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A real-time architecture for the identification of faulty magnetic sensors in the JET Tokamak
Andrej Trkov, Igor Lengar, Luka Snoj, L. Zabeo, D. F. Valcárcel, Adam V. Stephen, F. Sartori, F.G. Rimini, F. Maviglia, P.R. Lomas, H. Fernandes, R. Felton, G. De Tommasi, B. B. Carvalho, D. Alves, A.C. Neto, 2014

Povzetek: In a tokamak, the accurate estimation of the plasma boundary is essential to maximise the fusion performance and is also the first line of defence for the physical integrity of the device. In particular, the first wall components might get severely damaged if over-exposed to a high plasma thermal load. The most common approach to calculate the plasma geometry and related parameters is based in a large set of different types of magnetic sensors. Using this information, real-time plasma equilibrium codes infer a flux map and calculate the shape and geometry of the plasma boundary and its distance to a known reference (e.g. first wall). These are inputs to one or more controllers capable of acting on the shape and trajectory based in pre-defined requests. Depending on the device, the error of the estimated boundary distance must usually be less than 1 centimetre, which translates into very small errors on the magnetic measurement itself. Moreover, asymmetries in the plasma generated and surrounding magnetic fields can produce local shape deformations potentially leading to an unstable control of the plasma geometry. The JET tokamak was recently upgraded to a new and less thermally robust all-metal wall, also known as the ITER-like wall. Currently the shape controller system uses the output of a single reconstruction algorithm to drive the plasma geometry and the protection systems have no input from the plasma boundary reconstruction. These choices are historical and were due to architectural, hardware and processing power limitations. Taking advantage of new multi-core systems and of the already proved robustness of the JET real-time network, this paper proposes a distributed architecture for the real-time identification of faults in the magnetic measurements of the JET tokamak. Besides detecting simple faults, such as short-circuits and open-loops, the system compares the expected measurement at the coil location and the real measurement, producing a confidence valu- . Several magnetic reconstructions, using sensors from multiple toroidally distributed locations, can run in parallel, allowing for a voting or averaging scheme selection. Finally, any fault warnings can be directly fed to the real-time protection sequencer system, whose main function is to coordinate the protection of the JET's first wall.
DiRROS - Objavljeno: 24.11.2014; Ogledov: 2814; Prenosov: 0

Sedimentological and paleontological analysis of the Lower Jurassic part of the Zatrnik Formation on the Pokljuka plateau, Slovenia
Anja Vidervol, Boštjan Rožič, Duje Kukoč, Luka Gale

Povzetek: The uppermost Ladinian to Lower Jurassic Zatrnik Formation is the lithostratigraphic unit of the Mesozoic deeper marine Bled Basin. The uppermost part of the Zatrnik Formation and the transition into the overlying Ribnica Breccia was logged at the Zajamniki mountain pasture on the Pokljuka mountain plateau in the Julian Alps. The lowermost part the section belongs to the “classical” Zatrnik Formation and is dominated by beige micritic limestone and fine-grained calcarenite. Foraminifers Siphovalvulina, ?Everticyclammina, ?Mesoendothyra and ?Pseudopfenderina are present, indicating Early Jurassic age. The beige limestone is followed by light pink limestone of the uppermost Zatrnik Formation. Slumps are common in this interval, and crinoids are abundant. Alongside some species already present in beds lower in the succession, Meandrovoluta asiagoensis Fugagnoli & Rettori, Trocholina sp., Valvulinidae, small Textulariidae, Lagenida, and small ?Ophthalmidium alsooccur in this interval. Resedimented limestone predominates through the studied part of the Zatrnik Formation, indicating deposition on the slope or at the foot of the slope of the basin. The switch to crinoid-rich facies within the slumped interval of the Zatrnik Formation may reflect accelerated subsidence of the margins of the Julian Carbonate Platform in the Pliensbachian. The Zatrnik Formation is followed by the formation of the Pliensbachian (?) Ribnica Breccia. Impregnations of ferromanganese oxides, violet colour, and an increase in clay content are characteristic. The foraminiferal assemblage consists of Lenticulina, small elongated Lagenida, and epistominids. Individual beds of the Ribnica Breccia were deposited via debris flows. Enrichments in ferromanganese oxides point to slower sedimentation.
Ključne besede: Lower Jurassic, Bled Basin, Pokljuka Nappe, stratigraphy, foraminifer, Hierlatz facies, Ribnica Breccia, Zajamniki
DiRROS - Objavljeno: 09.03.2022; Ogledov: 133; Prenosov: 50
.pdf Celotno besedilo (11,45 MB)

Retrieval of vertical mass concentration distributions
Longlong Wang, Samo Stanič, Klemen Bergant, William Eichinger, Griša Močnik, Luka Drinovec, Janja Vaupotič, Miloš Miler, Mateja Gosar, Asta Gregorič, 2019

Povzetek: Aerosol vertical profiles are valuable inputs for the evaluation of aerosol transport models, in order to improve the understanding of aerosol pollution ventilation processes which drive the dispersion of pollutants in mountainous regions. With the aim of providing high-accuracy vertical distributions of particle mass concentration for the study of aerosol dispersion in small-scale valleys, vertical profiles of aerosol mass concentration for aerosols from different sources (including Saharan dust and local biomass burning events) were investigated over the Vipava valley, Slovenia, a representative hot-spot for complex mixtures of different aerosol types of both anthropogenic and natural origin. The analysis was based on datasets taken between 1–30 April 2016. In-situ measurements of aerosol size, absorption, and mass concentration were combined with lidar remote sensing, where vertical profiles of aerosol concentration were retrieved. Aerosol samples were characterized by SEM-EDX, to obtain aerosol morphology and chemical composition. Two cases with expected dominant presence of different specific aerosol types (mineral dust and biomass-burning aerosols) show significantly different aerosol properties and distributions within the valley. In the mineral dust case, we observed a decrease of the elevated aerosol layer height and subsequent spreading of mineral dust within the valley, while in the biomass-burning case we observed the lifting of aerosols above the planetary boundary layer (PBL). All uncertainties of size and assumed optical properties, combined, amount to the total uncertainty of aerosol mass concentrations below 30% within the valley. We have also identified the most indicative in-situ parameters for identification of aerosol type.
Ključne besede: valley air pollution, aerosol vertical distributions, lidar remote sensing, in-situ measurements, aerosol identification
DiRROS - Objavljeno: 03.03.2022; Ogledov: 107; Prenosov: 36
URL Celotno besedilo (0,00 KB)

Raba lesa v slovenskem biogospodarstvu
Luka Juvančič, Peter Prislan, Domen Arnič, 2019

Povzetek: Krčenje zalog fosilnih goriv, netrajnostno izkoriščanje naravnih virov in podnebne spremembe so dejavniki, ki pospešujejo prehod v biogospodarstvo. Tovrsten prehod omogočajo tehnologije in novo znanje pretvorbe biomase v različne produkte, med seboj povezane v kaskadnih in (energetsko in snovno) krožnih proizvodnih ciklih. Eno ključnih področij biogospodarstva je področje rabe lesa, ki trenutno prispeva eno tretjino k skupni dodani vrednosti slovenskega biogospodarstva. Glede na stanje v državah s primerljivimi naravnimi in strukturnimi danostmi Slovenija v razvoju biogospodarstva zaostaja. V pričujočem delu smo predstavili generične dejavnike, ki vplivajo na razvoj biogospodarstva ter pripravili pregled stanja slovenskega biogospodarstva na področju rabe lesa. Stanje slovenskega biogospodarstva uvrščamo v širši evropski okvir ter ocenjujemo nadaljnje možnosti razvoja rabe lesa.
Ključne besede: biogospodarstvo, lesna biomasa, obnovljivi viri energije, raba lesa, biorafinerije, kaskadna raba lesa
DiRROS - Objavljeno: 20.12.2019; Ogledov: 1760; Prenosov: 548
.pdf Celotno besedilo (422,48 KB)

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