| 1. |
- Abele, H., et al.
(författare)
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Particle physics at the European Spallation Source
- 2023
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Ingår i: Physics reports. - : Elsevier. - 0370-1573 .- 1873-6270. ; 1023, s. 1-84
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Forskningsöversikt (refereegranskat)abstract
- Presently under construction in Lund, Sweden, the European Spallation Source (ESS) will be the world’s brightest neutron source. As such, it has the potential for a particle physics program with a unique reach and which is complementary to that available at other facilities. This paper describes proposed particle physics activities for the ESS. These encompass the exploitation of both the neutrons and neutrinos produced at the ESS for high precision (sensitivity) measurements (searches).
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| 2. |
- Ferreira, Danton D., et al.
(författare)
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A new power quality deviation index based on principal curves
- 2015
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Ingår i: Electric power systems research. - : Elsevier BV. - 0378-7796 .- 1873-2046. ; 125, s. 8-14
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, a new power quality deviation index based on principal curves is proposed. The index provides a quantitative measure, which gives an idea of how much the monitored electrical signal has deviated from the nominal one. Differently of existing indices, the proposed index is a general index, i.e., it can be used for any type of disturbance in the monitored signal. In addition, the proposed index is used to perform a direct approach for detecting disturbances in power signals. This approach is able to detect the beginning and localize the disturbance by analyzing non-overlapping signal windows of one cycle of the fundamental component, leading to a simple method in terms of computational complexity
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| 3. |
- Ferreira, Danton D., et al.
(författare)
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Extracting the transient events from power system signals by independent component analysis
- 2016
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Ingår i: International Transactions on Electrical Energy Systems. - : Hindawi Limited. - 2050-7038. ; 26:4, s. 884-900
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a method for extracting transient events from the power system signal based on independent component analysis. The extraction of transients is important to diagnose the system in terms of power quality, because the computation of power quality indices from the extracted events is more efficient and easier to be carried out. Furthermore, the proposed method can be applied as a preprocessing tool for transient characterization in disturbance detection, classification, and identification systems. Both qualitative and quantitative analyses demonstrate the efficiency and the advantages of the proposed method in comparison with other approaches commonly used for the same purpose.
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| 4. |
- Ferreira-Palma, C., et al.
(författare)
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Effects of Cr on NiAl (β′) Precipitation in Ferritic Fe-Ni-Al Alloys
- 2021
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Ingår i: Metallurgical and Materials Transactions. A. - : Springer. - 1073-5623 .- 1543-1940. ; 52:9, s. 3777-3787
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Tidskriftsartikel (refereegranskat)abstract
- NiAl (β′)-strengthened ferritic alloys are promising candidates for high-temperature applications. They present a coherent precipitate–matrix interface and are usually alloyed with 10 wt pct Cr to improve corrosion resistance and provide solid solution strengthening. In this work, the effects of Cr content on the precipitation of β′ in Fe-Ni-Al ferritic alloys are studied using dilatometric analysis during continuous heating and cooling. The dilatometric data are correlated with microstructural observations, X-ray diffraction, and thermodynamic calculations. Additionally, isothermally annealed diffusion couples are used for determining the β′ phase stability during isothermal conditions. Results indicate that an increase in Cr shifts the dissolution of β′ to higher temperatures and the Curie point to lower values. Furthermore, the coarsening rate of the β′ phase increases with the concentration of Cr. The addition of Cr implies a tradeoff between beneficial aspects like increased corrosion resistance and extended β′ stability range against the partial loss of coherency and a higher coarsening rate. The agreement between thermodynamic calculations and the experimental data provides a useful insight for further materials development.
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| 5. |
- Gonçalves, Gil, et al.
(författare)
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Breakdown into nanoscale of graphene oxide : Confined hot spot atomic reduction and fragmentation
- 2014
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 4
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Tidskriftsartikel (refereegranskat)abstract
- Nano-graphene oxide (nano-GO) is a new class of carbon based materials being proposed for biomedical applications due to its small size, intrinsic optical properties, large specific surface area, and easy to functionalize. To fully exploit nano-GO properties, a reproducible method for its production is of utmost importance. Herein we report, the study of the sequential fracture of GO sheets onto nano-GO with controllable lateral width, by a simple, and reproducible method based on a mechanism that we describe as a confined hot spot atomic fragmentation/reduction of GO promoted by ultrasonication. The chemical and structural changes on GO structure during the breakage were monitored by XPS, FTIR, Raman and HRTEM. We found that GO sheets starts breaking from the defects region and in a second phase through the disruption of carbon bonds while still maintaining crystalline carbon domains. The breaking of GO is accompanied by its own reduction, essentially by the elimination of carboxylic and carbonyl functional groups. Photoluminescence and photothermal studies using this nano-GO are also presented highlighting the potential of this nanomaterial as a unique imaging/therapy platform
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| 6. |
- Nagata, Erick A., et al.
(författare)
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Real-Time Voltage Sag Detection and Classification for Power Quality Diagnostics
- 2020
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Ingår i: Measurement. - : Elsevier. - 0263-2241 .- 1873-412X. ; 164
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Tidskriftsartikel (refereegranskat)abstract
- This work proposes an innovative approach to detect, segment and classify voltage sags according to their causes. To detect and segment, Independent Component Analysis is used, with the advantage of being fast and with low computational effort in the operational stage, once it uses only 1/8 cycle of the fundamental component. For classification purposes, Higher-Order Statistics are used for feature extraction and the classifiers are based on Neural Networks and Support Vector Machines. It was tested signal windows of 1, 1/2, 1/4 and 1/8 cycle. For both detection/segmentation design and feature selection, it was used the metaheuristics Teaching-Learning-Based Optimization. Encouraging results were achieved for the simulated signals. In addition, real signals were used to evaluate the detection and segmentation method and good results were achieved in which a detection error rate of 0.86% was achieved.
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