9 research outputs found
Comparison of Three-phase Active Rectifier Solutions for Avionic Applications: Impact of the Avionic Standard DO-160 F and Failure Modes
In aircraft applications, there has been an increasing trend related with the More Electric Aircraft (MEA), which results in rapid rise in the electrical power demand on-board. One of its goals lies in minimizing weight and volume of the electrical subsystem while maintaining good power quality and efficiency. The main purpose of this paper is to present and analyze an electrical design of a three-phase Boost rectifier, a three-phase Buck rectifier and a three-phase Vienna rectifier for output power level of 10 kW and compare them in terms of weight, volume, efficiency etc. Moreover, the design is obliged to comply with specific sections of DO-160 standard for avionic equipment with 230 VAC, 360-800 Hz grid conditions. Even though all proposed solutions satisfy the standard requirements, it will be shown that the Vienna rectifier has the lowest volume and not considering failure modes, the better solution overall. However, due to increased number of semiconductors and additional circuitry required for soft start-up, the Buck rectifier would prove to be the more robust solution failure-wise
First -decay spectroscopy of and new -decay branches of
19 pags., 14 figs., 3 tabs.The decay of the neutron-rich and was investigated experimentally in order to provide new insights into the nuclear structure of the tin isotopes with magic proton number above the shell. The -delayed -ray spectroscopy measurement was performed at the ISOLDE facility at CERN, where indium isotopes were selectively laser-ionized and on-line mass separated. Three -decay branches of were established, two of which were observed for the first time. Population of neutron-unbound states decaying via rays was identified in the two daughter nuclei of and , at excitation energies exceeding the neutron separation energy by 1 MeV. The -delayed one- and two-neutron emission branching ratios of were determined and compared with theoretical calculations. The -delayed one-neutron decay was observed to be dominant -decay branch of even though the Gamow-Teller resonance is located substantially above the two-neutron separation energy of . Transitions following the decay of are reported for the first time, including rays tentatively attributed to . In total, six new levels were identified in on the basis of the coincidences observed in the and decays. A transition that might be a candidate for deexciting the missing neutron single-particle state in was observed in both decays and its assignment is discussed. Experimental level schemes of and are compared with shell-model predictions. Using the fast timing technique, half-lives of the , and levels in were determined. From the lifetime of the state measured for the first time, an unexpectedly large transition strength was deduced, which is not reproduced by the shell-model calculations.M.P.-S. acknowledges the funding support from the Polish National Science Center under Grants No.
2019/33/N/ST2/03023 and No. 2020/36/T/ST2/00547 (Doctoral scholarship ETIUDA). J.B. acknowledges
support from the Universidad Complutense de Madrid under the Predoctoral Grant No. CT27/16-
CT28/16. This work was partially funded by the Polish National Science Center under Grants No.
2020/39/B/ST2/02346, No. 2015/18/E/ST2/00217, and No. 2015/18/M/ST2/00523, by the Spanish
government via Projects No. FPA2017-87568-P, No. RTI2018-098868-B-I00, No. PID2019-104390GB-I00,
and No. PID2019-104714GB-C21, by the U.K. Science and Technology Facilities Council (STFC), the German BMBF
under Contract No. 05P18PKCIA, by the Portuguese FCT under the Projects No. CERN/FIS-PAR/0005/2017, and
No. CERN/FIS-TEC/0003/2019, and by the Romanian IFA Grant CERN/ISOLDE. The research leading to these
results has received funding from the European Union’s Horizon 2020 research and innovation programme under
Grant Agreement No. 654002. M.Str. acknowledges the funding from the European Union’s Horizon 2020 research
and innovation program under Grant Agreement No. 771036 (ERC CoG MAIDEN). J.P. acknowledges support from the
Academy of Finland (Finland) with Grant No. 307685. Work at the University of York was supported under STFC Grants
No. ST/L005727/1 and No. ST/P003885/1
DC/DC Fixed Frequency Resonant LLC Full-Bridge Converter with Series-Parallel Transformers for 10kW High Efficiency Aircraft Application
In modern aircraft designs, there is a need for new high power isolated DC/DC converters. Full bridge derived topologies are appropriate for these specifications. Aircraft specifications are demanding and a high power density is needed. In order to decrease volume, reactive component, such as the transformer have to be optimized in volume, weight and loses. High frequency is needed to decrease inductive component core size and magnetic integration is a key factor. With the use of high frequency, topologies that take advantage of both ZVS and q-ZCS can offer the best results. Resonant topologies have a lot of benefits for this kind of requirement in this application. In this paper, a comparison of different state of the art full-bridge based topologies is made. A detailed explanation of the benefits of the Series-Parallel solution is provided. Experimental result of the prototype are also shown to prove the concept
miniBELEN: A modular neutron counter for (, ) reactions
miniBELEN is a modular and transportable neutron moderated counter with a nearly flat neutron detection efficiency up to 10 MeV. Modularity implies that the moderator can be reassembled in different ways in order to obtain different types of response. The detector has been developed in the context of the Measurement of Alpha Neutron Yields (MANY) collaboration, which is a scientific effort aiming to carry out measurements of (, ) production yields, reaction cross-sections and neutron energy spectra. In this work we present and discuss several configurations of the miniBELEN detector. The experimental validation of the efficiency calculations using 252Cf sources and the measurement of the 27Al(, ) 30P reaction is also presented
Investigation of low-lying states in 133sn populated in the - Decay of 133in using isomer-selective laser ionization
6 pags., 3 figs. -- Open Access funded by Creative Commons Atribution Licence 4.0. -- Presented at the XXXV Mazurian Lakes Conference on Physics, Piaski, Poland, September 3–9, 2017.Excited states in the neutron-rich isotope 133Sn were studied via the ß decay of 133In. Isomer selective ionization using the ISOLDE RILIS enabled the ß decays of 133Ings (I¿ = 9=2+) and 133mIn (II¿ = 1=2-) to be studied independently for the first time. A description of the experimental setup at the ISOLDE Decay Station is presented together with preliminary results from the experiment.This work was supported in part by the National Science Centre, Poland
(NCN) under contracts No. UMO-2015/18/E/ST2/00217 and No. UMO-
2015/18/M/ST2/00523, by the Spanish MINECO via FPA2015-65035-P
project and by the Portuguese FCT via CERN/FIS-NUC/0004/2015 project.Peer Reviewe
Detailed spectroscopy of doubly magic Sn 132
18 pags., 11 figs., 4 tabs.The structure of the doubly magic Sn8250132 has been investigated at the ISOLDE facility at CERN, populated both by the β-decay of In132 and β - delayed neutron emission of In133. The level scheme of Sn132 is greatly expanded with the addition of 68 γ transitions and 17 levels observed for the first time in the β decay. The information on the excited structure is completed by new γ transitions and states populated in the β-n decay of In133. Improved delayed neutron emission probabilities are obtained both for In132 and In133. Level lifetimes are measured via the advanced time-delayed βγγ(t) fast-timing method. An interpretation of the level structure is given based on the experimental findings and the particle-hole configurations arising from core excitations both from the N = 82 and Z = 50 shells, leading to positive- and negative-parity particle-hole multiplets. The experimental information provides new data to challenge the theoretical description of Sn132.We acknowledge the support of the ISOLDE Collaboration
and the ISOLDE technical teams, and by the European
Union Horizon 2020 research and innovation programme
under Grant Agreement No. 654002. This work was partially
funded by the Spanish government via Projects No. FPA2015-
65035-P, No. FPA-64969-P, No. FPA2017-87568-P, and
No. RTI2018-098868-B-I00; the Polish National Science
Center under Contracts No. UMO-2015/18/E/ST2/00217,
No. UMO-2015/18/M/ST2/00523, and No. UMO2019/33/N/ST2/03023; the Portuguese FCT via
CERN/FIS-NUC/0004/2015 project; the German BMBF
under Contract No. 05P18PKCIA; the Romanian IFA Grant
CERN/ISOLDE; and by grants from the U.K. Science
and Technology Facilities Council, the Research Foundation
Flanders (FWO, Belgium), the Excellence of Science program
(EOS, FWO-FNRS, Belgium), and the GOA/2015/010
(BOF KU Leuven). J.B. acknowledges support from the
Universidad Complutense de Madrid under the Predoctoral
Grant No. CT27/16-CT28/1
ß decay of in 133:γ emission from neutron-unbound states in Sn 133
10 pags., 8 figs., 1 tab.-- Open Access funded by Creative Commons Atribution Licence 4.0Excited states in Sn133 were investigated through the ß decay of In133 at the ISOLDE facility. The ISOLDE Resonance Ionization Laser Ion Source (RILIS) provided isomer-selective ionization for In133, allowing us to study separately, and in detail, the ß-decay branch of In133J¿=(9/2+) ground state and its J¿=(1/2-) isomer. Thanks to the large spin difference of the two ß-decaying states of In133, it is possible to investigate separately the lower and higher spin states in the daughter, Sn133, and thus to probe independently different single-particle and single-hole levels. We report here new ¿ transitions observed in the decay of In133, including those assigned to the deexcitation of the neutron-unbound states.We acknowledge the support of the ISOLDE Collaboration and technical teams. This work was supported in
part by the Polish National Science Center under Contract No. UMO-2015/18/E/ST2/00217 and under Contract
No. UMO-2015/18/M/ST2/00523, by the Spanish MINECO
via FPA2015-65035-P project, by the Portuguese FCT via
CERN/FIS-NUC/0004/2015 and CERN-FIS-PAR-0005-2017
projects. The research leading to these results has received
funding from the European Union’s Horizon 2020 research
and innovation programme under Grant Agreement No.
654002