Study of the Indentation Process under Specific Technological Parameters

AbstractThere is a large variety of Compressive Forming Processes with different typologies and characteristics. In this paper, the indentation process is studied from the point of view of manufacturing. The influence of technological parameters such as friction and shape factor on the process has been studied. The aluminum alloy AA 6082 has been employed in this study due to its good mechanical properties, light weight and its capacity of being recycled. The Finite Element Method (FEM) has been used for the analysis. The indentation process has been studied under axisymmetric conditions. The forces to carry out the indentation process and the contact pressures have been obtained. Finally, it is shown that the forces and the contact pressures do not have a high dependency on the friction between the surfaces of the punch and the workpiece. The shape factor has a greater influence on the process, especially the width of the workpiece

Study of the Indentation Process under Specific Technological Parameters

AbstractThere is a large variety of Compressive Forming Processes with different typologies and characteristics. In this paper, the indentation process is studied from the point of view of manufacturing. The influence of technological parameters such as friction and shape factor on the process has been studied. The aluminum alloy AA 6082 has been employed in this study due to its good mechanical properties, light weight and its capacity of being recycled. The Finite Element Method (FEM) has been used for the analysis. The indentation process has been studied under axisymmetric conditions. The forces to carry out the indentation process and the contact pressures have been obtained. Finally, it is shown that the forces and the contact pressures do not have a high dependency on the friction between the surfaces of the punch and the workpiece. The shape factor has a greater influence on the process, especially the width of the workpiece

Complicaciones de los osteocondromas

Los osteocondromas o exostosis cartilaginosas son los tumores óseos más frecuentes, representando el 10-15 % de la totalidad. Parece ser más bien una alteración del desarrollo óseo más que un tumor verdadero. Suele tener una imagen radiográfica patognomónica. Los osteocondromas pueden ser solitarios o múltiples, estos últimos forman parte del síndrome de exostosis múltiples hereditarias, de transmisión autosómica dominante. Las complicaciones que pueden presentar, pueden ser óseas; deformidad del hueso donde asientan o fracturas del mismo, o de los tejidos que lo rodean, pudiendo provocar trastornos neurológicos, vasculares, bursitis, y la peor complicación, que es su malignización. Existen variantes de los osteocondromas como la exostosis subungueal, la displasia epifisaria hemimielica, y las exostosis en torreta y por tracción. Es importante conocer la apariencia radiológica de todos los tipos de exostosis, para diferenciarlas de sus posibles complicaciones.Osteochondroma, also termed osteocartlaginous exostoses represents the most common bone tumors and is a developmental lesion rather than a true neoplasm. It constitutes 10-15 % of all bone tumors. Its radiologic features are often pathognomonic. Osteochondromas may be solitary or multiple, the latter being associated with the autosomal dominant syndrome, hereditary multiple exostoses. Complications associated with osteochondroma include deformity, fracture, vascular compromise, neurologic sequelae, overlying bursa formation, and malignant transformation. Variant of osteochondroma include subungueal exostosis, dysplasia epiphysealis hemimelica, turret and traction exostoses. Recognition of the radiologic spectrum of appearances of osteochondroma and its variants allow prospective diagnosis and differentiation of the numerous potential complications

Short-term effects of impurities in the CO2 stream injected into fractured carbonates.

After the Paris Agreement in which 195 countries are involved, the Carbon Capture and Storage (CCS) is now an accepted technology in the United Nations Framework Convention on Climate Change (UNFCCC). In Spain, Fundación Ciudad de la Energía (CIUDEN) has successfully completed the full CCS chain, being CO2 captured in the Technology Development Centre in Cubillos del Sil (León, Spain) whereas that it is geologically stored in a deep saline aquifer, formed by fractured carbonates with poor matrix porosity, located in the Technology Development Plant (TDP) at Hontomín (Burgos, Spain). The results of the field tests, in which up to 150 tons of CO2 and synthetic air (5 %v of N2 and O2) were co-injected on site, are analyzed in this paper comparing the operational parameters gained during the injection of impure CO2 (pressures, temperatures and flow ranges) with its corresponding baseline previously determined (i.e. 1,500 tons of pure CO2 were injected during the reservoir hydraulic characterization). Besides that, the geochemical reactivity analysis of impure CO2 injected in this saline aquifer and its correlation with the results from laboratory tests were assessed. As main conclusions from laboratory scale results, a porosity diminution was measured after the injection of CO2 with 5 %v of SO2; apart from that, without SO2, the effluent pH was in the range of 7-8 whereas in case of CO2 and SO2, a pH of 1-2 was obtained. Otherwise and focused on field scale tests, a density decrease was detected comparing the base case (pure CO2) with the CO2 injection containing 5.1 %v of synthetic air. On the other hand, Ca2+, SO42-, Mg2+ and K+ migration effects in the rock were also detected and analyzed

Muros de escollera en urbanizaciones

The uneven and slopes terrain force us to intervene with rigid or flexible containment structures. Containment structures tend to be mostly of reinforced concrete or steel sheet piling. For some time, the use of stone jetties as containment structures and permanent stabilization in housing estates is being imposed. This type of structure has been used successfully in slopes of roads and jetties on port. When moving it to suburbia has disparaged some aspects, both design and calculation, not taking into account actions in risk areas, or eliminating essential components as filters and drain components. This document analyzes the work of intervention in two works affected in Motril (Granada, Spain) and Almeria (Spain), where the breakwaters were utilized, reaching recidivism in one of them. Guide for the design and construction of breakwaters in roadworks from the Ministry of Public Works in 1998, revised in 2006, [3] is a valuable document but requires a Decalogue of specific instructions for use in works of urbanization, in general of lower volume, and with the largest number of meetings of surfaces. Three-dimensionality is usually an important factor to take into account.Los desniveles y pendientes del terreno nos obligan a intervenir mediante estructuras de contención, rígidas o flexibles. Las estructuras de contención suelen ser en su mayor parte de hormigón armado o tablestacas metálicas. Desde hace algún tiempo se está imponiendo la utilización de escolleras de piedra como estructuras de contención y estabilización permanentes en urbanizaciones. Este tipo de estructuras ya habían sido usadas con éxito en taludes de carreteras y espigones de puerto. Al trasladarse a las urbanizaciones se ha menospreciado algunos aspectos, tanto de diseño y cálculo, no teniendo en cuenta las acciones sísmicas en zonas de riesgo como Motril, o eliminando componentes esenciales como filtros y drenajes. El presente documento analiza los trabajos de intervención realizados en dos obras siniestradas en Motril y Almería (España), donde se utilizaron las escolleras, uno de ellos incluso reincidente. La Guía para el diseño y construcción de escolleras en obras de carreteras del Ministerio de Fomento de 1998, revisada en 2006, es un valioso documento pero precisa de un decálogo de instrucciones precisas para su uso en obras de urbanización, en general de menor volumen, y con mayor número de encuentros de superficies. La tridimensionalidad suele ser un factor importante a tener en cuenta

Iniciación a la investigación en un laboratorio integrado de química

El reto planteado por la Convergencia al Espacio Europeo en la Educación Superior (EEES) supone una oportunidad para la reflexión y la puesta en marcha de iniciativas de mejora de la calidad en el ámbito de la docencia universitaria. Aprovechando este impulso, se propone un Proyecto de Innovación Docente en la asignatura troncal de “Experimentación en Química Inorgánica” del tercer curso de la Licenciatura en Química de la Universidad de Jaén.El trabajo presentado recoge la actuación en un laboratorio integrado de Química en el que se desarrollará el proceso de aplicación de los conocimientos adquiridos por los alumnos en las diversas asignaturas cursadas sobre sólidos inorgánicos, caracterización de sólidos adsorbentes, estudio de superficies, procesos de adsorción, técnicas quimiométricas y valorización de subproductos y concienciación medioambiental

A Single Amino Acid Substitution, Found in Mammals with Low Susceptibility to Prion Diseases, Delays Propagation of Two Prion Strains in Highly Susceptible Transgenic Mouse Models

Specific variations in the amino acid sequence of prion protein (PrP) are key determinants of susceptibility to prion diseases. We previously showed that an amino acid substitution specific to canids confers resistance to prion diseases when expressed in mice and demonstrated its dominant-negative protective effect against a variety of infectious prion strains of different origins and characteristics. Here, we show that expression of this single amino acid change significantly increases survival time in transgenic mice expressing bank vole cellular prion protein (PrP C ), which is inherently prone to misfolding, following inoculation with two distinct prion strains (the CWD-vole strain and an atypical strain of spontaneous origin). This amino acid substitution hinders the propagation of both prion strains, even when expressed in the context of a PrP C uniquely susceptible to a wide range of prion isolates. Non-inoculated mice expressing this substitution experience spontaneous prion formation, but showing an increase in survival time comparable to that observed in mutant mice inoculated with the atypical strain. Our results underscore the importance of this PrP variant in the search for molecules with therapeutic potential against prion diseases

Energy Relaxation in Nonlinear One-Dimensional Lattices

We study energy relaxation in thermalized one-dimensional nonlinear arrays of the Fermi-Pasta-Ulam type. The ends of the thermalized systems are placed in contact with a zero-temperature reservoir via damping forces. Harmonic arrays relax by sequential phonon decay into the cold reservoir, the lower frequency modes relaxing first. The relaxation pathway for purely anharmonic arrays involves the degradation of higher-energy nonlinear modes into lower energy ones. The lowest energy modes are absorbed by the cold reservoir, but a small amount of energy is persistently left behind in the array in the form of almost stationary low-frequency localized modes. Arrays with interactions that contain both a harmonic and an anharmonic contribution exhibit behavior that involves the interplay of phonon modes and breather modes. At long times relaxation is extremely slow due to the spontaneous appearance and persistence of energetic high-frequency stationary breathers. Breather behavior is further ascertained by explicitly injecting a localized excitation into the thermalized array and observing the relaxation behavior