Algunas observaciones en torno a la estructura, el dialogismo y el plurilingüismo en "La culpa es de los tlaxcaltecas" de Elena Garro

Mediante la vinculación entre el texto literario, la historia y los símbolos; el análisis de la trama, el argumento y la estructura, y la inclusión de algunos conceptos extraídos de Teoría y estética de la novela, de Mijail Bajtín, el presente trabajo aspira a demostrar el dinamismo dialógico verificado en "La culpa es de los tlaxcaltecas", de Elena Garro. Más allá de las consideraciones fantásticas, este cuento constituye la manifestación viva del encuentro entre múltiples cosmovisiones, destinadas a confrontar el discurso autoritario y oficial propio de la historia mexicana

Comunicación e identidades en Yawar fiesta de José María Arguedas: el festejo de las transformaciones

A la luz de algunos conceptos de Françoise Perus especialmente el de poética narrativa y de Mijail Bajtin tipos de novela y cronotopo , se analiza la novela Yawar fiesta de José María Arguedas. La premisa central radica en la demostración de que esta novela no se limita a exponer un conflicto entre indios y blancos, sino que presenta la confrontación entre numerosas visiones de mundo, las cuales se transforman notoriamente a lo largo del acontecimiento, de tal manera que la narración aparece como una unidad dinámic

Establishing the maximum carbon number for reliable quantitative gas chromatographic analysis of heavy ends hydrocarbons

This Thesis investigates the two main limitations of high temperature gas chromatography (HTGC) in the analysis of heavy n-alkanes: pyrolysis inside the GC column and incomplete elution. The former is studied by developing and reducing a radical pyrolysis model (7055 reactions) into a molecular pyrolysis model (127 reactions) capable of predicting low conversions of (nC14H30-nC80H162) at temperatures up to 430°C. Validation of predicted conversion with literature data for nC14H30, nC16H34 and nC25H52 yielded an error lower than 5.4%. The latter is addressed by developing an analytical model which solves recursively the diffusion and convection phenomena separately. The model is capable of predicting the position and molar distribution of components, using as main input the analytes’ distribution factors and yielded an error lower than 4.4% in the prediction of retention times. This thesis provides an extension of the data set of distribution factors of (nC12H26– nC98H198) in a SGE HT5 GC capillary column, based on isothermal GC measurements at both constant inlet pressure and flow rate. Finally, the above two models were coupled, yielding a maximum mass lost of 1.3 % in the case of nC80H162 due to pyrolysis and complete elution up to nC70H142, in a 12 m HT5 column

Influence of mix design parameters on dynamic segregation of self-consolidating concrete and consequences on performance of precast beams

Self-Consolidating Concrete (SCC) is more vulnerable to stability problems as a consequence of its high flowing ability compared to conventional vibrated concrete. Dynamic segregation refers to the tendency of the concrete constituents to separate from the suspended matrix, usually in horizontal direction while being cast into the formwork or due to an impact. Similarly to static segregation, dynamic segregation can affect the homogeneity of SCC. Therefore, it is highly essential to ensure a proper dynamic stability in order to enhance the uniformity of in-situ properties of pre-stressed beams. In this research project, the effects of SCC mix design parameters are investigated using the T-box test as a method to assess dynamic segregation. Changes in chemical admixture type and content, paste volume, sand-to-total aggregate ratio (S/A), w/cm and the width of the T-box have been evaluated. The results show that dynamic segregation of SCC is dependent on the rheological properties of the concrete, paste volume and S/A. In a second part, the influence of dynamic segregation on the uniformity of precast, pre-stressed beams is investigated. Six 9 m and three 18 m long beams were produced with SCC. To determine the uniformity of the mixture, a comparative survey across the beam height and along its length was performed. Also, the bond strength of pre-stress strands with SCC was investigated. Results from the UPV and compressive strength demonstrate a variation in the uniformity of the concrete, mainly at the casting point. For the bond strength, with increasing dynamic segregation, the bond between the strand and the concrete at the top 1/3rd of the beam height, relative to the bond in the middle 1/3rd, decreases --Abstract, page iii

Complexities observed during the development of a rheological testing procedure for small cement paste samples

“Rheology has been widely used to describe the flow properties of fresh cement-based suspensions. The use of a rheometer to characterize these properties is not a straightforward task due to the dependency to different preparation conditions, mixing processes, testing procedures and measuring instruments employed. In addition, shear and time dependency of the material which undergoes chemical and physical particle bonding, caused by hydration of cement and flocculation. Nevertheless, the characterization and understanding of the rheological behavior of cement-based materials have become essential with the recent introduction of novel applications like digital construction in the field of civil engineering, among others. Therefore, to be able to suitably adapt such properties, to optimize and to ensure consistent performance, there is a need to accurately measure the properties and to obtain repeatable and consistent results. This research work shows how changes in the testing procedure, rheometer geometry and resting time in between measurements impact the rheological properties of cement pastes. The results indicate that the time-evolution of the rheological properties is strongly dependent on the employed procedure, and the effect is attributed to shear-enhanced hydration. Also, the resting time enhances the increase in differential viscosity and is dependent on the admixture’s workability retention, as small or significant variations in the rheological properties are observed. The proper understanding of the advantages and disadvantages as well as the limitations of each geometry and procedure should be taken into account to avoid issues such as wall slip, sample spill, dryness, particles sedimentation, non-uniform shear rate applied, etc. that can be prevented”--Abstract, page iv

Diversity mdir receiver for space-time dispersive channels

A particular property of the cellebrated MDIR receiver is introduced in this communication, namely, the fact that full exploitation of the diversity is obtained with multiple beamformers when the channel is spatially and timely dispersive. Therefore a new structure is developped which provides better performance. The hardware need for this new receiver may be obtained through reconfigurability of the RAKE architectures available at the base station. It will be tested in the FDD mode of UTRA.Peer ReviewedPostprint (published version

CMA algoritmos de módulo constante en ecualización adaptativa

An adaptative digital filtering algorithm that can compensate for both frequency-selective multipath and interference on constant envelope modulated signals is presented. The reported algorithm adapts the coefficients of a finite- imoulse-response (FIR) digital filter. The main advantage of the CMA algorithm resides that it doesn't need trainig or reference signal in order to perfom. The adquisition or tracking; thus, it is continuosly adapted without further needs as DFE methods and references which fardly constraint the nobiastress of the Wiener approach.Peer ReviewedPostprint (published version

Rayleigh estimates: performing like SVD

This paper describes the structure of the so- called Rayleigh estimates and the features they share with indirect SVD like procedures. The problem of finding procedures of high resolution in spectral estimation is faced under the framework of non-linear estimates of the autocorrelation matrix and the low rank approximation to the frequency estimation problem. It is shown the existing relations hip between the proposed estimates and the principal component analysis. The main advantages of the procedure is that the performance of the spectral estimates reported herein is almost equal to SVD techniques, yet preserving a good asymptotic convergence to the actual power spectral density. Also, the procedure could be viewed under variotional concepts revealing its potential under adaptive schemes and data adaptive windowing for spectral estimation. In summary, the work shows how classical constrained Wiener filtering with data adaptive windowing can enhance the performance of SVD met hods with very low complexity.Peer ReviewedPostprint (published version

Relationship of cultural and class variables to attributional style and academic performance among college students

The present study examined the relative contribution of cultural (racial status versus cultural identification) and class (socioeconomic status versus perceived deprivation) variables to attributional style and academic achievement in minority and non-minority college students. In general, results indicated that minority and non-minority students utilize different types of motivating strategies in attaining academic success.Perceived deprivation was associated with a pessimistic attributional style and cultural identification was associated with academic performance only among minority students. Contrary to prediction, the relationships between class and cultural variables and academic performance was not mediated by attributional style. Results also suggest that objective estimates of socioeconomic status and perceived deprivation measure distinctly different constructs, as do racial status and cultural identification. Perceived deprivation and cultural identification appear to be more meaningful variables for assessing cultural and class influences on attributional style and academic achievement in minority individuals