123,526 research outputs found
Equalization of DC Bus Voltage in Three-Level NPC-HB Inverters for PV Applications by Even Harmonics Injection or Fundamental Phase Modulation
No full textThe issue of dynamic equalization of the dc bus voltages unbalance is considered in the case of single-phase split-capacitor three-level neutral-point-clamped (NPC) half-bridge inverters for photovoltaic (PV) inverters. The lack of a proper equalization strategy would lead to a rapid drift of dc bus voltages, causing stability problems to the inverter output current control loop and eventually to failure of the power stage. The novel proposal presented in this paper considers the injection of a 2nd harmonic current component (patent pending) or an equivalent modulation of the fundamental current reference phase angle. The presence of a 2nd harmonic component on the grid current is tolerable as far as EMC standards limitations are satisfied, being relatively high when compared to the dc current injection method, which is normally adopted. The proposed equalization strategy has been implemented and tested on a commercial PV inverter. Analytical developments as well as a simulation and experimental investigation are presented to prove the effectiveness of the proposal
Learning processes and agency in the decarbonization context: A systematic review through a cultural psychology point of view
No full textIn the scientific literature on energy transition toward decarbonization, the learning process is often described as a preferred way to achieve change. However, despite a large number of theoretical and empirical endeavors, a systematic understanding of the process is still lacking due to the diversity of disciplines and approaches and to the multi‐layered nature of the phenomenon. The aim of this systematic review is to highlight the dimensions of learning processes from a cultural psychological point of view in order to understand and assess different planes of the relation between humans and technology. We thus explore the literature following the PRISMA protocol. Through a narrative synthesis, we critically assess the theoretical and methodological advancement, the presence of cultural determinants, the value ascribed to agency, and the depoliticization risk. We found that: theories and methodologies still lack systematicity and concordance in their application; learning processes are studied with little focus on the context and are mostly treated as facilitators; agency mostly lacks a psychosocial focus, despite the exploration of multi‐level problems; and the depoliticization of learning is a matter of fact. Nevertheless, positive examples are present, although they are few. Epistemological and political implications are discussed, and a psychosocial conception of agency is proposed, together with a reflective stance for researchers
Persistence of chromosomal lesions induced in actively proliferating bone marrow cells of the mouse.
No full textThe persistence of chromosomal lesions induced in vivo by mitomycin C (MMC) was evaluated by cytogenetic analysis of mouse bone marrow cells. Chromosome aberration (CA) and micronucleus (MN) frequencies were estimated at different times after treatment, up to 42 days. The frequency of CA per cell decreased in the first 3 days after treatment, but a secondary peak appeared on the 4th day, followed by a stabilization around 0.03 CA per cell (significantly different from the control value), which persisted up to 17 days. At the next time intervals tested (28 and 42 days), the CA frequency returned to the control level. In disagreement with these data obtained directly on metaphases, the MN frequency, as evaluated in polychromatic erythrocytes, decreased quickly after treatment, reaching the control value on the 5th day. We attempted to enhance the sensitivity of the MN test by using CREST antibodies and indirect immunofluorescence. However, higher proportions of CREST- MN in treated than in control animals were observed only at short time intervals, confirming the results obtained with the conventional MN assa
System and method for offsetting the input voltage unbalance in multilevel inverters or the like
No full textThe system for offsetting the input voltage unbalance in multilevel inverters or the like comprises a control unit operatively associated with a multilevel inverter for converting direct current into alternate current, the control unit being suitable for piloting the multilevel inverter for generating an output current depending on a reference current, and an equalisation unit for equalising the input voltages of the multilevel inverter having first generation means of a harmonic component of order equal to the reference current, out of phase with respect to the fundamental component of the reference current, detection means of the unbalance of the input voltages to the multilevel inverter, regulation means of the amplitude of the harmonic component depending on the detected unbalance, for offsetting the unbalance. The method for offsetting the unbalance of the input voltages in multilevel inverters or the like comprises a control phase of a multilevel inverter for converting direct current into alternate current, in which the multilevel inverter is piloted for generating an output current depending on a reference current, a generation phase of a harmonic component of order equal to the reference current, out of phase with respect to the fundamental component of the reference current, a detection phase of the unbalance of the input voltages to the multilevel inverter and a regulation phase of the amplitude of the harmonic component depending on the detected unbalance, for offsetting the unbalance
SEUPD@CLEF: Team DAM on Reranking Using Sentence Embedders
No full textThis report gives an overview of the system developed by Team DAM for Task 1 of the LongEval Lab at CLEF 2024. The team members are students enrolled in the Computer Engineering master's program at the University of Padua. The team developed an information retrieval system which is then used to perform queries on a corpus of documents in French language, or in their translated English version
Un primo approccio all'abbinamento di record nell'indagine sulla valutazione della qualità della didattica
No full textMid-infrared spectroscopy and X-ray fluorescence for predicting fatty acids and minerals in milk
No full textSuperthin SCIP flap for reconstruction of subungual melanoma: Aesthetic functional surgery
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