| 1. |
- Alipour, Yousef, 1979-, et al.
(författare)
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The analysis of furnace wall deposits in a low-NOx waste wood-fired bubbling fluidised bed boiler
- 2012
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Ingår i: VGB PowerTech Journal. - : VGB Power Tech. - 1435-3199. ; 92:12, s. 96-100
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Increasing use is being made of biomass as fuel for electricity production as the price of natural wood continues to rise. Therefore, more use is being made of waste wood (recycled wood). However, waste wood contains more chlorine, zinc and lead, which are believed to increase corrosion rates. Corrosion problems have occurred on the furnace walls of a fluidised bed boiler firing 100 % waste wood under low-NOx conditions. The deposits have been collected and analysed in order to understand the impact of the fuel.
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| 2. |
- Alricsson, Marie, et al.
(författare)
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Spinal alignment, mobility of the hip and thoracic spine and prevalence of low back pain in young elite cross-country skiers.
- 2016
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Ingår i: Journal of Exercise Rehabilitation. - Seoul : Korean Society of Exercise Rehabilitation. - 2288-176X .- 2288-1778. ; 12:1, s. 21-28
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Tidskriftsartikel (refereegranskat)abstract
- This study investigated the association between spinal alignment, mobility of the hips and the thoracic spine and low back pain in adolescent cross-country skiers. Cohort of 51 elite cross-country skiers from a cross-country skiing high school in Sweden participated in the study. Sagittal spinal alignment, active range of motion in flexion, extension and rotation of the thoracic spine as well as passive and active extension of the hips were measured. The participants also completed a questionnaire regarding training, competition, skiing technique and occurrence of low back pain. A simple linear regression was calculated to predict pain score based on thoraco-lumbar relation, with a significant (P<0.05) regression equation of y=-0.069x+2.280 (standard error of estimate, 0.034). Participants with greater lordosis than kyphosis were more likely to suffer from low back pain than subjects without this offset. Thoracic mobility and passive or active hip extension showed no correlation with low back pain. Sagittal spinal alignment seems to be related with low back pain among young elite cross-country skiers. This study shows that range of motion of the thoracic spine and hips do not have an effect on the prevalence of low back pain in this population.
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| 3. |
- Andersson, Tova, et al.
(författare)
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Uppföljning av etappmålet för ökad resurshushållning i livsmedelskedjan : Data för år 2018
- 2019
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- I det här projektet har SMED utfört en uppföljning av etappmålet för en ökad resurshushållning i livsmedelskedjan som lyder: ”Insatser ska vidtas så att senast år 2020 sorteras minst 50 procent av matavfallet från hushåll, storkök, butiker och restauranger ut och behandlas biologiskt så att växtnäring tas tillvara, och minst 40 procent av matavfallet behandlas så att även energi tas tillvara”.I praktiken innebär målformuleringen att av det uppkomna matavfallet från ovan nämnda avfallskällor ska minst 50 procent rötas eller komposteras där minst 40 procent av de uppkomna matavfallsmängderna måste rötas så att växtnäringen i matavfallet tas tillvara.Uppföljningen visar att omkring 38 procent av det uppkomna matavfallet från konsumtionsledet rötas och komposteras år 2018 så att växtnäringsämnen tas tillvara. Detta kan jämföras med målet på 50 procent. Motsvarande andel som rötas och där återföring av näringsämnen sker uppgår till 33 procent år 2018, att jämföra med målet på 40 procent. Sverige är idag en bra bit från att klara återvinningsmålet som inte bedöms uppnås till år 2020.De faktorer som har störst potential att öka återvinningsgraden utifrån genomförd studie är:Öka mängden insamlat matavfall till biologisk behandling. Idag är den andelen ungefär 49 procent av de uppkomna matavfallsmängderna. I de hushåll som idag har möjlighet att sortera ut sitt matavfall finns det en stor potential att öka utsorteringen eftersom andelen matavfall i restavfallet i dessa hushåll är cirka 26 procent. Detta jämfört med omkring 35 procent i hushåll som inte har någon matavfallsinsamling. Regeringsbeslutet att ålägga kommunerna att tillhandahålla system för insamling av matavfall från hushåll senast 2021 (Regeringskansliet, 2019) är ett kraftfullt styrmedel som kommer att öka insamlingen av matavfall då det år 2018 var 82 % av kommunerna som erbjöd insamling av matavfall till hushållen (Avfall Sverige, 2019a) Minska rejektmängderna som uppstår vid förbehandlingen vid samrötningsanläggningar. Denna andel är idag cirka 24 procent av insamlade mängder matavfall. Det är viktigt att få en biogödsel med en så bra kvalitet och med så lite oönskade material som möjligt för att kunna återföra näringsämnen. Eftersom det idag inte finns någon teknik för att enbart ta bort oönskade material är det oundvikligt att matavfall hamnar i rejektet. Tidigare år har en ökad återföring av rötslam från kommunala avloppsreningsverk angetts som ett sätt att nå målet om återföring av näring. Idag är det omkring 72 procent av uppkomna mängder rötslam som avsätts på ett sådant sätt att det kan klassas som återföring av näringsämnen. Det finns dock en utredning som ska föreslå förbud mot spridning av avloppsslam på åkrar och krav på återvinning av fosfor (Regeringskansliet, 2019b). Resultatet av denna utredning och framtida krav på återföring av näringsämnen som ställs kommer medföra en stor påverkan på etappmålsuppföljningen, och troligen även på beräkningsmetod om det enbart är fosfor som kommer att återföras.
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| 4. |
- Casals, Nuria Fuertes, et al.
(författare)
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Influence of annealing oxide structure and composition on pickling of the duplex stainless steel 1.4462
- 2011
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Ingår i: 7th European Stainless Steel Conference: Science and Market, Proceedings. - : Associazione Italiana di Metallurgia. - 9788885298842
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Konferensbidrag (refereegranskat)abstract
- In this work, correlation between the oxide formation and pickling behaviour of a conventional duplex material - 1.4462 is reported. The materials investigated are the duplex grade 1.4462 and two single phase alloys with compositions corresponding to the respective phases of the duplex material. Annealing was conducted at 1070 °C for 8 minutes. Topography and composition of the oxide layer were analysed with GDOES, FIB, XRD, SEM-EDS and CLSM. The ferritic steel formed a thick chromium-enriched oxide with a silica-rich sublayer. On the austenitic steel, ironenriched nodules were observed in the centre of the grains, together with oxide ridges on the top of the grain boundaries. The oxide on the duplex grade differed depending on the phase; nodule formation was observed on the austenitic grains while a more homogenous oxide formed on the ferritic grains. Pickling was performed in a mixed nitric/hydrofluoric acid bath. The fastest removal was observed for the austenitic sample, followed by the duplex and the ferritic samples. The oxide on the austenitic sample spalled from the surface while the oxide on the ferritic grade was removed by dissolution rather than by spallation. A mixed behaviour was observed on the duplex grade where some zones pickled faster than others.
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| 5. |
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| 6. |
- Elger, Ragna, et al.
(författare)
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Laboratory testing to evaluate candidate alloys for superheaters in waste-fired boilers
- 2016
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Ingår i: Materials at High Temperature. - : Taylor and Francis Ltd.. - 0960-3409 .- 1878-6413. ; 33:6, s. 587-595
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Tidskriftsartikel (refereegranskat)abstract
- Two types of laboratory tests were used to evaluate the behaviour of a wide range of steels in chlorinating–sulphidising conditions: high temperature exposure after applying salt by dipping in an aqueous KCl/ZnCl2 solution and salt-bed test in a ZnCl2/NaCl/KCl/CaSO4 salt mixture. The exposures were performed at 500 °C in a gas comprising N2/HCl/SO2/O2/N2. For the alloy group with 20–30 wt-% chromium and 25–65 wt-% nickel, the extrapolated metal loss was below 0.2 mm/year in the salt dip, up to 6 mm/year in the salt-bed test with 10% Cl and up to 20 mm/year in the 20% Cl salt-bed test. The intermediate alloy group showed poorer performance in the salt-bed; Esshete1250 showed also large spallation in the salt dip test. Results were compared with plant-exposed samples. Further refinement of the salt dip test is suggested for material ranking in the superheater region of a waste or biomass-fired incinerator. © 2016 Swerea Kimab.
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| 7. |
- Flyg, Jesper, et al.
(författare)
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High temperature corrosion under simulated biomass deposit conditions
- 2009
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Konferensbidrag (refereegranskat)abstract
- Biomass is gaining increasing importance as a renewable energy source for the production of heat, electricity and transport fuels. However, corrosion issues are numerous and include accelerated wastage under ash and alkali salt deposits, erosion, and metal dusting in conjunction with gasification. This work focuses on deposit issues and is based on laboratory exposures for a total of 960 hours at 550°C (1022°F) and 700°C (1292°F) under deposits of 52.4 wt% KCl + 47.6 wt% K2SO4 in a nitrogen- based gaseous atmosphere containing 15% H2O, 5%O2, 13%CO 2 and 0.02%HCl. The materials tested include carbon steel, low alloyed steels with 2%Cr or 9%Cr, the austenitic AISI 304 and the high temperature grade 253MA (21%Cr, 11 %Ni, 1.6%Si, Ce). Metal loss data obtained from metallographic evaluation show the corrosion rate to decrease in this order and illustrate how materials substitution can permit an increase in process temperature. Examination of the reaction interface underlines the importance of both chlorination and oxidation in the materials corrosion process. © 2009 by NACE International.
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| 8. |
- Fritzson, Dag, et al.
(författare)
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Object-Oriented Mathematical Modelling – Applied to Machine Elements
- 1994
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Ingår i: Computers & structures. - : Elsevier. - 0045-7949 .- 1879-2243. ; 51:3, s. 241-253
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Tidskriftsartikel (refereegranskat)abstract
- Machine element analysis has a goal of describing function and other aspects of machine elements in a theoretical form. This paper shows how ideas from object-oriented modelling can be applied to machine element analysis. The models thus obtained are both easier to understand, better structured, and allow a higher degree of re-use than conventional models. An object-oriented model description is natural and suitable for machine element analysis. As a realistic example an equational model of rolling bearings is presented. The structure of the model is general, and applies to many types of rolling bearings. The model and one solution require approximately 200 + 200 equations. The model is extensible, e.g. simple submodels of detailed properties can be made more complex without altering the overall structure. The example model has been implemented in a language of our own design, ObjectMath (Object-oriented Mathematical language for scientific computing). Using ObjectMath, it is possible to model classes of equation objects, to support multiple and single inheritance of equations, to support composition of equations, and to solve systems of equations. Algebraic transformations can conveniently be done since ObjectMath models are translated into the Mathematica computer algebra language. When necessary, equations can be transformed to C++ code for efficient numerical solution. The re-use of equations through inheritance reduced the size of the model by a factor of two, compared to a direct representation of the model in the Mathematica computer algebra language.
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| 9. |
- Fritzson, Dag, et al.
(författare)
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Object-Oriented Mathematical Modelling - Applied to Rolling Bearings
- 1992
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Konferensbidrag (refereegranskat)abstract
- Machine element analysis has the goal of describing functionality and other important aspects of machine elements in theoretical form. A rolling bearing is a typical example of a machine element. The first issue covered in this paper is how ideas from object-oriented programming and modelling can be applied to machine element analysis. The models thus obtained are easier to understand, better structured, and allow a higher degree of re-use than conventional models. Our conclusion is that an object-oriented model description is natural for the machine element analyst and is suitable for machine element analysis.An equational model of rolling bearings is presented in this paper. The structure of the model is general, in three dimensions, and applies to many types of rolling bearings. Part of this generality is obtained by using parametric surfaces. In order to keep the presentation of the model understandable, we have simplified many details. Nevertheless, the model and one solution require approximately 200+200 equations. The model is also extensible, e.g., simple submodels of detailed properties can be made more complex without altering the overall structure.
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| 10. |
- Fritzson, Peter, et al.
(författare)
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High-level mathematical modeling and programming in Scientific Computing
- 1995
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Ingår i: IEEE Software. - : IEEE. - 0740-7459 .- 1937-4194. ; 12:4, s. 77-87
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Tidskriftsartikel (refereegranskat)abstract
- Scientific computing and advanced mechanical analysis demand high-level support for modeling and solving complex equations. To meet this need, the authors designed ObjectMath and applied it to real problems in machine-element analysis
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