Tribological behaviour of the low and high viscosity peek against steel using different contact pressures

In the market of polymers for tribological applications polyetheretherketone (PEEK) are often used for satisfying requests coming from industry regarding enhanced properties such as, thermal stability, friction and wear resistance. These properties promote the material to be used in so called high performance tribological applications. However, fundamental mechanisms governing friction and wear are not yet fully understood and neither is the influence of composition parameters. An important parameter is PEEK’s viscosity during manufacturing process which is heated up to semi-solid state, between its glass transition and melting temperature. This paper studies the friction and wear performance of low and high viscosity PEEK and pure PEEK under dry reciprocating sliding contact. The tests were performed in large scale specimens under flat-on-flat configuration to determine the transitions in tribological behaviour at different contact pressures. Tests were carried out at controlled atmosphere with 25 °C and a relative humidity of 50%. Contact pressures parameters were 4, 8 and 10 MPa used at a sliding speed of 20 mm/s. Post mortem analyses were carried out by means of 2-D surface topography and optical microscopy. The results show that the pure PEEK exhibits low coefficient of friction and wear rate when the contact pressure increase and similar behave for high and low viscosity PEEK

Aliskiren and the dual complement inhibition concept

In this issue of Clinical Kidney Journal, Plasse et al. report on the use of high-dose aliskiren as an adjunct therapy in a patient treated with eculizumab for haemolytic uraemic syndrome (HUS). This follows the recent description of the complement factor 3 (C3) activating activity of the enzyme renin and the successful therapeutic use of the direct renin inhibitor aliskiren in three cases of C3 glomerulopathy/dense deposit disease. We discuss the potential clinical and pathophysiological implications of these reports on nephropathies linked to complement, from HUS to C3 glomerulopathy to immunoglobulin A nephropathy as well as the concept of dual complement inhibition for kidney diseaseResearch by the authors was supported by FIS CP14/00133, PI16/ 02057, PI18/01366, PI19/00588, PI19/00815, DTS18/00032, ERAPerMed- JTC2018 (KIDNEY ATTACK AC18/00064 and PERSTIGAN AC18/00071, ISCIII-RETIC REDinREN RD016/0009), Fondos FEDER, FRIAT, Sociedad Española de Nefrología, Comunidad de Madrid B2017/BMD-3686 CIFRA2-CM

Intervenciones de Enfermería y Aplicación de cuidados durante la atención del parto de bajo riesgo según normas y protocolos en sala de Labor y parto, Hospital Escuela César Amador Molina, Matagalpa II semestre 2016

El principal objetivo de este es estudio es analizar las intervenciones y la Aplicación del cuidado de Enfermería según normas y protocolos durante la atención del parto en sala de labor y parto, HECAM, Matagalpa, II semestre 2016. Es de importancia ya que se obtiene conocimiento acerca de la eficacia y eficiencia de las intervenciones aplicadas en los cuidados con las pacientes en estudio, logra involucrar al personal de salud y estudiantes en el manejo de los cuidados de enfermería aplicando correctamente las normas y protocolos de bajo riesgo para lograr la atención de calidad y profundizar en el cuidado normatizado. Las principales conclusiones son: a) Se documentaron las intervenciones de enfermería durante la atención de los tres periodos del parto, establecidas en la Normativa 011, Normas y Protocolos para atención prenatal, parto, recién nacido/a y puerperio de bajo riesgo. b) Al comparar las intervenciones de enfermería con el cuidado aplicado se encontró que durante los tres periodos del parto el personal de enfermería en la mayoría de las usuarias cumple con las actividades de manera correcta. c) Al evaluar las intervenciones aplicadas por enfermería se encontró que a más de la mitad de las usuarias se le realizan las intervenciones de manera correcta y completa por lo que se valora el cuidado como satisfactori

Higiene y Seguridad Laboral en el área de Registro del Contribuyente de la Alcaldía Municipal de Jinotega durante el primer semestre del año 2015

El principal objetivo de esta investigación es analizar las medidas de Higiene y Seguridad que se aplican a los trabajadores del área de Registro del Contribuyente de la Alcaldía Municipal Jinotega durante el primer semestre del año 2015. La primera fase de la investigación consistió en recopilar la información necesaria para el desarrollo del trabajo, el cual permitió tener un mayor conocimiento de los aspectos generales de la Alcaldía, así como también de las variables de investigación acerca de Higiene y Seguridad Ocupacional. Posteriormente se realizó la investigación de campo en la que se utilizó la entrevista, la encuesta, dirigida a los trabajadores del área de Registro del Contribuyente, Jefa de área y responsable de RRHH así también la observación directa en oficinas del área; obteniendo resultados que permiten; identificar, describir y valorar la situación actual de la institución, acerca de medidas de Higiene y Seguridad Ocupacional. Así mismo, logramos darnos cuenta que la Municipalidad actualmente cuenta con Programa de Higiene y Seguridad Ocupacional, pero los trabajadores lo desconocen y así pues no contribuye a la prevención de enfermedades así como a la eliminación de accidentes de trabajo. Es necesario poner en práctica el Plan de Higiene y Seguridad, así como también distintos Recursos para brindar las condiciones necesarias a los trabajadores del área del Registro del Contribuyente de la Municipalida

The Effects of Voter Registration and Declining Political Party Competition on Turnout in the United States of America, 1880-1916

My dissertation explains the extent to which electoral institutions and declining political party competition precipitated a steep decline in U.S. turnout after 1896 from which the nation never recovered. Turnout dropped from 83 to 66 percent in less than ten years. This is a persistent puzzle in political science because data limitations have stymied empirical assessment of existing theories. Using original datasets on nineteenth century voter registration laws and records on political gambling on presidential elections from 1880 to 1916, I test the hypothesis that the shift in electoral behavior was a function of registration reforms and declining competition. I find that registration laws and political competition modestly explain the decline. Registration reforms explain one percent of the seventeen point turnout drop, and the combined effect of registration and declining competition is approximately two to three percentage points of the drop. I also found that the effect of registration are conditional on immigration, the effect is stronger in states with higher immigrant populations. For the most part, political party competition had a positive effect on turnout in the expected direction. In states remaining competitive after 1896, the long-term average effect of competition on turnout was an increase of about 14 percentage points. To validate this argument, I use election-betting data to create a measure of the public's perception of electoral competition in the states. My findings indicate that highly informed individuals accurately predicted election outcomes, which suggests the public was aware of the electoral competitiveness of presidential elections in the states. This means that perceptions about the electoral competitiveness of races likely influenced voters' decisions to participate. My dissertation advances our empirical and theoretical understanding of the interaction between institutions and political behavior and helps to inform the current debate on the potential implications that contemporary legal reforms in election laws might have on voter participation in America

Tribological behaviour of the low and high viscosity peek at various testing scales

Polyetheretherketone (PEEK) has become most attractive as a sliding bearing material in industrial applications, due to its excellent thermal stability, good friction and wear resistance. These properties promote the material to be used in so called high performance tribological applications. However, fundamental mechanisms governing friction and wear are not yet fully understood and neither is the influence of composition parameters. An important parameter is PEEK’s viscosity during injection moulding which is heated up to semi-solid state, between its glass transition and melting temperature. It is not known to what extent the injection viscosity, related to the applied temperature profile, affects subsequent tribological features. This paper studies the friction and wear performance of low and high viscosity PEEK under dry reciprocating sliding contact. The tests were performed with small and large scale specimens under pin-on-plate and flat-on-flat configuration, respectively; to determine the transitions in tribological behaviour at different scales and to identify the applications limits. Tests were carried out at controlled atmosphere with 25 °C and a relative humidity of 50%. Parameters such as contact pressures and sliding speed were limited at 10 MPa and 20 mm/s, respectively; post mortem analyses were carried out by means of 2-D surface topography and optical microscopy. The results show that PEEK injected at high viscosity exhibits a tribological performance with a relatively high coefficient of friction and high wear rate compare to PEEK injected at low viscosity

MCTS/EA hybrid GVGAI players and game difficulty estimation

In the General Video Game Playing competitions of the last years, Monte-Carlo tree search as well as Evolutionary Algorithm based controllers have been successful. However, both approaches have certain weaknesses, suggesting that certain hybrids could outperform both. We envision and experimentally compare several types of hybrids of two basic approaches, as well as some possible extensions. In order to achieve a better understanding of the games in the competition and the strength and weaknesses of different controllers, we also propose and apply a novel game difficulty estimation scheme based on several observable game characteristics

Dry sliding friction and wear response of WC-Co hardmetal pairs in linearly reciprocating and rotating contact

This paper presents an experimental evaluation of friction and wear properties of WC-Co cemented carbides. A comparison is made between unlubricated rotating and linearly reciprocating pin-onplate sliding pairs. The plate specimens were WC-10wt%Co grades surface finished by polishing or sequential wire-EDM steps, whereas WC-6wt%Co pins were used as counter body. The tests were carried out at room temperature using a sliding speed of 0.30m/s and mean Hertzain contact pressures of 1.76 and 2.08 GPa, i.e., normal contact loads of 15N and 25N, respectively. The worn surfaces on plate samples were quantified in terms of 2–D wear profiles obtained by means of surface topography scanning equipment. Wear mechanisms such as polishing and abrasion were identified using optical microscopy. Inferior tribological characteristics for wire-EDM surface finish compared to polishing were found. Higher friction coefficient and wear levels were measured in unidirectional rotating sliding experiments compared to linearly reciprocating test conditions