Search

KM is the process through which organizations generate value from their intellectual and knowledge-based assets 1. Implementation of Knowledge Management (KM) is an important issue for all types of nuclear organizations and in particular for Radioactive Waste Management (RWM) organizations. Thus, the fundamental objective of RWM is to manage the radioactive waste without adverse impact for human health and the environment during its radioactive waste lifetime. Considering the life cycle of the radioactive waste it is obvious that KM accompanies Safety Management (SM). The management of radioactive waste affects future generations and covers pretreatment, treatment, conditioning, storage and disposal. At all mentioned stages operators are dealing with information such as take the records, use the standards & templates, prepare the reports. Without adequate knowledge it would be impossible to carry out this work and conclusively safety will be under risk. It is clear, that managing the knowledge must be implemented at all stages of RWM with the integration of knowledge processes concentrating on the following four core activities: • To generate the knowledge • To store the knowledge • To share the knowledge • To distribute the knowledge and will be focused on • Information and Document Management • Human Resource Management • Knowledge Organizational Structure However, depending on the organization (Regulatory, Operations, R&D organizations) involved in RWM the used KM methods & tools will be different. Nuclear R&D organizations can be categorized into seven types oriented on types of functions undertaken by the respective organization. In 2012 IAEA2 has classified them as follows: (1.) Basic research functions, (2.) Applied research functions, (3.) Design R&D functions, (4.) Functions utilizing nuclear R&D facilities, (5.) Functions utilizing non-nuclear R&D facilities, (6.) Educational R&D functions and (7.) Technical support & service functions. Referring to R&D functions it becomes obvious that out of seven known Knowledge levels3 R&D organizations mainly use four (i.e. Organizational memory, Knowledge in Processes, Knowledge in Products & Services and Knowledge in People). An example for this is the KM initiatives in the Institute of Resource Ecology. The Institute of Resource Ecology is one of eight institutes of the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) where many administrative tasks are centralized. For example the human resources (HR) department, the financial department, the international department and the IT department are all administrated centrally by the HZDR. The HZDR has an internal platform which is used for administrative work, data & information management, communication and keeps employees updated with ongoing and upcoming activities in their institutes. Beside this platform, HZDR employees use different IT tools, e.g. Outlook, Mattemost, etc, for close cooperation. The employees skill development program is administrated by the center. This program follows the requirements collected from all HZDR employees. Continuous education and training programs for the HZDR employees and students, well organized in cooperation with partner organizations (TU-Dresden etc) do also support the knowledge capturing & sharing process. The centralized library has more than 40.000 books in hard copy and 16.300 e-books & journals and all are available for employees of the center. The repository of HZDR’s publications has more than 36.000 scientific papers. In addition, each institute has also an internal scientific database for employee’s needs. There are several formats of information and knowledge exchange in the Institute. To convince the employees of the importance of knowledge-sharing the institute provides series of different workshops regularly e.g. monthly seminars, workshops, department meetings, strategy and jour-fixe meetings in hybrid formats. Obviously, the critical knowledge in the institute is linked to research works. The critical knowledge here is defined as knowledge which is needed to meet the objectives of the Institute. The critical knowledge holders are well known. There are several practices applied in the institute for maintaining the knowledge and transfer it. First of all to mention here is the supervision & mentoring program for the PhD students by critical knowledge holders. Another one is the procedure for uploading publications and records to the internal repository. There are also two inhouse scientific databases at the IRE available for internal and external users: (1.) RES³T - Rossendorf Expert System for Surface and Sorption Thermodynamics and database and (2.) the Thermodynamic Reference Database (THEREDA). However, there is still a high demand for the development of Knowledge Preservation programs. The loss of knowledge in association with the retirement of knowledge holders is still an issue in the institute. This is true for all nuclear organizations. Different approaches have been used in industry. As an example, the approach applied by the Federal Company for Radioactive Waste Disposal (BGE) is described. Due to the restructuring of the nuclear waste-management landscape in Germany, BGE is since 2017 the national competence centre in Germany and responsible for the disposal of radioactive waste. For many decades, Research &Developement-work for this subject has been performed in Germany with an enormous stock of knowledge (topical and quantitative), but an overview is impaired due to the diffuse and local organisation of knowledge of the nuclear waste-management landscape. Research reports for example can be found in many archives, but no archive is complete and „Old stock of knowledge“(old documents, grey literature) has to be embedded in the new stock of knowledge. At the same time the imminent loss of expertise due to phasing out of nuclear energy production and mining in Germany must be considered as a limiting and partially critical factor, especially while reflecting the age structure of the BGE-staff and the restart of the new site selection procedure for disposal of highly radioactive waste products. Facing these prerequisites the newly formed internal department for knowledge management (KM) of the BGE is establishing an infrastructure for KM and generates a connection between KM platforms and knowledge holders in the company to make explicit, implicit and tacit knowledge available. The approach for the explicit knowledge is the provision of a digital information basis, into which current results from research and development are entered as a knowledge store. This knowledge store currently consists of more than 16.000 documents, mainly research reports and scientific publications, which are concerned with diverse topics for the final disposal of radioactive waste. The total stock of available internal company documents can be accessed with a browser-based text analysis software. Intelligent search algorithms render the textual contents accessible, combine them with synonyms and dictionaries deposited in the system and make the resulting hits of the search queries available for the user in order of importance in summarized and full text versions. Using specific query terms the software analyzes the available documents of the digital information basis and provides a brief description of the contents, the naming of relevant keywords, the identification of sources, compilers, institutions, knowledge carriers and an extended optimized information analysis of hits, as well as the possibility to access the complete document. The search options can be combined with established internet search engines as well as with queries of incorporated information or databank catalogue of national and international scientific institutions or libraries, which are concerned with research programs relevant for repositories4. The content volume of the digital information basis, as well as the amount of externally connected research sources is permanently growing. To further increase and optimize the information possibilities for employees of the BGE and to make implicit knowledge partly available, a variety of general and demand-oriented interactive knowledge maps have been and will be implemented in the intranet, which enable specific queries on topics, expert information, etc. To capture the tacit knowledge of persons who are leaving the company due to retirement, concerted concepts, e.g. interviews including transcriptions are used to make this individual knowledge available to the BGE-staff using the BGE internal tools for capturing and distributing implicit and explicit knowledge. Additional actions contain, e.g. the initiation and organisation of technical and professional talks on various topics and to establish them as a permanent and important exchange possibility in the company. While “How to use” seminars for the use of the broser-based text analysis software are already established and a permanent and reoccurring part in the company, further seminars and videos with “How to use” approach e.g. for demand-oriented interactice knowledge maps are in the implementations process as well as a Podcast series about Knowledge Management in the BGE. For the further development of person-related and further group-related knowledge, the BGE Knowledge Management group/department is compiling concepts, which can only be implemented together with the employee in the company and its own guiding principles as they border on certain interfaces in the organization/company, taking into account that all measures to share and distribute knowledge can only be a permanent success if it is voluntarily process without compulsion. By writing this paper we tried to illustrate the practical difference between KM initiatives in R&D and industry. However, the overlapping of the approaches at some certain stages are visible. The information management has been considered as an essential part of the knowledge management in both of organizations. The capture of the critical knowledge in both organizations remains a main issue even if the selected methods are different. The coaching & mentoring program which are well implemented at the IRE (HZDR), are may be difficult to realize/accomplish at the BGE. However, the pilot coaching program is planned at the BGE, but currently not available due to the “young” founding date in 2017. One of the main concerns of the BGE as an implementer, is the motivation and encouragement of all employees to share and distribute their knowledge and benefit from each other. Reference: 1. SANTOSUS, MEGAN, and SURMACZ, The ABCs of Knowledge Management, Knowledge Management Research Center, accessed on 09 December 2005 at http://www.cio.com/research/knowledge/edit/kmabcs.html. ) 2. IAEA, Knowledge Management for nuclear Research and Development organizations IAEA, Vienna, 2012 3. Jatinder N.D. Gupta, Sushil K. Sharma, Jeffrey Hsu, “An overview of Knowledge Management”, Knowledge management. I. Jennex, Murray E., 1956 4. Gunnar Hoefer, Sebastian Wanka, Peter L. Wellmann, Knowledge Management in the Federal Company for Radioactive Waste Disposal (BGE), Saf. Nucl. Waste Disposal, 1, 251–253, 2021

Significant advances have been achieved in recent years in Reversed Field Pinch (RFP) physics, both from the experimental and the theoretical point of view. The main theoretical advances are based on fully 3D nonlinear visco-resistive MHD simulations, which gained a deeper understanding of the RFP's magnetic self-organization. Improved confinement regimes have been explored with two different approaches in the RFP. The first is associated with the spontaneous topological bifurcation from a cylindrical to a helical magnetic equilibrium. Such equilibria are favored by high plasma current levels and are associated with the emergence of partially conserved magnetic flux surfaces, resulting in the onset of a transport barrier. A fundamental role in determining the improvement of the experimental results is played by advanced active feedback control systems for the control of MHD instabilities. The second approach is based on active control of the current profile, which can induce significant enhancements of the confinement properties. High confinement of fast particles has been also observed in RFP plasmas.

Delivery of substances into the inner ear via local routes is increasingly being used in clinical treatment. Studies have focused on methods to increase permeability through the round window membrane (RWM) and enhance drug diffusion into the inner ear. However, the clinical applications of those methods have been unclear and few studies have investigated the efficacy of methods in an inner ear injury model. Here, we employed the medium chain fatty acid caprate, a biologically safe, clinically applicable substance, to modulate tight junctions of the RWM. Intratympanic treatment of sodium caprate (SC) induced transient, but wider, gaps in intercellular spaces of the RWM epithelial layer and enhanced the perilymph and cochlear concentrations/uptake of dexamethasone. Importantly, dexamethasone co–administered with SC led to significantly more rapid recovery from noise-induced hearing loss at 4 and 8 kHz, compared with the dexamethasone-only group. Taken together, our data indicate that junctional modulation of the RWM by SC enhances dexamethasone uptake into the inner ear, thereby hastening the recovery of hearing sensitivity after noise trauma.

The superconducting tokamak JT-60SA is being built in Naka (Japan) under the Broader Approach Satellite Tokamak Programme jointly by Europe and Japan, and under the Japanese national programme. JT-60SA has an important supporting mission for the development of fusion energy: designed to achieve long pulses (100 s) and break-even equivalent plasmas, challenging high-beta operation beyond the no-wall limit. It will help in both the exploitation of ITER and in the definition of an optimized DEMO design. The device will be equipped with off-axis negative-NBI at 0.5 MeV beam energy, allowing current profile tailoring for advanced tokamak scenarios with fully noninductive current drive. The focus of the work is set on high ?N scenarios, in which kink-like instabilities (e.g., one or more RWMs) are potentially unstable and possibly lead to disruptions. In the framework of a joint European-Japanese collaboration, coordinated effort on MHD stability and control modelling is ongoing for the safe realization and exploitation of high-betaN plasmas. These scenarios offer a great opportunity to test and verify present models of RWM physics. The drift-kinetic damping model in particular will be considered in the present work, with a stability study in Scenario 5.1 -- like plasmas carried out with MARS-F/K. The challenge of active control is also addressed, taking advantage of the set of RWM control coils that JT-60SA will have. A dynamic simulator, based on the CarMa code, has been developed for feedback control modelling. A demonstration of this tool is given in one of the aforementioned plasmas, showing potential applications, results and latest developments.

The forthcoming device JT-60SA, under construction in Naka (Japan), is particularly well equipped for studying Advanced Tokamak scenarios with high N and a non-negligible fraction of energetic particles from neutral bean injectors [1][2]. These plasmas are prone to exhibit kink-like ideal MHD instabilities; one or more Resistive Wall Modes (RWM) in particular can be potentially unstable when operating beyond the no-wall pressure limit [3]. While a synergy of wave-particle resonances and active control will play a role in stabilizing RWMs, the present work focuses on the latter. An advanced modelling tool has been developed based on the CarMa code [4][5] which includes a detailed description of the passive stabilizing plate and active coils. As an improvement of previous results, simultaneous stabilization of the most unstable RWMs (n=1,2) is demonstrated, discussing the capabilities and limits of the feedback system. Different configurations of active coils are compared, taking advantage of the flexibility granted by the 18 independent power supplies. A realistic controller for the RWM loop is discussed and implemented in the model, combined with accurate positioning of magnetic sensors on the stabilizing plate and vacuum vessel. The performance of the mode-control algorithm is assessed by analyzing the eigenvalues of the closed-loop system. The development of the time simulation, describing mode dynamics, is also described.

Submitted by Cristina Santos (cmaria@ua.pt) on 2019-05-15T14:22:07Z No. of bitstreams: 1 Documento.pdf: 46288428 bytes, checksum: 3240496d34eb5330481211cab7d71154 (MD5) Made available in DSpace on 2019-05-15T14:22:07Z (GMT). No. of bitstreams: 1 Documento.pdf: 46288428 bytes, checksum: 3240496d34eb5330481211cab7d71154 (MD5) Previous issue date: 2018-12-18 Mestrado em Engenharia Mecânica

Traceability systems are very valuable to manufacturing companies, allowing to keep detailed records of its products history. The advent of Industry 4.0 further pushes this concept, integrating the Internet of Things into traceability by creating smart objects capable of communicating through the internet. RFID is the technology with the most potential for traceability due to its several advantages over technologies such as barcodes. The housings production line of Renault CACIA was used as the example of a shop oor on which to apply the proposed traceability system. This dissertation's system uses a cost e ective microchip, the ESP32, as the middleware that processes the messages exchanged with RFID Read/Write Modules, which are placed in several of the production line's stations. The Wi-Fi capabilities of ESP32 are also used to communicate the data with a server, which processes the data and performs queries to a MySQL database. This database was normalized, and applies speci cally to the housings production line, allowing to keep detailed records of every housing produced on the shop oor. A web graphical interface was developed, with its pages showing both real time data as well as historical production data. These web services can be accessed by any IoT device capable of accessing to the server. The developed solution showcases the viability of chips such as ESP32 to be integrated in RFID systems, allowing RFID readers and tags to be able to communicate through the internet Os sistemas de rastreabilidade são valiosos para as empresas fabricantes, permitindo manter um registo do histórico dos seus produtos. O surgimento da Indústria 4.0 avança ainda mais este conceito, integrando a Internet of Things na rastreabilidade ao criar objetos inteligentes capazes de comunicar pela Internet. A tecnologia RFID é a tecnologia com mais potencial na rastreabilidade devido às suas diversas vantagens quando comparada a tecnologias como os códigos de barra. A linha de produção de carters da Renault CACIA foi utilizada como um exemplo de um chão de fábrica no qual se aplica o sistema de rastreabilidade proposto. O sistema desta dissertação utiliza um microcontrolador de baixo custo, o ESP32, como o middleware respons ável por processar as mensagens trocadas com os leitores RFID, sendo estes colocados em vários postos da linha de produção. As capacidades Wi-Fi do ESP32 são utilizadas para comunicar com um server que processa os dados e faz queries a uma base de dados MySQL. Esta base de dados foi normalizada e aplica-se especi camente à linha de carters, permitindo manter registos detalhados sobre cada carter produzido na fábrica. Foi desenvolvida uma interface grá ca web, cujas páginas mostram informação em tempo real sobre a linha, assim como informação sobre o histórico da produção. Estes serviços web podem ser acedidos por qualquer equipamento da IoT capaz de aceder ao server. A solução desenvolvida demonstra a viabilidade da integração de chips como o ESP32 em sistemas de RFID, permitindo que leitores e etiquetas RFID comuniquem pela Internet Mestrado em Engenharia Mecânica

Mobile ad hoc network is collection of wireless mobile nodes that are communicating each other without needed any backbone, access point. Mobile nodes change the Mobility frequently due to dynamic nature of MANET. Mobile node is an autonomous node is communicating each other using different wireless ad hoc network routing protocols. The comparison performance was made by small networks on CBR application apply from source node to destination nodes. The mobility model used was Random Way Point Model for randomly nodes placement because dynamic nodes change frequently every node was set randomly. In this article compare the various wireless routing protocols are Ad-hoc On demand Distance Vector, Dynamic Source Routing, Dynamic MANET on demand Routing and Zone Routing Protocol in ad-hoc networks. The performances analysis and evaluate is done performance metrics such as Average Jitter, Throughput, Average End to End delay, Packet Delivery Ratio on CBR traffic load. This simulation works done by Qualnet 5.0.2 simulator tools.

JT-60SA is the satellite tokamak under construction in Naka, Japan, in the framework of the EU-JA -Broader Approach? Agreement. In JT-60SA, to attain steady-state high-beta plasmas, suppression of Resistive Wall Modes (RWM) is necessary. At this purpose, a passive stabilizing plate (SP) and an active control system based on 18 in-vessel sector coils (SC) are foreseen. In the past years, physics studies have been carried out to produce the inputs for the design of the RWM control system and the SC design evolved accordingly. In the present arrangement, the coils are placed on the plasma side of SP, to minimize the magnetic shielding effects of passive structures. Electromagnetic analyses on SC have been carried out in support to the evaluation of the different coil design solutions and to derive the requirements for the related power supply system (RWM-PS). To achieve the highest flexibility in RWM control, it has been devised to feed each SC independently, with currents following 18 real-time references. In 2012, the SC design has been further improved by increasing the number of turns from 2 to 8. This allowed reducing the rated current, thus the voltage drops on the feeders and the power required from RWM-PS. To keep the RWM under control with relatively low Ampere-turns (2.2 kAt), the RWM-PS has to guarantee very fast dynamics (current bandwidth: 3 kHz; maximum latency: 50 us), largely beyond that of standard industrial applications. This paper firstly reports the main requirements for the RWM control system. Then, the reference design of the RWM-PS is described. It includes an ac/dc conversion system, dc-link capacitor banks and a set of 18 fast inverters. The advantages of the proposed scheme are discussed and the main electrical parameters are shown in detail. The main requirements of the control section are given, with details on possible implementation and interfaces with JT-60SA central control.

The Power Supply system for Resistive Wall Modes (RWM) control in the JT-60SA experiment is an Italian in-kind contribution to JT-60SA within the Broader Approach Agreement. A very efficient control of RWM is necessary to access plasma currents with high ?N values (3-5) sustained for a hundred seconds, as foreseen in the JT-60SA research plan. The development of the whole RWM control system (coils, power supplies and control) went through several steps of optimization; the Ynal coil conYguration consists in three toroidal rings of six coils placed on the plasma side of the stabilizing plate, inside the vacuum vessel; the coils are individually fed by dedicated power ampliYers, controlled in real time. A key aspect highlighted by the physics studies was the need of a very fast reaction of the control system to prevent an excessive growth of the plasma instabilities and to limit the power required for their control. The main requirements for the power ampliYers were a peak current of 300 A, output voltage of 240 V, bandwidth of 3 kHz and a latency shorter than 50 ?s. The fulYllment of such a fast dynamics was addressed via an R&D program which led to an innovative design solution adopting hybrid Silicon-Silicon Carbide (Si-SiC) semiconductor for the power ampliYers and to the development of a new sophisticated inverter on-board control. The schedule of the procurement was Ynalized in 2015 and was articulated in a relatively longer phase, for the detailed design, prototype development and testing, in comparison with the manufacturing phase, due to the high level of innovation. The delivery to Japan is expected in September 2018. An overview of the main phases of the development and realization of this advanced system, the Yrst in fusion experiments adopting SiC semiconductors, will be presented.

This thesis represents the summary of the research activities carried out during a three-years Ph.D. project. The work is divided into two parts, with the common feature of investigating the physical properties related to stability and control of Magneto-Hydro-Dynamic modes in fusion relevant plasmas. One of the aims of the work is to better understand the interaction between such plasmas and a wide range of 3-dimensional electro-magnetic boundary conditions. This part of the research has been carried out on the RFX-mod device, where advanced control strategies have been developed thanks to its state-of-the-art magnetic feedback system. A variety of interlaced problems have been addressed, starting with the improvement of the vacuum magnetic field spectrum through actuator-sensor decoupling, compensation of broken or deactivated coils with simple and real-time applicable strategies and multi-modal Resistive Wall Mode control with varying coil number and geometry. This has allowed to develop relevant control optimization techniques and knowledge for both the Reversed Field Pinch and Tokamak configurations. The former is an excellent playground for RWM studies, given the instability spectrum that is naturally developing. For the latter configuration instead, RWM stability is considered to be one major milestone to be achieved along the road to a commercial fusion reactor. The second part of the work is dedicated to this issue, and deals with the stability properties of Advanced Tokamak scenarios, with reference to the JT-60SA experiment in particular. Studies to understand RWM physics in high beta plasmas, where fluid rotation profiles and hot ions populations from Neutral Beams can play an important role, have been carried out with the MARS-F/K linear MHD codes. If detailed physics such as kinetic effects is coupled to a simplified description of the passive/active structures on one side, on the other hand a simplified plasma can be coupled to a complex 3-D model of the structures to assess realistic active control capabilities of a given system. Different tools are used and described for studying RWM damping physics, and to five a proof-of-principle for feedback control of such instabilities in Advanced Tokamak plasmas operating beyond the no-wall pressure limit.

Efficient control of Resistive-Wall-Modes (RWM) is mandatory in JT-60SA, the satellite tokamak under construction in Naka (Japan), since one of its main objectives is to reach steady-state high-beta plasmas. The RWM control system is based on a set of 18 in-vessel sector coils, placed on the plasma side of a conductive wall and independently fed by a dedicated fast power supply system (RWM-PS). This is the first PS system for fast control of plasma instabilities in fusion experiments adopting SiC semiconductors. The paper will give an overview of the whole final design with particular emphasis on the newest features and on the interface issues for an efficient integration with the JT-60SA power and control systems., 29th Symposium on Fusion Technology (SOFT2016)

In the framework of EU – JA “Broader Approach” Agreement, the JT-60SA satellite tokamak will be built in Naka, Japan. In JT-60SA, to achieve the steady-state high beta plasma, suppression of Resistive Wall Modes (RWM) is necessary. Therefore, a passive stabilizing plate and a RWM active control system based on in-vessel coils are foreseen for JT-60SA. In the present design, this system consists in 18 sector coils, 6 in the toroidal, 3 in the poloidal direction, rated for a maximum current of 2.5 kA and fed by a dedicated fast power supply system. The coils shall produce sufficient radial magnetic field at the plasma edge, and the active control system shall be fast enough to react in real time to the plasma instabilities. In addition, during fast transients of the plasma current, significant loop voltage could be induced along the sector coils, which could result in over-currents in the coils and in the power supplies. This paper deals with the electromagnetic analyses on the sector coils of JT-60SA, with the main aim to determine the voltage/current characteristic of the coils and, at the same time, to have a first estimation of amplitude and shape of the produced magnetic field; different sector coil design solutions were considered and evaluated. The studies on the coil over-currents during plasma disruption or vertical displacement events are also presented. The results give useful indications in support to the development of the sector coils and power supply design and the identification of their electrical and functional requirements.

This document contains the Technical Specification for the Supplier for the procurement of the Power Supply System for Resistive Wall Mode (RWM) control for JT -60SA Satellite Tokamak.

This document contains the AoC Procurement Plan of the Power Supply System for RWM control for JT-60SA Satellite Tokamak.

The theoretical studies on the Resistive Wall Modes (RWM) and non-resonant Fishbone-Like External kink Mode (FLEM) in Reversed Field Pinch (RFP) plasmas are reported, and comparison is made with the Tokamaks. Various features of these two instabilities in the RFP and Tokamak configurations are investigated in order to provide an in-depth understanding on the mode physics. The toroidal MHD-kinetic hybrid stability code MARS-K was applied to the studies, which takes into account the drift kinetic effects of thermal particles as well as the isotropic/anisotropic energetic particles (EPs). The RWM behaviour in the RFP plasmas with shaped cross section is investigated first, and it is found to be quite different from Tokamaks. Furthermore, the EPs effects on RWMs are studied in both RFP and Tokamak plasmas, considering both isotropic and anisotropic energetic ions (EIs). Besides the RWMs, this study also finds the triggering of the FLEM instability, which is driven by the precessional motion of energetic ions. FLEMs can coexist or couple with the RWMs, depending on the plasma parameters. The MARS-K code is also applied to the study of the RWM stability in the JT-60SA Tokamaks, and the preliminary results are provided.

The JT-60SA satellite tokamak will be built in Naka, Japan. One of the main aims of this machine is to achieve steady-state high-beta plasmas. To reach this result, passive stabilizing plate (SP) and resistive wall modes (RWM) active control system based on 18 in-vessel coils will be installed. In the present design, these coils are placed on the plasma side of the SP, behind the first wall. This solution maximizes the efficiency in producing fast magnetic fields into the plasma by minimizing the shielding effect of the passive structures. Then, if the power supply (PS) and the control system have sufficient dynamic performance, it is possible to control the RWM with very low magnetic fields. This allows minimizing the Ampere-turns and the power requested to control the RWM. Conversely, the very fast dynamics required represents one of the main issues for the design of the RWM control system. This paper, after having recalled the main specification data for the RWM control system deriving from the physics studies, describes the analyses performed to complete the set of requirements necessary for the PS design. The characterization of coils and feeders is shown and the voltage necessary to produce the required current and bandwidth is quantified. Possible connections among PS and coils are analyzed in order to achieve the highest possible flexibility in controlling the RWM with a reduced set of independent PS. Finally, considerations on reasonable voltage margins to cope with load uncertainties are given.

A MANET is an interconnection of mobile devices by wireless links, which forms a dynamic topology. Routing protocols play a vital role in transmission of data across the network. The two major classifications of routing protocols are unipath and multipath. In this paper, we have evaluated the performance of a widely used on-demand multipath routing protocol called AOMDV. This protocol has been selected due to its edge over other protocols in various aspects, such as reducing delay, routing load etc. The evaluation of AOMDV protocol is carried out in terms of four scenario patterns such as RWM, RPGM, MGM, and GMM in two different traffic patterns such as CBR and TCP using NS2 and Bonn Motion.

Control of MHD instabilities using a conducting wall together with external magnetic fields is an important route to improved performance and reliability in fusion devices. Active control of MHD modes is of interest for both the Advanced Tokamak and the Reversed Field Pinch (RFP) configurations. A wide range of unstable, current driven MHD modes is present in the RFP. An ideally conducting wall facing the plasma can in principle provide stabilization to these modes. However, a real, resistive wall characterized by a wall field diffusion time, cannot stabilize the ideal MHD modes unless they rotate with Alfvénic velocity, which is usually not the case. With a resistive wall, the ideal modes are converted into resistive wall modes (RWM) with growth rates comparable to the inverse wall time. Resistive wall modes have been studied in the EXTRAP T2R thin shell RFP device. Growth rates have been measured and found in agreement with linear MHD stability calculations. An advanced system for active control has been developed and installed on the EXTRAP T2R device. The system includes an array of 128 active saddle coils, fully covering the torus surface. Experiments on EXTRAP T2R have for the first time demonstrated simultaneous active suppression of multiple independent RWMs. In experiments with a partial array, coupling of different modes due to the limited number of feedback coils has been observed, in agreement with theory. Different feedback strategies, such as the intelligent shell, the rotating shell, and mode control have been studied. Further, feedback operation with different types of magnetic field sensors, measuring either the radial or the toroidal field components have been compared QC 20100929

This study investigates the validity of the random walk model for an emerging stock market (Amman Stock Exchange, ASE). The study examines for all assumptions implied by the random walk model using aggregate daily data. The results suggest that the behaviour of the ASE return series is inconsistent with the random walk model, which implies informationally inefficient.