Search results for "electrical"
showing 10 items of 11048 documents
Co-teaching that works; Special and General Educators’ Perspectives on Collaboration
2021
There are surprisingly few studies analysing collaboration between special and general educators that has been proven to work well. The aim of the present study is to explore the perspectives of sp...
Meaningful time for professional growth or a waste of time?: a study in five countries on teachers' experiences within master's dissertation/thesis w…
2020
The relationship between master’s thesis work and teachers’ professional development has rarely been explored empirically, yet. Drawing upon a larger study, this paper investigates how teachers who were studying for or who have recently graduated from Master of Education programmes offered in five countries – Poland, Portugal, England, Latvia, Romania – perceive the usefulness of dissertation/thesis work for their professional development and how they attempt to use their MA research results in their (future) teaching practice. Results suggest that although most respondents recognized their MA dissertation/thesis work as having a positive impact on their professional development by enhancin…
A Lexicon-based Approach for Sentiment Classification of Amazon Books Reviews in Italian Language
2016
We present a system aimed at the automatic classification of the sentiment orientation expressed into book reviews written in Italian language. The system we have developed is found on a lexicon-based approach and uses NLP techniques in order to take into account the linguistic relation between terms in the analyzed texts. The classification of a review is based on the average sentiment strenght of its sentences, while the classification of each sentence is obtained through a parsing process inspecting, for each term, a window of previous items to detect particular combinations of elements giving inversions or variations of polarity. The score of a single word depends on all the associated …
Nonlinear femtosecond pulse propagation in an all-solid photonic bandgap fiber
2009
Nonlinear femtosecond pulse propagation in an all-solid photonic bandgap fiber is experimentally and numerically investigated. Guiding light in such fiber occurs via two mechanisms: photonic bandgap in the central silica core or total internal reflection in the germanium doped inclusions. By properly combining spectral filtering, dispersion tailoring and pump coupling into the fiber modes, we experimentally demonstrate efficient supercontinuum generation with controllable spectral bandwidth.
Practices of Writing in Ethnographic Work
2020
Although the practice of writing is key to the production of ethnographic knowledge, the topic remains understudied. Using material from our own ethnographic research in the fields of air travel and cultural heritage as data, we develop a reflexive account of ethnographic writing. We examine in detail the practices of jotting down observations, writing field notes, analytic annotating, ordering and rearranging, and drafting and revising papers. The article takes a praxeological stance, conceptualizing writing as a practice that is simultaneously cognitive, embodied, and material. Our analysis finds that writing influences and shapes all stages of ethnographic work, from orienting perception…
Performance Study of Twisted Darrieus Hydrokinetic Turbine With Novel Blade Design
2021
Abstract Twisted Darrieus water turbine is receiving growing attention for small-scale hydropower generation. Accordingly, the need for raised water energy conversion incentivizes researchers to focus on the blade shape optimization of twisted Darrieus turbine. In view of this, experimental analysis has been performed to appraise the efficiency of a spiral Darrieus water rotor in the present work. To better the performance parameters of the studied water rotor with twisted blades, three novel blade shapes, namely U-shaped blade, V-shaped blade, and W-shaped blade, have been numerically tested using a computational fluid dynamics three-dimensional numerical model. The maximum power coefficie…
Thermal response test analysis for U-pipe vertical borehole heat exchangers under groundwater flow conditions
2021
[EN] Conventional models used in the analysis of thermal response test data only consider conduction as heat transfer mechanism. In cases where presence of groundwater is detected, convection heat transmission plays an important role, so its influence must be determined in the calculation of the effective thermal conductivity, usually overestimated in these situations, increasing its value the higher the power injected and the time elapsed. In this work, based on the data collected in a borehole located at UPV (Valencia) in which have been carried out three thermal response tests with different characteristics, has been implemented a variation of the finite line source model introducing an …
3-Phase grid-connected building integrated photovoltaic system with reactive power control capability
2020
Abstract Recently, a tendency in the growing of grid-connected building integrated photovoltaic (BIPV) systems has been noticed in most countries. Hence, high penetration of PV power into the system network can be observed in many points in the network. This may cause severe problems on the distribution network due to the intermittent nature of PV systems. As a feasible solution, the reactive power capability of voltage source inverter in PV systems can be employed rather than approaching expensive grid infrastructures in the distribution network. The purpose of this study is to implement a 3-phase grid-connected (BIPV) system with reactive power control to regulate the system voltage and i…
Multifarious pretreatment strategies for the lignocellulosic substrates for the generation of renewable and sustainable biofuels: A review
2020
Abstract Currently major part of the world’s energy requirements is fulfilled by fossil resources. Severe economic and environmental problems along with their limited resources are still a major issue. Long-term environmental and commercial concern has focussed into huge research in the past decades to replace fossil fuels with renewable sources of energy. The main focus of energy research is lignocellulosic substrates, which seems to be the best for energy application due to easily availability, cost-effective and environment favourable production process. Therefore, lignocellulosic materials provide economical, environmental and energetic benefits with an alternative to traditional or hig…
Analysing the effects of power swing on wind farms using instantaneous impedances
2020
Abstract Most of the grid disturbances happen due to the presence of faults and power swing. This article focuses on power swing in view of the amount of penetration of renewable energy resources especially the wind farms. There are two sections. First section approached power swing by deriving a mathematical expression which would be able to track the locus of impedance in time domain and subsequently analyze resistance and reactance simultaneously with respect to time. It used a grid comprising of generator, transmission line and load. The derived expression was compared with a power swing generated using RTDS model and the results were analyzed in R-X plane. Second section analyses the i…