Fasti Societatis Jesu, res. et personas memorabiles ejusdem Societatis per singulos anni dies reprasentantes

UANL

Les juguetes i els dies. ' Los juguetes y los días'.

Catálogo de la exposición sobre juguetes realizada del 5 al 25 de febrero de 1987 en el Claustro de Sant Antoniet (Palma de Mallorca) y que permite conocer el origen de los juegos y juguetes desde los orígenes de la humanidad, pero especialmente el juguete tradicional de las Islas Baleares, hecho de plomo, de madera, de cartón y de lata, juguete artesano que ha quedado en el recuerdo: la cometa, la peonza, las balas, los recortables, el diábolo, las figuritas, La principal función del juguete es el desarrollo de la imaginación, la creatividad y la destreza en el niño, pues éstas le prepararan para la vida adulta. El instrumento que une el mundo imaginario del alumno con las personas adultas es el juguete, que no representa otra cosa que las realidades y los valores del alumno en miniatura.

La volta al món en 80 dies o més. 'La vuelta al mundo en 80 días o más'.

Documento incluído en el volumen 'Experiències d'innovació educativa. Ensenyament a Secundària'. Se trata de una experiencia para ESO que aborda temáticas de ciencias sociales y de lengua y literatura; todo ello bajo la introducción en el currículum de las nuevas tecnologías de la información. Consiste en realizar la vuelta al mundo siguiendo las etapas del viaje de Phileas Fogg en la novela de Jules Verne. Durante la experiencia se hace imprescindible la lectura de dicha obra. El trabajo propuesto es en equipos. La finalidad última es conocer otras culturas, motivar el trabajo en grupo y el intercambio de ideas y acercar la tecnología a la literatura. Se describen los objetivos y contenidos de la experiencia, el material utilizado, el proceso y estrategias de desarrollo y la evaluación de la innovación.

PUC: valoració dels primers 100 dies

Presentació amb les dades estadístiques dels dos últims mesos del PUC, Préstec de Llibres entre Biblioteques del Consorci de Biblioteques Universitàries de Catalunya (CBUC)

Stencil dies: new tools for an old trade

Traces the invention and development of stencil dies in the USA in the middle decades of the nineteenth century, focussing on the work of M. J. Metcalf, A. J. Fullam, and S. M. Spencer.

Tribological Testing of Some Potential PVD and CVD Coatings for Steel Wire Drawing Dies

Cemented carbide is today the most frequently used drawing die material in steel wire drawing applications. This is mainly due to the possibility to obtain a broad combination of hardness and toughness thus meeting the requirements concerning strength, crack resistance and wear resistance set by the wire drawing process. However, the increasing cost of cemented carbide in combination with the possibility to increase the wear resistance of steel through the deposition of wear resistant CVD and PVD coatings have enhanced the interest to replace cemented carbide drawing dies with CVD and PVD coated steel wire drawing dies. In the present study, the possibility to replace cemented carbide wire drawing dies with CVD and PVD coated steel drawing dies have been investigated by tribological characterisation, i.e. pin-on-disc and scratch testing, in combination with post-test observations of the tribo surfaces using scanning electron microscopy, energy dispersive X-ray spectroscopy and 3D surface profilometry. Based on the results obtained, CVD and PVD coatings aimed to provide improved tribological performance of steel wire drawing dies should display a smooth surface topography, a high wear resistance, a high fracture toughness (i.e. a high cracking and chipping resistance) and intrinsic low friction properties in contact with the wire material. Also, the steel substrate used must display a sufficient load carrying capacity and resistance to thermal softening. Of the CVD and PVD coatings evaluated in the tribological tests, a CVD TiC and a PVD CrC/C coating displayed the most promising results.

Marginal fit of nickel-chromium copings before and after internal adjustments with duplicated stone dies and disclosing agent.

STATEMENT OF PROBLEM: Despite careful procedures, master stone dies may be damaged during laboratory procedures. The dentist routinely adjusts castings because the marginal fit of casting is not as accurate as on the dies. PURPOSE: This study evaluated the technique of internal adjustment of castings with use of duplicated stone dies and a disclosing agent to improve marginal fit discrepancy. MATERIAL AND METHODS: Thirty-two nickel-chromium copings were fabricated and simulated standard clinical and laboratory procedures with 2 variables: tooth preparation convergence angles of 6 and 18 degrees, with or without internal relief. Master stone dies and their duplicates were selected for coping construction and internal adjustment, respectively. A specimen positioning device was coupled with a Toolmakers microscope to allow reproducibility of measurements. Each coping was evaluated at 8 locations of its marginal perimeter, before and after internal adjustment. RESULTS: Marginal fit discrepancy of copings were significantly reduced with an internal adjustment technique (mean > 52%) for all experimental groups. Tooth preparations with greater convergence and internally relieved castings recorded a better marginal fit. CONCLUSION: The casting internal adjustment technique with use of duplicated stone dies and a disclosing agent substantially reduced marginal fit discrepancy.

Automated optimization of polymer extrusion dies using finite element analysis

An extrusion die is used to continuously produce parts with a constant cross section; such as sheets, pipes, tire components and more complex shapes such as window seals. The die is fed by a screw extruder when polymers are used. The extruder melts, mixes and pressures the material by the rotation of either a single or double screw. The polymer can then be continuously forced through the die producing a long part in the shape of the die outlet. The extruded section is then cut to the desired length. Generally, the primary target of a well designed die is to produce a uniform outlet velocity without excessively raising the pressure required to extrude the polymer through the die. Other properties such as temperature uniformity and residence time are also important but are not directly considered in this work. Designing dies for optimal outlet velocity variation using simple analytical equations are feasible for basic die geometries or simple channels. Due to the complexity of die geometry and of polymer material properties design of complex dies by analytical methods is difficult. For complex dies iterative methods must be used to optimize dies. An automated iterative method is desired for die optimization. To automate the design and optimization of an extrusion die two issues must be dealt with. The first is how to generate a new mesh for each iteration. In this work, this is approached by modifying a Parasolid file that describes a CAD part. This file is then used in a commercial meshing software. Skewing the initial mesh to produce a new geometry was also employed as a second option. The second issue is an optimization problem with the presence of noise stemming from variations in the mesh and cumulative truncation errors. In this work a simplex method and a modified trust region method were employed for automated optimization of die geometries. For the trust region a discreet derivative and a BFGS Hessian approximation were used. To deal with the noise in the function the trust region method was modified to automatically adjust the discreet derivative step size and the trust region based on changes in noise and function contour. Generally uniformity of velocity at exit of the extrusion die can be improved by increasing resistance across the die but this is limited by the pressure capabilities of the extruder. In optimization, a penalty factor that increases exponentially from the pressure limit is applied. This penalty can be applied in two different ways; the first only to the designs which exceed the pressure limit, the second to both designs above and below the pressure limit. Both of these methods were tested and compared in this work.