analysis revealed clustering based on plo...
16
objeto de conferencia
Publicado 2005
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The Andes are classically considered to represent the type of orogenie chains resulting from the subduction of an oceanic plate beneath a continental plate. In spite of a considerable literature invoJving stratigraphie, paleogeographie, structural, magmatic and geophysical data, any model that convincingly ex plains the modality of the Andean surrection has been emerged. Ali the current models focused on the importance of the subducting plate and very few considerations on the heterogeneity of continental plate. Paleogeographie reconstructions, structural evidences and magmatic and metallogenic evolution of Southern Peruvian Western Cordillera and Northern Chi.lean Domeyko Cordillera are used to identify a structure that delineates two different lithospheric blocks.
17
artículo
Publicado 2023
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Seismic demands obtained from nonlinear static analysis play an important role in performance-based design or evaluation. It has been proved that the invariant patterns of load distribution most used in this kind of analysis are not always appropriate to represent the seismic action in structures when getting into the inelastic range. This study aims to compare the structural demands obtained from nonlinear static analysis using different basic patterns of load distribution with those obtained from the rigorous nonlinear time-history analyzes, which are considered as the benchmark. Four seismic intensities were considered, as well as two structure heights. The maximum average displacement of the top of the last level obtained from the different non-linear time-history analyzes was adopted as the objective displacement in the pushover analyzes with each pattern. The results show the lack ...
18
artículo
Publicado 2021
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The article aims to discuss the effects of the Covid 19 pandemic on Brazilian higher education in 2020. The experience of remote classes, using virtual communication technologies during the pandemic, changed the learning relationships between teachers and students. These changes did not happened in a homogeneous and linear manner. This text discusses the different uses of these technologies and how these processes have contributed to strengthening existing educational inequalities. The arguments were structured in three moments, in order to consider processes that occurred before, during and after the pandemic. To deal with education inequalities after the pandemic, three challenges are suggested.
19
artículo
Publicado 2021
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The article aims to discuss the effects of the Covid 19 pandemic on Brazilian higher education in 2020. The experience of remote classes, using virtual communication technologies during the pandemic, changed the learning relationships between teachers and students. These changes did not happened in a homogeneous and linear manner. This text discusses the different uses of these technologies and how these processes have contributed to strengthening existing educational inequalities. The arguments were structured in three moments, in order to consider processes that occurred before, during and after the pandemic. To deal with education inequalities after the pandemic, three challenges are suggested.
20
artículo
Publicado 2013
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This work is focused on the modeling and development of a CBIR (Content-based image retrieval) system applied to the recovery of digital medical images of a human body, denominated M-CBIR. This model is composed on two methodologies: features extraction techniques and metric data structures. When this set of techniques is applied to the search of different human body regions, it can retrieve the most relevant similar images to a query image. A real database of medical images composed of 772 medical studies was used to compare the robustness of the extraction techniques and evaluate the performance of the system, through four different extractors. The objective of this work will result in a digital atlas of human body for medical radiological center. Finally, analysis and conclusions are also discussed.
