| 1. |
- Andersson, Johan, et al.
(författare)
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Extracting Simulation Models from Complex Embedded Real-Time Systems
- 2006
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Ingår i: Proceedings of the 2006 International Conference on Software Engineering Advances, ICSEA'06, Tahiti, French Polynesia. - 0769527035 ; , s. Article number 4031792-
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Konferensbidrag (refereegranskat)abstract
- A modeling process is presented for extracting timingaccurate simulation models from complex embedded real-time systems. The process is supported by two complementary methods for tool-supported model extraction, Model Synthesis and Hybrid Model Extraction. The generated models enable impact analysis for complex real-time systems with respect to dynamic system properties, such as timing and resource usage. This can make software maintenance more predictable with respect to time-to-market and development costs, since timing errors can be identified early and avoided. The contribution of the paper is the modeling process, the Hybrid Model Extraction method and an interactive modeling tool, MASS, designed to support Hybrid Model Extraction of large implementations in C.
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| 2. |
- Andersson, Joel Håkan, 1981
(författare)
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Hot Cracking and Grain Boundary Weaknesses of Nickel - Based Superalloys
- 2008
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Abstract Grain boundary weaknesses of nickel-based superalloys not only materialize during service in the hot turbine engine sections but also during the weld manufacturing. The performance, in this respect, of the most commonly used alloys at Volvo Aero Corporation (VAC), 718 and the higher temperature capacity Waspaloy, are therefore the main subjects for this thesis. The emerging Allvac 718® PLUSTM (718 Plus) is also included due to the prospect of replacing the expensive Waspaloy. The overall emphasis is on weldability through Varestraint testing but limited work was initially carried out on notch rupture sensitivity of 718 Plus.The notch rupture testing of 718Plus emphasized the importance of the secondary phases like delta-phase in the grain boundaries.Hot cracks were observed in all alloys with re-solidified products on the liquated and re-solidified grain boundaries. Grain boundary liquation and segregation of alloying elements was considered to be the primary reason for liquation of HAZ grain boundaries which caused cracking.Evidence of constitutional liquation of Nb rich MC type carbides in alloy 718 and 718 Plus were found in the region adjacent to the fusion zone and also on the cracked grain boundaries. The resolidified products along the hot cracks consisted of γ + MC type carbide and γ + Laves eutectics.
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| 3. |
- Andersson, Joel Håkan, 1981
(författare)
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Solidification Cracking of Alloy Allvac 718Plus and Alloy 718 at Transvarestraint Testing
- 2008
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Ingår i: EPD Congress 2008, TMS, ed. S. M. Howard, 2008.. ; , s. 157-169
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Allvac 718Plus is a newly developed superalloy with a good potential for use in fabricatedaircraft engine structures when service temperatures exceed 650°C; the limit for standard alloy718. Fabrication involves welding, where cracking usually is a prohibitive factor. Comparison ofthe solidification cracking behavior between these two alloys was made by Transvarestrainttesting. It was shown that the total amount of cracking was significantly lower for 718Plus alloy,which was associated with a lower amount of γ/Laves or γ/NbC eutectic-type constituents. Thisin turn is believed to be due to the lower iron content of the Allvac 718Plus material. Theanalysis of alloying element segregation both within primary dendrite and interdendriticconstituents clearly indicates that the segregation of Nb is the controlling factor in determiningthe final solidification microstructure in these alloys. The Nb concentrations of these constituentsare significantly higher compared to the bulk alloy concentration. This was confirmed by theSEM-EDS analysis and calculations assessed with JMatPro, the latter also indicated that alloy718 is more prone to form Laves and NbC eutectic-type constituents compared to Allvac 718Plusmaterial.
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| 4. |
- Andersson, Joel, 1981-, et al.
(författare)
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Hot Cracking of Allvac 718Plus, Alloy 718 and Waspaloy at Varestraint Testing
- 2008
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Ingår i: 4th International Symposium on Aerospace Materials and Manufacturing Processes. - Montreal : Canadian Institute of Mining, Metallurgy and Petroleum. - 9781617386169 ; , s. 401-413, s. 401-413
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Konferensbidrag (refereegranskat)abstract
- Varestraint testing together with DSC and SEM-EDX analyses have been performed as means of investigating the hot cracking susceptibility of Allvac 718Plus, alloy 718 and Waspaloy. The solidification sequences in Allvac 718Plus and alloy 718 were very similar to each other starting by an initial solidification of the gamma phase, gamma/MC reaction at around 1260°C and then finally ending the sequence by gamma/Laves eutectic reaction at around 1150°C. Waspaloy had the same solidification sequence, except no Laves phase formation takes place, and solidification started at a somewhat higher temperature as compared to alloy 718 and the solidification sequence ends by a gamma/MC reaction at around 1245°C. The total amount of hot cracking in Waspaloy was shown to be much less than that in alloy 718 and in Allvac 718Plus which is believed to be related to the presence of the Laves eutectic in the latter two alloys with corresponding larger solidification ranges. Hot cracking of 718Plus is slightly less than in 718.
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| 5. |
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| 6. |
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| 7. |
- El-Sayed, Najib M., et al.
(författare)
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The genome sequence of Trypanosoma cruzi, etiologic agent of Chagas disease.
- 2005
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 309:5733, s. 409-15
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Tidskriftsartikel (refereegranskat)abstract
- Whole-genome sequencing of the protozoan pathogen Trypanosoma cruzi revealed that the diploid genome contains a predicted 22,570 proteins encoded by genes, of which 12,570 represent allelic pairs. Over 50% of the genome consists of repeated sequences, such as retrotransposons and genes for large families of surface molecules, which include trans-sialidases, mucins, gp63s, and a large novel family (>1300 copies) of mucin-associated surface protein (MASP) genes. Analyses of the T. cruzi, T. brucei, and Leishmania major (Tritryp) genomes imply differences from other eukaryotes in DNA repair and initiation of replication and reflect their unusual mitochondrial DNA. Although the Tritryp lack several classes of signaling molecules, their kinomes contain a large and diverse set of protein kinases and phosphatases; their size and diversity imply previously unknown interactions and regulatory processes, which may be targets for intervention.
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| 8. |
- Gustavsson, Joel, et al.
(författare)
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A thermodynamic study of silicon containing gas around a blast furnace raceway
- 2005
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Ingår i: ISIJ International. - : Iron and Steel Institute of Japan. - 0915-1559 .- 1347-5460. ; 45:5, s. 662-668
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Tidskriftsartikel (refereegranskat)abstract
- The equilibrium conditions for silicon transfer from ash to the liquid metal phase via SiO gas have been discussed by several authors. However, no published calculations have been found using the most modern thermodynamic models available. Since there are major differences in the results of calculations using different thermodynamic models and the models are continuously being improved, new equilibrium calculations on SiO and SiS gas formation have been performed using the recently developed models. Different ingoing compositions of coke ash, coal powder ash and blast air were used in the calculations. The compositions chosen represent blast furnace no. 3 at SSAB in Lulea, Sweden. Temperature was found to be the major factor influencing the equilibrium silicon level in the gas phase. At low temperatures (below 1 600 degrees C the total gas pressure was also seen to influence the silicon content in the gas phase. The main reason for this is that below 1 600 degrees C, the amount of liquid slag at equilibrium increases with the total gas pressure. Liquid slag contains large amounts of silica that then can not be found in the gas phase. Higher carbon activity is usually expected to result in higher SiO gas levels in the blast furnace. The equilibrium calculations show that increased carbon activity increases the amount of silicon in the gas phase at temperatures up to about 1 600 degrees C, but that at higher temperatures SiC is formed that decreases the equilibrium silicon level in the gas phase.
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| 9. |
- Gustavsson, Joel, et al.
(författare)
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Comparison of calculated equilibrium and operation data for blast furnace with focus on silicon
- 2009
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Ingår i: Ironmaking & steelmaking. - 0301-9233 .- 1743-2812. ; 36:5, s. 341-353
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Tidskriftsartikel (refereegranskat)abstract
- An investigation of reactions involving blast furnace hot metal, slag and gas at equilibrium was carried out. Performed calculations were based on estimated total gas pressures, measured temperatures and hot metal and slag compositions. Calculated element contents of liquid phases were found to be very similar to their corresponding values determined through measurement when formation of the gas phase was suppressed. This resulted in higher equilibrium CO partial pressures compared to the measured total gas pressure in the bustle ring. When only equilibrium conditions were considered, the predicted amount of silicon was much higher than the measured. A comparison of activity coefficients of elements in the hot metal using different calculation models was also carried out. Two different models based on dilute solutions were compared with the TCFe3 database developed for the software Thermo-Calc, which can handle higher alloying concentrations. Considerably different calculation results were found among the different models studied.
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| 10. |
- Huselius, Joel, et al.
(författare)
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Automatic Generation and Validation of Models of Legacy Software
- 2006
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Ingår i: Proceedings of the 12:th IEEE International Conference on Embedded and Real-Time Computing Systems and Applications (RTCSA), Sydney, Australia. - 9780769526768 ; , s. 342-349
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Konferensbidrag (refereegranskat)abstract
- The modeling approach is not used to its full potential in maintenance of legacy systems. Often, models do not even exist. The main reasons being that the economic implications and practical hurdles in manually maintaining models of in-use legacy systems are considered too high by the industry. In this paper, we present a method for automated validation of models automatically generated from recordings of executing real-time embedded systems. This forms an essential constituent of a unified process for the automatic modeling of legacy software. We also present a study in which we automatically model a state-of-practice industrial robot control system, the results of which are clearly positive indicators of the viability of our approach.
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| 11. |
- Larsson, Jonas, et al.
(författare)
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Knit On Demand : Simulation of an agile production and shop model for fashion products
- 2007
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Konferensbidrag (refereegranskat)abstract
- In fashion business customer demand is changing due to fashion trends and new designs. Time from customer demand to customer demand fulfillment is essential for company’s ability to compete in the fashion retailing business. During the last 20 years there has been a dramatic technical development in the production of flat knitted garments. This has made it possible to rationalize design and production in a way that it’s possible to make a knitted garment ready made directly in the knitting machine, with a minimum of after coming processes. Objective of this paper is to present a design, production and shop model for the “Knit on Demand” concept and show of how this new production technology could be implemented in a fast fashion logistics system. A business model with the knitting machines and production equipment located in the store is presented. The customer takes part in the design process and garments are customized to fulfill actual demand. Aim is to present a lead time simulation of design- and production processes involved in the shop concept. Result is a model with starting point in customer demand and final point in demand fulfillment. Simulation shows that the customer could have an own designed garment in 2-5 hours. Simulation of the developed shop model is done in the software tool AutoMod. Methodology for this paper is based on a research project of the Knit on demand concept idea at the University College of Borås, literature research and discussions with suppliers of knitting production equipment.
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| 12. |
- Peterson, Joel, et al.
(författare)
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Knit on demand : development and simulation of a production and shop model for customised knitted garments
- 2008
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Ingår i: International Journal of Fashion Design, Technology and Education. - : Taylor & Francis Ltd.. - 1754-3266 .- 1754-3274. ; 1:2, s. 89-99
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Tidskriftsartikel (refereegranskat)abstract
- Development of computer technology and the Internet has made mass customisation of products more common in fashion design of today. Development in production of knitted garments has made it possible to make garments ready made, directly in the knitting machine. The objective of this article is to present a design, production and shop model for the ‘‘Knit on Demand’’ concept and to show how the complete garment knitting technology could be used for customised products. A business model with production equipment located in store is presented. Customers are involved in the design process and garments are customised to fulfil actual demand. A lead time simulation of design and production processes in the shop concept is presented. Simulation in the software tool AutoModTM shows that the customer could have a self-designed garment in two to five hours.
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| 13. |
- Samuelsson, Joel, 1973-
(författare)
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Tolkning och utfyllning : Undersökningar kring ett förmögenhetsrättsteoretiskt tema
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This is a thesis in contract law concerning the distinction between interpretation of contracts (“tolkning”) and construction of contracts (“utfyllning”) traditionally upheld within Scandinavian doctrine. To some extent, this distinction has always been a source of conceptual confusion, but in late-modern times, it has, in certain respects, become almost unintelligible – owing to the gradual loss of function of the form of rationality that originally sustained it. The distinction is now a mere artefact. In itself, this fact does, of course, not make this particular conceptual contraption exceptional. As they are absorbed into the language of contract law, all successful contract law concepts undergoes a process of reification. In the case of the distinction between interpretation and construction, the result is, however, unusually curious.In its traditional form, the distinction expresses the hope for a law of contract that is organized according to scientific principles. It rests on the assumption that it is desirable and possible, in principle, to separate science from non-science. It presupposes that questions of fact are separable from questions of law, Is from Ought, and the uncovering of the meaning of legal documents from the application of the rules they contain. The distinction promises that it is possible to escape the confines of the law-text, to reach beyond the text and the play of words constituting its interpretation, in order to ground interpretive discourse in factual reality. Yet, the distinction itself is nothing but text, i e, nothing but law.Drawing on the Kantian tradition, specifically on the writings of Wittgenstein, the author subjects this contradictory structure to criticism. The aim of the study is, however, not to once and for all remove the contradiction. On the contrary, the policy advocated is one of acceptance – mediated through historical awareness. By distancing ourselves from the vision of law and science that is immanent in the distinction under scrutiny, we would be able to come to terms with the hermeneutical side of contract interpretation, and with the inscrutability of the subjective dimension of the contract construct. When interpretation is called for, it is due to the very fact that there is no verifiable intention, yet the conclusions of the interpreter are given in the form of reports on what the parties actually intended. This, the author concludes, does not make the interpretation of contracts unscientific, even though we, being Scandinavian private law lawyers, were fostered to think otherwise.
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| 14. |
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| 15. |
- Sjöberg, Göran, 1946, et al.
(författare)
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New Materials in the Design and Manufacturing of Hot Structures for Aircraft Engines – Allvac 718Plus
- 2009
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Ingår i: ISABE 2009, Montreal, Canada.
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Konferensbidrag (refereegranskat)abstract
- Several efforts have been made to develop an alloy with the same versatility as the most common superalloy, Alloy 718, but with an ability to meet operating requirements for aircraft engine parts at 50 ºC higher temperature, i.e. 700 ºC. None of these alloy development efforts have been very successful for various reasons. Today a new promising alloy, Allvac 718Plus, has emerged as result of a joint effort between metal producers and aircraft engine companies. The weldability of this new alloy was examined in comparison with that of alloy 718 both by normal Varestraint and by Tranvarestraint testing. The results indicate that the weldability of 718Plus is at par with alloy 718 which also makes this alloy an interesting candidate for the Volvo Aero assembly type hot structural parts. However, the alloy must be offered in form of sheet material and as castings before the full potential can be used in such structures.
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