| 44521. |
- Strasser, Thomas I., et al.
(författare)
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A Review of Architectures and Concepts for Intelligence in Future Electric Energy Systems
- 2015
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Ingår i: IEEE Transactions on Industrial Electronics. - 0278-0046 .- 1557-9948. ; 62:4, s. 2424-2438
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Tidskriftsartikel (refereegranskat)abstract
- Renewable energy sources are one key enabler to decrease greenhouse gas emissions and to cope with the anthropogenic climate change. Their intermittent behavior and limited storage capabilities present a new challenge to power system operators to maintain power quality and reliability. Additional technical complexity arises from the large number of small distributed generation units and their allocation within the power system. Market liberalization and changing regulatory framework lead to additional organizational complexity. As a result, the design and operation of the future electric energy system have to be redefined. Sophisticated information and communication architectures, automation concepts, and control approaches are necessary in order to manage the higher complexity of so-called smart grids. This paper provides an overview of the state of the art and recent developments enabling higher intelligence in future smart grids. The integration of renewable sources and storage systems into the power grids is analyzed. Energy management and demand response methods and important automation paradigms and domain standards are also reviewed
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| 44522. |
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| 44523. |
- Strasser, Thomas I., et al.
(författare)
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Towards an IEC 61499 compliance profile for smart grids review and analysis of possibilities
- 2012
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Ingår i: IECON 2012 - 38th Annual Conference on IEEE Industrial Electronics Society. - : IEEE Communications Society. - 9781467324199 - 9781467324205 ; , s. 3750-3757
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Konferensbidrag (refereegranskat)abstract
- The electric energy system is changing more and more into a Smart Grid. A key technology in order to transform the actual grid is the information and communication technology. This means that advanced management, automation, control and communication concepts and systems have to be developed in order to cope with changing and challenging future requirements in the intelligent grid; especially the large-scale integration of distributed energy systems and electric vehicles. As a result of this trend, the future grid will consist of a huge number of intelligent electronic devices in order to manage the distributed and complex nature of Smart Girds. In order to guarantee a high level of interoperability, which is a major requirement for Smart Grids and its related components and devices, the International Electrotechnical Commission has introduced the IEC 61850 standard for power utility automation. Since it covers only interoperability and communication issues, a proper design, modeling and implementation approach is required. The main aim of this paper therefore is to discuss the usage of IEC 61850 together with the IEC 61499 reference model for distributed automation and the development of a related IEC 61499 Compliance Profile for Smart Grids
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| 44524. |
- Streicher, D, et al.
(författare)
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Demonstration of measurements using impulse-radar, ultrasonic echo and impact-echo on a pre-stressed concrete railway bridge in Duisburg / Germany : Sustainable Bridges Background document SB 3.17
- 2007
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Rapport (refereegranskat)abstract
- Non-destructive test- (NDT-) methods are not yet commonly used for inspection of concrete structures. The automated application of enhanced methods as impulse radar, ultra sonic echo and impact-echo during inspection and condition assessment of existing prestressed concrete bridge structures is tested in this deliverable. These methods were used at a railway bridge in Duisburg/Germany to determine thickness of structures and to localize reinforcementand tendon ducts. The automated tests were performed in October 2005.As results, the tendon ducts in the area of the bridge deck and the web were located using impulse-radar and ultrasonic echo. Advantage of echo-measurement set-up is the accessibility only from one side. The accuracy of the determination of the thickness of the structures or the concrete cover of rebar and tendons depends on the calculation of the wave velocities. Structural elements of known thickness or the radar CMP (Common Mid Point) measurements might be used as references for calibration of the wave velocities. Accurate information about the localisation of tendons was not achieved with impact-echo at this bridge. But investigations have shown that geometry-effects can be reduced by measurements in transmission arrangement.
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| 44525. |
- Strid, J., et al.
(författare)
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Microstructure and plasticity of An Al-Al6Fe directionally solidified eutectic alloy
- 1985
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Ingår i: Materials Science and Technology. - : Informa UK Limited. - 0267-0836 .- 1743-2847. ; 1:2, s. 161-166
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Tidskriftsartikel (refereegranskat)abstract
- The microstructure and plasticity of a directionally solidified Al-Al//6Fe eutectic alloy was investigated using quantitative STEM-EDX microanalysis, in situ tensile testing in STEM/SEM, and light/electron optical studies of microstructure before and following drawing and extrusion to wire. It is found that in spite of the brittle nature of the aligned Al//6Fe rods, the alloy as a whole is relatively ductile and can even be drawn or extruded to wire. In the deformed condition the Al//6Fe rods are broken up and the fragmens distributed uniformly throughout the aluminum matrix. The tensile strength and ductility of these drawn wires are good, 400 MN m** minus **2 and 83% area reduction, respectively. Microanalysis studies show that the iron content of the aluminum matrix following solidification is 0. 04 at. %, corresponding to an undercooling of approx. 3 K below the eutectic temperature. The iron content of the matrix can be reduced further by precipitation treatments.
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| 44526. |
- Strid, J., et al.
(författare)
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On the chemistry and stability of complex carbides and nitrides in microalloyed steels
- 1985
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Ingår i: Acta Metallurgica. - : Elsevier BV. - 0001-6160. ; 33:11, s. 2057-2074
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Tidskriftsartikel (refereegranskat)abstract
- Light optical and elctron microscopy, and quantitative (STEM-EDX) micro-analysis are employed to characterize a number of different Ti-micro-alloyed steels, containing various alloying additions including high and low levels of nitrogen, and a Nb-steel is used as a comparison. Weld thermal cycling treatments substantially change particle compositions compared to the as-received (rolled or normalized) conditions, and even the energy input of the welding process is of importance in this respect. As a general rule, TiN-containing steels provide for good grain growth control during weld cycling, although the presence of additional alloying elements in the particles may affect particle stability in a complicated way. It is shown that equilibrium thermodynamics can be used to make reasonable predictions of particle compositions provided the prior heat treatment is such to allow the particles to remain near their equilibrium condition
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| 44527. |
- Strid, Jan
(författare)
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On the chemistry and stability of ternary precipitates in microalloyed steels
- 1984
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Light optical-, electron microscopy and Charpy-V-notch testing is used to characterize a number of different Ti-microalloyed steels, containing various alloying additions including high and low levels of nitrogen, and a Nb-steel is used as a comparison. The steels are studied in both the as-received and weld simulated conditions. Particular emphasis is placed on measuring the particle size distribution and chemical compositions of the complex carbides and nitrides formed in these steels, and this is carried out on extracted particles using quantitative STEM-EDX microanalysis. It is found that while individual particles inevitably reflect the compositions of the steel in which they have formed, the relative amounts of the various metallic elements present in particles are very much a function of the prior thermal treatment of the alloy. Thus, weld thermal cycling treatments substantially change particle compositions compared to the as received (rolled or normalized) conditions, and even the energy input of the welding process is of importance in this respect. As a general rule, TiN-containing steels provide for good grain growth control during weld cycling, although the presence of additional alloying elements in the particles may affect particle stability in a complicated way. It is shown that equilibrium thermodynamics can be used to make reasonable predictions of particle compositions provided the prior heat treatment is such to allow the particles to remain near their equilibrium condition. In certain cases, as in weld thermal cycling, this is not possible and it is then necessary to take the diffusional kinetics of individual elements in particles into account, if compositional changes are to be understood.
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| 44528. |
- Strid, J., et al.
(författare)
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On the strength, deformation and fracture of directional eutectic alloys tested in uniaxial tension
- 1982
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Ingår i: Scandinavian journal of metallurgy. - 0371-0459 .- 1600-0692. ; 11:6, s. 295-298
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Tidskriftsartikel (refereegranskat)abstract
- Three dimensional eutectic alloys, Al-Cu, Al-Fe and Ag-Cu, are investigated using SEM and TEM to characterize the microstructures, and in-situ uniaxial tensile testing in the high resolution SEM stage of a STEM to study the detailed deformation and fracture mechanisms. It is found that if predictions of the strength and fracture behaviour of these alloys are to be reliable, the effect of both the interlamellar spacings and the many different types of eutectic inhomogeneities must be accounted for.
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| 44529. |
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| 44530. |
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