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Rostfritt stål till stora vattentankar utomhus : En jämförelse mellan austenitiska och rostfria stålEdling, Erika, Börjesson, Malin, Rogeman, Niklas, Naim Katea, Sarmad, Bengtsson, Jenny, Söderberg Breivik, Johan, Wessman, Markus January 2012 (has links)
The austenitic stainless steel 316L has been compared to duplex stainless steels to be able to highlight a choice of material for manufacturing of spare tanks used for cooling water at nuclear power stations on the Swedish west coast. In this report 316L and the duplex stainless steels 2205, 2304 and LDX 2404 have been compared according to corrosion resistance, strength, manufacturing aspects and prices. The steels arranged by increasing corrosion resistance: 316L < 2304 < LDX 2404 < 2205. The steels arranged by increasing strength (considering the thickness of the plates needed for construction): 316L < 2304 < LDX 2404 and 2205. The steels arranged by increasing price/tank: 2304 < LDX 2404 < 2205 < 316L. One of the duplex stainless steels is recommended rather than the austenitic stainless steel 316L. In terms of price 2304 is preferable to 2205 and LDX 2404. When it comes to corrosion resistance 2205 is superior to 2304 and can sometimes be considered as unnecessary good and therefore not relevant for this application.
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An?lise da efici?ncia espectral considerando a duplexa??o e o perfil de tr?fego para bandas licenciadas / Analysis of the espectral efficiency considering duplexing and the profile of traffic in licensed bandsSavoine, M?rcia Maria 06 February 2009 (has links)
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Previous issue date: 2009-02-06 / This work presents the comparison made through simulations of discreet events, accomplished with the software ARENA, the techniques of Time Division Duplex (TDD) and Frequency Division Duplex (FDD). Techniques present in the pattern IEEE 802.16 and used by WiMAX in the bi-directional channels of uplink and downlink. The simulation model considered in the line of arrival of the services the concept FIFO (First-In, First-Out) and the simulations were accomplished considering five applications (Streaming, Download, Web, E-mail and Small-Transaction) for downlink and uplink. The number of channels in the Base Station varied from 4 to 60, with a throughput of 600 kbps. The regarded efficiency parameter was the minimum number of channels necessary in each one of the standard channels. The simulations were accomplished in three sceneries., In the first scenery it was considered the same profile of traffic for downlink and uplink, in the second scenery a traffic of downlink 2, 5, 10 and 15 times larger than the one of uplink. And, in the third scenery it was considered different proportions of traffics varying from 2 to 5 times more, 5 to 10 times more and from 10 to 15 times more. The analyses were done considering as efficiency parameter the converge of the waiting time of the users. ,It was verified that in asymmetric data traffic, the TDD technique was more efficient and there were spectrum idleness in the FDD technique. / Este trabalho apresenta a compara??o efetuada por meio de simula??es de eventos discretos, realizadas com o software ARENA, das t?cnicas de Duplexa??o por Divis?o no Tempo (TDD) e Duplexa??o por Divis?o da Freq??ncia (FDD), t?cnicas presentes no padr?o IEEE 802.16 e utilizadas pelo WiMAX nos canais bidirecionais de uplink e downlink. O modelo de simula??o considerou na fila de chegada dos servi?os o conceito FIFO (First-In, First-Out) e as simula??es foram realizadas considerando cinco aplica??es (Streaming, Download, Web, E-mail e Small-Transaction) para downlink e uplink. O n?mero de canais na Base Station variou de 4 a 60, com um throughput de 600 kbps. O par?metro de efici?ncia considerado foi o n?mero m?nimo de canais necess?rio em cada um dos canais padr?es. As simula??es foram realizadas em tr?s cen?rios, sendo que, no primeiro cen?rio se considerou o mesmo perfil de tr?fego para downlink e uplink, no segundo cen?rio com tr?fego de downlink 2, 5, 10 e 15 vezes maior que o de uplink. E, no terceiro cen?rio com propor??es variadas de tr?fegos variando de 2 a 5 vezes mais, 5 a 10 vezes mais e de 10 a 15 vezes mais. Realizadas as simula??es foram feitas as an?lises dos desempenhos, tomando como par?metro de efici?ncia a taxa de chegada e o tempo de espera do usu?rio perante aplica??es t?picas utilizadas na tecnologia de banda licenciada WiMAX, que segue este padr?o. A an?lise efetuada permitiu identificar, dada estas condi??es de tr?fego, qual das t?cnicas seria a mais indicada. Constatou-se ainda que em tr?fego de dados assim?tricos a t?cnica TDD se apresentou mais eficiente e, observou-se existir ociosidade de espectro na t?cnica FDD.
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Machine learning for the prediction of duplex stainless steel mechanical properties : Hardness evolution under low temperature agingGiard, Baptiste, Karlsson, Sofia January 2021 (has links)
Duplex stainless steels, DSS are stainless steels that consist of the two phases austenite and ferrite. The DSS have superb properties and are widely used in industries such as nuclear power and in pressure vessels, pipes and in pipelines. The use of DSS are limited due to embrittlement which occurs at temperatures from 250 to 550 oC. This imposes a general limited service temperature of 250 oC. The mechanism mainly responsible for the embrittlement is a phase separation occurring in the ferrite phase. Furthermore, there is a direct link between the phase separation and the mechanical properties: the ferrite hardness increases whereas the toughness decreases under low temperature aging. In this thesis, the low-temperature embrittlement of duplex stainless steels was studied through machine learning modelling and experimental hardness- and microscopy measurements. The resulting model describes the data with an accuracy, R-squared = 0.94. In combination with the experimental results, nickel was identified as an important parameter for the hardness evolution. This work aims to provide a fundamental study for understanding the importance of alloying elements on the phase separation in DSS, and provides a new methodology via a combination of machine learning and key experiments for the material design. / Duplexa rostfria stål är rostfria stål som består av de båda faserna ferrit och austenit. De har extraordinära egenskaper och används brett inom industrin, t ex. i kärnkraftverk och i tryckkärl och pipelines. Användningen av duplexa rostfria stål är begränsad p.g.a. försprödning som uppstår i legeringarna vid temperaturer mellan 250-550 oC, vilket medför att den tillåtna temperaturen vid användning begränsas till under 250 oC. Den främsta orsaken till försprödningen är en fasseparation i den ferrita fasen under åldring vid låg temperatur. Vidare leder fasseparationen till mekaniska förändringar i ferritfasen: hårdheten ökar medan segheten minskar. I den här rapporten undersöks försprödningen av duplexa rostfria stål vid åldring med hjälp av datormodellering med maskininlärning samt av experimentella hårdhets- och mikroskopiska mätningar. Modellen hade en noggrannhet (determinationsko- efficienten, R2) på 0.94. Resultatet från modellen visade tillsammans med de experimentella resultaten att nickel är ett legeringsämne som har stor betydelse för hårdhetsökningen. Detta arbete syftar till att utgöra en grundläggande studie för att förstå påverkan från olika legeringsämnen på fasseparationer i DSS, och bidrar med en ny metodik för materialdesign som kombinerar maskininlärning och utvaldaexperiment. / EIT RawMaterial Project ENDUREIT
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