Our Sun is a variable star. The magnetic fields in the Sun play an important role for the existence of a wide variety of phenomena on the Sun. Among those, sunspots are the slowly evolving features of the Sun but solar ares and coronal mass ejections are highly dynamic phenomena. Hence, the solar magnetic fields could affect the Earth directly or indirectly through the Sun's open magnetic flux, solar wind, solar are, coronal mass ejections and total solar irradiance variations. These large scale magnetic fields originate due to Magnetohydrodynamic dynamo process inside the solar convection zone converting the kinetic energy of the plasma motions into the magnetic energy. Currently the most promising model to understand the large scale magnetic fields of the Sun is the Flux Transport Dynamo (FTD) model. FTD models are mostly axisymmetric models, though the non-axisymmetric 3D FTD models are started to develop recently. In these models, we assume the total magnetic fields of the Sun consist of poloidal and toroidal components and solve the magnetic induction equation kinematicaly in the sense that velocity fields are invoked motivated from the observations. Differential rotation stretches the poloidal field to generate the toroidal field. When toroidal eld near the bottom of the convection zone become magnetically buoyant, it rises through the solar convection zone and pierce the surface to create bipolar sunspots. While rising through the solar convection zone, the Coriolis force keeps on acting on the flux tube, which introduces a tilt angle between bipolar sunspots. Since the sunspots are the dense region of magnetic fields, they diffuse away after emergence. The leading polarity sunspots (close to equator) from both the hemisphere cancel each other across the equator and trailing polarity sunspots migrate towards the pole to generate effective poloidal fields. This mechanism for generation of poloidal field from the decay of sunspots is known as Babcock-Leighton process. After the poloidal field is generated, the meridional flow carries this field to the pole and further to the bottom of the convection zone where differential rotation again acts on it to generate toroidal field. Hence the solar dynamo goes on by oscillation between the poloidal field and toroidal field, where they can sustain each other through a cyclic feedback process. Just like other physical models, FTD models have various assumptions and approximations to incorporate these different processes. Some of the assumptions are observationally verified and some of them are not. Considering the availability of observed data, many approximations have been made in these models on the theoretical basis. In this thesis, we present various studies leading to better understanding of the different processes and parameters of FTD models, which include magnetic buoyancy, meridional circulation and Babcock-Leighton process. In the introductory Chapter 1, we first present the observational features of the solar magnetic fields, theoretical background of the FTD models and motivation for investigating different processes. Most of the results of our work are presented in Chapters 2 - 7. In the Chapters 2 - 5, we explain various important issues regarding the treatment of magnetic buoyancy, irregularities of the solar cycle during descending phase, effect of different spatial structure of meridional flow on the dynamo and how dynamo generated fields would a ect the meridional ow using 2D axisymmetric Flux Transport Dynamo model. In the Chapters 6 & 7, the build up of polar fields from the decay of sunspots and a proper treatment of Babcock-Leighton process by invoking realistic convective flows, are presented using 3D Flux Transport Dynamo model. Finally the conclusions and future works are given in the Chapter 8. In 2D axisymmetric Flux Transport Dynamo models, the rise of the toroidal magnetic field through the convection zone due to magnetic buoyancy and then the generation of the poloidal magnetic field from these bipolar sunspots, has been treated mainly in two ways|a non-local method and a local method. In Chapter 2, we have analyzed the advantages and disadvantages of both the methods. We find that none of them are satisfactory to depict the correct picture of magnetic buoyancy because it is an inherently 3D process. Unless we go to the 3D framework of Flux Transport Dynamo models, we have to treat the magnetic buoyancy in such simplistic way. We find that the non-local treatment of magnetic buoyancy is very robust for a large span of parameter space but it does not take into account the depletion of flux from the bottom of the convection zone which has a significant importance in irregularity study of the solar cycle. The local treatment of magnetic buoyancy includes the flux depletion from the bottom of the convection zone and treats the magnetic buoyancy much realistically than the non-local treatment. But this local treatment of magnetic buoyancy is not so robust. We also pointed out that the long-standing issue about appearance of sunspots in the low-latitudes needs to be studied carefully. In Chapter 3, we have studied various irregularities of the solar cycle during its decaying phase. We have reported that the decay rate of the cycle is strongly correlated with amplitude of the same cycle as well as the amplitude of the next cycle from different sunspot proxies like sunspot number, sunspot area and 10.7 cm radio flux data. We explain these correlation from flux transport dynamo models. We nd that the correlations can only be reproduced if we introduce stochastic fluctuations in the meridional circulations. We also reproduced most of the correlation found in ascending and descending phase of the solar cycle from century long sunspot area data (Mandal et al., 2017) from Kodaikanal observatory, India which are in great agreement with the correlations found earlier from Greenwich sunspots data. In most of the FTD models, a single cell meridional circulation is assumed within the solar convection zone, with the equatorward return flow at its bottom. But with recent development in helioseismology, plenty of results have come out about various spatial structure of meridional circulation (Zhao et al., 2013; Schad et al., 2013; Rajaguru & Antia, 2015; Jackiewicz et al., 2015). Some helioseismology group (Zhao et al., 2013) reported that the meridional circulation has a double cell structure in solar convection zone and some groups (Schad et al., 2013; Jackiewicz et al., 2015) have reported a multi-cellular structure of meridional circulation in the convection zone. By probing the supergranular motion Hathaway (2012) estimated that the meridional ow has an equatorward return ow at the upper convection zone 70 Mm below the surface. In view of the above observed results, we have discussed in Chapter 4 what would happen to Flux Transport Dynamo model if we consider other structure of meridional circulation instead of single cell meridional circulation encompassing whole convection zone. We nd that the our dynamo model works perfectly ne as long as there is an equatorward propagation at the bottom of the convection zone. Our model also works with shallow meridional circulation as found by Hathaway (2012), if we consider the latitudinal pumping in our model. The temporal variation of meridional circulation on the surface is also observed from various measurement techniques. Chou & Dai (2001) rst observed a variation of meridional circulation with the solar cycle from their helioseismic measurements. Hathaway & Rightmire (2010) also found a variation up to 5 m s 1 for the solar cycle 23 by measuring the magnetic elements on the surface of the Sun. Recently Komm et al. (2015) have analyzed MDI and HMI Dopplergram data and reported a solar cyclic variation with detail latitudinal dependence. To explain this variation of the meridional circulation with the solar cycle, we construct a theoretical model by coupling the equation of the meridional circulation (the component of the vorticity equation within the solar convection zone) with the equations of the flux transport dynamo model in Chapter 5. We consider the back reaction due to the Lorentz force of the dynamo-generated magnetic fields and study the perturbations produced in the meridional circulation due to it. This enables us to model the variations of the meridional circulation without developing a full theory of the meridional circulation itself. We obtain results which reproduce the observational data of solar cycle variations of the meridional circulation reasonably well. We get the best results on assuming the turbulent viscosity acting on the velocity field to be comparable to the magnetic diffusivity (i.e. on assuming the magnetic Prandtl number to be close to unity). We have to assume an appropriate bottom boundary condition to ensure that the Lorentz force cannot drive a flow in the sub-adiabatic layers below the bottom of the tachocline. Our results are sensitive to this bottom boundary condition. We also suggest a hypothesis how the observed inward flow towards the active regions may be produced. In Chapter 6 and Chapter 7, we have studied some of the aspects of solar magnetic eld generation process using 3D dynamo model that were not possible to study earlier using axisymmetric 2D Flux Transport dynamo models. We have used the 3D dynamo model developed by Mark Miesch (Miesch & Dikpati, 2014; Miesch & Teweldebirhan, 2016) and study how polar fields build up from the decay of sunspots more realistically in Chapter 6. We first reproduce the observed butter y diagram and periodic solution considering higher diffusivity value than earlier reported results and use it as a reference model to study the build up polar fields by putting a single sunspot pair in one hemisphere and two sunspot pairs in both the hemispheres. The build up of the polar fields from the decay of sunspots are studied earlier using Surface Flux Transport model (Wang et al., 1989; Baumann et al., 2004; Cameron et al., 2010) which solve only radial component of the induction equation on the surface of the Sun ( | plane). But these 2D SFT models have some inherent limitation for not considering the 3D vectorial nature of the magnetic fields and subsurface processes. We have shown that not considering the vectorial nature and subsurface process has an important effect on the development of the polar fields. We have also studied the effect of a few large sunspot pairs violating Hale's law on the strength of the polar field in this Chapter. We nd that such ant-Hale sunspot pairs do produce some effect on the polar fields, if they appear at higher latitudes during the mid-phase of the solar cycle|but the effect is not dramatic. In Chapter 7, we have incorporated observed surface convective ows directly in our 3D dynamo model. As we know that the observed convective flows on the photosphere (e.g., supergranulation, granulation) play a key role in the Babcock-Leighton (BL) process to generate large scale polar fields from sunspots fields. In most surface flux transport (SFT) and BL dynamo models, the dispersal and migration of surface fields is modeled as an effective turbulent diffusion. Recent SFT models have incorporated explicit, realistic convective flows in order to improve the fidelity of convective transport but, to our knowledge, this has not yet been implemented in previous BL models. Since most Flux-Transport (FT)/BL models are axisymmetric, they do not have the capacity to include such flows. We present the first kinematic 3D FT/BL model to explicitly incorporate realistic convective flows based on solar observations. Though we describe a means to generalize these flows to 3D, we find that the kinematic small-scale dynamo action they produce disrupts the operation of the cyclic dynamo. Cyclic solution is found by limiting the convective flow to surface flux transport. The results obtained are generally in good agreement with the observed surface flux evolution and with non-convective models that have a turbulent diffusivity on the order of 3 1012 cm 2 s 1 (300 km2 s 1). However, we nd that the use of a turbulent diffusivity underestimates the dynamo efficiency, producing weaker mean fields than in the convective models. Also, the convective models exhibit mixed polarity bands in the polar regions that have no counterpart in solar observations. Also, the explicitly computed turbulent electromotive force (emf) bears little resemblance to a diffusive flux. We also find that the poleward migration speed of poloidal flux is determined mainly by the meridional flow and the vertical diffusion.

Este estudo tem como objetivo estudar o fósforo total e as especiações de fósforo nos sedimentos superficiais associados aos processos biogeoquímicos em dois sistemas estuarinos, na plataforma continental sudeste e na região polar antártica. Amostras de água de fundo foram coletadas em dois períodos sazonais (verão-inverno) nos estuários sob diferentes graus de impacto ambiental antrópico. A metodologia de extração das frações de (SEDEX) aplicada para obter as especiações químicas de fósforo foi testada com padrões certificados antes das análises. Os resultados foram reprodutivos e a eficiência da extração foi aceitável. As concentrações das espécies químicas de fósforo sedimentar nos dois estuários mostraram diferenças entre os setores seguindo as características granulométricas, influência da maré, condições redox das águas de fundo bem como, as ações antrópicas reveladas pelos dados quantitativos e qualitativos. Uma influência sazonal mínima foi observada. No caso da plataforma sudeste, altos valores de matéria orgânica foram observados em núcleos ao longo da plataforma, junto às estações externas das radiais de Santos e Ilha Grande mostrando uma diferenciação acompanhada pelas frações de fósforo orgânico e carbono orgânico. Nas demais radiais, altos valores de CaCO3 foram observados nas estações mais externas. Na Baía do Almirantado as frações predominantes foram P mineral, P detrítico, P-ligado à apatita autigênica, sendo que a forma orgânica foi baixa e associada a baixos valores de carbono orgânico. A quantificação e distribuição das espécies de fósforo nos sedimentos constituem importante ferramenta para compreender o ciclo biogeoquímico do fósforo e dos demais nutrientes nos ecossistemas marinhos. / This work aims to study the total and chemical species of phosphorus in the surface sediments associated to the biogeochemical processes in two estuarine systems, the southeastern continental shelf and Antarctic polar region. Bottom water samples were collected in two seasonal periods (summer-winter) in the estuaries under different degrees of environmental anthorpic impacts. The fraction extraction methodology (SEDEX) applied to obtain the chemical phosphorus species was tested in relation to the certified standards before analyses. The results were reproductive and the extraction efficiency was acceptable. The chemical species concentrations of sedimentary phosphorus in the two estuarine systems showed differences between sectors following the granulometric characteristics, tide influence, redox conditions of the bottom waters as well as anthropic actions revealed by quantitative and qualitative data. A minimum seasonal influence was observed. In the case of eastern continental shelf, high values of organic matter were found in nuclei distribution along the platform in the external stations of Santos and Ilha Grande radials showing a differentiation accompanied by organic phosphorus and C org., fractions. In the other radials high CaCO3 values were observed in the external stations. In the Admiralty Bay the predominant fractions were detrital apatite and authigenic/biogenic apatite, being that organic form was low, linked to low values of organic carbon. The quantification and distribution of P species in the sediments constitute important tools to understand the P and the other nutrient biogeochemical cycles in the sea ecosystems

The ongoing changes in the extent and the properties of sea ice, associated with the warming climate, are affecting the polar ecosystem and the interactions between the atmosphere, sea ice and the underlying waters. How sea ice biogeochemistry will change in the foreseeable future is currently uncertain, but is a crucial problem to tackle.<p>To better understand how sea ice biogeochemistry could change, we investigated the factors regulating the distribution of some dissolved compounds (e.g. nutrients, dissolved organic matter (DOM)) and gaseous compounds (e.g. Ar, O2, N2, CH4) in sea ice, from ice growth to ice decay. The results were obtained from a 19-day indoor experiment in Hamburg (Germany) and a five-month-long field survey in Barrow (Alaska). They were then compared to the physical properties of the ice (temperature, salinity, and other derived parameters such as brine volume fraction) and different biological parameters (bacterial activity, bacterial abundance, chlorophyll-a and phaeopigments).<p>Our work indicates that the physical properties of sea ice exert a strong influence on the distribution of the biogeochemical compounds in the ice, through their impact on brine dynamics, gas bubble formation and ice permeability. We have described 4 stages of brine dynamics, which affect the distribution of the dissolved compounds (e.g. silicate and DOM) in sea ice. However, inert gas (Ar) shows a different dynamic in comparison to the dissolved compounds, indicating a different transport pathway. We suggest that the formation of gas bubbles in sea ice is responsible for that different transport pathway, because gas bubbles should move upward owing to their buoyancy in comparison to brine, while dissolved compounds are drained downward due to gravity. Our observations further indicate that the critical permeability threshold for the upward gas bubble transport should range between 7.5 and 10 % of brine volume fraction, which is higher than the 5 % suggested for the downward brine transport. Increasing ice permeability and prolonged gas exchange tend to draw gas concentrations toward their solubility values, except when the under-ice water is supersaturated relative to the atmosphere (e.g. CH4) or when in-situ production occurs in sea ice (e.g. O2).<p>Because ammonium and O2 obviously accumulate in the ice layers where convection is limited, we suggest that the changes of these biogeochemical compounds in sea ice depend on the competing effect between the physical transport and the biological activity; the biological impact on these biogeochemical compounds in sea ice is obvious when the biological production rate exceeds largely the physical transport rate. We further discussed on the potential of using Ar and N2 as inert tracers to correct the physical controls on O2 and to determine the net community production in sea ice.<p>In addition to the physical and biological controls, the chemical properties of some biogeochemical compounds (e.g. nitrate, ammonium, DOM) may further influence their distribution in sea ice; further investigations are however needed to confirm this.<p>Finally, based on our findings, we present an update of the processes regulating the distribution of gases in sea ice, with references to recent observations supporting each of the process. We also provide some insights on how sea ice biogeochemistry could change in the future and the research priorities for an accurate quantification of these changes.<p><p>Les changements dans l’extension et les propriétés de la glace de la mer, liés au réchauffement climatique, affectent l’écosystème polaire, ainsi que les interactions entre l’atmosphère, la glace de mer et l’eau sous-jacente. Cependant, des incertitudes subsistent quant aux changements potentiels qui affecteront la biogéochimie de la glace de mer dans un futur proche.<p>Afin de mieux comprendre les changements potentiels qui affecteront la biogéochimie de la glace de mer, nous avons étudié les facteurs qui influencent la distribution de certains composés dissouts (e.g. nutriments, matière organique dissoute (DOM)) et gazeux (e.g. Ar, O2, N2, CH4) au sein de la glace de mer, depuis la croissance de la glace, jusqu’à sa fonte. Les résultats ont été obtenus à partir d’une expérience de 19 jours dans un bassin expérimental à Hambourg (Allemagne) et une étude de terrain de 5 mois à Barrow (Alaska). Ils ont été ensuite comparés aux propriétés physiques de la glace (température, salinité et autres paramètres dérivés) et à des paramètres biologiques (activité bactérienne, abondance bactérienne, chlorophylle-a et phaeopigments).<p>Nos travaux ont montré que les propriétés physiques de la glace exercent une forte influence sur la répartition des composes biogéochimiques dans la glace de mer, à travers leur impact sur la dynamique des saumures, la formation de bulles de gaz et la perméabilité de la glace. Nous avons décrit 4 stades dans la dynamique des saumures qui influencent la distribution des composés dissouts (e.g. silice et DOM) dans la glace. Cependant, le gaz inerte étudié (Ar) montre une dynamique différente de celle des composés dissouts, indiquant un mécanisme de transport différent. Nous suggérons que la formation de bulles de gaz dans la glace de mer est le mécanisme responsable de cette différence, parce que les bulles de gaz devraient migrer vers le haut, à cause de leur différence de densité par rapport aux saumures, alors que les saumures sont drainées vers le bas à cause de la gravité. Nos observations montrent également que le seuil critique de perméabilité pour l’ascension des bulles de gaz devrait se trouver entre 7.5 et 10 % de volume relatif en saumure ;seuil qui est plus élevé que les 5 % suggérés pour le transport de saumure vers le bas. L’augmentation de la perméabilité de la glace et les échanges de gaz prolongés tendent à amener les concentrations de gaz vers leur valeur de solubilité, sauf lorsque l’eau sous-jacente présente une sursaturation parrapport à l’atmosphère (e.g. CH4), ou lorsque une production in-situ se produit au sein de la glace (e.g. O2).<p>Etant donné que l’ammonium et O2 s’accumulent clairement dans les couches de glace où la convection est limitée, nous suggérons que les variations de ces composés biogéochimiques dans la glace dépendent de la balance entre le transport physique et l’activité biologique ;l’impact de cette dernière sur les composés biogéochimiques est particulièrement visible lorsque le taux de production biologique du composé excède largement la vitesse d’élimination du composé par le transport physique. Nous avons ensuite discuté du potentiel d’utiliser Ar et N2 comme traceurs inertes pour corriger l’impact des processus physiques sur les variations de O2, afin de déterminer la production communautaire nette dans la glace de mer.<p>Les propriétés chimiques de certains composés biogéochimiques (e.g. nitrate, ammonium, DOM) pourraient également influencer leur répartition au sein de la glace de mer, en plus des processus physiques et biologiques. Cependant, il est nécessaire d’avoir plus d’études à ce sujet pour confirmer cela.<p>Enfin, sur base de nos résultats, nous présentons une mise à jour des processus qui régulent la répartition des gaz dans la glace de mer, avec des références à des observations récentes qui illustrent chacun des processus. Nous donnons également un aperçu des changements qui pourraient affecter la biogéochimie de la glace de mer à l’avenir, et des pistes de recherches pour une quantification précise de ces changements. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

The present work related to apply hot-melt ink-jet process for imaging at offset lithographic printing form, to utilise a reusable surface for many times and particularly related to validating thermal and ultrasonic erasing processes. This dissertation investigated systematically the role of certain factors towards affecting erasing image area process on print surfaces. Thermal erasing process approved to melt and suck the image area from the surface, the results were adopted by using contact angle measurements and scanning electron microscope. Ultrasonic erasing process permitted to solve the image area by choosing erasing chemistries, influence of selected erasing chemistries on printing surface, and evaluation the process, the results were tested by UV/Vis spectrometer, contact angle, profileometery and visual microscope. / Der Fortschritt im Bereich von Charakterisierung und Verständnis für Hot-melt Ink Jet Prozesse zur Bebilderung von Offsetdruckform-Zylindern ist ein Ergebnis dieser Forschung. Die Systematik dieser Arbeit basiert auf einem theoretischen Teil, um einen geeigneten Löschprozess auszuwählen. Der Löschprozess hängt von den Eigenschaften des Hot-melt Ink Jet Materials und der genutzten Aluminiumdruckoberfläche ab. Diese werden systematisch im Labormaßstab experimentell untersucht. Der thermische Prozess wurde einerseits durch Benetzbarkeitsprüfungen und anderseites durch Rasterelektronmikroskopaufnahmen bewertet.Der Ultraschallprozess ist ein nasser Löschprozess. Die Untersuchungen wurden in vier Stufen systematisch durchgeführt - Auswahl vom geeigneten Lösungsmitteln - Einflüsse von ausgewählten Lösungsmitteln auf nicht beschichtete und beschichtete Aluminium platten - Evaluation eines Ultraschalllöschprozesses - Validation eines Löschprozesses; zur Bewertung des Löschprozesses wurden mehrere Druckplattenproben bebildert und gelöscht Die Ergebnisse wurden durch UV/Vis Spektrometer, Kontaktwinkel, Profiliometrie und Visuelle Mikroskopie getestet.

Background:  In recent years the interest in self-care has expanded, with sleep playing a big part. Concurrently, the development of self-monitoring wristwatches has enabled individuals to track their sleep. Commonly these are called sleep trackers. Since many sleep trackers are not developed for clinical use, their credibility is questionable, and it is unclear how they compare to clinical sleep trackers.  Aim: This study aims to obtain a clear understanding of which of the sleep trackers ActiGraph GT9X Link and Polar Vantage V2 is most reliable when measuring sleep. ActiGraph GT9X Link is developed for clinical purposes, and Polar Vantage V2 is developed for commercial use. To quantify the comparison, the differences in measuring multiple sleep parameters will be observed.  Method:  An empirical study was conducted with 16 participants included. Each participant wore both watches for one night’s sleep and journaled their sleep in a sleep diary. The data was then collected and analyzed with a Wilcoxon signed-rank test.  Results:  The result highlighted that ActiGraph GT9X Link had a wider distribution of the sleep parameters in comparison to Polar Vantage V2, with three out of five sleep parameters showing a significant difference. Polar Vantage V2 also conformed better to the sleep diary for almost all 16 participants.  Conclusion:  Polar Vantage V2 has a significantly higher accuracy in tracking many sleep parameters than ActiGraph GT9X Link. What the future holds for ActiGraph GT9X Link is unclear since it was outperformed by a commercially used wristwatch which does not meet the EU requirements of a medical device by MDR (regulations for medical devices, EU 2017/745). / Under senare år har intresset för allmänhälsan ökat, och i ett mer tekniskt samhälle är information mer lättillgängligt än någonsin. Ett av de främsta bidragen till förbättrad hälsa är att individen får högkvalitativ sömn. Detta görs enklast genom att man sover tillräckligt länge, men det handlar även om att spendera tillräcklig med tid oavbrutet i de olika sömnstadierna som sker under sömnen. Dessa sömnstadier heter REM (Rapid eye movement) och NREM (Non rapid eye movement) sömn. REM är det stadiet då individen drömmer. I denna fas återhämtas kroppens kognitiva förmåga. NREM är en gruppering av alla övriga sömnstadier, vanligen kallat för lättsömn och djupsömn. Att få tillräckligt med tid inom dessa sömnstadier är väsentligt för kroppens fysiska återhämtning. Polysomnografi (PSG) är en metod som används inom klinisk neurofysiologi för att undersöka individens sömn och dess relaterade parametrar. Generellt anses det som den gyllene standarden för sömnmätning, då den mäter alla relevanta parametrar som har koppling till sömnen. Metoden är dessvärre dyr samt omständlig för patienten då den kräver elektrodkopplingar över hela kroppen, och måste göras i en kontrollerad miljö. Kliniken har därför infört aktivitetsmätare med sömnmätningsfunktioner, även kallat sömnmätare. Beroende på dess utformning och inställningar så kan sömnmätare bäras på bland annat handleden, höften eller fotleden. Sömnmätare utgår huvudsakligen ifrån rörelser för att bedöma sömn. För detta används en inbyggd accelerometer, vilket är en sensor som mäter rörelser och omvandlar det till en signal. Signalen tolkas med inbyggda sömnalgoritmer, för att bedöma minutvis om individen sover eller ej. I moderna sömnmätare finns det vanligtvis även flera inbyggda sensorer. Dessa bevakar vissa fysiologiska parametrar och användarens omgivning för att assistera vid sömnbedömningen. Ofta förekommer en fotopletysmograf i moderna sömnmätare, vilket är en sensor som mäter bland annat pulsen. I dessa sömnmätare så används specialiserade sömnalgoritmer, där både användarens rörelser och puls tas hänsyn till för sömnbedömning.  En välstuderad sömnmätare är ActiGraph GT9X Link, som används på det Energimetaboliska Laboratoriet (EML) på Akademiska sjukhuset i Uppsala, denna är endast utrustad med en accelerometer. ActiGraph GT9X Link är utvecklad för kliniska bedömningar, och har validerats av mycket forskning. Samtidigt har många kommersiella sömnmätare börjat utvecklas. En av dessa är Polar Vantage V2, som är utrustad med både accelerometer och fotopletysmograf. Dock har det inte gjorts någon tidigare jämförande forskning kring Polar Vantage V2:s sömnmätning.  I detta projekt utfördes en jämförande studie mellan ActiGraph GT9X Link och Polar Vantage V2. Den empiriska studien innehöll 16 deltagare, där varje deltagare fick under en natt bära båda sömnmätarna samtidigt och sova hemma. Syftet av studien var att jämföra sömnmätarna för att se vilken som har pålitligast sömnregistrering. Eftersom studien inte innefattade PSG fanns det inget referensvärde att förhålla sig till, istället användes en kompletterande sömndagbok som deltagarna själva fyllde i. Där fick deltagarna ange när de la sig till sängs, när de vaknade samt tider för eventuella avbrott under natten.  För att bedöma vilken sömnmätare som ansågs pålitligast så observerades skillnader mellan båda sömnmätarna och med sömndagboken. Ifall en sömnmätare skulle skilja sig avsevärt iv mycket i sin sömnmätning skulle det tyda på att den var mindre pålitlig. Frågeställningen som användes var: “hur skiljer sig de två sömnmätarna ActiGraph GT9X Link och Polar Vantage V2 vid insamling av sömnlängd, sömneffektivitet och avbrott med hänsyn till en sömndagbok?”. Datainsamling skedde med respektive sömnmätares mjukvara och sömndagbok, och sammanställdes sedan i Excel. All data visualiserades i Excel med punktoch låddiagram, samt analyserades skillnaderna mellan sömnmätarna i Rstudio med hypotestester.  Utifrån syftet av studien tyder resultaten på att ActiGraph GT9X Link är mindre pålitlig än Polar Vantage V2 vid sömnregistrering. I resultaten hade GT9X Link en större spridning av samtliga sömnparametrar i jämförelse med Polar Vantage V2. Dessutom avvek GT9X Link mer från sömndagboken för nästan alla testpersoner. Från hypotestesterna kunde Vantage V2 bevisa en signifikant högre precision i att mäta flera sömnparametrar än GT9X Link.  Hur framtiden ser ut för GT9X Link är oklart, då en kommersiell sömnmätare tydligt överträffar dess kapabilitet gällande sömnregistrering. Samtidigt saknar den kommersiella sömnmätaren från Polar klassificering som en medicinteknisk produkt. Den strider därmed mot EU-förordningen av medicintekniska produkter (MDR) för klinisk användning. På grund av detta går det endast att rekommendera Vantage V2 över GT9X Link i sammanhang som ej berör patienter, exempelvis vidare forskningsarbete kring sömn.

Dynamic Systems Theory (DST) and spectral analysis are employed to study the tropospheric jet stream and the stratospheric polar vortex. The objective is to investigate the relationship between Rossby wave activity and inverse persistence and dimensionality of geopotential height at 250 hPa and 10 hPa, as these two dynamical indicators are expected to show a characteristic behavior of Rossby wave harmonics. The results show that persistent states exhibit suppressed Rossby wave activity for eastward-propagating Rossby waves, whereas it is increased for the westward counterpart. Positive anomalies of spectral power at positive phase speeds are present for less persistent states. Events with low dimensionality relate to the suppression of most Rossby waves, while an increase in spectral power is present during high dimensional states. The results were more pronounced in the stratosphere compared to the troposphere with different spatial patterns of geopotential height anomalies due to additional factors influencing the location of Rossby waves. Furthermore, Sudden Stratospheric Warmings (SSWs) are connected to a decrease in persistence up to 2 weeks prior, followed by a significant increase in persistence and dimensionality, and reduced integrated spectral power. Strong Polar Vortex events (SPVs) exhibit the opposite behavior with an increase in persistence before and a decrease in persistence and dimensionality, and higher ISP afterward. Additionally, SSWs (SPVs) exhibit a suppression (enhancement) of Rossby wave activity in the stratosphere and to a lesser extent in the troposphere for eastwards traveling waves.

Master of Science / Department of Electrical and Computer Engineering / Anil Pahwa / The unusual weather events during the polar vortex of 2014 illuminated the needs for fuel diversity for power generation in order to allow reliable operation of the electricity grid. A system wide reliability assessment for winter months should be undertaken in addition to the summer months to ensure reliable operation of the electricity grid throughout the year. Severe weather conditions that lead to equipment malfunction during the polar vortex should be thoroughly investigated and remediations to ensure satisfactory future performance of the grid must be undertaken. Environmentally unfriendly emissions from power plants must be minimized but diversity of generation fuel must be maintained. Future energy policies must be formulated with consideration that approximately 14 GW of coal generation in Pennsylvania Jersey Maryland Regional Transmission Organization’s control area available during the polar vortex will be retired by 2015 and replaced with plants that utilize fuel types other than coal.

Thesis (MEng)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Thermodynamic models have been investigated extensively since Johannes van der Waals first devised a mathematical relation capable of predicting both vapour and liquid phases for a mixture at equilibrium. With the advent of modern computing power, these equations of state have gone from their humble empirical beginnings to the comprehensive and fundamentally derived models we have today. One such physically sound model is the Statistical Associating Fluid Theory (SAFT) family of equations, derived from the molecular perturbation theories of the 1980’s. The relative youth of this thermodynamic framework has meant that much work has gone into modification and optimisation of the model recently. The variants of particular interest to this work are the simplified perturbed chain SAFT equations with the Jog & Chapman (sPC-SAFTJC) and Gross & Vrabec (sPC-SAFTGV) polar terms. Each of the polar terms supports one adjustable polar parameter that relates to the quantity of polar segments in the reference fluid but not necessarily its position in the carbon chain. The strength of polar interactions is known to decrease as the functional group moves away from the terminal methyl group and the effects of steric hindrance increase. Thus, in question here is whether the models can account for the change in polar interactions associated with the changing position of the polar group, by only adjusting the values of the existing pure component parameters; that is, in lieu of a position specific parameter. The carbonyl group in ketone molecules is one such polar group, and it is this homologous series that is the focus of this study. The decrease in polar interactions as the carbonyl group in a ketone molecule shifts centrally is apparent from the lower boiling points of the isomers where the polar group is central as compared to those where the functional group is nearer the terminal methyl group. The effect of this functional group shift on binary phase behaviour has not previously been assessed for any system however, as the lack of experimental data attests. Thus, experiments had to be conducted to generate phase equilibrium data for systems comprising each structural isomer of a mid-length ketone with a common second component with no functionality. This limitation was imposed to isolate the cause of experimentally observed phenomena to the shifting polar group alone. The generated data could then be appropriately modelled using the polar sPC-SAFT variants and the capabilities of each model, as outlined above, assessed. To this end, isobaric binary vapour-liquid equilibrium data were measured for 2-, 3- & 4-heptanone with three separate normal alkanes of similar length (n-octane, n-nonane & n-decane) at 40kPa. The apparatus used was a dynamic Gillespie VLE still with temperature and pressure accuracies of 0.03°C and 1.6mbar respectively. Equipment verification was achieved through the reproduction of experimental data for the ethanol/1-butanol system at 1.013bar. The vapour and liquid samples for all nine systems were analysed by gas chromatography with a maximum compositional error of ±0.022 mole fraction. All reported data were found to be thermodynamically consistent using both the L/W and McDermott-Ellis consistency tests. When paired with a common n-alkane, all three structural heptanone isomers displayed similar qualitative trends in phase behaviour. Minimum boiling azeotropes were measured in all nine systems; in the high alkane region for n-octane systems (~98 mole%), the equal concentration region for n-nonane systems (34 mole% to 53 mole%) and in the very dilute n-alkane region for n-decane systems (~3 mole%). The n-nonane systems in particular highlighted the effect of shifting functional group, with completely separate phase envelopes away from the pure alkane composition space evident in a particularly small temperature range. Modelling was performed using in-house developed software, with pure component parameters generated for each system using five different regression procedures. The first was traditional fitting of the segment diameter (σ), segment number (m), segment energy (є/k) and the respective polar parameter (xp, np) to DIPPR correlations of pure component saturated vapour pressure, liquid density and the heat of vaporisation. The latter four procedures included the fixing of the polar parameter according to functional group correlations and the three instances of including the binary VLE data set for each of the three alkanes considered in this work. When applied to the nine binary ketone-alkane systems measured in this work, excellent predictions of the experimental data were in evidence in most cases and only small binary interaction parameters were necessary to correlate the data where pure predictions were poor. The performance of the parameter sets based on the fixing of the polar parameter and the inclusion of VLE data were consistent and of a high quality for both models, with near identical parameters generated in all four cases for each of the nine systems. The parameter sets generated in this fashion were shown to be applicable not only to the systems measured in this work, but also successfully predicted the independently measured experimental data of the n-hexane/4-heptanone system. It was thus concluded that either of these regression alternatives are viable for the generation of accurate component parameters, and the choice of VLE data set included is trivial. The pure predictions of the sPC-SAFTGV model were generally better than its sPC-SAFTJC counterpart, particularly in the case of the traditionally regressed parameter sets. sPC-SAFTGV displayed constant qualitative agreement with the experimental data for each of the heptanone isomers with a given n-alkane. The quality of the predictions of sPC-SAFTJC, however, worsened significantly as the polar interactions diminished from 2- to 4-heptanone, with no predictions even possible for the least polar isomer. This was attributed to the different perturbation theories used in the development of these terms, but a more detailed study would be necessary to confirm this. This work thus shows an apparent inability of the sPC-SAFTJC equation of state to account for the decreasing polar interactions associated with the carbonyl group in a ketone molecule shifting centrally, while sPC-SAFTGV produces qualitatively good fits for all three isomers. These flaws can be overcome through the incorporation of VLE data in the regression procedure if such data is available, or otherwise through the use of group specific correlations for fixing the polar parameter value. / AFRIKAANSE OPSOMMING: Sedert Johannes van der Waals die eerste wiskundige verhouding ontwikkel het wat beide die damp- en vloeibare fases van 'n mengsel by ewewig kon voorspel, is die veld van termodinamiese modellering al deeglik ondersoek. Na die koms van die moderne rekenaars het hierdie vergelykings van hul nederige empiriese wortels gegroei tot die omvattende, fundamentele modelle wat ons vandag het. Een so 'n fundamenteel gebaseerde familie van vergelykings is die ‘Statistical Associating Fluid Theory’ (SAFT) modelle, wat afgelei is vanaf molekulêre versteuringsteorieë, ontwikkel in die 1980s. Hierdie relatiewe jong modelle het in die afgelope ruk aansienlike aanpassing en optimering ondervind. Modelvariante van besondere belang tot hierdie werk, is die vereenvoudigde versteurde ketting of ‘simplified perturbed chain’ SAFT vergelykings, met Jog & Chapman (sPC- SAFTJC) en Gross & Vrabec (sPC- SAFTGV) polêre terme. In die sPC-SAFT toestandsvergelyking word elkeen van die polêre terme ondersteun deur een polêre veranderlike. Hierdie veranderlike is afhanklik van die aantal polêre segmente in die verwysingsvloeistof, maar nie noodwendig hul posisie in die koolstofketting nie. Daarteen is dit bekend dat die polêre interaksies tussen molekules swakker word soos die polêre groep wegbeweeg van die terminale metielgroep, en steriese hindernis ʼn groter rol begin speel. Dus is die vraag of die model die verandering in die polêre interaksie, as gevolg van veranderende posisie van die polêre groep, kan voorspel deur in plek van ʼn posisie afhanklike parameter, slegs ʼn aanpassing van die polêre waardes van die suiwer komponente te maak. Die karbonielgroep in ketoon molekules is een so 'n polêre groep, en ʼn homoloë reeks ketone word in hierdie studie ondersoek. Die afname in die polêre interaksie soos wat die karbonielgroep in 'n ketoon molekule weg skuif vanaf die terminale metiel groep is sigbaar deur die afname in kookpunt van die verskillende isomere. Hierdie effek van die funksionele groepsposisie op binêre fasegedrag is nog nie voorheen vir enige stelsels geëvalueer nie en geen eksperimentele data is vrylik beskikbaar nie. Om hierdie tekortkoming in die literatuur aan te spreek, is eksperimentele fase ewewig data gemeet. ʼn Reeks stelsels is ondersoek wat elk bestaan uit ʼn struktuurisomeer van ʼn mid-lengte ketoon en ʼn tweede komponent met geen funksionele bydrae. Eksperimente is so opgestel om die effek van die skuiwende polêre groep op die fasegedrag te isoleer en kwalitatief te ondersoek. Die gegenereerde data is dan gemodelleer met behulp van die polêre sPC- SAFT variante, soos hierbo gespesifiseer, en die vermoëns van elke model is beoordeel. Isobariese binêre fase ewewig data is by 40kPa gemeet vir damp-vloeistof stelsels bestaande uit 2, 3 & 4 heptanoon, gemeng met drie verskillende normaal alkane van vergelykbare kettinglengte (n-oktaan, n-nonaan & n-dekaan). Die apparaat wat gebruik was is 'n dinamiese Gillespie VLE eenheid met temperatuur- en drukakkuraatheid van 0,03°C en 1.6mbar, onderskeidelik. Die akkuraatheid van die toerusting is bevestig deur eksperimentele data vir ʼn etanol/1-butanol stelsel by 1.013bar te reproduseer. Die damp en vloeibare monsters vir al nege stelsels is ontleed deur gaschromatografie met 'n maksimum komposisionele fout van ± 0,022 (molfraksie). Alle data is as termodinamies konsekwent gevind deur van beide die L/W en McDermott-Ellis konsekwentheidstoetse gebruik te maak. Mengsels van die drie strukturele isomere van heptanoon met ʼn gemene n-alkaan het tydens eksperimente soortgelyke kwalitatiewe tendense in fasegedrag getoon. Gedurende eksperimente is die lae kookpunt asiotrope gemeet vir al nege stelsels. Die asiotrope verskyn in die hoë alkaan konsentrasies (~98 mol%) vir n-oktaan stelsels, medium konsentrasies (34 mol% tot 53 mol%) vir n-nonaan stelsels en baie verdunde konsentrasies (~ 3 mol%) vir n-dekaan stelsels. Die n-nonaan stelsels beeld veral die effek van die verskuiwing van die funksionele groep uit, met diskrete fasegrense wat duidelik apart staan van die suiwer alkaan ruimte, binne ʼn klein temperatuurverskil. Modellering van die stelsels is uitgevoer met behulp van sagteware wat in-huis ontwikkel is. Suiwer komponent data is gegenereer vir elke stelsel deur van vyf verskillende regressie prosedures gebruik te maak. Die eerste is die tradisionele passing van die segment deursnee (σ), segment nommer (m), segment energie (є/k) en die onderskeie polêre parameters (xp, np) op DIPPR korrelasies van die suiwer komponent versadigde dampdruk, vloeistof digtheid en die hitte van verdamping. Die oorblywende vier prosedures sluit in die bepaling van die polêre parameter deur funksionelegroep korrelasies, en drie gevalle waar die binêre VLE data vir elk van die drie alkane ingesluit is. Deur hierdie prosedures op die modellering van die nege binêre ketoon/alkaan stelsels toe te pas, is uitstekende passings van die eksperimentele data verkry met slegs baie klein binêre interaksie parameters nodig waar voorspellings minder akkuraat was. Die prestasie van die parameter stelle, gebaseer op die bepaling van die polêre parameter en die insluiting van VLE data, is konsekwent en van 'n hoë gehalte vir albei modelle, met 'n byna identiese parameters gegenereer in al vier gevalle vir elk van die nege stelsels. Die parameter stelle wat op hierdie metode gegenereer is, is nie net toepaslik gevind op eksperimentele data gemeet in hierdie werk nie, maar ook op onafhanklike data vir die n-heksaan/4-heptanoon stelsel. Daar is tot die gevolgtrekking gekom dat beide van die regressie alternatiewe lewensvatbaar is vir die generasie van akkurate suiwer komponent parameters, en dat die insluiting van die VLE data triviaal is. Die suiwer sPC - SAFTGV voorspelling was oor die algemeen beter as die suiwer sPC- SAFTJC model met die voorspelling van data, veral in die geval van passings gedoen met parameters verkry vanaf tradisionele regressie metodes. sPC- SAFTGV het ʼn voortdurende, kwalitatiewe ooreenkoms met eksperimentele data getoon vir elk van die nege stelsels. Daarteen het voorspellings deur sPC- SAFTJC beduidend verswak soos die polêre interaksies afgeneem het vanaf 2- na 4- heptanoon, met geen akkurate voorspelling moontlik vir die minste polêre isomeer nie. Die verskynsel kan toegeskryf word aan die verskil in versteuringsteorieë wat gebruik word in die ontwikkeling van die onderskeie toestandsvergelykings, maar ʼn meer in-diepte ondersoek is nodig om hierdie teorie te bevestig. Hierdie werk toon dus 'n skynbare onvermoë van die sPC - SAFTJC toestandsvergelyking om die verandering in polêre interaksie, as gevolg van die veranderende posisie van die polêre groep, vir die karbonielgroep in ʼn ketoon te voorspel, terwyl die sPC-SAFTGV toestandsvergelyking goeie kwalitatiewe passings vir al drie isomere bied. Hierdie tekortkominge kan oorkom word deur VLE data, indien beskikbaar, in die regressie prosedure in te sluit, of deur die gebruik van groep spesifieke korrelasies vir die aanpassing van die polêre parameter.

The mean strengths of the wintertime stratospheric polar vortices are known to be related to the phase of the quasi-biennial oscillation (QBO) in the tropical stratosphere from circulation statistics - the "Holton-Tan relationship". The principal topic of this thesis is improving understanding of the mechanism behind the QBO's influence. Following the example of previous studies, the QBO influence on the Northern Hemisphere (NH) extratropics on monthly time scales in an observational reanalysis is examined, and is shown to closely resemble the stratospheric Northern annular mode (NAM). It is argued that this may not be informative about the mechanism, as the response could be NAM-like for many different mechanisms. It is suggested that examining the transient response of the NH extratropics to forcing by the QBO would be much more informative, particularly on time scales of a few days. In a primitive equation model of the middle atmosphere, the long-term stratospheric NH response to imposed zonal torques is often found to be NAM-like under perpetual January conditions, with wave feedbacks making a very important contribution. However, the response in runs with a seasonal cycle is not NAM-like. Investigation of the transient responses indicates the wave feedbacks are qualitatively similar in each case but only strong enough under perpetual January conditions to make the long-term response NAM-like. This supports the hypothesis that feedbacks from large-scale dynamics tend to make the stratospheric response to arbitrary forcings NAM-like, and therefore indicates that the long-term response is not generally useful for understanding forcing mechanisms. Examining the short-term transient response to known torques is found to be more successful at inferring information about the torques than several other previously proposed methods. Finally, the short-term transient response of the NH extratropics to forcing by the easterly QBO phase in a general circulation model is found to be consistent with the proposed mechanism of Holton and Tan (1980), indicating that this mechanism plays a role in the Holton-Tan relationship.

Les codes polaires constituent une classe de codes correcteurs d’erreurs inventés récemment qui suscite l’intérêt des chercheurs et des industriels, comme en atteste leur sélection pour le codage des canaux de contrôle dans la prochaine génération de téléphonie mobile (5G). Un des enjeux des futurs réseaux mobiles est la virtualisation des traitements numériques du signal, et en particulier les algorithmes de codage et de décodage. Afin d’améliorer la flexibilité du réseau, ces algorithmes doivent être décrits de manière logicielle et être déployés sur des architectures programmables. Une telle infrastructure de réseau permet de mieux répartir l’effort de calcul sur l’ensemble des noeuds et d’améliorer la coopération entre cellules. Ces techniques ont pour but de réduire la consommation d’énergie, d’augmenter le débit et de diminuer la latence des communications. Les travaux présentés dans ce manuscrit portent sur l’implémentation logicielle des algorithmes de décodage de codes polaires et la conception d’architectures programmables spécialisées pour leur exécution.Une des caractéristiques principales d’une chaîne de communication mobile est l’instabilité du canal de communication. Afin de remédier à cette instabilité, des techniques de modulations et de codages adaptatifs sont utilisées dans les normes de communication.Ces techniques impliquent que les décodeurs supportent une vaste gamme de codes : ils doivent être génériques. La première contribution de ces travaux est l’implémentation logicielle de décodeurs génériques des algorithmes de décodage "à Liste" sur des processeurs à usage général. En plus d’être génériques, les décodeurs proposés sont également flexibles.Ils permettent en effet des compromis entre pouvoir de correction, débit et latence de décodage par la paramétrisation fine des algorithmes. En outre, les débits des décodeurs proposés atteignent les performances de l’état de l’art et, dans certains cas, les dépassent.La deuxième contribution de ces travaux est la proposition d’une nouvelle architecture programmable performante spécialisée dans le décodage de codes polaires. Elle fait partie de la famille des processeurs à jeu d’instructions dédiés à l’application. Un processeur de type RISC à faible consommation en constitue la base. Cette base est ensuite configurée,son jeu d’instructions est étendu et des unités matérielles dédiées lui sont ajoutées. Les simulations montrent que cette architecture atteint des débits et des latences proches des implémentations logicielles de l’état de l’art sur des processeurs à usage général. La consommation énergétique est réduite d’un ordre de grandeur. En effet, lorsque l’on considère le décodage par annulation successive d’un code polaire (1024,512), l’énergie nécessaire par bit décodé est de l’ordre de 10 nJ sur des processeurs à usage général contre 1 nJ sur les processeurs proposés.La troisième contribution de ces travaux est également une architecture de processeur à jeu d’instructions dédié à l’application. Elle se différencie de la précédente par l’utilisation d’une méthodologie de conception alternative. Au lieu d’être basée sur une architecture de type RISC, l’architecture du processeur proposé fait partie de la classe des architectures déclenchées par le transport. Elle est caractérisée par une plus grande modularité qui permet d’améliorer très significativement l’efficacité du processeur. Les débits mesurés sont alors supérieurs à ceux obtenus sur les processeurs à usage général. La consommation énergétique est réduite à environ 0.1 nJ par bit décodé pour un code polaire (1024,512) avec l’algorithme de décodage par annulation successive. Cela correspond à une réduction de deux ordres de grandeur en comparaison de la consommation mesurée sur des processeurs à usage général. / Polar codes are a recently invented class of error-correcting codes that are of interest to both researchers and industry, as evidenced by their selection for the coding of control channels in the next generation of cellular mobile communications (5G). One of the challenges of future mobile networks is the virtualization of digital signal processing, including channel encoding and decoding algorithms. In order to improve network flexibility, these algorithms must be written in software and deployed on programmable architectures.Such a network infrastructure allow dynamic balancing of the computational effort across the network, as well as inter-cell cooperation. These techniques are designed to reduce energy consumption, increase through put and reduce communication latency. The work presented in this manuscript focuses on the software implementation of polar codes decoding algorithms and the design of programmable architectures specialized in their execution.One of the main characteristics of a mobile communication chain is that the state of communication channel changes over time. In order to address issue, adaptive modulationand coding techniques are used in communication standards. These techniques require the decoders to support a wide range of codes : they must be generic. The first contribution of this work is the software implementation of generic decoders for "List" polar decoding algorithms on general purpose processors. In addition to their genericity, the proposed decoders are also flexible. Trade-offs between correction power, throughput and decodinglatency are enabled by fine-tuning the algorithms. In addition, the throughputs of the proposed decoders achieve state-of-the-art performance and, in some cases, exceed it.The second contribution of this work is the proposal of a new high-performance programmable architecture specialized in polar code decoding. It is part of the family of Application Specific Instruction-set Processors (ASIP). The base architecture is a RISC processor. This base architecture is then configured, its instruction set is extended and dedicated hardware units are added. Simulations show that this architecture achieves through puts and latencies close to state-of-the-art software implementations on generalpurpose processors. Energy consumption is reduced by an order of magnitude. The energy required per decoded bit is about 10 nJ on general purpose processors compared to 1nJ on proposed processors when considering the Successive Cancellation (SC) decoding algorithm of a polar code (1024,512).The third contribution of this work is also the design of an ASIP architecture. It differs from the previous one by the use of an alternative design methodology. Instead of being based on a RISC architecture, the proposed processor architecture is part of the classof Transport Triggered Architectures (TTA). It is characterized by a greater modularity that allows to significantly improve the efficiency of the processor. The measured flowrates are then higher than those obtained on general purpose processors. The energy consumption is reduced to about 0.1 nJ per decoded bit for a polar code (1024,512) with the SC decoding algorithm. This corresponds to a reduction of two orders of magnitude compared to the consumption measured on general purpose processors.