37 research outputs found
Low-Power Instrument Transformers and Energy Meters: Opportunities and Obstacles
Low-Power Instrument Transformers (LPITs) are becoming the preferred measurement device in the medium voltage (MV) distribution network (DN). They have several benefits compared to legacy solutions. However, the adoption of LPITs results in the need for adapting the grid and its assets to accept them. One practical example is using LPITs as the current and voltage source for energy meters (EMs), which are also used for billing purposes. The resulting measurement chain introduces several metrological challenges that must be studied and investigated. Therefore, in this work, the scenarios of LPITs and energy meters are introduced along with the latest relevant international standards. Afterwards, the opportunities and obstacles due to the implementation of the LPIT plus energy meter measurement chain are discussed. The discussion focuses on metrological requirements, accuracy evaluation, target uncertainty, and influence quantities affecting the performance of the devices
The mixing of airborne contaminants by the repeated passage of people along a corridor
Abstract
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On Optimal Two-Impulse Earth-Moon Transfers in a Four-Body Model
In this paper two-impulse Earth-Moon transfers are treated in the restricted four-body problem with the Sun, the Earth, and the Moon as primaries. The problem is formulated with mathematical means and solved through direct transcription and multiple shooting strategy. Thousands of solutions are found, which make it possible to frame known cases as special points of a more general picture. Families of solutions are defined and characterized, and their features are discussed. The methodology described in this paper is useful to perform trade-off analyses, where many solutions have to be produced and assessed
PERFORMANCE EVALUATION OF INSTRUMENT TRANSFORMERS IN POWER QUALITY MEASUREMENTS: ACTIVITIES AND RESULTS FROM 19NRM05 IT4PQ PROJECT
A study of low-energy transfer orbits to the Moon: towards an operational optimization technique
In the Earth-Moon system, low-energy orbits are transfer trajectories from
the earth to a circumlunar orbit that require less propellant consumption when
compared to the traditional methods. In this work we use a Monte Carlo approach
to study a great number of such transfer orbits over a wide range of initial
conditions. We make statistical and operational considerations on the resulting
data, leading to the description of a reliable way of finding "optimal" mission
orbits with the tools of multi-objective optimization
The ventilation of buildings and other mitigating measures for COVID-19: a focus on wintertime.
The year 2020 has seen the emergence of a global pandemic as a result of the disease COVID-19. This report reviews knowledge of the transmission of COVID-19 indoors, examines the evidence for mitigating measures, and considers the implications for wintertime with a focus on ventilation.This work was undertaken as a contribution to the Rapid Assistance in Modelling the Pandemic (RAMP) initiative, coordinated by the Royal Society
DOENÇAS DIAGNOSTICADAS PELO LABORATÓRIO DE PATOLOGIA VETERINÁRIA EM 2017
Este trabalho apresenta a casuística de diagnósticos no ano de 2017 do Laboratório de Patologia Veterinária do IFC Campus Concórdia. Foram 230 diagnósticos em bovinos, 32 em ovinos e 93 em suínos, totalizando 355. Destes, 247 (69,6%) foram através de necropsias e 108 (30,4%) através de amostras formolizadas enviadas por veterinários. Em bovinos as doenças mais incidentes foram anaplasmose e babesiose com 11 casos cada (4,8%); endocardite com 7 casos (3,0%); hemoncose com 6 casos (2,6%) e retículo pericardite traumática com 6 casos (2,6%). Já em ovinos foi hemoncose com 5 casos (15,7%) e suínos doença de Glässer e colibacilose com 6 casos cada (6,4%).
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The ventilation of buildings and other mitigating measures for COVID-19: a focus on wintertime.
The year 2020 has seen the emergence of a global pandemic as a result of the disease COVID-19. This report reviews knowledge of the transmission of COVID-19 indoors, examines the evidence for mitigating measures, and considers the implications for wintertime with a focus on ventilation.This work was undertaken as a contribution to the Rapid Assistance in Modelling the Pandemic (RAMP) initiative, coordinated by the Royal Society
The ventilation of buildings and other mitigating measures for COVID-19: a focus on wintertime.
The year 2020 has seen the emergence of a global pandemic as a result of the disease COVID-19. This report reviews knowledge of the transmission of COVID-19 indoors, examines the evidence for mitigating measures, and considers the implications for wintertime with a focus on ventilation
Combined low-thrust propulsion and invariant manifold trajectories to capture NEOs in the Sun–Earth circular restricted three-body problem
In this paper, a method to capture near-Earth objects (NEOs) incorporating low-thrust propulsion into the invariant manifolds technique is investigated. Assuming that a tugboat-spacecraft is in a rendez-vous condition with the candidate asteroid, the aim is to take the joint spacecraft-asteroid system to a selected periodic orbit of the Sun–Earth restricted three-body system: the orbit can be either a libration point periodic orbit (LPO) or a distant prograde periodic orbit (DPO) around the Earth. In detail, low-thrust propulsion is used to bring the joint spacecraft-asteroid system from the initial condition to a point belonging to the stable manifold associated to the final periodic orbit: from here onward, thanks to the intrinsic dynamics of the physical model adopted, the flight is purely ballistic. Dedicated guided and capture sets are introduced to exploit the combined use of low-thrust propulsion with stable manifolds trajectories, aiming at defining feasible first guess solutions. Then, an optimal control problem is formulated to refine and improve them. This approach enables a new class of missions, whose solutions are not obtainable neither through the patched-conics method nor through the classic invariant manifolds technique