120 research outputs found
Dissolved Boundaries and Fluid Spaces: The Spatial Imagination of Amitav Ghosh in the Shadow Lines
No full textAmitav Ghosh s The Shadow Lines is a classic exposition of the defining postmodern notion of the fluidity of space The novel through its overt transnational character explores the idea of dissolution of space through its conceptual dismantlement of national boundaries across the globe Through various events and episodes that occur in the text its characters continually transit across national borders thereby breaching the spatial confinements created by them and unleash themselves into the limitless arena of transnational space that is fluid unstable and categorically transversal The text whose plot spans across the pre- and post-independent times in the subcontinent overtly exemplifies how the postmodern space defies all notions of structuration stability and territorial confinement for it is fluid indeterminate and fluctuating in nature Based on these precepts this article analyzes the fickle and indeterminate nature of the fluid space that permeates across conceptually dissolved national boundaries and frontiers in the subcontinent as effectively demonstrated in Amitav Ghosh s award-winning novel The Shadow Line
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Growth Miracles and Growth Debacles: Exploring Root Causes
No full textIn this fascinating book, Sambit Bhattacharyya presents a detailed account of the socio-economic processes that create broad variations in living standards across the globe. The author examines the world's economic history over the last five centuries, replete with growth miracles and growth debacles: growth in Britain was steady, yet China lost her early advantage; North America settler colonies performed significantly better than those of Asia and Africa; Australia and Argentina were notably similar at the start of the twentieth century but delivered strikingly different growth outcomes. The book argues that these differences in growth rate are best explained by an interplay of factors, namely economic, political and geographical. In conclusion it presents long-run comparative growth narratives for Africa, China, India, the Americas, Russia and Western Europe. Presenting a unique and original analytical framework to explain economic growth and decline, and bridging empirical growth literature and economic history, this book will prove a stimulating read for both academic and professional economists, and scholars of economic history and economic growth. Other social scientists including sociologists, political scientists and economic historians will also find the book to be of great value
Penggabungan Sumber Internet Load Balancing Dua ISP Di Mikrotik Dengan Metode PCC Guna Memberikan Akses Internet Untuk Penggunaan Chrome Book (Studi Kasus Di SMP Negeri 1 Sambit)
No full textThe need for internet access is currently very high, both to find information, articles and the latest knowledge. Many schools have integrated the internet network into the teaching and learning process. It is hoped that students can easily find material and understand lessons, namely SMP Negeri 1 Sambit, an educational institution that has made it one of the main sources of internet access in the teaching and learning process, namely by using Chrome Books as learning media. SMP Negeri 1 Sambit wants a stable and reliable internet connection. Therefore a solution emerged to combine the two ISPs (Internet Service Provider) and make the proxy a network link. The author uses the PCC (Per Connection Classifier) method, which is a method that can be used in Load Balancing. With this PCC method, it can be used to group connection traffic that goes through or in and out of the router into several groups and divides the load on both internet connection lines so that overload does not occur.
Keywords: ISP (Internet Service Provider), Dual internet connection, Mikrotik, PCC (Per Connection Classifier), Chrome Book
レアアースフリー窒化物フェリ磁性体の磁壁制御
No full text筑波大学University of Tsukuba博士（工学）Doctor of Philosophy in Engineering2022【要旨】thesi
Advanced Modelling of Whole Bioprocesses - From Ultra scale-down Analysis to Prediction of Industrial-scale Behaviour
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Manipulation de parois de domaine dans les nitrures ferrimagnétiques anti-pérovskites
No full textThe boundaries between magnetic domains are known as domain walls (DW). The motion of these DWs using magnetic fields or spin polarized currents has been one of the main focus of spintronics research in the last two decades. One mechanism leading to current induced domain wall motion is the spin transfer torque, where the spin polarized current is generated within the ferromagnetic layer and exerts a torque on the local magnetic moments of the domain walls. The other mechanism is the spin orbit torque, which is now widely used for the domain wall motion experiments, and where the spin polarized current is generated by an adjacent heavy metal layer.Recently, current-induced magnetization dynamics in ferrimagnets has become an active field of research. The magnetic and/or the angular momentum compensation can be achieved by either changing the temperature or by changing the composition of the materials. As the magnetization or the angular momentum that has to be reversed is small close to these points, previous reports on ferrimagnets have evidenced large domain wall velocities under action of spin orbit torques. In this manuscript we will focus on current-driven domain wall dynamics in an epitaxial rare-earth free ferrimagnetic nitride, Manganese Nitride (Mn4N), using spin transfer torques.We show that epitaxially grown Mn4N thin films grown on SrTiO3 substrate have a very low magnetization and mm-scale domains with very low pinning. On this system, DW motion was studied by fabricating nanowires by e-beam lithography. Using magneto optic kerr measurements, we measured a high domain wall velocity of more than 900 m/s in Mn4N at J = 1.3 TA/sq.m, at room temperature, with only spin transfer torque.In order to reach the compensation point, different samples were grown epitaxially while increasing the doping Ni concentration. X-ray magnetic circular dichroism (XMCD) measurements showed that the Ni atoms preferentially occupy the corner site in Mn4N. Since the magnetic moment carried by the Ni atoms is anti-parallel to that of Mn corner atoms , increasing the Ni content decreases the net magnetic moment. Beyond a critical Ni concentration, the net magnetization is then expected to be reversed. Using the values from neutron diffraction measurements, the expected magnetic compensation point lies around Ni atomic concentration of x = 0.18 which corresponds to 3.6% of Ni. The presence of the magnetic compensation point around this concentration is confirmed by XMCD and Anomalous Hall effect measurements. The DW velocity is found to increase as the Ni concentration gets closer to the angular momentum compensation point, with a velocity up to 2000 m/s before the compensation point and approaching 3000 m/s after crossing the compensation point. Interestingly it was also observed that the DW motion direction is reversed beyond the compensation point. In order to explain these results, we used the q–ϕ model, expanded to a ferrimagnetic system consisting of two sub-lattices, and using effective magnetic parameters for the two sub-lattices. If one assumes that the spin polarization does not change after the angular momentum compensation point, the DW motion reversal is therefore due to a relative change of orientation of the net spin polarization with respect to global magnetization.To confirm the validity of these assumptions, ab-initio calculations were performed, showing that the net magnetization is reversed at the Ni concentration x = 0.15, which match well with our experimental results. The simulations confirms that the conduction occurs through the Mn face centered sites, and that the spin polarization remains in the same direction (given by corner sites) while the net magnetization direction is reversed.The studied materials, composed of abundant elements, and free of critical elements such as rare-earths and heavy metals, are thus promising candidates for sustainable spintronics applications.Les frontières entre les domaines magnétiques sont appelées parois de domaine (DW). Le mouvement de ces parois à l'aide de champs magnétiques ou de courants polarisés en spin a été l'un des principaux axes de recherche en spintronique des deux dernières décennies. Un mécanisme conduisant au mouvement de paroi sous courant est le couple de transfert de spin, où le courant polarisé en spin est généré dans la couche ferromagnétique. L'autre mécanisme est le couple spin-orbite, aujourd’hui largement utilisé, et où le courant polarisé en spin est généré par une couche adjacente de matériau spin-orbite. Récemment, le contrôle de l'aimantation par injection de courant dans les matériaux ferrimagnétiques est devenu un important domaine de recherche. La compensation magnétique et/ou de moment cinétique peut être obtenue en modifiant la température ou en modifiant la composition des matériaux. Comme l'aimantation qui doit être renversée est faible près de ces points, des études récentes ont mis en évidence de grandes vitesses de DW sous l'action de couples spin-orbite. Dans ce manuscrit, nous traitons de la propagation des parois de domaine sous l’effet d’un couple de transfert de spin dans un nitrure ferrimagnétique épitaxié, le nitrure de manganèse (Mn4N).Nous montrons que les couches minces de Mn4N développées par épitaxie sur un substrat de SrTiO3 ont une très faible aimantation, et des domaines à l'échelle millimétrique avec un ancrage très faible. Dans ce système, le mouvement des parois de domaine a été étudié en fabriquant des nanofils par lithographie. En utilisant des mesures d’effet Kerr magnéto-optiques, nous avons mesuré des vitesses de paroi de plus de 900 m/s dans Mn4N à J = 1.3 TA/sq.m, à température ambiante, et avec seulement un couple de transfert de spin.Afin d'atteindre le point de compensation, différents échantillons ont été épitaxiés par substitution de Ni. Des mesures de dichroïsme circulaire magnétique aux rayons X(XMCD) ont montré que les atomes de Ni occupent préférentiellement le site du coin à Mn4N. Puisque le moment magnétique porté par les atomes de Ni est anti-parallèle à celui des Mn de coin, l'augmentation de la teneur en Ni diminue le moment magnétique net. Au-delà d'une concentration critique en Ni, l'aimantation nette devrait alors s'inverser. En utilisant les valeurs des mesures de diffraction des neutrons, le point de compensation magnétique attendu se situe autour de 3.6 % de Ni. La présence du point de compensation magnétique autour de cette concentration est confirmée par des mesures de XMCD et d'effet Hall anormal. Les vitesses de la paroi augmentent à mesure que la concentration de Ni se rapproche du point de compensation, avec une vitesse atteignant 2000 m/s avant le point de compensation et approchant 3000 m/s après avoir traversé le point de compensation. Nous avons également observé une inversion de la direction du mouvement de la paroi au-delà du point de compensation. Afin d'expliquer ces résultats, nous avons utilisé le modèle q – ϕ. Si l'on suppose que la polarisation de spin ne change pas après le point de compensation du moment cinétique, l'inversion du mouvement de la paroi du domaine est due à un changement relatif d'orientation de la polarisation de spin nette par rapport à l'aimantation globale. Pour confirmer la validité de ces hypothèses, des calculs ab-initio ont été effectués, montrant que l'aimantation nette est inversée à la concentration de Ni x = 0.15, ce qui correspond bien à nos résultats expérimentaux. Les simulations confirment que la conduction électrique à lieu principalement sur les atomes de centres de faces , et qu’à la transition la polarisation du spin reste dans la même direction alors que la direction de l'aimantation nette est inversée. Les matériaux étudiés, composés d'éléments abondants, et exempts d'éléments critiques comme les terres rares et les métaux lourds, sont ainsi des candidats prometteurs pour des applications de spintronique durable
Human-in-the-loop and graph theoretic aspects of a smart control room
No full textAugust 2021School of EngineeringIndustry 4.0 and Smart manufacturing paradigms aim to make manufacturing processes flexible, enabling the human-in-the-loop to make better decisions and develop the workforce. The dissertation presents the concept of a Smart Control Room (SCR) that is envisioned to play a key role in manufacturing plants and organizations. Three major aspects of the SCR are presented in detail. A key role of the SCR is to use high-fidelity plantwide models to assist operators in better decision making and forecasting. The development of a rigorous plantwide flowsheet of the Vinyl Acetate Monomer process in Aspen Dynamics and MATLAB is presented. Key improvements of the MATLAB nonlinear model, specifically for the distillation column are discussed. A simulated study of the distillation column startup is also presented.
Operator training for various levels of expertise during complicated plant operations is an area where automation algorithms can play a key role. To explore this, the development of a Human-in-The-Loop Supervisory Model Predictive Control (HiTL MPC) algorithm is presented. Using a single-input single output example, it is shown that the algorithm is able to accept human suggested inputs and based on degrees of cooperation, the final control output is computed. The successful performance of the algorithm with a multi-input multi-output example using the VAM upstream flowsheet is also demonstrated, with switching of manual and automatic input pairs occurring during the process.
The data arising out of a process plant is hierarchical and networked in nature. To understand this, a novel graph theoretic and Graph Signal Processing based approach is discussed in detail. The filtering and predictive performance of the tool is also presented with the use of industrial data of a cryogenic air separation unit.Ph
Manipulation of Domain Walls in Anti-perovskite Ferrimagnetic Nitrides
No full textLes frontières entre les domaines magnétiques sont appelées parois de domaine (DW). Le mouvement de ces parois à l'aide de champs magnétiques ou de courants polarisés en spin a été l'un des principaux axes de recherche en spintronique des deux dernières décennies. Un mécanisme conduisant au mouvement de paroi sous courant est le couple de transfert de spin, où le courant polarisé en spin est généré dans la couche ferromagnétique. L'autre mécanisme est le couple spin-orbite, aujourd’hui largement utilisé, et où le courant polarisé en spin est généré par une couche adjacente de matériau spin-orbite. Récemment, le contrôle de l'aimantation par injection de courant dans les matériaux ferrimagnétiques est devenu un important domaine de recherche. La compensation magnétique et/ou de moment cinétique peut être obtenue en modifiant la température ou en modifiant la composition des matériaux. Comme l'aimantation qui doit être renversée est faible près de ces points, des études récentes ont mis en évidence de grandes vitesses de DW sous l'action de couples spin-orbite. Dans ce manuscrit, nous traitons de la propagation des parois de domaine sous l’effet d’un couple de transfert de spin dans un nitrure ferrimagnétique épitaxié, le nitrure de manganèse (Mn4N).Nous montrons que les couches minces de Mn4N développées par épitaxie sur un substrat de SrTiO3 ont une très faible aimantation, et des domaines à l'échelle millimétrique avec un ancrage très faible. Dans ce système, le mouvement des parois de domaine a été étudié en fabriquant des nanofils par lithographie. En utilisant des mesures d’effet Kerr magnéto-optiques, nous avons mesuré des vitesses de paroi de plus de 900 m/s dans Mn4N à J = 1.3 TA/sq.m, à température ambiante, et avec seulement un couple de transfert de spin.Afin d'atteindre le point de compensation, différents échantillons ont été épitaxiés par substitution de Ni. Des mesures de dichroïsme circulaire magnétique aux rayons X(XMCD) ont montré que les atomes de Ni occupent préférentiellement le site du coin à Mn4N. Puisque le moment magnétique porté par les atomes de Ni est anti-parallèle à celui des Mn de coin, l'augmentation de la teneur en Ni diminue le moment magnétique net. Au-delà d'une concentration critique en Ni, l'aimantation nette devrait alors s'inverser. En utilisant les valeurs des mesures de diffraction des neutrons, le point de compensation magnétique attendu se situe autour de 3.6 % de Ni. La présence du point de compensation magnétique autour de cette concentration est confirmée par des mesures de XMCD et d'effet Hall anormal. Les vitesses de la paroi augmentent à mesure que la concentration de Ni se rapproche du point de compensation, avec une vitesse atteignant 2000 m/s avant le point de compensation et approchant 3000 m/s après avoir traversé le point de compensation. Nous avons également observé une inversion de la direction du mouvement de la paroi au-delà du point de compensation. Afin d'expliquer ces résultats, nous avons utilisé le modèle q – ϕ. Si l'on suppose que la polarisation de spin ne change pas après le point de compensation du moment cinétique, l'inversion du mouvement de la paroi du domaine est due à un changement relatif d'orientation de la polarisation de spin nette par rapport à l'aimantation globale. Pour confirmer la validité de ces hypothèses, des calculs ab-initio ont été effectués, montrant que l'aimantation nette est inversée à la concentration de Ni x = 0.15, ce qui correspond bien à nos résultats expérimentaux. Les simulations confirment que la conduction électrique à lieu principalement sur les atomes de centres de faces , et qu’à la transition la polarisation du spin reste dans la même direction alors que la direction de l'aimantation nette est inversée. Les matériaux étudiés, composés d'éléments abondants, et exempts d'éléments critiques comme les terres rares et les métaux lourds, sont ainsi des candidats prometteurs pour des applications de spintronique durable.The boundaries between magnetic domains are known as domain walls (DW). The motion of these DWs using magnetic fields or spin polarized currents has been one of the main focus of spintronics research in the last two decades. One mechanism leading to current induced domain wall motion is the spin transfer torque, where the spin polarized current is generated within the ferromagnetic layer and exerts a torque on the local magnetic moments of the domain walls. The other mechanism is the spin orbit torque, which is now widely used for the domain wall motion experiments, and where the spin polarized current is generated by an adjacent heavy metal layer.Recently, current-induced magnetization dynamics in ferrimagnets has become an active field of research. The magnetic and/or the angular momentum compensation can be achieved by either changing the temperature or by changing the composition of the materials. As the magnetization or the angular momentum that has to be reversed is small close to these points, previous reports on ferrimagnets have evidenced large domain wall velocities under action of spin orbit torques. In this manuscript we will focus on current-driven domain wall dynamics in an epitaxial rare-earth free ferrimagnetic nitride, Manganese Nitride (Mn4N), using spin transfer torques.We show that epitaxially grown Mn4N thin films grown on SrTiO3 substrate have a very low magnetization and mm-scale domains with very low pinning. On this system, DW motion was studied by fabricating nanowires by e-beam lithography. Using magneto optic kerr measurements, we measured a high domain wall velocity of more than 900 m/s in Mn4N at J = 1.3 TA/sq.m, at room temperature, with only spin transfer torque.In order to reach the compensation point, different samples were grown epitaxially while increasing the doping Ni concentration. X-ray magnetic circular dichroism (XMCD) measurements showed that the Ni atoms preferentially occupy the corner site in Mn4N. Since the magnetic moment carried by the Ni atoms is anti-parallel to that of Mn corner atoms , increasing the Ni content decreases the net magnetic moment. Beyond a critical Ni concentration, the net magnetization is then expected to be reversed. Using the values from neutron diffraction measurements, the expected magnetic compensation point lies around Ni atomic concentration of x = 0.18 which corresponds to 3.6% of Ni. The presence of the magnetic compensation point around this concentration is confirmed by XMCD and Anomalous Hall effect measurements. The DW velocity is found to increase as the Ni concentration gets closer to the angular momentum compensation point, with a velocity up to 2000 m/s before the compensation point and approaching 3000 m/s after crossing the compensation point. Interestingly it was also observed that the DW motion direction is reversed beyond the compensation point. In order to explain these results, we used the q–ϕ model, expanded to a ferrimagnetic system consisting of two sub-lattices, and using effective magnetic parameters for the two sub-lattices. If one assumes that the spin polarization does not change after the angular momentum compensation point, the DW motion reversal is therefore due to a relative change of orientation of the net spin polarization with respect to global magnetization.To confirm the validity of these assumptions, ab-initio calculations were performed, showing that the net magnetization is reversed at the Ni concentration x = 0.15, which match well with our experimental results. The simulations confirms that the conduction occurs through the Mn face centered sites, and that the spin polarization remains in the same direction (given by corner sites) while the net magnetization direction is reversed.The studied materials, composed of abundant elements, and free of critical elements such as rare-earths and heavy metals, are thus promising candidates for sustainable spintronics applications
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