Constitutive modelling of Sandvik 1RK91

A physically based constitutive equation is being developed for the maraging\ud stainless steel Sandvik 1RK91. The steel is used to make precision parts. These parts are formed through multistage forming operations and heat treatments from cold rolled and annealed sheets. The specific alloy is designed to be thermodynamically unstable, so that deformation even at room temperatures can bring about a change in the phase of face centred cubic austenite to either hexagonal closed packed martensite and/or, body centred cubic martensite. This solid state phase change is a function of the strain path, strain, strain rate and temperature. Thus, the fraction of the new phase formed depends on the state of stress at a given location in the part being formed. Therefore a set of experiments is being conducted in order to quantify the stress-strain behavior of this steel under various stress states, strain, strain rate as well as temperature. A magnetic sensor records the fraction of ferromagnetic martensite formed from paramagnetic austenite. A thermocouple as well as an infra red thermometer is used to log the change in temperature of the steel during a mechanical test. The force-displacement data are converted to stress-strain data after correcting for the changes in strain rate and temperature. These data are then cast into a general form of constitutive equation and the transformation equations are derived from Olson-Cohen type functions

Propuesta alternativa de definicion de perfiles en CODELCO-Chile, division El Teniente

66 p.La empresa Chilena CODELCO-CHILE, ha implementado dentro de su corporación el software integrado SAP R3, el que Ies permite mejorar su gestión, entre ellas la de modernizar y optimizar procesos, facilitar el acceso a la información y construir un lenguaje y una cultura corporativa. Este software integrado es un sistema de información que permite una gran cantidad de posibilidades de consultas, ingresos, modificaciones y/o eliminaciones de información de diferentes materias, es decir, SAP R3 integra distintos tipos de información en una gran base de datos, los cuales son utilizados por los módulos que compone el sistema. Para el use del sistema los encargados de la implementación han otorgado permisos o autorizaciones a los usuarios sobre SAP R3, denominándose Perfiles SAP, pero Ia definición incorrecta ha provocado problemas de sobrecostos para la División. El presente proyecto tendrá por finalidad proponer un método alternativo de definición de perfiles bajo una metodología denominadas Redes IDA, que esta basada en una descripción de los procesos básicos de gestión en los cuales participan los usuarios. A partir de la descripción de procesos de gestión, se especifican roles de usuario que son la base de la definición de perfiles

Entanglement fidelity for electron-electron interaction in strongly coupled semiclassical plasma and under external fields

This paper presents the effects of AB-flux field and electric field on electron-electron interaction, encircled by a strongly coupled semiclassical plasma. We found that weak external fields are required to perpetuate a low-energy elastic electron-electron interaction in a strongly coupled semiclassical plasma. The entanglement fidelity in the interaction process has been examined. We have used partial wave analysis to derive the entanglement fidelity. We found that for a weak electric field, the fidelity ratio for electron-electron interaction increase as projectile energy increase but remains constant or almost zero for a strong electric field. Our results provide an invaluable information on how the efficiency of entanglement fidelity for a low-energy elastic electron-electron interaction in a strongly coupled semiclassical plasma can be influenced by the presence of external fields

Tribología de nuevas capas autolubricantes producidas mediante PVD

Las capas de MoS2 depositadas mediante PVD tienen baja fricción en vacío pero se degradan con facilidad al aire, especialmente en presencia de humedad. Este trabajo describe el desarrollo de nuevas capas de MoS^ modificadas con WC. En ensayos de "bola sobre disco" a 0,75 GPa, las capas presentaron una fricción muy baja y estable (< 0,04) en vacío. Se obtuvo una durabilidad superior a 1 millón de ciclos, mostrando un desgaste de 1,3 X 10e-16 me3 /Nm, mejorado respecto a otras capas de MoS2. El coeficiente de fricción aumentó a 0,15 y la durabilidad disminuyó hasta 1 a 3 x 10e5 ciclos en aire hasta 70 % HR. El análisis superficial mostró ratios de S/Mo superiores a 1,2, con menos del 2 % de oxígeno, demostrando carácter lubricante.MoS2 coatings, deposited by PVD show a low friction under vacuum conditions, but degrade easily under atmospheric conditions. This work describes the development of a new type of MoSx, coating, modified with WC. These coatings presented a very low and stable friction coefficient lower than 0.04 when tested under vacuum at 0.75 GPa in a ball on disc tribometer. Durability was higher than 1 million wear cycles, showing a wear rate of 1.3 10e-16 m3 /Nm. When tested under atmospheric conditions and up to 70 % RH, friction increased to 0.15 and durability reached a lower value of up to 3 x 10e5 cycles. Surface analyses in these coatings showed S/Mo ratios higher than 1.2 and with oxygen levels lower than 2 %, demonstrating the lubricant character of the coating.Ministerio de Ciencia y Tecnología (proyecto MAT2001-1399-C02-02) Departamento de Educación, Universidades e Investigación del Gobierno Vasco (proyecto PI-2001-12)

Load absorption force-time characteristics following the second pull of weightlifting derivatives

The purpose of this study was to compare the load absorption force-time characteristics of weightlifting catching and pulling derivatives. Twelve resistance-trained men performed repetitions of the hang power clean (HPC), jump shrug (JS), and hang high pull (HHP) on a force platform with 30, 45, 65, and 80% of their one repetition maximum (1RM) HPC. Load absorption phase duration, mean force, and work were calculated from the force-time data. The HHP produced a significantly longer load absorption phase duration compared to the HPC (p < 0.001, d = 3.77) and JS (p < 0.001, d = 5.48), while no difference existed between the HPC and JS (p = 0.573, d = 0.51). The JS produced significantly greater load absorption mean forces compared to the HPC (p < 0.001, d = 2.85) and HHP (p < 0.001, d = 3.75), while no difference existed between the HPC and HHP (p = 0.253, d = 0.37). Significantly more load absorption work was performed during the JS compared to the HPC (p < 0.001, d = 5.03) and HHP (p < 0.001, d = 1.69), while HHP load absorption work was also significantly greater compared to the HPC (p < 0.001, d = 4.81). The weightlifting pulling derivatives examined in the current study (JS and HHP) produced greater load absorption demands following the second pull compared to the weightlifting catching derivative (HPC). The JS and HHP may be used as effective training stimuli for load absorption during impact tasks such as jumping

The Portrayal of Epilepsy in Meena Meets Her Match

Epilepsy is a spectrum disorder characterized by random and unprovoked seizures that affects approximately 470,000 children living in the U.S. (Epilepsy Foundation, n.d.). Despite this prevalence, few contemporary, middle-grade books reflect the experiences of children with epilepsy. Books that appropriately reflect diverse experiences are validating and important in a multicultural world (Bishop, 1990). Not only should books represent students with multiple diverse experiences (such as living with epilepsy), but also they must do so in an empathetic, inclusive, and informative way. This Book Analysis Project critically considers how epilepsy is portrayed in Meena Meets Her Match (Manternach, 2019), a contemporary, middle-grade book in which the protagonist, a third-grade girl, is diagnosed with epilepsy. In the analysis, the portrayal of epilepsy in Manternach’s book is discussed in accordance with epilepsy research, testimonies, and other evidence-based sources. In addition, two plans for lessons intended to teach middle-grade audiences about living with epilepsy are presented