The ring compression test: Analysis of dimensions and canonical geometry

The compression ring test is universally accepted as a perfectly valid method by which determine simply and reliably the adhesion friction factor in a plastic deformation process. Its methodology is based on the application of geometric changes as both the reduction in thickness as the decrease in bore inner diameter in the strained ring itself. In this paper the performance of that test is the basis for establishing the coefficient of friction on a forging process so that, given this, its application to Upper Bound Theorem (UBT) by model Triangular Rigid Zones (TRZ), enable the establishment an intercomparison with empirical force, reaching a cuasivalidation of this Theorem in a certain range.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

A comparative study of image processing thresholding algorithms on residual oxide scale detection in stainless steel production lines

The present work is intended for residual oxide scale detection and classification through the application of image processing techniques. This is a defect that can remain in the surface of stainless steel coils after an incomplete pickling process in a production line. From a previous detailed study over reflectance of residual oxide defect, we present a comparative study of algorithms for image segmentation based on thresholding methods. In particular, two computational models based on multi-linear regression and neural networks will be proposed. A system based on conventional area camera with a special lighting was installed and fully integrated in an annealing and pickling line for model testing purposes. Finally, model approaches will be compared and evaluated their performance..Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Sovereign debt default risk and Covid-19 - the impact of the Covid-19 pandemic on sovereign default risk and the relevance of fiscal space in developed and developing economies

In the first months of the COVID-19 pandemic CDS spreads over the world ramped up. I study how market perception for sovereign debt default (represented by 5- year CDS spreads) evolved depending on the intensity of the economic shock caused by the spread of COVID-19, in developed and developing economies. Using a threshold model, I find a statistically significant relation between the increase in COVID-19 and the increase in CDS spreads for developed economies, with that impact being more than doubled when the country is fiscally constrained. For developing economies, I conclude that the shock in CDS spreads is mostly driven by global-risk factors

Application of the Upper Bound Theorem to indentation processes with tilted punch by means of Modular Model

Nowadays, the indentation processes are resuming it importance due to the new deformation processes that are being developed, as the Incremental Forming Process (IFP) or the Localized-Incremental Forming Process (LIFP) [1]. In this paper, a tilt punch is considered in order to cover the largest possible number of cases in the study of the indentation,. Thus, using combinations of flat and tilt punches, it will be possible to analyze complex geometries in future studies. Present study shows the analysis of the indentation process by the Upper Bound Theorem (UBT), when it is performed with a tilt punch. A modular model is developed, compound by two modules of Triangular Rigid Zones (TRZ) each [2], which adapts to the configuration of the punch.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Introduccion a la vida devota [Texto impreso]

El directorio de religiosos con port. y pag. propiasSign.: [calderon-3calderon]4, A-V4, X2Esc. xil. en por

Upper bound solutions of ring compression test

El presente trabajo aborda una particularización del proceso de forja, estudiando la deformación de un anillo. El conformado plástico se realiza mediante el empleo del Teorema del Límite Superior y siguiendo el modelo de Bloques Rígidos Triangulares para calcular la carga mínima necesaria para deformar plásticamente la pieza. Se establece la pieza a deformar como un anillo de geometría determinada por el denominado Ensayo de Compresión de Anillo (Ring Compression Test) bajo su configuración canónica, justificándose asimilar el proceso a uno de deformación plana. Se plantea desde una nueva perspectiva el estudio del radio neutro (radio a partir del cual el material de la pieza fluye en sentidos contrarios), elemento clave en la solución del problema.Universidad de Málaga, C.E.I. Andalucía Tec

Título: Declaracion mistica de los Cantares de Salomòn

Sign.: [calderón]4, 2[calderón]8, A-Z8 2A8, 2B4Notas a pie de págApost. margTexto a dos col., excepto en los prelsLetra capital orlada y frisos tip. a lo largo de la obraContiene: Tabla de los capitulos, p. [7]-[9

The Upper Bound Theorem in forging processes: Model of Triangular Rigid Zones on parts with horizontal symmetry

The analysis to determine the necessary forces with which to achieve a plastic deformation in metallic materials, in particular, in forging processes and under conditions of plain strain, has been raised over the years through a double approach; on the one hand, by analytical methods that involve a great complexity in their developments but that allow a direct understanding of the parameters that direct these processes. On the other hand, numerical methods, in which, thanks to the enormous development of computer technology, they provide solutions with a high approximation but, in most cases, do not allow to interpret independently the effect of each one of the parameters that come into play. The development of computers relegated analytical methods to the background. An alternative of great interest to apply these methods comes from the study of the Upper Bound Theorem by means of the Triangular Rigid Zones (TRZ) Model. One of the main limitations in the application of this model come from the fact that it is necessary to define a kinematically admissible velocity field and for complex geometric configurations of parts, this field becomes increasingly complicated. A new approach has delimited, from a theoretical perspective, a modular configuration based on a General Module formed by three TRZ that adapts to any geometry of flat surfaces of the part. Another limitation of the Upper Bound Method is the consideration of the plain strain represented by a flat section with double symmetry. Obviously, this imposition only allows to study a limited number of part configurations, which restricts its application in forging processes since the great majority of forged parts do not present geometrically this double symmetry. The present work releases one of these boundary conditions allowing to expand the possibilities of application of this method.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Aviso para las viudas.

San Pablo instruye todos los prelados en la persona de su Timoteo, diciendo: «Honra las viudas que son verdaderamente viudas». Para ser, pues, verdaderamente viuda, son necesarias estas cosa