Search results for "pac"
showing 10 items of 28794 documents
Partial Discharges in HVDC Cables - The Effect of the Temperature Gradient During Load Transients
2021
The paper investigates the role of the space charge accumulation phenomena in the inception of Partial Discharges (PD) in a defect within the bulk of the dielectrics of a High Voltage Direct Current (HVDC) cable. It is widespread accepted that the number of PD occurring in an HVDC cable during its lifetime is largely less than that under AC voltage stress. This is essentially due to higher values of the voltage between the conductor and the screen needed to trigger PD under a steady DC voltage than the same value under AC stress. Nevertheless, due to the dependency of the electrical conductivity of the insulation on the electric field and temperature, PD in HVDC cables is strongly influence…
Development of bidirectional dc-dc converters for hybrid power sources - Final Report
2018
A Bidirectional Isolated Full-Bridge Converter was designed, prototyped and tested. The device is intended to interface a Bank of Supercapacitors with a battery-powered bus, in order to boost the capability of supplying large power peaks. The converter was based on the Isolated Dual Active Bridge configuration. When driven by an external control voltage, it is capable of generating in both directions a train of current pulses, with 2kW peak power, for any battery voltage in the range 24-32V and for any supercapacitor voltage in the range 35-70V. Worst-case battery current was 70A. Pulse duration was 100ms with 50% duty cycle and 1 ms rise time.
An Innovative Coupling Solution for Power Line Communication in MV Electrical Networks
2019
One of the main problems in the diffusion of power line communication (PLC) in medium voltage (MV) networks is the need of a dedicated PLC coupler to be installed all over the network. To avoid this problem, the authors have studied, prototyped and patented an innovative PLC coupling solution which uses electrical elements embedded in most of the switchgears already installed in MV networks, i.e. the capacitive dividers of the voltage detecting systems (VDS). The new solution prototype is described in this paper, highlighting the advantages in terms of a significant reduction of both direct costs of equipment and infrastructures and indirect costs of installation and service interruption. T…
L’intériorisation de l’espace: le désert chez Fromentin et Saint-Exupéry
2009
Cette étude se propose de tracer un parcours à travers l’analyse d’un désert mental et littéraire, réel et intériorisé. Il s’agit de comprendre une modalité de perception de l’espace du désert à travers l’expression artistique, notamment l’écriture de deux écrivains tels que E. Fromentin et A. de Saint- Exupéry. Premièrement nous allons aborder la question de la perception du désert en tant que paysage et par conséquent sa cristallisation en images transformant la réalité géographique des lieux. Le désert sera donc analysé en relation à la culture occidentale en tant que son même contrepoint ou bien en tant que terme de référence pour la définition de l’identité collective. Ensuite on abord…
Comparison of Post-Weld Treatment of High-Strength Steel Welded Joints in Medium Cycle Fatigue
2010
This paper presents a comparison of three post-weld treatments for fatigue life improvement of welded joints. The objective is to determine the most suitable post-weld treatment for implementation in mass production of certain crane components manufactured from very high-strength steel. The processes investigated are: burr grinding, TIG dressing and ultrasonic impact treatment. The focus of this investigation is on the so-called medium cycle area, i.e. 10 000-500 000 cycles and very high stress ranges. In this area of fatigue design, the use of very high strength steel becomes necessary, since the stress range can exceed the yield-strength of ordinary structural steel, especially when consi…
Articulating the Practice Architectures of Collaborative Research Practice
2016
This chapter explores a collaborative practice of comparative data analysis through the researching activities of four researchers from Australia and Finland. We interrogate the ontological and empirical reality we experienced while engaged in a practice of analysing narrative data on mentoring. In this chapter, we are not reporting on the outcomes of our analysis of mentoring practice; instead we focus on our collaborative engagement, articulating the practice architectures of our research practice. This collaborative research practice was pre-figured by: (1) philosophical traditions instituted through a theory of practice architectures; and (2) normalised practices of researching mentorin…
Intervención farmacéutica sobre la prescripción inapropiada del paciente mayor polimedicado en diferentes niveles asistenciales
2017
A medida que aumenta la esperanza de vida de la población, las personas viven más tiempo con discapacidad y múltiples morbilidades. Esta situación tiene importante repercusión en los sistemas de salud a nivel mundial por su relación directa con el incremento de la cronicidad, pluripatología y polimedicación. Está demostrado que a mayor número de fármacos prescritos, aunque éstos fuesen apropiados, mayor es la posibilidad de que haya alguno no necesario y de que aparezcan efectos adversos prevenibles. La polimedicación es apropiada, cuando el paciente toma muchos fármacos, pero todos ellos tienen indicación clínica. Y polimedicación es inapropiada, cuando se toman más medicamentos de los clí…
Estudio cohortes ambispectivo de supervivencia y período libre de enfermedad en pacientes con cáncer de mama sometidas a estimulación ovárica control…
2020
El cáncer de mama es la neoplasia más común entre las mujeres. Su tratamiento puede afectar a la capacidad reproductiva. La estimulación ovárica controlada para la vitrificación de ovocitos es una de las técnicas para la preservar la fertilidad. Existen pocos estudios que evalúen el riesgo potencial de someter a pacientes con cáncer de mama a esta técnica. Además, muchas de estas investigaciones tienen limitaciones en la metodología, como el insuficiente tamaño muestral y el período de seguimiento corto. Objetivo: valorar la seguridad (supervivencia libre de enfermedad y supervivencia general) a largo plazo de la estimulación ovárica controlada para la preservación de fertilidad en mujeres …
Prevalence of Burnout Syndrome in a sample of brazilian university professors
2013
O docente integra um grupo de risco para o desenvolvimento da Síndrome de Burnout (SB). Este estudo investigou a prevalência da SB em 169 professores universitários da cidade de Piracicaba-SP, por meio do Questionário de Avaliação para a Síndrome de Burnout (CESQT versão brasileira). O valor de consistência interna alfa de Cronbach foi satisfatório para todas as dimensões do questionário. Os resultados mostraram que 11,2% dos professores apresentaram Perfil 1 e 3% Perfil 2 da SB. A prevalência encontrada é motivo de preocupação e merece atenção, não só pelos danos que a SB provoca na saúde física, mental e social do profissional, mas também pela influência na qualidade de ensino praticado n…
Examining pre-service teachers' Technological Pedagogical Content Knowledge as evolving knowledge domains : A longitudinal approach
2019
The aim of this study is to outline the development and changes in pre‐service teachers' technological pedagogical content knowledge (TPACK) assessments during the first 3 years in teacher education. Specifically, research was conducted at three measurement points over a 3‐year teacher education period. The target group consisted of pre‐service teachers (N = 148) from three Finnish universities. Results indicate a growth in confidence related to all TPACK areas during the research period. The strongest gains were in pedagogical content knowledge. In addition, the gains were larger in other areas related to pedagogical knowledge than areas related to technology or content knowledge. In areas…