Search results for "formation [jet]"
showing 10 items of 6317 documents
A Cost-Effective Solution for Clearing High-Impedance Ground Faults in Overhead Low-Voltage Lines
2019
Downed distribution conductors in overhead distribution systems may not be a concern for equipment but greatly challenge the safety of persons, as well as the integrity of properties. Standard overcurrent protective devices may not be able to detect the magnitudes of currents resulting from high-impedance ground faults. Sophisticated relays able to detect high-impedance ground faults have been available to electric utilities. However, their implementation is rather uncommon, especially in developing countries, most likely due to their costs. In this paper, the authors formalize the problem, and propose a possible cost-effective solution for low-voltage overhead lines with neutral wire. This…
Energy and economic assessment of a small domestic wind turbine in Palermo
2016
The cost effectiveness of micro-wind technology is closely linked to the annual energy production plants, which strongly depends on the wind characteristics and on the morphological properties of the installation site. The power curve of a wind turbine, supplied by manufacturers, characterizes the theoretical energy performance that it should have at a particular site. The behavior of a wind turbine in the field is affected by the speed but also by wind direction variations. At each change of direction and speed, the turbine will try to adapt to new conditions and the phase transition negatively influences the energy production. In order to experimentally confirm what above mentioned, the a…
Formation of microbial organic carbonates during the Late Jurassic from the Northern Tethys (Amu Darya Basin, Uzbekistan): implications for Jurassic …
2020
23 pages; International audience; The Late Jurassic was a period of major global carbon cycle perturbations with episodes of anoxia leading to regional accumulation of organic matter in sediments worldwide. The Tubiegatan section (SW Gissar Mountains, Uzbekistan) located in the Northern Tethys, shows atypical organic-rich limestone and marl deposits (up to 6% of total organic carbon) marked by pronounced negative excursions of δ13Ccarb (amplitude of ca. 12‰) and δ13Corg (amplitude of ca. 4‰) recorded during the Middle Oxfordian (Transversarium Zone). A transdisciplinary approach including sedimentology, palynofacies characterization, mineralogy, organic and inorganic geochemistry was carrie…
Min-Type Control Strategy of a DC-DC Synchronous Boost Converter
2019
International audience; This paper presents the analysis and design of a min-type strategy to control a synchronous boost converter in continuous conduction mode. The strategy uses a nonlinear switching surface to establish the change of topology in the converter and is analyzed by means of a sliding-mode control approach. Subsequently, the min-type strategy is modified by a hybrid control formulation, which introduces a hysteresis width and a dwell-time to obtain a finite switching frequency in the start-up and steady-state respectively. The hybrid control formulation is implemented digitally by means of a microprocessor which processes the samples of inductor current and capacitor voltage…
Examining mediators of change in wellbeing, stress, and depression in a blended, Internet-based, ACT intervention for university students
2020
A coach-guided Acceptance and Commitment Therapy (ACT) intervention that uses a blended approach of two face-to-face and five online sessions (iACT; N = 33) has been found to be more effective than a waiting-list control condition (WLC; N = 35) at enhancing the wellbeing of university students while also reducing stress and depression. The present study explored possible mediators of change that may account for the outcomes of the study. Mediation analyses revealed that changes in the non-reactivity subscale of mindfulness mediated changes in wellbeing, depression, and stress in the iACT group. In addition, changes in the sense of coherence subscale of meaningfulness mediated changes in all…
Different Measurement Setup Configurations for Space Charge test in Mini Cable Specimens with the PEA Method
2019
Under DC stress, the space charge accumulation is believed one of the most responsible of dielectrics ageing. For this reason, due to the increase of the HVDC transmission, a recommendation has been proposed. The latter want to introduce the space charge measure, with the PEA method, in cable specimens during the prequalification or type tests. Considering the several issues related to this kind of measures the aim of the proposed work is find a measurement setup for mini cable specimens which is able to provide a clear and clean space charge profile. Therefore, different tests have been made in this work. In particular, the length of the cable specimen, the width of the pulse electrodes, a…
A new approach to calibrate the thermal conditions in space charge measurements on HVDC mini-cables
2019
The PEA method is currently widespread used for space charge measurements in mini-cables in order to qualify the behavior of semicon-dielectric-semicon compound under electric and thermal stress. The main goal of this research is to quantitatively evaluate the relationship between the thermal boundary conditions applied to cables or mini-cables and the maximum local electric field due to the accumulated space charge. Hitherto, several research groups have obtained thermal gradients over the dielectric's radius heating the conductor by Joule effect due to an induced current. In this paper, a numerical approach is offered to calibrate the heat exchange boundary conditions to apply to a sample…
ON-LINE CONSTRUCTION OF A SMALL AUTOMATON FOR A FINITE SET OF WORDS
2012
In this paper we describe a "light" algorithm for the on-line construction of a small automaton recognising a finite set of words. The algorithm runs in linear time. We carried out good experimental results on real dictionaries, on biological sequences and on the sets of suffixes (resp. factors) of a set of words that shows how our automaton is near to the minimal one. For the suffixes of a text, we propose a modified construction that leads to an even smaller automaton. We moreover construct linear algorithms for the insertion and deletion of a word in a finite set, directly from the constructed automaton.
Minimalism for the Win : User-Centered Design for Guidance in Industrial Maintenance
2022
Background: We conducted an exploratory study to test the delivery of technical instructions built on the principles of minimalism. The aim was to investigate how we could support target users’ skill levels in a context-sensitive manner. Literature review: Related work examines minimalism, user needs and profiling, and industrial maintenance and technician experience. Research questions: 1. How can the semantic structure of DITA XML be utilized in delivering technical information to users based on their skill levels? 2. How would a layered system of information support the principles of minimalism? Methodology: We created material and tested the concept in user studies with maintenance pers…
An Exact Solution for the Level-Crossing Rate and the Average Duration of Fades of the Envelope of Sum-of-Cisoids Processes
2012
Authors version of an article published in the journal: Procedia Technology. Also available from the publisher at: http://dx.doi.org/10.1016/j.protcy.2012.03.004 Sum-of-cisoids (SOC) processes provide a physically and numerically appealing framework for the modelling and simulation of a wide class of mobile radio channels. This paper is concerned with the problem of finding a general solution for the level-crossing rate (LCR) and the average duration of fades (ADF) of the envelope of SOC processes. Exact expressions are derived for the LCR and the ADF by taking into account that the inphase component, the quadrature component, and the time derivatives of the inphase and quadrature component…