Search results for "Flow"
showing 10 items of 5185 documents
Uncertainty evaluation in load flow analysis: real MV distribution networks case studies
2018
This work investigates the measurement uncertainty impact on load flow analysis in medium voltage (MV) distribution networks. The considered algorithm is a simplified load flow algorithm (LFA), developed by authors, which is based on the load power measurements at each secondary substation and one voltage measurement at the slack bus (i.e. the voltage at the MV bus bars of the primary substation). In the viewpoint of a real implementation, to reduce monitoring system costs, the LFA makes use of low voltage (LV) load power measurements for all the substations except those of MV users, where MV transducers are usually already installed. The uncertainties on LFA input quantities (load powers a…
Research in reduction of meters under registration: experience and results achieved in field tests and in laboratory in Palermo
2010
Does taking additional Maths classes improve university performance?
2022
Several recent studies in educational literature showed how students’ skills in maths affect their success at higher levels of education. The aim of this paper is to evaluate the effect of taking additional maths class at high school on first-year performance of Italian university students. However, university performance and the choice of the high-school depend on several factors that make this evaluation challenging. Using information coming from three different sources, we carry out a multilevel propensity score procedure to estimate the average treatment effect between the applied sciences track and the traditional scientific one. After balancing for school- and student-level covariates…
Itsesensuuri ja flow-tila vastavoimina
2011
Tutkimuksen kohteena on itsesensuuri ja flow-tila. Tutkimus keskittyy tarkastelemaan kirjoittamista prosessina sekä itsesensuurin ja flow-tilan vastavoimaisuutta tämän prosessin sisällä. Kirjallisuuskatsauksen pohjalta pyrin löytämään vastauksen asettamaani tutkimusongelmaan ja siitä jakautuviin tutkimuskysymyksiin: Mistä kirjoittajan itsesensuurissa on kysymys ja miten kirjoittajan itsesensuurin ylittämistä voidaan edesauttaa? Teoreettisena lähtökohtana on psykoanalyyttinen tutkimus. Käsityksen mukaan yksilössä vaikuttaa tuntemattomia voimia joiden energia on viettiperäistä ja päämäärät juontavat syvälle yksilön lapsuuteen. Minä on rakentunut jakautuen tiedostamattomaan ja tietoiseen tasoo…
Poliolefiny i woski poliolefinowe. Cz. II. Energia aktywacji przepływu lepkiego
2020
Przedstawiono wyniki badań właściwości reologicznych wybranych gatunków polietylenów małej i dużej gęstości oraz otrzymanych z nich wosków. Na podstawie wyznaczonych dla nich zależności lepkości od temperatury wyznaczono energie aktywacji przepływu lepkiego tych polimerów. W celu wyjaśnienia zależności wyznaczonego parametru od właściwości tworzywa wykonano również analizy masy cząsteczkowej i dyspersyjności oraz struktury makrocząsteczek, głównie stopnia rozgałęzienia, zarówno polietylenów, jak i wosków. Uzyskane wyniki pozwoliły na ocenę właściwości przetwórczych wytypowanych tworzyw.
Levels and Changes of Physical Activity in Adolescents during the COVID-19 Pandemic: Contextualizing Urban vs. Rural Living Environment
2020
The COVID-19 pandemic and the social distancing implemented shortly after influence physical activity levels (PALs). The purpose of this investigation was to evaluate the changes in PAL and factors associated with PALs among Croatian adolescents while considering the impact of community (urban vs. rural living environment). The sample included 823 adolescents (mean age: 16.5 ±
¿Me voy o me quedo? Factores que influyen en la decisión de abandonar el lugar de nacimiento.
2014
Múltiples factores influyen en la decisión de dispersarse y en cuándo iniciar la dispersión, y su estudio proporciona evidencias de las causas y los determinantes de la dispersión. Los animales abandonan el lugar de nacimiento para dar solución a tres problemas fundamentales: pérdida de calidad del hábitat, competencia por los recursos, y riesgo de consanguinidad. La dispersión, sin embargo, no se lleva a cabo hasta que los individuos alcanzan una condición física adecuada, que permita alcanzar con éxito un nuevo lugar de asentamiento.
Vortex dynamics in rotating counterflow and plane Couette and Poiseuille turbulence in superfluid Helium
2008
An equation previously proposed to describe the evolution of vortex line density in rotating counterflow turbulent tangles in superfluid helium is generalized to incorporate nonvanishing barycentric velocity and velocity gradients. Our generalization is compared with an analogous approach proposed by Lipniacki, and with experimental results by Swanson et al. in rotating counterflow, and it is used to evaluate the vortex density in plane Couette and Poiseuille flows of superfluid helium.
Vortex line density in plane Couette flow in superfluid helium
2009
Practical Strategies for Stable Operation of HFF-QCM in Continuous Air Flow
2013
Currently there are a few fields of application using quartz crystal microbalances (QCM). Because of environmental conditions and insufficient resolution of the microbalance, chemical sensing of volatile organic compounds in an open system was as yet not possible. In this study we present strategies on how to use 195 MHz fundamental quartz resonators for a mobile sensor platform to detect airborne analytes. Commonly the use of devices with a resonant frequency of about 10 MHz is standard. By increasing the frequency to 195 MHz the frequency shift increases by a factor of almost 400. Unfortunately, such kinds of quartz crystals tend to exhibit some challenges to obtain a reasonable signal-to…