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- Golpayegani, Ardeshir, 1975, et al.
(författare)
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Microstructure of a Creep-Resistant 10 Pct Chromium Steel Containing 250 ppm Boron
- 2011
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Ingår i: Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science. - : Springer Science and Business Media LLC. - 1073-5623 .- 1543-1940. ; 42:4, s. 940-951
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Tidskriftsartikel (refereegranskat)abstract
- The microstructure of a trial martensitic chromium steel containing a high content of boron (250 ppm) was characterized in detail in the as-tempered and aged conditions. This steel has a similar composition and heat treatment as the TAF steel that still is unsurpassed in creep strength among all 9 to 12 pct chromium steels. Characterization was performed by using scanning electron microscopy, energy-filtered transmission electron microscopy, secondary ion mass spectroscopy, and atom probe tomography. Focus was placed on investigating different types of precipitates that play a key role in improving the creep resistance of these steels. The low tempering temperature of 963 K (690 A degrees C) is enough for the precipitation of the full volume fraction of both MX and M23C6. A high boron content, more than 1 at. pct, was found in M23C6 precipitates and they grow slowly during aging. The high boron level in the steel results in metal borides rather than BN with the approximate formula (Mo0.66Cr0.34)(2)(Fe0.75V0.25)B-2. Two families of MX precipitates were found, one at lath boundaries about 35 nm in size and one dense inside the laths, only 5 to 15 nm in size.
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| 4. |
- Baravdish, George, et al.
(författare)
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PDE-SVD Based Audio Denoising
- 2012
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Ingår i: Proceedings of the 5th International Symposium on Communications Control and Signal Processing (ISCCSP), 2012. - Piscataway, NJ, USA : IEEE. - 9781467302746 ; , s. 1-6
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Konferensbidrag (refereegranskat)abstract
- In this paper we present a new method for denoising audio signals. The method is based on the Singular Value Decomposition (SVD) of the frame matrix representing the signal inthe Overlap Add decomposition. Denoising is performed by modifying both the singular values, using a tapering model, and the singular vectors of the representation, using a nonlinear PDE method. The performance of the method is evaluated and compared with denoising obtained by filtering.
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| 5. |
- Johansson, Lars-Olof, et al.
(författare)
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Dynamics in an innovation boundary context : exploring a living labprocess from a community of practice perspective
- 2011
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Ingår i: Proceedings of IRIS 2011. - Turku : Turku Centre for Computer Science. - 9789521226489 ; , s. 1-
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Konferensbidrag (refereegranskat)abstract
- This paper is based on studies of a living lab process, which is an open, user-centric, innovation approach, where several actors from industry, user groups and academia are involved. We aim to describe and analyze the dynamics in an innovation boundary context based on a living lab process. An action-oriented research approach was applied and the empirical results are from The Find Project (TFP), with the aim of customizing an ICT product based on the needs of a user group. The findings are analyzed from a community of practice perspective where the three different communities i) researchers from Halmstad Living Lab (HLL), ii) ICT developers (ICTD), and iii) next of kin's to demented elderly persons (NOKD) represented the units of analysis. The analysis identified several boundary situations that played a vital role for the innovation process. The contribution of our research to innovation theory is a process model describing the dynamics in an innovation boundary context with regard to boundary objects-in-use as well as to brokering. The research highlights two different levels of brokering: i) product/service brokering; and ii) process brokering.
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| 7. |
- Knuts, Sören, 1962, et al.
(författare)
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Data Driven Continuous Improvement by Six Sigma in Aircraft Industry
- 2014
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Ingår i: ENBIS-14 in Linz 21 – 25 September 2014.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Continuous improvements initiated by unsatisfactory output variation often require data or combinations of data from other up-stream variation sources than previously monitored. Three Six Sigma projects have been recently carried out in order to improve the process capability of welded components at GKN Aerospace. Common to these three projects are problems with the measurement systems and sub-sequent analysis related to the Key Characteristics (KC) evaluation. Parameters are traditionally monitored relative their individual requirements but not to the combined set of measures that form the KC. All three projects identified a need to establish a standardized procedure to develop data collection and analysis procedures relative specific KC based on downstream requirements in order to be able to evaluate KC baseline capability.The aim with this article is to recognize the development of an overall measurement system (containing probes, data collection routines and analysis procedures) as enabler of Continuous Improvement of downstream KC capability requirements.Note: GKN Aerospace is a Tier 2 supplier in the Aerospace business with a large variety of components that is available on more than 90% of all new engines.
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| 9. |
- Leisse, Ingmar, et al.
(författare)
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Coordinated voltage control in medium and low voltage distribution networks with wind power and photovoltaics
- 2013
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Ingår i: PowerTech (POWERTECH), 2013 IEEE Grenoble.
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Konferensbidrag (refereegranskat)abstract
- Distributed Generation (DG) installations have been increasing during the last years. Wind power and photovoltaics are two of the most common renewable energy sources for DG typically connected to the distribution network (DN) originally planned and built to supply loads. DG units connected to the DN impact the voltage where customers are connected. Network voltage is an important quality criterion in DN. Voltage rise caused by DG units may become one of the limiting factors for the hosting capacity of wind power and photovoltaics in DNs. Increasing the hosting capacity by network rebuilding is possible but it is expensive and time consuming. Coordinated voltage control has been proposed to increase network capacity without the need of reinforcement. Simulations based on an existing medium and low voltage DN with wind power and photovoltaics are presented. It is shown that coordinated voltage control can increase the hosting capacity and avoid network reinforcement.
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| 10. |
- Leisse, Ingmar, et al.
(författare)
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Electricity Meters for Coordinated Voltage Control in Medium Voltage Networks with Wind Power
- 2010
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Ingår i: Innovative Smart Grid Technologies Conference Europe (ISGT Europe), 2010 IEEE PES. - 9781424485086 - 9781424485093 ; , s. 1-7
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Konferensbidrag (refereegranskat)abstract
- During the last years the amount of electricity generated by Distributed Energy Resources (DER), especially wind turbines, has been increasing a lot. These Distributed Generation (DG) units are often connected to rural distribution networks, where they have a large impact on the voltage and the network losses. The network voltage at the customers point of connection is an important quality criteria and has to follow different standards as e.g. EN 50160. Therefore the voltage change caused by the integration of production units in the distribution network is an important aspect when integrating more DG in distribution networks and often a limiting factor for the maximum DG capacity which is possible to integrate into an existing network without reinforcement. Using the available voltage band more efficient by applying coordinated voltage control is a possibility to increase the hosted DG capacity in an existing distribution network without reinforcement of the network. To get the actual network status the new generation of electricity meters, which have the feasibility to communicate real time voltage measurements from the customers side to a network controller, give some benefits to a more flexible and coordinated voltage control in the network. The voltage range in the network will be used adapted to the actual load and generation situation instead of using worst case assumptions as it is good practice until now. A main part of the voltage control in medium voltage distribution networks is done by the on-load tap changer (OLTC) which takes the voltage at the consumers point of connection into account. A generic 10 kV distribution network with three typical types of feeders, as pure load, pure generation and mixed load and generation feeder, has been outlined. Coordinated voltage control is implemented by a central voltage controller. Simulations on the voltage and the network losses have been done and will be presented in this paper. The maximum DG capacity in the test system increases most when introducing coordinated control of the OLTC but also the use of reactive power adds some benefit. Further increase of the DG capacity by more extensive use of curtailment is always possible but due to economical aspects not favoured.
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