Power quality monitoring data management and analysis for distribution networks

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Eriyttämisen vaikutus oppilaiden liikuntamotivaatioon

Kandidaatintutkielmamme on kirjallisuuskatsaus, joka käsittelee eriyttämisen ja motivaation merkitystä liikunnanopetuksessa. Tämän lisäksi tutkimme eriyttämisen ja motivaation välistä suhdetta toisiinsa. Lähdemme tutkielmassamme liikkeelle liikunnanopetuksen määrittelemisestä, jonka jälkeen selvitämme mitä on eriyttäminen ja kuinka sitä toteutetaan liikunnanopetuksessa. Käymme myös läpi eri motivaatioteorioiden avulla miten motivaatio syntyy ja miten opettaja voi vaikuttaa oppilaidensa liikuntamotivaatioon. Lopuksi perehdymme siihen, kuinka eriyttäminen vaikuttaa oppilaiden liikuntamotivaatioon. Aiheemme on todella ajankohtainen, sillä nykypäivänä oppilasryhmät ovat yhä heterogeenisempiä oppilaiden liikunnallisten taitojen vaihdellessa suuresti, minkä vuoksi eriyttäminen nousee todella tärkeäksi elementiksi liikuntatunneilla. Opettajan on osattava tarjota sopivan haastavia tehtäviä jokaiselle oppilaalle yksilöllisesti, ja tätä painotetaan myös Perusopetuksen opetussuunnitelman perusteissa 2014. Lisäksi opettajan on tärkeää olla tietoinen soveltavan liikunnan mahdollisuuksista, mikä tarkoittaa oppilaiden erityistarpeiden ja vammojen huomioimista. Liikunnanopetuksen tarkoituksena on ottaa jokainen ryhmän jäsen huomioon parhaalla mahdollisella tavalla. Oppilaiden yksilöllisyys tulee ilmi myös oppilaiden motivaatiossa, sillä toisten oppilaiden liikuntamotivaatio on paljon suurempi kuin toisten. Opettajalla on mahdollisuus vaikuttaa oppilaiden motivaation kasvuun pitämällä huoli, että tunneilla tarjotaan kaikille autonomian tunnetta, pätevyyden kokemuksia sekä sosiaalisen yhteenkuuluvuuden tunnetta. Opettajan rooli myönteisen motivaatioilmaston luomisessa on suuri. Opettajan on hyvä pyrkiä luomaan liikuntatunneille enemmin tehtäväsuuntautunut motivaatioilmasto, jossa vertailu perustuu itsevertailuun, kuin minäsuuntautunut motivaatioilmasto, jossa oppilaat vertailevat suorituksia toisiinsa. Korostamalla tehtäväsuuntautuneisuutta tehdessään pedagogisia ratkaisuja opettaja voi vaikuttaa oppilaiden motivaatioon eriyttämisen kautta

Grid-connected PV power plant induced power quality problems - Experimental evidence

This paper presents new findings on phenomena contributing to flicker and voltage variations caused by grid-connected photovoltaic (PV) inverters. The voltage variations caused by two different 6 kW single-phase grid-connected PV inverters were studied during climatic variations by varying their grid-coupling impedance. Two different methods for characterizing the PV-plant induced voltage variations were studied: the short-term flicker index (Pst) and the 10 minute very-short voltage variation value (VSV). The results clearly indicate that PV inverter power fluctuations induced by cloud shading and enhancement have a significant effect on the VSV value, but not on Pst. PV inverters have a clear effect on the Pst as well, but the main contributors are related to the inverter design rather than the power fluctuations caused by clouds. The main contributor in the elevated Pst values could be traced back to the poor design of the maximum power point tracking (MPPT) of the inverters. The MPPT caused subharmonic current variations at a frequency of approximately 8 Hz which is close to the most sensitive frequency of human eye. Another factor causing rapid voltage variations in low irradiance conditions was the current transients related to the inverter start-up and shut-down. Harmonic current distortion is also a potential PV inverter related power quality (PQ) issue. This study indicates that although the current total harmonic distortion (THD) may be very large at low power levels the total demand distortion (TDD) of the PV inverters is almost constant regardless of the output power and the harmonic current had only a very limited effect on the voltage quality even at the weakest network having a short-circuit current of Isc=250 A. Thus, voltage variations caused by the PV inverters were the main PQ issue in the studied networks. The investigations also clearly show that a part of the power quality problems found i- the PV plants are caused by the poor design of the PV inverters.acceptedVersionPeer reviewe

Dielectric properties and partial discharge endurance of polypropylene-silica nanocomposite

This paper presents the results of the dielectric properties and partial discharge endurance measurements conducted on polypropylene (PP)-silica nanocomposite. The material compounds were analyzed with micro-Raman spectroscopy, X-ray tomography and transmission electron microscopy (TEM). ac and dc breakdown strength of the materials was measured. Dielectric response, capacitance and loss factor of the film samples were measured as a function of temperature and frequency. Partial discharge (PD) endurance of the reference PP and PP Silica nanocomposite was studied as a function of ac voltage. Material surfaces were analyzed after PD stress with optical microscopy. All dielectric measurements were done for oriented thin films with a thickness of 11-23 ?m. The results were analyzed statistically to determine the effects of the additive on the properties of PP. The paper discusses the potential of PP Silica nanocomposite with a view to high voltage applications, especially power capacitors

Bolometer operating at the threshold for circuit quantum electrodynamics

| openaire: EC/H2020/824109/EU//EMP | openaire: EC/H2020/681311/EU//QUESS | openaire: EC/H2020/670743/EU//QuDeT | openaire: EC/H2020/820505/EU//QMiCSRadiation sensors based on the heating effect of absorbed radiation are typically simple to operate and flexible in terms of input frequency, so they are widely used in gas detection, security, terahertz imaging, astrophysical observations and medical applications. Several important applications are currently emerging from quantum technology and especially from electrical circuits that behave quantum mechanically, that is, circuit quantum electrodynamics. This field has given rise to single-photon microwave detectors and a quantum computer that is superior to classical supercomputers for certain tasks. Thermal sensors hold potential for enhancing such devices because they do not add quantum noise and they are smaller, simpler and consume about six orders of magnitude less power than the frequently used travelling-wave parametric amplifiers. However, despite great progress in the speed and noise levels of thermal sensors, no bolometer has previously met the threshold for circuit quantum electrodynamics, which lies at a time constant of a few hundred nanoseconds and a simultaneous energy resolution of the order of 10h gigahertz (where h is the Planck constant). Here we experimentally demonstrate a bolometer that operates at this threshold, with a noise-equivalent power of 30 zeptowatts per square-root hertz, comparable to the lowest value reported so far, at a thermal time constant two orders of magnitude shorter, at 500 nanoseconds. Both of these values are measured directly on the same device, giving an accurate estimation of 30h gigahertz for the calorimetric energy resolution. These improvements stem from the use of a graphene monolayer with extremely low specific heat as the active material. The minimum observed time constant of 200 nanoseconds is well below the dephasing times of roughly 100 microseconds reported for superconducting qubits and matches the timescales of currently used readout schemes, thus enabling circuit quantum electrodynamics applications for bolometers.Peer reviewe