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Glavatskih, Sergei
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Filippov, A., Azancheev, N., Shah, F. U., Glavatskikh, S. & Antzutkin, O. (2016). Self-Diffusion of Phosphonium Bis(Salicylato)Borate Ionic Liquid in Pores of Vycor Porous Glass (ed.). Microporous and Mesoporous Materials, 230, 128-134
Öppna denna publikation i ny flik eller fönster >>Self-Diffusion of Phosphonium Bis(Salicylato)Borate Ionic Liquid in Pores of Vycor Porous Glass
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2016 (Engelska)Ingår i: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 230, s. 128-134Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

1H NMR pulsed field gradient was used to study self-diffusion of a phosphonium bis(salicylato)borate ionic liquid ([P6,6,6,14][BScB]) in the pores of Vycor porous glass at 296 K. Confinement in pores increases diffusion coefficients of the ions by a factor of 35. However, some [P6,6,6,14][BScB] ions demonstrated apparent diffusion coefficients much lower than their mean values, which may be due to partially restricted diffusion of the ions. We suggest that this fraction corresponds to areas where ions are confined by pore ‘necks’ (micropores) and empty voids. Heating of the ionic liquid / Vycor system at 330 K led to a change in the diffusivity of the ions, because of their redistribution in the pores. The size of the bounded regions is on the order of 1 µm, as estimated from the dependence of the ion diffusivity on the diffusion time.

Nyckelord
Ionic liquid, diffusion, porous structure, Chemistry - Physical chemistry, Kemi - Fysikalisk kemi
Nationell ämneskategori
Fysikalisk kemi
Forskningsämne
Gränsytors kemi; Maskinelement
Identifikatorer
urn:nbn:se:ltu:diva-4613 (URN)10.1016/j.micromeso.2016.04.044 (DOI)000378661100015 ()2-s2.0-84968542987 (Scopus ID)29657a03-d69a-499b-941f-b7995f1efb77 (Lokalt ID)29657a03-d69a-499b-941f-b7995f1efb77 (Arkivnummer)29657a03-d69a-499b-941f-b7995f1efb77 (OAI)
Anmärkning

Validerad; 2016; Nivå 2; 20160508 (andfil)

Tillgänglig från: 2016-09-29 Skapad: 2016-09-29 Senast uppdaterad: 2018-07-10Bibliografiskt granskad
Taher, M., Shah, F. U., Filippov, A., Baets, P. D., Glavatskih, S. & Antzutkin, O. (2014). Halogen-free pyrrolidinium bis(mandelato)borate ionic liquids: some physicochemical properties and lubrication performance as additives to polyethylene glycol (ed.). Paper presented at . RSC Advances, 4(58), 30617-30623
Öppna denna publikation i ny flik eller fönster >>Halogen-free pyrrolidinium bis(mandelato)borate ionic liquids: some physicochemical properties and lubrication performance as additives to polyethylene glycol
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2014 (Engelska)Ingår i: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 4, nr 58, s. 30617-30623Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

This work reports on the synthesis and physicochemical characterisation of novel halogen-free boron containing ionic liquids (hf-BILs) with dialkylpyrrolidinium cations [CnC1Pyrr]+, n ¼ 4–14, and bis(mandelato)borate anion [BMB]. All the synthesised compounds are liquids at room temperature. It was found that the thermal properties and density of these hf-BILs are affected by the length of the longest alkyl chain connected to the nitrogen atom in the pyrrolidinium cations. Differential scanning calorimetry measurements revealed that glass transition temperatures of these ionic liquids are in the temperature range from 218 to 241 K. Interestingly, the glass transition temperatures follow the “odd– even” effect related to the number of carbons (n) in one of the alkyl chains of [CnC1Pyrr]+. It was also found that hf-BILs' density decreases with an increase in the alkyl chain length of [CnC1Pyrr]+. It is suggested that the “odd–even” effect is associated with the difference in packing and specific interactions of cations and anions of this class of hf-BILs. Their lubricating properties, as 3 wt% additives in polyethylene glycol (PEG), were evaluated in steel–steel contacts. PEG with hf BILs additive provided significantly lower wear and friction compared to the neat PEG and 5W40 engine oil. It was found that shortening the length of the longest alkyl chain in the cations of [CnC1Pyrr][BMB] significantly reduces frictional losses. Antiwear properties of [CnC1Pyrr][BMB] in PEG follow the same trend.

Nationell ämneskategori
Fysikalisk kemi
Forskningsämne
Gränsytors kemi
Identifikatorer
urn:nbn:se:ltu:diva-14686 (URN)10.1039/c4ra02551b (DOI)000340500300022 ()2-s2.0-84904823642 (Scopus ID)e1ad5695-e00f-4175-a4f1-c6dacc62bb8f (Lokalt ID)e1ad5695-e00f-4175-a4f1-c6dacc62bb8f (Arkivnummer)e1ad5695-e00f-4175-a4f1-c6dacc62bb8f (OAI)
Anmärkning
Validerad; 2014; 20140716 (mamtah)Tillgänglig från: 2016-09-29 Skapad: 2016-09-29 Senast uppdaterad: 2018-07-10Bibliografiskt granskad
Simmons, G. F., Cha, M., Aidanpää, J.-O., Cervantes, M. & Glavatskih, S. (2014). Steady state and dynamic characteristics for guide bearings of a hydro-electric unit (ed.). Paper presented at . Proceedings of the Institution of mechanical engineers. Part J, journal of engineering tribology, 228(8), 836-848
Öppna denna publikation i ny flik eller fönster >>Steady state and dynamic characteristics for guide bearings of a hydro-electric unit
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2014 (Engelska)Ingår i: Proceedings of the Institution of mechanical engineers. Part J, journal of engineering tribology, ISSN 1350-6501, E-ISSN 2041-305X, Vol. 228, nr 8, s. 836-848Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Experiments are conducted using a 10-MW Kaplan hydropower machine which is outfitted with an extensive array of sensors to determine oil film thickness, pad load and oil temperature in all three guide bearings as well as motion of the shaft in relation to both the bearing housings and the concrete foundation. Test results for all journal bearings are compared to a commercial rotor dynamics model and results for the central journal bearing are compared to a multi-physics model to provide insight into the machine's steady state and dynamic characteristics and their variations during normal operation.

Nationell ämneskategori
Annan maskinteknik Strömningsmekanik och akustik
Forskningsämne
Datorstödd maskinkonstruktion; Strömningslära
Identifikatorer
urn:nbn:se:ltu:diva-8452 (URN)10.1177/1350650114533101 (DOI)000340210500002 ()2-s2.0-84904610818 (Scopus ID)6f5e1c5c-5475-4cdf-9191-31f889581a8d (Lokalt ID)6f5e1c5c-5475-4cdf-9191-31f889581a8d (Arkivnummer)6f5e1c5c-5475-4cdf-9191-31f889581a8d (OAI)
Anmärkning
Validerad; 2014; 20140519 (andbra)Tillgänglig från: 2016-09-29 Skapad: 2016-09-29 Senast uppdaterad: 2018-07-10Bibliografiskt granskad
Filippov, A., Taher, M., Shah, F. U., Glavatskih, S. & Antzutkin, O. (2014). The effect of the cation alkyl chain length on density and diffusion in dialkylpyrrolidinium bis(mandelato)borate ionic liquids (ed.). Paper presented at . Physical Chemistry, Chemical Physics - PCCP, 16(48), 26798-26805
Öppna denna publikation i ny flik eller fönster >>The effect of the cation alkyl chain length on density and diffusion in dialkylpyrrolidinium bis(mandelato)borate ionic liquids
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2014 (Engelska)Ingår i: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 16, nr 48, s. 26798-26805Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

The physicochemical properties of ionic liquids are strongly affected by the selective combination of the cations and anions comprising the ionic liquid. In particular, the length of the alkyl chains of ions has a clear influence on the ionic liquid's performance. In this paper, we study the self-diffusion of ions in a series of halogen-free boron-based ionic liquids (hf-BILs) containing bis(mandelato)borate anions and dialkylpyrrolidinium cations with long alkyl chains CnH2n+1 with n from 4 to 14 within a temperature range of 293-373 K. It was found that the hf-BILs with n = 4-7 have very similar diffusion coefficients, while hf-BILs with n = 10-14 exhibit two liquid sub-phases in almost the entire temperature range studied (293-353 K). Both liquid sub-phases differ in their diffusion coefficients, while values of the slower diffusion coefficients are close to those of hf-BILs with shorter alkyl chains. To explain the particular dependence of diffusion on the alkyl chain length, we examined the densities of the hf-BILs studied here. It was shown that the dependence of the density on the number of CH2 groups in long alkyl chains of cations can be accurately described using a "mosaic type" model, where regions of long alkyl chains of cations (named 'aliphatic' regions) and the residual chemical moieties in both cations and anions (named 'ionic' regions) give additive contributions. Changes in density due to an increase in temperature and the number of CH2 groups in the long alkyl chains of cations are determined predominantly by changes in the free volume of the 'ionic' regions, while 'aliphatic' regions are already highly compressed by van der Waals forces, which results in only infinitesimal changes in their free volumes with temperature.

Nationell ämneskategori
Fysikalisk kemi
Forskningsämne
Gränsytors kemi
Identifikatorer
urn:nbn:se:ltu:diva-5123 (URN)10.1039/c4cp03996c (DOI)000345453200050 ()25372279 (PubMedID)2-s2.0-84911933461 (Scopus ID)324a4266-3629-4316-a20a-690d2ae6b496 (Lokalt ID)324a4266-3629-4316-a20a-690d2ae6b496 (Arkivnummer)324a4266-3629-4316-a20a-690d2ae6b496 (OAI)
Anmärkning
Validerad; 2014; 20141111 (andbra)Tillgänglig från: 2016-09-29 Skapad: 2016-09-29 Senast uppdaterad: 2018-07-10Bibliografiskt granskad
Cupillard, S., Cervantes, M. & Glavatskih, S. (2014). Thermohydrodynamic analysis of a journal bearing with a microgroove on the shaft (ed.). Paper presented at . Computational Thermal Sciences, 6(1), 47-57
Öppna denna publikation i ny flik eller fönster >>Thermohydrodynamic analysis of a journal bearing with a microgroove on the shaft
2014 (Engelska)Ingår i: Computational Thermal Sciences, ISSN 1940-2503, E-ISSN 1940-2554, Vol. 6, nr 1, s. 47-57Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

In this study, thermohydrodynamic performance of a journal bearing with a microgroove created on the shaft is analyzed. A plain journal bearing is modeled using a computational fluid dynamics (CFD) software package. Navier-Stokes and energy equations are solved. The rotor-stator interaction is treated by using a computational grid deformation technique. The goal is to examine the pressure/temperature distribution in the bearing film. Results are presented in terms of typical bearing parameters as well as flow patterns. Results are also compared to the bearing with a smooth shaft. The effect induced by a microgroove on pressure distribution is explained for different bearing configurations, eccentricities, and microgroove depths. It is shown that the microgroove produces a local drop in pressure which, averaged over one revolution, decreases the load carrying capacity. The load carrying capacity is further decreased by using deeper microgrooves. With thermal effects considered, the microgroove carries more cold lubricant into the warmest regions of the bearing. This effect, more pronounced with deeper microgrooves, is due to a global flow recirculation inside the microgroove, which improves mixing

Nationell ämneskategori
Strömningsmekanik och akustik
Forskningsämne
Strömningslära
Identifikatorer
urn:nbn:se:ltu:diva-4703 (URN)10.1615/ComputThermalScien.2014005894 (DOI)2-s2.0-84897783176 (Scopus ID)2af836ae-788a-453f-bbd7-79b2b8ebdb0c (Lokalt ID)2af836ae-788a-453f-bbd7-79b2b8ebdb0c (Arkivnummer)2af836ae-788a-453f-bbd7-79b2b8ebdb0c (OAI)
Anmärkning
Validerad; 2014; 20140422 (johsod)Tillgänglig från: 2016-09-29 Skapad: 2016-09-29 Senast uppdaterad: 2018-07-10Bibliografiskt granskad
Cha, M., Isaksson, P. & Glavatskih, S. (2013). Influence of pad compliance on nonlinear dynamic characteristics of tilting pad journal bearings (ed.). Paper presented at . Tribology International, 57, 46-53
Öppna denna publikation i ny flik eller fönster >>Influence of pad compliance on nonlinear dynamic characteristics of tilting pad journal bearings
2013 (Engelska)Ingår i: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 57, s. 46-53Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

The effect of padcompliance on the dynamic response of tiltingpadjournalbearings is investigated. Padcompliance is varied by changing pivot geometry and Young’s modulus of pad backing and pad liner. Two pad support configurations are considered: one that allows only circumferential tilt and another one that allows both circumferential and axial tilts. Journal orbits, oil film pressure and oil film thickness are compared and discussed. It is shown that higher pad backing compliance significantly increases the journal orbit size and results in an increase in oil film pressure while oil film thickness is decreased. With a compliant liner, oil film pressure is decreased while oil film thickness is increased. Tapers at the pad edges are essential to increase the global minimum oil film thickness in compliant liner bearings.

Nationell ämneskategori
Tribologi (ytteknik omfattande friktion, nötning och smörjning)
Forskningsämne
Maskinelement
Identifikatorer
urn:nbn:se:ltu:diva-15341 (URN)10.1016/j.triboint.2012.07.005 (DOI)000311474800006 ()2-s2.0-84864545767 (Scopus ID)ed68d578-fb19-4316-a409-8f34b1110365 (Lokalt ID)ed68d578-fb19-4316-a409-8f34b1110365 (Arkivnummer)ed68d578-fb19-4316-a409-8f34b1110365 (OAI)
Anmärkning
Validerad; 2013; 20120731 (ysko)Tillgänglig från: 2016-09-29 Skapad: 2016-09-29 Senast uppdaterad: 2018-07-10Bibliografiskt granskad
Filippov, A., Shah, F. U., Taher, M., Glavatskih, S. & Antzutkin, O. (2013). NMR self-diffusion study of a phosphonium bis(mandelato)borate ionic liquid (ed.). Paper presented at . Physical Chemistry, Chemical Physics - PCCP, 15(23), 9281-9287
Öppna denna publikation i ny flik eller fönster >>NMR self-diffusion study of a phosphonium bis(mandelato)borate ionic liquid
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2013 (Engelska)Ingår i: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 15, nr 23, s. 9281-9287Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Newly synthesized halogen-free boron based ionic liquids (hf-BILs) composed of chelated orthoborate anionsand phosphonium cations have hydrolytic stability, low melting point and outstanding wear and frictionreducing properties. We report here the peculiarities of self-diffusion in one representative from this class,trihexyltetradecylphosphonium bis(mandelato)borate, [P6,6,6,14][BMB], in the temperature range of itspractical interest, 20–100 1C. NMR techniques demonstrated complicated diffusional behaviour – the ionicliquid can exist in one or two liquid ‘‘phases’’. In the low-temperature range (20–50 1C), two phases coexistwhere the cations, [P6,6,6,14], are contained mainly in the phase with slower diffusion coefficients while theanions, [BMB], are in the phase with faster diffusion coefficients. Cations have lower diffusion coefficientswith a factor of 20 as compared with the anions, an effect which is caused by aggregation of cations intodomains due to so-called ‘‘hydrophobic interaction’’ of their hydrocarbon chains. As the temperature risesabove 60 1C, the two phases merge into one where both ions have equal diffusion coefficients. This iscaused by thermal motion making the cation domains smaller in size and more easily interacting withanions. As a result, anions and cations diffuse in this high-temperature range as a pair.

Nyckelord
Ionic liquid, self-diffusion, Chemistry - Organic chemistry, Kemi - Organisk kemi
Nationell ämneskategori
Fysikalisk kemi
Forskningsämne
Gränsytors kemi
Identifikatorer
urn:nbn:se:ltu:diva-3456 (URN)10.1039/C3CP51132D (DOI)000319285000048 ()23661052 (PubMedID)2-s2.0-84878064165 (Scopus ID)14749ff0-b757-4764-bb65-ba35cfe7a272 (Lokalt ID)14749ff0-b757-4764-bb65-ba35cfe7a272 (Arkivnummer)14749ff0-b757-4764-bb65-ba35cfe7a272 (OAI)
Anmärkning
Validerad; 2013; 20130506 (andfil)Tillgänglig från: 2016-09-29 Skapad: 2016-09-29 Senast uppdaterad: 2018-07-10Bibliografiskt granskad
Simmons, G. F., Aidanpää, J.-O., Cervantes, M. & Glavatskih, S. (2013). Operational transients in the guide bearings of a 10 MW Kaplan turbine (ed.). Paper presented at . International journal on hydropower and dams, 20(5), 94-100
Öppna denna publikation i ny flik eller fönster >>Operational transients in the guide bearings of a 10 MW Kaplan turbine
2013 (Engelska)Ingår i: International journal on hydropower and dams, ISSN 1352-2523, Vol. 20, nr 5, s. 94-100Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Experiments are conducted using a 10 MW Kaplan hydropower machine with a PowerFormerT M generator, the Porjus U9 research machine. This machine is outfitted with an extensive array of sensors to determine oil film thickness, pad tilting, pad load and oil temperature in all three guide bearings as well as motion of the shaft in relation to both the bearing housings and the concrete foundation. Test results for all three guide bearings are examined during both steady state and transient operation.

Nationell ämneskategori
Strömningsmekanik och akustik Teknisk mekanik
Forskningsämne
Strömningslära; Hållfasthetslära
Identifikatorer
urn:nbn:se:ltu:diva-3125 (URN)0e8eada6-acb2-47f0-b908-16742fd62740 (Lokalt ID)0e8eada6-acb2-47f0-b908-16742fd62740 (Arkivnummer)0e8eada6-acb2-47f0-b908-16742fd62740 (OAI)
Anmärkning
Validerad; 2013; 20131008 (cervante)Tillgänglig från: 2016-09-29 Skapad: 2016-09-29 Senast uppdaterad: 2017-11-24Bibliografiskt granskad
Golchin, A., Simmons, G. F. & Glavatskih, S. (2012). Break-away friction of PTFE materials in lubricated conditions (ed.). Paper presented at Nordic Symposium on Tribology : 08/06/2010 - 11/06/2010. Tribology International, 48(April), 54-62
Öppna denna publikation i ny flik eller fönster >>Break-away friction of PTFE materials in lubricated conditions
2012 (Engelska)Ingår i: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 48, nr April, s. 54-62Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

This study investigates the tribological characteristics at initiation of sliding (break-away friction) of several polytetrafluoroethylene based materials. Four PTFE composites, pure PTFE, and white-metal were tested in a reciprocating tribo-meter with the block on plate configuration against a steel counter surface. Apparent contact pressure and oil temperature were varied from 1-8 MPa and 25-85\degc respectively. SEM investigations revealed wear patterns of the PTFE materials and the abrasive nature of hard fillers.Bronze-filled, carbon-filled, and pure PTFE were found to provide lower break-away friction and less variation over the course of testing and generally superior properties.

Nationell ämneskategori
Tribologi (ytteknik omfattande friktion, nötning och smörjning)
Forskningsämne
Maskinelement
Identifikatorer
urn:nbn:se:ltu:diva-31510 (URN)10.1016/j.triboint.2011.03.025 (DOI)000302394700009 ()2-s2.0-84857238721 (Scopus ID)5b41b981-d9a3-4662-a5b3-6e26ce05d8a9 (Lokalt ID)5b41b981-d9a3-4662-a5b3-6e26ce05d8a9 (Arkivnummer)5b41b981-d9a3-4662-a5b3-6e26ce05d8a9 (OAI)
Konferens
Nordic Symposium on Tribology : 08/06/2010 - 11/06/2010
Anmärkning

Validerad; 2012; 20110407 (gresim); Konferensartikel i tidskrift

Tillgänglig från: 2016-09-30 Skapad: 2016-09-30 Senast uppdaterad: 2019-03-29Bibliografiskt granskad
Simmons, G. F., Kuznetsov, E. & Glavatskih, S. (2012). Powerplant lubricant selection for improved efficiency and environmental impact reduction (ed.). In: (Ed.), (Ed.), Proceedings of the ASME International Mechanical Engineering Congress and Exposition: 2010 Energy systems: analysis, thermodynamics and sustainability, nanoengineering for energy, engineering to address climate change : presented at ASME 2010 International Mechanical Engineering Congress and Exposition, November 12 - 18, 2010, Vancouver, BC, Canada ;. Paper presented at ASME International Mechanical Engineering Congress & Exposition : 12/11/2010 - 18/11/2010 (pp. 429-437). New York: American Society of Mechanical Engineers, 5
Öppna denna publikation i ny flik eller fönster >>Powerplant lubricant selection for improved efficiency and environmental impact reduction
2012 (Engelska)Ingår i: Proceedings of the ASME International Mechanical Engineering Congress and Exposition: 2010 Energy systems: analysis, thermodynamics and sustainability, nanoengineering for energy, engineering to address climate change : presented at ASME 2010 International Mechanical Engineering Congress and Exposition, November 12 - 18, 2010, Vancouver, BC, Canada ;, New York: American Society of Mechanical Engineers , 2012, Vol. 5, s. 429-437Konferensbidrag, Publicerat paper (Refereegranskat)
Abstract [en]

Computational models were used to optimize bearing performance by adjusting a number of lubricant properties. This computational optimization showed that the most beneficial characteristics to hydrodynamic bearing operation were high viscosity index (VI) and high specific heat capacity. Four environmentally adapted synthetic lubricants were developed to provide these characteristics including: ISO VG32 with 259 VI, ISO VG22 with 245 VI, ISO VG22 with 336 VI, and ISO VG15 with 226 VI. A full scale bearing test machine was then operated with these lubricants in addition to mineral based turbine oils, ISO VG68 with 103 VI and ISO VG32 with 105 VI, to determine the effect on bearing performance and to validate the models. The new lubricants reduced bearing power loss by up to 20% and significantly reduced bearing temperatures with somewhat reduced film thickness. The machine was then operated to provide equivalent minimum viscosity with the new lubricants by varying inlet temperature, finding that changes in power loss were less substantial with equivalent minimum viscosity. Comparison of simulated and experimental results led to development of a simple, practical method to estimate benefits and operational parameters for lubricants based on viscosity grade, viscosity index and a simplified description of the machine's bearings. Other, less tangible, factors considered are bio-degradeability and impact of power loss reduction

Ort, förlag, år, upplaga, sidor
New York: American Society of Mechanical Engineers, 2012
Nationell ämneskategori
Tribologi (ytteknik omfattande friktion, nötning och smörjning)
Forskningsämne
Maskinelement
Identifikatorer
urn:nbn:se:ltu:diva-32002 (URN)10.1115/IMECE2010-37419 (DOI)84881400856 (Scopus ID)659372f0-fc66-11df-8b95-000ea68e967b (Lokalt ID)9780791844298 (ISBN)659372f0-fc66-11df-8b95-000ea68e967b (Arkivnummer)659372f0-fc66-11df-8b95-000ea68e967b (OAI)
Konferens
ASME International Mechanical Engineering Congress & Exposition : 12/11/2010 - 18/11/2010
Anmärkning
Godkänd; 2012; 20130826 (andbra)Tillgänglig från: 2016-09-30 Skapad: 2016-09-30 Senast uppdaterad: 2018-01-14Bibliografiskt granskad
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